diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index f1afdd473cf..08d62162ddc 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -16,6 +16,11 @@ repos:
   - id: trailing-whitespace
     exclude: .patch
 
+- repo: https://github.com/psf/black
+  rev: 20.8b1
+  hooks:
+  - id: black
+
 - repo: https://gitlab.com/pycqa/flake8
   rev: 3.8.3
   hooks:
diff --git a/docs/html/conf.py b/docs/html/conf.py
index 2ef2647ce72..a35452f0da0 100644
--- a/docs/html/conf.py
+++ b/docs/html/conf.py
@@ -16,7 +16,7 @@
 import re
 import sys
 
-on_rtd = os.environ.get('READTHEDOCS', None) == 'True'
+on_rtd = os.environ.get("READTHEDOCS", None) == "True"
 
 docs_dir = os.path.dirname(os.path.dirname(__file__))
 # If extensions (or modules to document with autodoc) are in another directory,
@@ -30,13 +30,13 @@
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 # extensions = ['sphinx.ext.autodoc']
-extensions = ['sphinx.ext.extlinks', 'pip_sphinxext', 'sphinx.ext.intersphinx']
+extensions = ["sphinx.ext.extlinks", "pip_sphinxext", "sphinx.ext.intersphinx"]
 
 # intersphinx
 intersphinx_cache_limit = 0
 intersphinx_mapping = {
-    'pypug': ('https://packaging.python.org/', None),
-    'pypa': ('https://www.pypa.io/en/latest/', None),
+    "pypug": ("https://packaging.python.org/", None),
+    "pypa": ("https://www.pypa.io/en/latest/", None),
 }
 
 
@@ -44,17 +44,17 @@
 templates_path = []
 
 # The suffix of source filenames.
-source_suffix = '.rst'
+source_suffix = ".rst"
 
 # The encoding of source files.
 # source_encoding = 'utf-8'
 
 # The master toctree document.
-master_doc = 'index'
+master_doc = "index"
 
 # General information about the project.
-project = 'pip'
-copyright = '2008-2020, PyPA'
+project = "pip"
+copyright = "2008-2020, PyPA"
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
@@ -62,7 +62,7 @@
 #
 # The short X.Y version.
 
-version = release = 'dev'
+version = release = "dev"
 
 # Readthedocs seems to install pip as an egg (via setup.py install) which
 # is somehow resulting in "import pip" picking up an older copy of pip.
@@ -70,14 +70,14 @@
 # read the version direct from the __init__.py file. (Yes, this is
 # fragile, but it works...)
 
-pip_init = os.path.join(docs_dir, '..', 'src', 'pip', '__init__.py')
+pip_init = os.path.join(docs_dir, "..", "src", "pip", "__init__.py")
 with open(pip_init) as f:
     for line in f:
         m = re.match(r'__version__ = "(.*)"', line)
         if m:
             __version__ = m.group(1)
             # The short X.Y version.
-            version = '.'.join(__version__.split('.')[:2])
+            version = ".".join(__version__.split(".")[:2])
             # The full version, including alpha/beta/rc tags.
             release = __version__
             break
@@ -95,14 +95,14 @@
 # non-false value, then it is used:
 # today = ''
 # Else, today_fmt is used as the format for a strftime call.
-today_fmt = '%B %d, %Y'
+today_fmt = "%B %d, %Y"
 
 # List of documents that shouldn't be included in the build.
 # unused_docs = []
 
 # List of directories, relative to source directory, that shouldn't be searched
 # for source files.
-exclude_patterns = ['build/']
+exclude_patterns = ["build/"]
 
 # The reST default role (used for this markup: `text`) to use for all documents
 # default_role = None
@@ -119,15 +119,15 @@
 # show_authors = False
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
+pygments_style = "sphinx"
 
 # A list of ignored prefixes for module index sorting.
 # modindex_common_prefix = []
 
 extlinks = {
-    'issue': ('https://github.com/pypa/pip/issues/%s', '#'),
-    'pull': ('https://github.com/pypa/pip/pull/%s', 'PR #'),
-    'pypi': ('https://pypi.org/project/%s/', ''),
+    "issue": ("https://github.com/pypa/pip/issues/%s", "#"),
+    "pull": ("https://github.com/pypa/pip/pull/%s", "PR #"),
+    "pypi": ("https://pypi.org/project/%s/", ""),
 }
 
 # -- Options for HTML output --------------------------------------------------
@@ -140,12 +140,12 @@
 # further.  For a list of options available for each theme, see the
 # documentation.
 html_theme_options = {
-    'collapsiblesidebar': True,
-    'externalrefs': True,
-    'navigation_depth': 3,
-    'issues_url': 'https://github.com/pypa/pip/issues',
-    'codebgcolor': '#eeffcc',
-    'codetextcolor': '#333333',
+    "collapsiblesidebar": True,
+    "externalrefs": True,
+    "navigation_depth": 3,
+    "issues_url": "https://github.com/pypa/pip/issues",
+    "codebgcolor": "#eeffcc",
+    "codetextcolor": "#333333",
 }
 
 # Add any paths that contain custom themes here, relative to this directory.
@@ -173,7 +173,7 @@
 
 # If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
 # using the given strftime format.
-html_last_updated_fmt = '%b %d, %Y'
+html_last_updated_fmt = "%b %d, %Y"
 
 # If true, the Docutils Smart Quotes transform (originally based on
 # SmartyPants) will be used to convert characters like quotes and dashes
@@ -192,10 +192,7 @@
 smartquotes_action = "qe"
 
 # Custom sidebar templates, maps document names to template names.
-html_sidebars = {
-    '**': ['localtoc.html', 'relations.html'],
-    'index': ['localtoc.html']
-}
+html_sidebars = {"**": ["localtoc.html", "relations.html"], "index": ["localtoc.html"]}
 
 # Additional templates that should be rendered to pages, maps page names to
 # template names.
@@ -222,7 +219,7 @@
 # html_file_suffix = ''
 
 # Output file base name for HTML help builder.
-htmlhelp_basename = 'pipdocs'
+htmlhelp_basename = "pipdocs"
 
 
 # -- Options for LaTeX output -------------------------------------------------
@@ -237,11 +234,11 @@
 # (source start file, target name, title, author, documentclass [howto/manual])
 latex_documents = [
     (
-        'index',
-        'pip.tex',
-        u'pip Documentation',
-        u'pip developers',
-        'manual',
+        "index",
+        "pip.tex",
+        u"pip Documentation",
+        u"pip developers",
+        "manual",
     ),
 ]
 
@@ -266,37 +263,26 @@
 
 # List of manual pages generated
 man_pages = [
-    (
-        'index',
-        'pip',
-        u'package manager for Python packages',
-        u'pip developers',
-        1
-    )
+    ("index", "pip", u"package manager for Python packages", u"pip developers", 1)
 ]
 
 
 def to_document_name(path, base_dir):
-    """Convert a provided path to a Sphinx "document name".
-    """
+    """Convert a provided path to a Sphinx "document name"."""
     relative_path = os.path.relpath(path, base_dir)
     root, _ = os.path.splitext(relative_path)
-    return root.replace(os.sep, '/')
+    return root.replace(os.sep, "/")
 
 
 # Here, we crawl the entire man/commands/ directory and list every file with
 # appropriate name and details
-man_dir = os.path.join(docs_dir, 'man')
-raw_subcommands = glob.glob(os.path.join(man_dir, 'commands/*.rst'))
+man_dir = os.path.join(docs_dir, "man")
+raw_subcommands = glob.glob(os.path.join(man_dir, "commands/*.rst"))
 if not raw_subcommands:
-    raise FileNotFoundError(
-        'The individual subcommand manpages could not be found!'
-    )
+    raise FileNotFoundError("The individual subcommand manpages could not be found!")
 for fname in raw_subcommands:
     fname_base = to_document_name(fname, man_dir)
-    outname = 'pip-' + fname_base.split('/')[1]
-    description = u'description of {} command'.format(
-        outname.replace('-', ' ')
-    )
+    outname = "pip-" + fname_base.split("/")[1]
+    description = u"description of {} command".format(outname.replace("-", " "))
 
-    man_pages.append((fname_base, outname, description, u'pip developers', 1))
+    man_pages.append((fname_base, outname, description, u"pip developers", 1))
diff --git a/docs/pip_sphinxext.py b/docs/pip_sphinxext.py
index 6cc7a2c82ec..84e5663c649 100644
--- a/docs/pip_sphinxext.py
+++ b/docs/pip_sphinxext.py
@@ -18,9 +18,7 @@ class PipCommandUsage(rst.Directive):
 
     def run(self):
         cmd = create_command(self.arguments[0])
-        usage = dedent(
-            cmd.usage.replace('%prog', 'pip {}'.format(cmd.name))
-        ).strip()
+        usage = dedent(cmd.usage.replace("%prog", "pip {}".format(cmd.name))).strip()
         node = nodes.literal_block(usage, usage)
         return [node]
 
@@ -34,19 +32,18 @@ def run(self):
         desc = ViewList()
         cmd = create_command(self.arguments[0])
         description = dedent(cmd.__doc__)
-        for line in description.split('\n'):
+        for line in description.split("\n"):
             desc.append(line, "")
         self.state.nested_parse(desc, 0, node)
         return [node]
 
 
 class PipOptions(rst.Directive):
-
     def _format_option(self, option, cmd_name=None):
         bookmark_line = (
             ".. _`{cmd_name}_{option._long_opts[0]}`:"
-            if cmd_name else
-            ".. _`{option._long_opts[0]}`:"
+            if cmd_name
+            else ".. _`{option._long_opts[0]}`:"
         ).format(**locals())
         line = ".. option:: "
         if option._short_opts:
@@ -59,7 +56,7 @@ def _format_option(self, option, cmd_name=None):
             metavar = option.metavar or option.dest.lower()
             line += " <{}>".format(metavar.lower())
         # fix defaults
-        opt_help = option.help.replace('%default', str(option.default))
+        opt_help = option.help.replace("%default", str(option.default))
         # fix paths with sys.prefix
         opt_help = opt_help.replace(sys.prefix, "<sys.prefix>")
         return [bookmark_line, "", line, "", "    " + opt_help, ""]
@@ -82,9 +79,7 @@ def run(self):
 
 class PipGeneralOptions(PipOptions):
     def process_options(self):
-        self._format_options(
-            [o() for o in cmdoptions.general_group['options']]
-        )
+        self._format_options([o() for o in cmdoptions.general_group["options"]])
 
 
 class PipIndexOptions(PipOptions):
@@ -93,7 +88,7 @@ class PipIndexOptions(PipOptions):
     def process_options(self):
         cmd_name = self.arguments[0]
         self._format_options(
-            [o() for o in cmdoptions.index_group['options']],
+            [o() for o in cmdoptions.index_group["options"]],
             cmd_name=cmd_name,
         )
 
@@ -110,49 +105,48 @@ def process_options(self):
 
 
 class PipReqFileOptionsReference(PipOptions):
-
     def determine_opt_prefix(self, opt_name):
         for command in commands_dict:
             cmd = create_command(command)
             if cmd.cmd_opts.has_option(opt_name):
                 return command
 
-        raise KeyError('Could not identify prefix of opt {}'.format(opt_name))
+        raise KeyError("Could not identify prefix of opt {}".format(opt_name))
 
     def process_options(self):
         for option in SUPPORTED_OPTIONS:
-            if getattr(option, 'deprecated', False):
+            if getattr(option, "deprecated", False):
                 continue
 
             opt = option()
             opt_name = opt._long_opts[0]
             if opt._short_opts:
-                short_opt_name = '{}, '.format(opt._short_opts[0])
+                short_opt_name = "{}, ".format(opt._short_opts[0])
             else:
-                short_opt_name = ''
+                short_opt_name = ""
 
-            if option in cmdoptions.general_group['options']:
-                prefix = ''
+            if option in cmdoptions.general_group["options"]:
+                prefix = ""
             else:
-                prefix = '{}_'.format(self.determine_opt_prefix(opt_name))
+                prefix = "{}_".format(self.determine_opt_prefix(opt_name))
 
             self.view_list.append(
-                '  *  :ref:`{short}{long}<{prefix}{opt_name}>`'.format(
+                "  *  :ref:`{short}{long}<{prefix}{opt_name}>`".format(
                     short=short_opt_name,
                     long=opt_name,
                     prefix=prefix,
-                    opt_name=opt_name
+                    opt_name=opt_name,
                 ),
-                "\n"
+                "\n",
             )
 
 
 def setup(app):
-    app.add_directive('pip-command-usage', PipCommandUsage)
-    app.add_directive('pip-command-description', PipCommandDescription)
-    app.add_directive('pip-command-options', PipCommandOptions)
-    app.add_directive('pip-general-options', PipGeneralOptions)
-    app.add_directive('pip-index-options', PipIndexOptions)
+    app.add_directive("pip-command-usage", PipCommandUsage)
+    app.add_directive("pip-command-description", PipCommandDescription)
+    app.add_directive("pip-command-options", PipCommandOptions)
+    app.add_directive("pip-general-options", PipGeneralOptions)
+    app.add_directive("pip-index-options", PipIndexOptions)
     app.add_directive(
-        'pip-requirements-file-options-ref-list', PipReqFileOptionsReference
+        "pip-requirements-file-options-ref-list", PipReqFileOptionsReference
     )
diff --git a/noxfile.py b/noxfile.py
index 1746bb69915..7e41b20aba1 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -13,6 +13,7 @@
 
 sys.path.append(".")
 from tools.automation import release  # isort:skip  # noqa
+
 sys.path.pop()
 
 nox.options.reuse_existing_virtualenvs = True
@@ -76,13 +77,14 @@ def test(session):
         run_with_protected_pip(
             session,
             "wheel",
-            "-w", LOCATIONS["common-wheels"],
-            "-r", REQUIREMENTS["common-wheels"],
+            "-w",
+            LOCATIONS["common-wheels"],
+            "-r",
+            REQUIREMENTS["common-wheels"],
         )
     else:
-        msg = (
-            "Re-using existing common-wheels at {}."
-            .format(LOCATIONS["common-wheels"])
+        msg = "Re-using existing common-wheels at {}.".format(
+            LOCATIONS["common-wheels"]
         )
         session.log(msg)
 
@@ -91,8 +93,12 @@ def test(session):
     if os.path.exists(sdist_dir):
         shutil.rmtree(sdist_dir, ignore_errors=True)
     session.run(
-        "python", "setup.py", "sdist",
-        "--formats=zip", "--dist-dir", sdist_dir,
+        "python",
+        "setup.py",
+        "sdist",
+        "--formats=zip",
+        "--dist-dir",
+        sdist_dir,
         silent=True,
     )
     generated_files = os.listdir(sdist_dir)
@@ -127,11 +133,11 @@ def get_sphinx_build_command(kind):
         return [
             "sphinx-build",
             "-W",
-            "-c", "docs/html",  # see note above
-            "-d", "docs/build/doctrees/" + kind,
-            "-b", kind,
-            "docs/" + kind,
-            "docs/build/" + kind,
+            "-c=docs/html",  # see note above
+            f"-d=docs/build/doctrees/{kind}",
+            f"-b={kind}",
+            f"docs/{kind}",
+            f"docs/build/{kind}",
         ]
 
     session.run(*get_sphinx_build_command("html"))
@@ -174,7 +180,9 @@ def prepare_release(session):
     release.generate_authors(AUTHORS_FILE)
     if release.modified_files_in_git():
         release.commit_file(
-            session, AUTHORS_FILE, message=f"Update {AUTHORS_FILE}",
+            session,
+            AUTHORS_FILE,
+            message=f"Update {AUTHORS_FILE}",
         )
     else:
         session.log(f"# No changes to {AUTHORS_FILE}")
@@ -221,7 +229,7 @@ def build_release(session):
 
         tmp_dist_paths = (build_dir / p for p in tmp_dists)
         session.log(f"# Copying dists from {build_dir}")
-        os.makedirs('dist', exist_ok=True)
+        os.makedirs("dist", exist_ok=True)
         for dist, final in zip(tmp_dist_paths, tmp_dists):
             session.log(f"# Copying {dist} to {final}")
             shutil.copy(dist, final)
@@ -235,7 +243,7 @@ def build_dists(session):
 
     has_forbidden_git_untracked_files = any(
         # Don't report the environment this session is running in
-        not untracked_file.startswith('.nox/build-release/')
+        not untracked_file.startswith(".nox/build-release/")
         for untracked_file in release.get_git_untracked_files()
     )
     if has_forbidden_git_untracked_files:
@@ -280,9 +288,7 @@ def upload_release(session):
         f"pip-{version}.tar.gz",
     ]
     if sorted(distfile_names) != sorted(expected_distribution_files):
-        session.error(
-            f"Distribution files do not seem to be for {version} release."
-        )
+        session.error(f"Distribution files do not seem to be for {version} release.")
 
     session.log("# Upload distributions")
     session.run("twine", "upload", *distribution_files)
diff --git a/setup.cfg b/setup.cfg
index 45fd58a3e7a..450f953e4a5 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,4 +1,5 @@
 [isort]
+profile = black
 skip =
     ./build,
     .nox,
@@ -6,16 +7,15 @@ skip =
     .scratch,
     _vendor,
     data
-multi_line_output = 3
 known_third_party =
     pip._vendor
 known_first_party =
     pip
     tests
 default_section = THIRDPARTY
-include_trailing_comma = true
 
 [flake8]
+max-line-length = 88
 exclude =
     ./build,
     .nox,
@@ -28,6 +28,8 @@ ignore =
     G200, G202,
     # pycodestyle checks ignored in the default configuration
     E121, E123, E126, E133, E226, E241, E242, E704, W503, W504, W505,
+    # black adds spaces around ':'
+    E203,
 per-file-ignores =
     # G: The plugin logging-format treats every .log and .error as logging.
     noxfile.py: G
diff --git a/setup.py b/setup.py
index 0557690deca..f2fa49f9db5 100644
--- a/setup.py
+++ b/setup.py
@@ -12,28 +12,27 @@ def read(rel_path):
     here = os.path.abspath(os.path.dirname(__file__))
     # intentionally *not* adding an encoding option to open, See:
     #   https://github.com/pypa/virtualenv/issues/201#issuecomment-3145690
-    with codecs.open(os.path.join(here, rel_path), 'r') as fp:
+    with codecs.open(os.path.join(here, rel_path), "r") as fp:
         return fp.read()
 
 
 def get_version(rel_path):
     for line in read(rel_path).splitlines():
-        if line.startswith('__version__'):
+        if line.startswith("__version__"):
             # __version__ = "0.9"
             delim = '"' if '"' in line else "'"
             return line.split(delim)[1]
     raise RuntimeError("Unable to find version string.")
 
 
-long_description = read('README.rst')
+long_description = read("README.rst")
 
 setup(
     name="pip",
     version=get_version("src/pip/__init__.py"),
     description="The PyPA recommended tool for installing Python packages.",
     long_description=long_description,
-
-    license='MIT',
+    license="MIT",
     classifiers=[
         "Development Status :: 5 - Production/Stable",
         "Intended Audience :: Developers",
@@ -50,17 +49,15 @@ def get_version(rel_path):
         "Programming Language :: Python :: Implementation :: CPython",
         "Programming Language :: Python :: Implementation :: PyPy",
     ],
-    url='https://pip.pypa.io/',
-    keywords='distutils easy_install egg setuptools wheel virtualenv',
+    url="https://pip.pypa.io/",
+    keywords="distutils easy_install egg setuptools wheel virtualenv",
     project_urls={
         "Documentation": "https://pip.pypa.io",
         "Source": "https://github.com/pypa/pip",
         "Changelog": "https://pip.pypa.io/en/stable/news/",
     },
-
-    author='The pip developers',
-    author_email='distutils-sig@python.org',
-
+    author="The pip developers",
+    author_email="distutils-sig@python.org",
     package_dir={"": "src"},
     packages=find_packages(
         where="src",
@@ -77,12 +74,9 @@ def get_version(rel_path):
         "console_scripts": [
             "pip=pip._internal.cli.main:main",
             "pip{}=pip._internal.cli.main:main".format(sys.version_info[0]),
-            "pip{}.{}=pip._internal.cli.main:main".format(
-                *sys.version_info[:2]
-            ),
+            "pip{}.{}=pip._internal.cli.main:main".format(*sys.version_info[:2]),
         ],
     },
-
     zip_safe=False,
-    python_requires='>=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*',
+    python_requires=">=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*",
 )
diff --git a/src/pip/__main__.py b/src/pip/__main__.py
index 7c2505fa5bd..65a6963dc87 100644
--- a/src/pip/__main__.py
+++ b/src/pip/__main__.py
@@ -7,12 +7,12 @@
 # of sys.path, if present to avoid using current directory
 # in pip commands check, freeze, install, list and show,
 # when invoked as python -m pip <command>
-if sys.path[0] in ('', os.getcwd()):
+if sys.path[0] in ("", os.getcwd()):
     sys.path.pop(0)
 
 # If we are running from a wheel, add the wheel to sys.path
 # This allows the usage python pip-*.whl/pip install pip-*.whl
-if __package__ == '':
+if __package__ == "":
     # __file__ is pip-*.whl/pip/__main__.py
     # first dirname call strips of '/__main__.py', second strips off '/pip'
     # Resulting path is the name of the wheel itself
@@ -22,5 +22,5 @@
 
 from pip._internal.cli.main import main as _main  # isort:skip # noqa
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     sys.exit(_main())
diff --git a/src/pip/_internal/build_env.py b/src/pip/_internal/build_env.py
index a08e63cd051..44327464c73 100644
--- a/src/pip/_internal/build_env.py
+++ b/src/pip/_internal/build_env.py
@@ -27,15 +27,14 @@
 
 
 class _Prefix:
-
     def __init__(self, path):
         # type: (str) -> None
         self.path = path
         self.setup = False
         self.bin_dir = get_paths(
-            'nt' if os.name == 'nt' else 'posix_prefix',
-            vars={'base': path, 'platbase': path}
-        )['scripts']
+            "nt" if os.name == "nt" else "posix_prefix",
+            vars={"base": path, "platbase": path},
+        )["scripts"]
         # Note: prefer distutils' sysconfig to get the
         # library paths so PyPy is correctly supported.
         purelib = get_python_lib(plat_specific=False, prefix=path)
@@ -47,19 +46,18 @@ def __init__(self, path):
 
 
 class BuildEnvironment(object):
-    """Creates and manages an isolated environment to install build deps
-    """
+    """Creates and manages an isolated environment to install build deps"""
 
     def __init__(self):
         # type: () -> None
-        temp_dir = TempDirectory(
-            kind=tempdir_kinds.BUILD_ENV, globally_managed=True
-        )
+        temp_dir = TempDirectory(kind=tempdir_kinds.BUILD_ENV, globally_managed=True)
 
-        self._prefixes = OrderedDict((
-            (name, _Prefix(os.path.join(temp_dir.path, name)))
-            for name in ('normal', 'overlay')
-        ))
+        self._prefixes = OrderedDict(
+            (
+                (name, _Prefix(os.path.join(temp_dir.path, name)))
+                for name in ("normal", "overlay")
+            )
+        )
 
         self._bin_dirs = []  # type: List[str]
         self._lib_dirs = []  # type: List[str]
@@ -71,17 +69,19 @@ def __init__(self):
         # - ensure .pth files are honored
         # - prevent access to system site packages
         system_sites = {
-            os.path.normcase(site) for site in (
+            os.path.normcase(site)
+            for site in (
                 get_python_lib(plat_specific=False),
                 get_python_lib(plat_specific=True),
             )
         }
-        self._site_dir = os.path.join(temp_dir.path, 'site')
+        self._site_dir = os.path.join(temp_dir.path, "site")
         if not os.path.exists(self._site_dir):
             os.mkdir(self._site_dir)
-        with open(os.path.join(self._site_dir, 'sitecustomize.py'), 'w') as fp:
-            fp.write(textwrap.dedent(
-                '''
+        with open(os.path.join(self._site_dir, "sitecustomize.py"), "w") as fp:
+            fp.write(
+                textwrap.dedent(
+                    """
                 import os, site, sys
 
                 # First, drop system-sites related paths.
@@ -104,34 +104,37 @@ def __init__(self):
                 for path in {lib_dirs!r}:
                     assert not path in sys.path
                     site.addsitedir(path)
-                '''
-            ).format(system_sites=system_sites, lib_dirs=self._lib_dirs))
+                """
+                ).format(system_sites=system_sites, lib_dirs=self._lib_dirs)
+            )
 
     def __enter__(self):
         # type: () -> None
         self._save_env = {
             name: os.environ.get(name, None)
-            for name in ('PATH', 'PYTHONNOUSERSITE', 'PYTHONPATH')
+            for name in ("PATH", "PYTHONNOUSERSITE", "PYTHONPATH")
         }
 
         path = self._bin_dirs[:]
-        old_path = self._save_env['PATH']
+        old_path = self._save_env["PATH"]
         if old_path:
             path.extend(old_path.split(os.pathsep))
 
         pythonpath = [self._site_dir]
 
-        os.environ.update({
-            'PATH': os.pathsep.join(path),
-            'PYTHONNOUSERSITE': '1',
-            'PYTHONPATH': os.pathsep.join(pythonpath),
-        })
+        os.environ.update(
+            {
+                "PATH": os.pathsep.join(path),
+                "PYTHONNOUSERSITE": "1",
+                "PYTHONPATH": os.pathsep.join(pythonpath),
+            }
+        )
 
     def __exit__(
         self,
         exc_type,  # type: Optional[Type[BaseException]]
         exc_val,  # type: Optional[BaseException]
-        exc_tb  # type: Optional[TracebackType]
+        exc_tb,  # type: Optional[TracebackType]
     ):
         # type: (...) -> None
         for varname, old_value in self._save_env.items():
@@ -143,8 +146,8 @@ def __exit__(
     def check_requirements(self, reqs):
         # type: (Iterable[str]) -> Tuple[Set[Tuple[str, str]], Set[str]]
         """Return 2 sets:
-            - conflicting requirements: set of (installed, wanted) reqs tuples
-            - missing requirements: set of reqs
+        - conflicting requirements: set of (installed, wanted) reqs tuples
+        - missing requirements: set of reqs
         """
         missing = set()
         conflicting = set()
@@ -155,8 +158,7 @@ def check_requirements(self, reqs):
                     if ws.find(Requirement.parse(req)) is None:
                         missing.add(req)
                 except VersionConflict as e:
-                    conflicting.add((str(e.args[0].as_requirement()),
-                                     str(e.args[1])))
+                    conflicting.add((str(e.args[0].as_requirement()), str(e.args[1])))
         return conflicting, missing
 
     def install_requirements(
@@ -164,7 +166,7 @@ def install_requirements(
         finder,  # type: PackageFinder
         requirements,  # type: Iterable[str]
         prefix_as_string,  # type: str
-        message  # type: str
+        message,  # type: str
     ):
         # type: (...) -> None
         prefix = self._prefixes[prefix_as_string]
@@ -173,42 +175,50 @@ def install_requirements(
         if not requirements:
             return
         args = [
-            sys.executable, os.path.dirname(pip_location), 'install',
-            '--ignore-installed', '--no-user', '--prefix', prefix.path,
-            '--no-warn-script-location',
+            sys.executable,
+            os.path.dirname(pip_location),
+            "install",
+            "--ignore-installed",
+            "--no-user",
+            "--prefix",
+            prefix.path,
+            "--no-warn-script-location",
         ]  # type: List[str]
         if logger.getEffectiveLevel() <= logging.DEBUG:
-            args.append('-v')
-        for format_control in ('no_binary', 'only_binary'):
+            args.append("-v")
+        for format_control in ("no_binary", "only_binary"):
             formats = getattr(finder.format_control, format_control)
-            args.extend(('--' + format_control.replace('_', '-'),
-                         ','.join(sorted(formats or {':none:'}))))
+            args.extend(
+                (
+                    "--" + format_control.replace("_", "-"),
+                    ",".join(sorted(formats or {":none:"})),
+                )
+            )
 
         index_urls = finder.index_urls
         if index_urls:
-            args.extend(['-i', index_urls[0]])
+            args.extend(["-i", index_urls[0]])
             for extra_index in index_urls[1:]:
-                args.extend(['--extra-index-url', extra_index])
+                args.extend(["--extra-index-url", extra_index])
         else:
-            args.append('--no-index')
+            args.append("--no-index")
         for link in finder.find_links:
-            args.extend(['--find-links', link])
+            args.extend(["--find-links", link])
 
         for host in finder.trusted_hosts:
-            args.extend(['--trusted-host', host])
+            args.extend(["--trusted-host", host])
         if finder.allow_all_prereleases:
-            args.append('--pre')
+            args.append("--pre")
         if finder.prefer_binary:
-            args.append('--prefer-binary')
-        args.append('--')
+            args.append("--prefer-binary")
+        args.append("--")
         args.extend(requirements)
         with open_spinner(message) as spinner:
             call_subprocess(args, spinner=spinner)
 
 
 class NoOpBuildEnvironment(BuildEnvironment):
-    """A no-op drop-in replacement for BuildEnvironment
-    """
+    """A no-op drop-in replacement for BuildEnvironment"""
 
     def __init__(self):
         # type: () -> None
@@ -222,7 +232,7 @@ def __exit__(
         self,
         exc_type,  # type: Optional[Type[BaseException]]
         exc_val,  # type: Optional[BaseException]
-        exc_tb  # type: Optional[TracebackType]
+        exc_tb,  # type: Optional[TracebackType]
     ):
         # type: (...) -> None
         pass
@@ -236,7 +246,7 @@ def install_requirements(
         finder,  # type: PackageFinder
         requirements,  # type: Iterable[str]
         prefix_as_string,  # type: str
-        message  # type: str
+        message,  # type: str
     ):
         # type: (...) -> None
         raise NotImplementedError()
diff --git a/src/pip/_internal/cache.py b/src/pip/_internal/cache.py
index def8dd64a18..a0b5c56411c 100644
--- a/src/pip/_internal/cache.py
+++ b/src/pip/_internal/cache.py
@@ -37,11 +37,11 @@ class Cache(object):
     """An abstract class - provides cache directories for data from links
 
 
-        :param cache_dir: The root of the cache.
-        :param format_control: An object of FormatControl class to limit
-            binaries being read from the cache.
-        :param allowed_formats: which formats of files the cache should store.
-            ('binary' and 'source' are the only allowed values)
+    :param cache_dir: The root of the cache.
+    :param format_control: An object of FormatControl class to limit
+        binaries being read from the cache.
+    :param allowed_formats: which formats of files the cache should store.
+        ('binary' and 'source' are the only allowed values)
     """
 
     def __init__(self, cache_dir, format_control, allowed_formats):
@@ -85,8 +85,7 @@ def _get_cache_path_parts_legacy(self, link):
 
     def _get_cache_path_parts(self, link):
         # type: (Link) -> List[str]
-        """Get parts of part that must be os.path.joined with cache_dir
-        """
+        """Get parts of part that must be os.path.joined with cache_dir"""
 
         # We want to generate an url to use as our cache key, we don't want to
         # just re-use the URL because it might have other items in the fragment
@@ -120,17 +119,11 @@ def _get_cache_path_parts(self, link):
 
     def _get_candidates(self, link, canonical_package_name):
         # type: (Link, str) -> List[Any]
-        can_not_cache = (
-            not self.cache_dir or
-            not canonical_package_name or
-            not link
-        )
+        can_not_cache = not self.cache_dir or not canonical_package_name or not link
         if can_not_cache:
             return []
 
-        formats = self.format_control.get_allowed_formats(
-            canonical_package_name
-        )
+        formats = self.format_control.get_allowed_formats(canonical_package_name)
         if not self.allowed_formats.intersection(formats):
             return []
 
@@ -152,14 +145,13 @@ def get_path_for_link_legacy(self, link):
 
     def get_path_for_link(self, link):
         # type: (Link) -> str
-        """Return a directory to store cached items in for link.
-        """
+        """Return a directory to store cached items in for link."""
         raise NotImplementedError()
 
     def get(
         self,
-        link,            # type: Link
-        package_name,    # type: Optional[str]
+        link,  # type: Link
+        package_name,  # type: Optional[str]
         supported_tags,  # type: List[Tag]
     ):
         # type: (...) -> Link
@@ -170,14 +162,11 @@ def get(
 
 
 class SimpleWheelCache(Cache):
-    """A cache of wheels for future installs.
-    """
+    """A cache of wheels for future installs."""
 
     def __init__(self, cache_dir, format_control):
         # type: (str, FormatControl) -> None
-        super(SimpleWheelCache, self).__init__(
-            cache_dir, format_control, {"binary"}
-        )
+        super(SimpleWheelCache, self).__init__(cache_dir, format_control, {"binary"})
 
     def get_path_for_link_legacy(self, link):
         # type: (Link) -> str
@@ -208,8 +197,8 @@ def get_path_for_link(self, link):
 
     def get(
         self,
-        link,            # type: Link
-        package_name,    # type: Optional[str]
+        link,  # type: Link
+        package_name,  # type: Optional[str]
         supported_tags,  # type: List[Tag]
     ):
         # type: (...) -> Link
@@ -219,9 +208,7 @@ def get(
             return link
 
         canonical_package_name = canonicalize_name(package_name)
-        for wheel_name, wheel_dir in self._get_candidates(
-            link, canonical_package_name
-        ):
+        for wheel_name, wheel_dir in self._get_candidates(link, canonical_package_name):
             try:
                 wheel = Wheel(wheel_name)
             except InvalidWheelFilename:
@@ -230,7 +217,9 @@ def get(
                 logger.debug(
                     "Ignoring cached wheel %s for %s as it "
                     "does not match the expected distribution name %s.",
-                    wheel_name, link, package_name,
+                    wheel_name,
+                    link,
+                    package_name,
                 )
                 continue
             if not wheel.supported(supported_tags):
@@ -252,8 +241,7 @@ def get(
 
 
 class EphemWheelCache(SimpleWheelCache):
-    """A SimpleWheelCache that creates it's own temporary cache directory
-    """
+    """A SimpleWheelCache that creates it's own temporary cache directory"""
 
     def __init__(self, format_control):
         # type: (FormatControl) -> None
@@ -262,9 +250,7 @@ def __init__(self, format_control):
             globally_managed=True,
         )
 
-        super(EphemWheelCache, self).__init__(
-            self._temp_dir.path, format_control
-        )
+        super(EphemWheelCache, self).__init__(self._temp_dir.path, format_control)
 
 
 class CacheEntry(object):
@@ -286,9 +272,7 @@ class WheelCache(Cache):
 
     def __init__(self, cache_dir, format_control):
         # type: (str, FormatControl) -> None
-        super(WheelCache, self).__init__(
-            cache_dir, format_control, {'binary'}
-        )
+        super(WheelCache, self).__init__(cache_dir, format_control, {"binary"})
         self._wheel_cache = SimpleWheelCache(cache_dir, format_control)
         self._ephem_cache = EphemWheelCache(format_control)
 
@@ -306,8 +290,8 @@ def get_ephem_path_for_link(self, link):
 
     def get(
         self,
-        link,            # type: Link
-        package_name,    # type: Optional[str]
+        link,  # type: Link
+        package_name,  # type: Optional[str]
         supported_tags,  # type: List[Tag]
     ):
         # type: (...) -> Link
@@ -318,8 +302,8 @@ def get(
 
     def get_cache_entry(
         self,
-        link,            # type: Link
-        package_name,    # type: Optional[str]
+        link,  # type: Link
+        package_name,  # type: Optional[str]
         supported_tags,  # type: List[Tag]
     ):
         # type: (...) -> Optional[CacheEntry]
diff --git a/src/pip/_internal/cli/autocompletion.py b/src/pip/_internal/cli/autocompletion.py
index 329de602513..eb489114a1c 100644
--- a/src/pip/_internal/cli/autocompletion.py
+++ b/src/pip/_internal/cli/autocompletion.py
@@ -17,17 +17,16 @@
 
 def autocomplete():
     # type: () -> None
-    """Entry Point for completion of main and subcommand options.
-    """
+    """Entry Point for completion of main and subcommand options."""
     # Don't complete if user hasn't sourced bash_completion file.
-    if 'PIP_AUTO_COMPLETE' not in os.environ:
+    if "PIP_AUTO_COMPLETE" not in os.environ:
         return
-    cwords = os.environ['COMP_WORDS'].split()[1:]
-    cword = int(os.environ['COMP_CWORD'])
+    cwords = os.environ["COMP_WORDS"].split()[1:]
+    cword = int(os.environ["COMP_CWORD"])
     try:
         current = cwords[cword - 1]
     except IndexError:
-        current = ''
+        current = ""
 
     parser = create_main_parser()
     subcommands = list(commands_dict)
@@ -42,12 +41,16 @@ def autocomplete():
     # subcommand options
     if subcommand_name is not None:
         # special case: 'help' subcommand has no options
-        if subcommand_name == 'help':
+        if subcommand_name == "help":
             sys.exit(1)
         # special case: list locally installed dists for show and uninstall
         should_list_installed = (
-            subcommand_name in ['show', 'uninstall'] and
-            not current.startswith('-')
+            subcommand_name
+            in [
+                "show",
+                "uninstall",
+            ]
+            and not current.startswith("-")
         )
         if should_list_installed:
             installed = []
@@ -69,13 +72,15 @@ def autocomplete():
                     options.append((opt_str, opt.nargs))
 
         # filter out previously specified options from available options
-        prev_opts = [x.split('=')[0] for x in cwords[1:cword - 1]]
+        prev_opts = [x.split("=")[0] for x in cwords[1 : cword - 1]]
         options = [(x, v) for (x, v) in options if x not in prev_opts]
         # filter options by current input
         options = [(k, v) for k, v in options if k.startswith(current)]
         # get completion type given cwords and available subcommand options
         completion_type = get_path_completion_type(
-            cwords, cword, subcommand.parser.option_list_all,
+            cwords,
+            cword,
+            subcommand.parser.option_list_all,
         )
         # get completion files and directories if ``completion_type`` is
         # ``<file>``, ``<dir>`` or ``<path>``
@@ -86,7 +91,7 @@ def autocomplete():
             opt_label = option[0]
             # append '=' to options which require args
             if option[1] and option[0][:2] == "--":
-                opt_label += '='
+                opt_label += "="
             print(opt_label)
     else:
         # show main parser options only when necessary
@@ -94,19 +99,17 @@ def autocomplete():
         opts = [i.option_list for i in parser.option_groups]
         opts.append(parser.option_list)
         flattened_opts = chain.from_iterable(opts)
-        if current.startswith('-'):
+        if current.startswith("-"):
             for opt in flattened_opts:
                 if opt.help != optparse.SUPPRESS_HELP:
                     subcommands += opt._long_opts + opt._short_opts
         else:
             # get completion type given cwords and all available options
-            completion_type = get_path_completion_type(cwords, cword,
-                                                       flattened_opts)
+            completion_type = get_path_completion_type(cwords, cword, flattened_opts)
             if completion_type:
-                subcommands = list(auto_complete_paths(current,
-                                                       completion_type))
+                subcommands = list(auto_complete_paths(current, completion_type))
 
-        print(' '.join([x for x in subcommands if x.startswith(current)]))
+        print(" ".join([x for x in subcommands if x.startswith(current)]))
     sys.exit(1)
 
 
@@ -119,16 +122,16 @@ def get_path_completion_type(cwords, cword, opts):
     :param opts: The available options to check
     :return: path completion type (``file``, ``dir``, ``path`` or None)
     """
-    if cword < 2 or not cwords[cword - 2].startswith('-'):
+    if cword < 2 or not cwords[cword - 2].startswith("-"):
         return None
     for opt in opts:
         if opt.help == optparse.SUPPRESS_HELP:
             continue
-        for o in str(opt).split('/'):
-            if cwords[cword - 2].split('=')[0] == o:
+        for o in str(opt).split("/"):
+            if cwords[cword - 2].split("=")[0] == o:
                 if not opt.metavar or any(
-                        x in ('path', 'file', 'dir')
-                        for x in opt.metavar.split('/')):
+                    x in ("path", "file", "dir") for x in opt.metavar.split("/")
+                ):
                     return opt.metavar
     return None
 
@@ -150,15 +153,16 @@ def auto_complete_paths(current, completion_type):
         return
     filename = os.path.normcase(filename)
     # list all files that start with ``filename``
-    file_list = (x for x in os.listdir(current_path)
-                 if os.path.normcase(x).startswith(filename))
+    file_list = (
+        x for x in os.listdir(current_path) if os.path.normcase(x).startswith(filename)
+    )
     for f in file_list:
         opt = os.path.join(current_path, f)
         comp_file = os.path.normcase(os.path.join(directory, f))
         # complete regular files when there is not ``<dir>`` after option
         # complete directories when there is ``<file>``, ``<path>`` or
         # ``<dir>``after option
-        if completion_type != 'dir' and os.path.isfile(opt):
+        if completion_type != "dir" and os.path.isfile(opt):
             yield comp_file
         elif os.path.isdir(opt):
-            yield os.path.join(comp_file, '')
+            yield os.path.join(comp_file, "")
diff --git a/src/pip/_internal/cli/base_command.py b/src/pip/_internal/cli/base_command.py
index 8f14aa6b7a1..bbb15a971df 100644
--- a/src/pip/_internal/cli/base_command.py
+++ b/src/pip/_internal/cli/base_command.py
@@ -12,10 +12,7 @@
 
 from pip._internal.cli import cmdoptions
 from pip._internal.cli.command_context import CommandContextMixIn
-from pip._internal.cli.parser import (
-    ConfigOptionParser,
-    UpdatingDefaultsHelpFormatter,
-)
+from pip._internal.cli.parser import ConfigOptionParser, UpdatingDefaultsHelpFormatter
 from pip._internal.cli.status_codes import (
     ERROR,
     PREVIOUS_BUILD_DIR_ERROR,
@@ -35,10 +32,7 @@
 from pip._internal.utils.filesystem import check_path_owner
 from pip._internal.utils.logging import BrokenStdoutLoggingError, setup_logging
 from pip._internal.utils.misc import get_prog, normalize_path
-from pip._internal.utils.temp_dir import (
-    global_tempdir_manager,
-    tempdir_registry,
-)
+from pip._internal.utils.temp_dir import global_tempdir_manager, tempdir_registry
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 from pip._internal.utils.virtualenv import running_under_virtualenv
 
@@ -46,10 +40,11 @@
     from optparse import Values
     from typing import Any, List, Optional, Tuple
 
-    from pip._internal.utils.temp_dir import \
-        TempDirectoryTypeRegistry as TempDirRegistry
+    from pip._internal.utils.temp_dir import (
+        TempDirectoryTypeRegistry as TempDirRegistry,
+    )
 
-__all__ = ['Command']
+__all__ = ["Command"]
 
 logger = logging.getLogger(__name__)
 
@@ -62,13 +57,13 @@ def __init__(self, name, summary, isolated=False):
         # type: (str, str, bool) -> None
         super(Command, self).__init__()
         parser_kw = {
-            'usage': self.usage,
-            'prog': '{} {}'.format(get_prog(), name),
-            'formatter': UpdatingDefaultsHelpFormatter(),
-            'add_help_option': False,
-            'name': name,
-            'description': self.__doc__,
-            'isolated': isolated,
+            "usage": self.usage,
+            "prog": "{} {}".format(get_prog(), name),
+            "formatter": UpdatingDefaultsHelpFormatter(),
+            "add_help_option": False,
+            "name": name,
+            "description": self.__doc__,
+            "isolated": isolated,
         }
 
         self.name = name
@@ -78,7 +73,7 @@ def __init__(self, name, summary, isolated=False):
         self.tempdir_registry = None  # type: Optional[TempDirRegistry]
 
         # Commands should add options to this option group
-        optgroup_name = '{} Options'.format(self.name.capitalize())
+        optgroup_name = "{} Options".format(self.name.capitalize())
         self.cmd_opts = optparse.OptionGroup(self.parser, optgroup_name)
 
         # Add the general options
@@ -102,7 +97,7 @@ def handle_pip_version_check(self, options):
         """
         # Make sure we do the pip version check if the index_group options
         # are present.
-        assert not hasattr(options, 'no_index')
+        assert not hasattr(options, "no_index")
 
     def run(self, options, args):
         # type: (Values, List[Any]) -> int
@@ -142,10 +137,7 @@ def _main(self, args):
             user_log_file=options.log,
         )
 
-        if (
-            sys.version_info[:2] == (2, 7) and
-            not options.no_python_version_warning
-        ):
+        if sys.version_info[:2] == (2, 7) and not options.no_python_version_warning:
             message = (
                 "pip 21.0 will drop support for Python 2.7 in January 2021. "
                 "More details about Python 2 support in pip can be found at "
@@ -159,10 +151,7 @@ def _main(self, args):
                 ) + message
             deprecated(message, replacement=None, gone_in="21.0")
 
-        if (
-            sys.version_info[:2] == (3, 5) and
-            not options.no_python_version_warning
-        ):
+        if sys.version_info[:2] == (3, 5) and not options.no_python_version_warning:
             message = (
                 "Python 3.5 reached the end of its life on September "
                 "13th, 2020. Please upgrade your Python as Python 3.5 "
@@ -176,17 +165,15 @@ def _main(self, args):
         #       This also affects isolated builds and it should.
 
         if options.no_input:
-            os.environ['PIP_NO_INPUT'] = '1'
+            os.environ["PIP_NO_INPUT"] = "1"
 
         if options.exists_action:
-            os.environ['PIP_EXISTS_ACTION'] = ' '.join(options.exists_action)
+            os.environ["PIP_EXISTS_ACTION"] = " ".join(options.exists_action)
 
         if options.require_venv and not self.ignore_require_venv:
             # If a venv is required check if it can really be found
             if not running_under_virtualenv():
-                logger.critical(
-                    'Could not find an activated virtualenv (required).'
-                )
+                logger.critical("Could not find an activated virtualenv (required).")
                 sys.exit(VIRTUALENV_NOT_FOUND)
 
         if options.cache_dir:
@@ -216,7 +203,7 @@ def _main(self, args):
                 issue=8333,
             )
 
-        if 'resolver' in options.unstable_features:
+        if "resolver" in options.unstable_features:
             logger.critical(
                 "--unstable-feature=resolver is no longer supported, and "
                 "has been replaced with --use-feature=2020-resolver instead."
@@ -229,35 +216,40 @@ def _main(self, args):
             return status
         except PreviousBuildDirError as exc:
             logger.critical(str(exc))
-            logger.debug('Exception information:', exc_info=True)
+            logger.debug("Exception information:", exc_info=True)
 
             return PREVIOUS_BUILD_DIR_ERROR
-        except (InstallationError, UninstallationError, BadCommand,
-                SubProcessError, NetworkConnectionError) as exc:
+        except (
+            InstallationError,
+            UninstallationError,
+            BadCommand,
+            SubProcessError,
+            NetworkConnectionError,
+        ) as exc:
             logger.critical(str(exc))
-            logger.debug('Exception information:', exc_info=True)
+            logger.debug("Exception information:", exc_info=True)
 
             return ERROR
         except CommandError as exc:
-            logger.critical('%s', exc)
-            logger.debug('Exception information:', exc_info=True)
+            logger.critical("%s", exc)
+            logger.debug("Exception information:", exc_info=True)
 
             return ERROR
         except BrokenStdoutLoggingError:
             # Bypass our logger and write any remaining messages to stderr
             # because stdout no longer works.
-            print('ERROR: Pipe to stdout was broken', file=sys.stderr)
+            print("ERROR: Pipe to stdout was broken", file=sys.stderr)
             if level_number <= logging.DEBUG:
                 traceback.print_exc(file=sys.stderr)
 
             return ERROR
         except KeyboardInterrupt:
-            logger.critical('Operation cancelled by user')
-            logger.debug('Exception information:', exc_info=True)
+            logger.critical("Operation cancelled by user")
+            logger.debug("Exception information:", exc_info=True)
 
             return ERROR
         except BaseException:
-            logger.critical('Exception:', exc_info=True)
+            logger.critical("Exception:", exc_info=True)
 
             return UNKNOWN_ERROR
         finally:
diff --git a/src/pip/_internal/cli/cmdoptions.py b/src/pip/_internal/cli/cmdoptions.py
index 2f640b2cbb2..58e2fc2408c 100644
--- a/src/pip/_internal/cli/cmdoptions.py
+++ b/src/pip/_internal/cli/cmdoptions.py
@@ -46,8 +46,8 @@ def raise_option_error(parser, option, msg):
       option: an Option instance.
       msg: the error text.
     """
-    msg = '{} error: {}'.format(option, msg)
-    msg = textwrap.fill(' '.join(msg.split()))
+    msg = "{} error: {}".format(option, msg)
+    msg = textwrap.fill(" ".join(msg.split()))
     parser.error(msg)
 
 
@@ -58,8 +58,8 @@ def make_option_group(group, parser):
     group  -- assumed to be dict with 'name' and 'options' keys
     parser -- an optparse Parser
     """
-    option_group = OptionGroup(parser, group['name'])
-    for option in group['options']:
+    option_group = OptionGroup(parser, group["name"])
+    for option in group["options"]:
         option_group.add_option(option())
     return option_group
 
@@ -78,13 +78,15 @@ def check_install_build_global(options, check_options=None):
     def getname(n):
         # type: (str) -> Optional[Any]
         return getattr(check_options, n, None)
+
     names = ["build_options", "global_options", "install_options"]
     if any(map(getname, names)):
         control = options.format_control
         control.disallow_binaries()
         warnings.warn(
-            'Disabling all use of wheels due to the use of --build-option '
-            '/ --global-option / --install-option.', stacklevel=2,
+            "Disabling all use of wheels due to the use of --build-option "
+            "/ --global-option / --install-option.",
+            stacklevel=2,
         )
 
 
@@ -95,17 +97,18 @@ def check_dist_restriction(options, check_target=False):
     :param options: The OptionParser options.
     :param check_target: Whether or not to check if --target is being used.
     """
-    dist_restriction_set = any([
-        options.python_version,
-        options.platform,
-        options.abi,
-        options.implementation,
-    ])
-
-    binary_only = FormatControl(set(), {':all:'})
+    dist_restriction_set = any(
+        [
+            options.python_version,
+            options.platform,
+            options.abi,
+            options.implementation,
+        ]
+    )
+
+    binary_only = FormatControl(set(), {":all:"})
     sdist_dependencies_allowed = (
-        options.format_control != binary_only and
-        not options.ignore_dependencies
+        options.format_control != binary_only and not options.ignore_dependencies
     )
 
     # Installations or downloads using dist restrictions must not combine
@@ -145,10 +148,11 @@ class PipOption(Option):
 
 help_ = partial(
     Option,
-    '-h', '--help',
-    dest='help',
-    action='help',
-    help='Show help.',
+    "-h",
+    "--help",
+    dest="help",
+    action="help",
+    help="Show help.",
 )  # type: Callable[..., Option]
 
 isolated_mode = partial(
@@ -166,111 +170,119 @@ class PipOption(Option):
 require_virtualenv = partial(
     Option,
     # Run only if inside a virtualenv, bail if not.
-    '--require-virtualenv', '--require-venv',
-    dest='require_venv',
-    action='store_true',
+    "--require-virtualenv",
+    "--require-venv",
+    dest="require_venv",
+    action="store_true",
     default=False,
-    help=SUPPRESS_HELP
+    help=SUPPRESS_HELP,
 )  # type: Callable[..., Option]
 
 verbose = partial(
     Option,
-    '-v', '--verbose',
-    dest='verbose',
-    action='count',
+    "-v",
+    "--verbose",
+    dest="verbose",
+    action="count",
     default=0,
-    help='Give more output. Option is additive, and can be used up to 3 times.'
+    help="Give more output. Option is additive, and can be used up to 3 times.",
 )  # type: Callable[..., Option]
 
 no_color = partial(
     Option,
-    '--no-color',
-    dest='no_color',
-    action='store_true',
+    "--no-color",
+    dest="no_color",
+    action="store_true",
     default=False,
     help="Suppress colored output.",
 )  # type: Callable[..., Option]
 
 version = partial(
     Option,
-    '-V', '--version',
-    dest='version',
-    action='store_true',
-    help='Show version and exit.',
+    "-V",
+    "--version",
+    dest="version",
+    action="store_true",
+    help="Show version and exit.",
 )  # type: Callable[..., Option]
 
 quiet = partial(
     Option,
-    '-q', '--quiet',
-    dest='quiet',
-    action='count',
+    "-q",
+    "--quiet",
+    dest="quiet",
+    action="count",
     default=0,
     help=(
-        'Give less output. Option is additive, and can be used up to 3'
-        ' times (corresponding to WARNING, ERROR, and CRITICAL logging'
-        ' levels).'
+        "Give less output. Option is additive, and can be used up to 3"
+        " times (corresponding to WARNING, ERROR, and CRITICAL logging"
+        " levels)."
     ),
 )  # type: Callable[..., Option]
 
 progress_bar = partial(
     Option,
-    '--progress-bar',
-    dest='progress_bar',
-    type='choice',
+    "--progress-bar",
+    dest="progress_bar",
+    type="choice",
     choices=list(BAR_TYPES.keys()),
-    default='on',
+    default="on",
     help=(
-        'Specify type of progress to be displayed [' +
-        '|'.join(BAR_TYPES.keys()) + '] (default: %default)'
+        "Specify type of progress to be displayed ["
+        + "|".join(BAR_TYPES.keys())
+        + "] (default: %default)"
     ),
 )  # type: Callable[..., Option]
 
 log = partial(
     PipOption,
-    "--log", "--log-file", "--local-log",
+    "--log",
+    "--log-file",
+    "--local-log",
     dest="log",
     metavar="path",
     type="path",
-    help="Path to a verbose appending log."
+    help="Path to a verbose appending log.",
 )  # type: Callable[..., Option]
 
 no_input = partial(
     Option,
     # Don't ask for input
-    '--no-input',
-    dest='no_input',
-    action='store_true',
+    "--no-input",
+    dest="no_input",
+    action="store_true",
     default=False,
-    help="Disable prompting for input."
+    help="Disable prompting for input.",
 )  # type: Callable[..., Option]
 
 proxy = partial(
     Option,
-    '--proxy',
-    dest='proxy',
-    type='str',
-    default='',
-    help="Specify a proxy in the form [user:passwd@]proxy.server:port."
+    "--proxy",
+    dest="proxy",
+    type="str",
+    default="",
+    help="Specify a proxy in the form [user:passwd@]proxy.server:port.",
 )  # type: Callable[..., Option]
 
 retries = partial(
     Option,
-    '--retries',
-    dest='retries',
-    type='int',
+    "--retries",
+    dest="retries",
+    type="int",
     default=5,
     help="Maximum number of retries each connection should attempt "
-         "(default %default times).",
+    "(default %default times).",
 )  # type: Callable[..., Option]
 
 timeout = partial(
     Option,
-    '--timeout', '--default-timeout',
-    metavar='sec',
-    dest='timeout',
-    type='float',
+    "--timeout",
+    "--default-timeout",
+    metavar="sec",
+    dest="timeout",
+    type="float",
     default=15,
-    help='Set the socket timeout (default %default seconds).',
+    help="Set the socket timeout (default %default seconds).",
 )  # type: Callable[..., Option]
 
 
@@ -278,88 +290,91 @@ def exists_action():
     # type: () -> Option
     return Option(
         # Option when path already exist
-        '--exists-action',
-        dest='exists_action',
-        type='choice',
-        choices=['s', 'i', 'w', 'b', 'a'],
+        "--exists-action",
+        dest="exists_action",
+        type="choice",
+        choices=["s", "i", "w", "b", "a"],
         default=[],
-        action='append',
-        metavar='action',
+        action="append",
+        metavar="action",
         help="Default action when a path already exists: "
-             "(s)witch, (i)gnore, (w)ipe, (b)ackup, (a)bort.",
+        "(s)witch, (i)gnore, (w)ipe, (b)ackup, (a)bort.",
     )
 
 
 cert = partial(
     PipOption,
-    '--cert',
-    dest='cert',
-    type='path',
-    metavar='path',
+    "--cert",
+    dest="cert",
+    type="path",
+    metavar="path",
     help="Path to alternate CA bundle.",
 )  # type: Callable[..., Option]
 
 client_cert = partial(
     PipOption,
-    '--client-cert',
-    dest='client_cert',
-    type='path',
+    "--client-cert",
+    dest="client_cert",
+    type="path",
     default=None,
-    metavar='path',
+    metavar="path",
     help="Path to SSL client certificate, a single file containing the "
-         "private key and the certificate in PEM format.",
+    "private key and the certificate in PEM format.",
 )  # type: Callable[..., Option]
 
 index_url = partial(
     Option,
-    '-i', '--index-url', '--pypi-url',
-    dest='index_url',
-    metavar='URL',
+    "-i",
+    "--index-url",
+    "--pypi-url",
+    dest="index_url",
+    metavar="URL",
     default=PyPI.simple_url,
     help="Base URL of the Python Package Index (default %default). "
-         "This should point to a repository compliant with PEP 503 "
-         "(the simple repository API) or a local directory laid out "
-         "in the same format.",
+    "This should point to a repository compliant with PEP 503 "
+    "(the simple repository API) or a local directory laid out "
+    "in the same format.",
 )  # type: Callable[..., Option]
 
 
 def extra_index_url():
     # type: () -> Option
     return Option(
-        '--extra-index-url',
-        dest='extra_index_urls',
-        metavar='URL',
-        action='append',
+        "--extra-index-url",
+        dest="extra_index_urls",
+        metavar="URL",
+        action="append",
         default=[],
         help="Extra URLs of package indexes to use in addition to "
-             "--index-url. Should follow the same rules as "
-             "--index-url.",
+        "--index-url. Should follow the same rules as "
+        "--index-url.",
     )
 
 
 no_index = partial(
     Option,
-    '--no-index',
-    dest='no_index',
-    action='store_true',
+    "--no-index",
+    dest="no_index",
+    action="store_true",
     default=False,
-    help='Ignore package index (only looking at --find-links URLs instead).',
+    help="Ignore package index (only looking at --find-links URLs instead).",
 )  # type: Callable[..., Option]
 
 
 def find_links():
     # type: () -> Option
     return Option(
-        '-f', '--find-links',
-        dest='find_links',
-        action='append',
+        "-f",
+        "--find-links",
+        dest="find_links",
+        action="append",
         default=[],
-        metavar='url',
+        metavar="url",
         help="If a URL or path to an html file, then parse for links to "
-             "archives such as sdist (.tar.gz) or wheel (.whl) files. "
-             "If a local path or file:// URL that's a directory,  "
-             "then look for archives in the directory listing. "
-             "Links to VCS project URLs are not supported.",
+        "archives such as sdist (.tar.gz) or wheel (.whl) files. "
+        "If a local path or file:// URL that's a directory,  "
+        "then look for archives in the directory listing. "
+        "Links to VCS project URLs are not supported.",
     )
 
 
@@ -372,46 +387,51 @@ def trusted_host():
         metavar="HOSTNAME",
         default=[],
         help="Mark this host or host:port pair as trusted, even though it "
-             "does not have valid or any HTTPS.",
+        "does not have valid or any HTTPS.",
     )
 
 
 def constraints():
     # type: () -> Option
     return Option(
-        '-c', '--constraint',
-        dest='constraints',
-        action='append',
+        "-c",
+        "--constraint",
+        dest="constraints",
+        action="append",
         default=[],
-        metavar='file',
-        help='Constrain versions using the given constraints file. '
-        'This option can be used multiple times.'
+        metavar="file",
+        help="Constrain versions using the given constraints file. "
+        "This option can be used multiple times.",
     )
 
 
 def requirements():
     # type: () -> Option
     return Option(
-        '-r', '--requirement',
-        dest='requirements',
-        action='append',
+        "-r",
+        "--requirement",
+        dest="requirements",
+        action="append",
         default=[],
-        metavar='file',
-        help='Install from the given requirements file. '
-        'This option can be used multiple times.'
+        metavar="file",
+        help="Install from the given requirements file. "
+        "This option can be used multiple times.",
     )
 
 
 def editable():
     # type: () -> Option
     return Option(
-        '-e', '--editable',
-        dest='editables',
-        action='append',
+        "-e",
+        "--editable",
+        dest="editables",
+        action="append",
         default=[],
-        metavar='path/url',
-        help=('Install a project in editable mode (i.e. setuptools '
-              '"develop mode") from a local project path or a VCS url.'),
+        metavar="path/url",
+        help=(
+            "Install a project in editable mode (i.e. setuptools "
+            '"develop mode") from a local project path or a VCS url.'
+        ),
     )
 
 
@@ -423,16 +443,19 @@ def _handle_src(option, opt_str, value, parser):
 
 src = partial(
     PipOption,
-    '--src', '--source', '--source-dir', '--source-directory',
-    dest='src_dir',
-    type='path',
-    metavar='dir',
+    "--src",
+    "--source",
+    "--source-dir",
+    "--source-directory",
+    dest="src_dir",
+    type="path",
+    metavar="dir",
     default=get_src_prefix(),
-    action='callback',
+    action="callback",
     callback=_handle_src,
-    help='Directory to check out editable projects into. '
+    help="Directory to check out editable projects into. "
     'The default in a virtualenv is "<venv path>/src". '
-    'The default for global installs is "<current dir>/src".'
+    'The default for global installs is "<current dir>/src".',
 )  # type: Callable[..., Option]
 
 
@@ -446,7 +469,9 @@ def _handle_no_binary(option, opt_str, value, parser):
     # type: (Option, str, str, OptionParser) -> None
     existing = _get_format_control(parser.values, option)
     FormatControl.handle_mutual_excludes(
-        value, existing.no_binary, existing.only_binary,
+        value,
+        existing.no_binary,
+        existing.only_binary,
     )
 
 
@@ -454,7 +479,9 @@ def _handle_only_binary(option, opt_str, value, parser):
     # type: (Option, str, str, OptionParser) -> None
     existing = _get_format_control(parser.values, option)
     FormatControl.handle_mutual_excludes(
-        value, existing.only_binary, existing.no_binary,
+        value,
+        existing.only_binary,
+        existing.no_binary,
     )
 
 
@@ -462,15 +489,18 @@ def no_binary():
     # type: () -> Option
     format_control = FormatControl(set(), set())
     return Option(
-        "--no-binary", dest="format_control", action="callback",
-        callback=_handle_no_binary, type="str",
+        "--no-binary",
+        dest="format_control",
+        action="callback",
+        callback=_handle_no_binary,
+        type="str",
         default=format_control,
-        help='Do not use binary packages. Can be supplied multiple times, and '
-             'each time adds to the existing value. Accepts either ":all:" to '
-             'disable all binary packages, ":none:" to empty the set (notice '
-             'the colons), or one or more package names with commas between '
-             'them (no colons). Note that some packages are tricky to compile '
-             'and may fail to install when this option is used on them.',
+        help="Do not use binary packages. Can be supplied multiple times, and "
+        'each time adds to the existing value. Accepts either ":all:" to '
+        'disable all binary packages, ":none:" to empty the set (notice '
+        "the colons), or one or more package names with commas between "
+        "them (no colons). Note that some packages are tricky to compile "
+        "and may fail to install when this option is used on them.",
     )
 
 
@@ -478,26 +508,31 @@ def only_binary():
     # type: () -> Option
     format_control = FormatControl(set(), set())
     return Option(
-        "--only-binary", dest="format_control", action="callback",
-        callback=_handle_only_binary, type="str",
+        "--only-binary",
+        dest="format_control",
+        action="callback",
+        callback=_handle_only_binary,
+        type="str",
         default=format_control,
-        help='Do not use source packages. Can be supplied multiple times, and '
-             'each time adds to the existing value. Accepts either ":all:" to '
-             'disable all source packages, ":none:" to empty the set, or one '
-             'or more package names with commas between them. Packages '
-             'without binary distributions will fail to install when this '
-             'option is used on them.',
+        help="Do not use source packages. Can be supplied multiple times, and "
+        'each time adds to the existing value. Accepts either ":all:" to '
+        'disable all source packages, ":none:" to empty the set, or one '
+        "or more package names with commas between them. Packages "
+        "without binary distributions will fail to install when this "
+        "option is used on them.",
     )
 
 
 platform = partial(
     Option,
-    '--platform',
-    dest='platform',
-    metavar='platform',
+    "--platform",
+    dest="platform",
+    metavar="platform",
     default=None,
-    help=("Only use wheels compatible with <platform>. "
-          "Defaults to the platform of the running system."),
+    help=(
+        "Only use wheels compatible with <platform>. "
+        "Defaults to the platform of the running system."
+    ),
 )  # type: Callable[..., Option]
 
 
@@ -514,9 +549,9 @@ def _convert_python_version(value):
         # The empty string is the same as not providing a value.
         return (None, None)
 
-    parts = value.split('.')
+    parts = value.split(".")
     if len(parts) > 3:
-        return ((), 'at most three version parts are allowed')
+        return ((), "at most three version parts are allowed")
 
     if len(parts) == 1:
         # Then we are in the case of "3" or "37".
@@ -527,7 +562,7 @@ def _convert_python_version(value):
     try:
         version_info = tuple(int(part) for part in parts)
     except ValueError:
-        return ((), 'each version part must be an integer')
+        return ((), "each version part must be an integer")
 
     return (version_info, None)
 
@@ -539,10 +574,9 @@ def _handle_python_version(option, opt_str, value, parser):
     """
     version_info, error_msg = _convert_python_version(value)
     if error_msg is not None:
-        msg = (
-            'invalid --python-version value: {!r}: {}'.format(
-                value, error_msg,
-            )
+        msg = "invalid --python-version value: {!r}: {}".format(
+            value,
+            error_msg,
         )
         raise_option_error(parser, option=option, msg=msg)
 
@@ -551,48 +585,55 @@ def _handle_python_version(option, opt_str, value, parser):
 
 python_version = partial(
     Option,
-    '--python-version',
-    dest='python_version',
-    metavar='python_version',
-    action='callback',
-    callback=_handle_python_version, type='str',
+    "--python-version",
+    dest="python_version",
+    metavar="python_version",
+    action="callback",
+    callback=_handle_python_version,
+    type="str",
     default=None,
-    help=dedent("""\
+    help=dedent(
+        """\
     The Python interpreter version to use for wheel and "Requires-Python"
     compatibility checks. Defaults to a version derived from the running
     interpreter. The version can be specified using up to three dot-separated
     integers (e.g. "3" for 3.0.0, "3.7" for 3.7.0, or "3.7.3"). A major-minor
     version can also be given as a string without dots (e.g. "37" for 3.7.0).
-    """),
+    """
+    ),
 )  # type: Callable[..., Option]
 
 
 implementation = partial(
     Option,
-    '--implementation',
-    dest='implementation',
-    metavar='implementation',
+    "--implementation",
+    dest="implementation",
+    metavar="implementation",
     default=None,
-    help=("Only use wheels compatible with Python "
-          "implementation <implementation>, e.g. 'pp', 'jy', 'cp', "
-          " or 'ip'. If not specified, then the current "
-          "interpreter implementation is used.  Use 'py' to force "
-          "implementation-agnostic wheels."),
+    help=(
+        "Only use wheels compatible with Python "
+        "implementation <implementation>, e.g. 'pp', 'jy', 'cp', "
+        " or 'ip'. If not specified, then the current "
+        "interpreter implementation is used.  Use 'py' to force "
+        "implementation-agnostic wheels."
+    ),
 )  # type: Callable[..., Option]
 
 
 abi = partial(
     Option,
-    '--abi',
-    dest='abi',
-    metavar='abi',
+    "--abi",
+    dest="abi",
+    metavar="abi",
     default=None,
-    help=("Only use wheels compatible with Python "
-          "abi <abi>, e.g. 'pypy_41'.  If not specified, then the "
-          "current interpreter abi tag is used.  Generally "
-          "you will need to specify --implementation, "
-          "--platform, and --python-version when using "
-          "this option."),
+    help=(
+        "Only use wheels compatible with Python "
+        "abi <abi>, e.g. 'pypy_41'.  If not specified, then the "
+        "current interpreter abi tag is used.  Generally "
+        "you will need to specify --implementation, "
+        "--platform, and --python-version when using "
+        "this option."
+    ),
 )  # type: Callable[..., Option]
 
 
@@ -623,7 +664,7 @@ def prefer_binary():
         dest="prefer_binary",
         action="store_true",
         default=False,
-        help="Prefer older binary packages over newer source packages."
+        help="Prefer older binary packages over newer source packages.",
     )
 
 
@@ -633,8 +674,8 @@ def prefer_binary():
     dest="cache_dir",
     default=USER_CACHE_DIR,
     metavar="dir",
-    type='path',
-    help="Store the cache data in <dir>."
+    type="path",
+    help="Store the cache data in <dir>.",
 )  # type: Callable[..., Option]
 
 
@@ -677,9 +718,10 @@ def _handle_no_cache_dir(option, opt, value, parser):
 
 no_deps = partial(
     Option,
-    '--no-deps', '--no-dependencies',
-    dest='ignore_dependencies',
-    action='store_true',
+    "--no-deps",
+    "--no-dependencies",
+    dest="ignore_dependencies",
+    action="store_true",
     default=False,
     help="Don't install package dependencies.",
 )  # type: Callable[..., Option]
@@ -694,37 +736,40 @@ def _handle_build_dir(option, opt, value, parser):
 
 build_dir = partial(
     PipOption,
-    '-b', '--build', '--build-dir', '--build-directory',
-    dest='build_dir',
-    type='path',
-    metavar='dir',
-    action='callback',
+    "-b",
+    "--build",
+    "--build-dir",
+    "--build-directory",
+    dest="build_dir",
+    type="path",
+    metavar="dir",
+    action="callback",
     callback=_handle_build_dir,
-    help='(DEPRECATED) '
-         'Directory to unpack packages into and build in. Note that '
-         'an initial build still takes place in a temporary directory. '
-         'The location of temporary directories can be controlled by setting '
-         'the TMPDIR environment variable (TEMP on Windows) appropriately. '
-         'When passed, build directories are not cleaned in case of failures.'
+    help="(DEPRECATED) "
+    "Directory to unpack packages into and build in. Note that "
+    "an initial build still takes place in a temporary directory. "
+    "The location of temporary directories can be controlled by setting "
+    "the TMPDIR environment variable (TEMP on Windows) appropriately. "
+    "When passed, build directories are not cleaned in case of failures.",
 )  # type: Callable[..., Option]
 
 ignore_requires_python = partial(
     Option,
-    '--ignore-requires-python',
-    dest='ignore_requires_python',
-    action='store_true',
-    help='Ignore the Requires-Python information.'
+    "--ignore-requires-python",
+    dest="ignore_requires_python",
+    action="store_true",
+    help="Ignore the Requires-Python information.",
 )  # type: Callable[..., Option]
 
 no_build_isolation = partial(
     Option,
-    '--no-build-isolation',
-    dest='build_isolation',
-    action='store_false',
+    "--no-build-isolation",
+    dest="build_isolation",
+    action="store_false",
     default=True,
-    help='Disable isolation when building a modern source distribution. '
-         'Build dependencies specified by PEP 518 must be already installed '
-         'if this option is used.'
+    help="Disable isolation when building a modern source distribution. "
+    "Build dependencies specified by PEP 518 must be already installed "
+    "if this option is used.",
 )  # type: Callable[..., Option]
 
 
@@ -754,62 +799,62 @@ def _handle_no_use_pep517(option, opt, value, parser):
 
 use_pep517 = partial(
     Option,
-    '--use-pep517',
-    dest='use_pep517',
-    action='store_true',
+    "--use-pep517",
+    dest="use_pep517",
+    action="store_true",
     default=None,
-    help='Use PEP 517 for building source distributions '
-         '(use --no-use-pep517 to force legacy behaviour).'
+    help="Use PEP 517 for building source distributions "
+    "(use --no-use-pep517 to force legacy behaviour).",
 )  # type: Any
 
 no_use_pep517 = partial(
     Option,
-    '--no-use-pep517',
-    dest='use_pep517',
-    action='callback',
+    "--no-use-pep517",
+    dest="use_pep517",
+    action="callback",
     callback=_handle_no_use_pep517,
     default=None,
-    help=SUPPRESS_HELP
+    help=SUPPRESS_HELP,
 )  # type: Any
 
 install_options = partial(
     Option,
-    '--install-option',
-    dest='install_options',
-    action='append',
-    metavar='options',
+    "--install-option",
+    dest="install_options",
+    action="append",
+    metavar="options",
     help="Extra arguments to be supplied to the setup.py install "
-         "command (use like --install-option=\"--install-scripts=/usr/local/"
-         "bin\"). Use multiple --install-option options to pass multiple "
-         "options to setup.py install. If you are using an option with a "
-         "directory path, be sure to use absolute path.",
+    'command (use like --install-option="--install-scripts=/usr/local/'
+    'bin"). Use multiple --install-option options to pass multiple '
+    "options to setup.py install. If you are using an option with a "
+    "directory path, be sure to use absolute path.",
 )  # type: Callable[..., Option]
 
 global_options = partial(
     Option,
-    '--global-option',
-    dest='global_options',
-    action='append',
-    metavar='options',
+    "--global-option",
+    dest="global_options",
+    action="append",
+    metavar="options",
     help="Extra global options to be supplied to the setup.py "
-         "call before the install command.",
+    "call before the install command.",
 )  # type: Callable[..., Option]
 
 no_clean = partial(
     Option,
-    '--no-clean',
-    action='store_true',
+    "--no-clean",
+    action="store_true",
     default=False,
-    help="Don't clean up build directories."
+    help="Don't clean up build directories.",
 )  # type: Callable[..., Option]
 
 pre = partial(
     Option,
-    '--pre',
-    action='store_true',
+    "--pre",
+    action="store_true",
     default=False,
     help="Include pre-release and development versions. By default, "
-         "pip only finds stable versions.",
+    "pip only finds stable versions.",
 )  # type: Callable[..., Option]
 
 disable_pip_version_check = partial(
@@ -819,7 +864,7 @@ def _handle_no_use_pep517(option, opt, value, parser):
     action="store_true",
     default=False,
     help="Don't periodically check PyPI to determine whether a new version "
-         "of pip is available for download. Implied with --no-index.",
+    "of pip is available for download. Implied with --no-index.",
 )  # type: Callable[..., Option]
 
 
@@ -830,105 +875,106 @@ def _handle_merge_hash(option, opt_str, value, parser):
     if not parser.values.hashes:
         parser.values.hashes = {}
     try:
-        algo, digest = value.split(':', 1)
+        algo, digest = value.split(":", 1)
     except ValueError:
-        parser.error('Arguments to {} must be a hash name '  # noqa
-                     'followed by a value, like --hash=sha256:'
-                     'abcde...'.format(opt_str))
+        parser.error(
+            "Arguments to {} must be a hash name "  # noqa
+            "followed by a value, like --hash=sha256:"
+            "abcde...".format(opt_str)
+        )
     if algo not in STRONG_HASHES:
-        parser.error('Allowed hash algorithms for {} are {}.'.format(  # noqa
-                     opt_str, ', '.join(STRONG_HASHES)))
+        parser.error(
+            "Allowed hash algorithms for {} are {}.".format(  # noqa
+                opt_str, ", ".join(STRONG_HASHES)
+            )
+        )
     parser.values.hashes.setdefault(algo, []).append(digest)
 
 
 hash = partial(
     Option,
-    '--hash',
+    "--hash",
     # Hash values eventually end up in InstallRequirement.hashes due to
     # __dict__ copying in process_line().
-    dest='hashes',
-    action='callback',
+    dest="hashes",
+    action="callback",
     callback=_handle_merge_hash,
-    type='string',
+    type="string",
     help="Verify that the package's archive matches this "
-         'hash before installing. Example: --hash=sha256:abcdef...',
+    "hash before installing. Example: --hash=sha256:abcdef...",
 )  # type: Callable[..., Option]
 
 
 require_hashes = partial(
     Option,
-    '--require-hashes',
-    dest='require_hashes',
-    action='store_true',
+    "--require-hashes",
+    dest="require_hashes",
+    action="store_true",
     default=False,
-    help='Require a hash to check each requirement against, for '
-         'repeatable installs. This option is implied when any package in a '
-         'requirements file has a --hash option.',
+    help="Require a hash to check each requirement against, for "
+    "repeatable installs. This option is implied when any package in a "
+    "requirements file has a --hash option.",
 )  # type: Callable[..., Option]
 
 
 list_path = partial(
     PipOption,
-    '--path',
-    dest='path',
-    type='path',
-    action='append',
-    help='Restrict to the specified installation path for listing '
-         'packages (can be used multiple times).'
+    "--path",
+    dest="path",
+    type="path",
+    action="append",
+    help="Restrict to the specified installation path for listing "
+    "packages (can be used multiple times).",
 )  # type: Callable[..., Option]
 
 
 def check_list_path_option(options):
     # type: (Values) -> None
     if options.path and (options.user or options.local):
-        raise CommandError(
-            "Cannot combine '--path' with '--user' or '--local'"
-        )
+        raise CommandError("Cannot combine '--path' with '--user' or '--local'")
 
 
 no_python_version_warning = partial(
     Option,
-    '--no-python-version-warning',
-    dest='no_python_version_warning',
-    action='store_true',
+    "--no-python-version-warning",
+    dest="no_python_version_warning",
+    action="store_true",
     default=False,
-    help='Silence deprecation warnings for upcoming unsupported Pythons.',
+    help="Silence deprecation warnings for upcoming unsupported Pythons.",
 )  # type: Callable[..., Option]
 
 
 unstable_feature = partial(
     Option,
-    '--unstable-feature',
-    dest='unstable_features',
-    metavar='feature',
-    action='append',
+    "--unstable-feature",
+    dest="unstable_features",
+    metavar="feature",
+    action="append",
     default=[],
-    choices=['resolver'],
+    choices=["resolver"],
     help=SUPPRESS_HELP,  # TODO: drop this in pip 20.3
 )  # type: Callable[..., Option]
 
 use_new_feature = partial(
     Option,
-    '--use-feature',
-    dest='features_enabled',
-    metavar='feature',
-    action='append',
+    "--use-feature",
+    dest="features_enabled",
+    metavar="feature",
+    action="append",
     default=[],
-    choices=['2020-resolver', 'fast-deps'],
-    help='Enable new functionality, that may be backward incompatible.',
+    choices=["2020-resolver", "fast-deps"],
+    help="Enable new functionality, that may be backward incompatible.",
 )  # type: Callable[..., Option]
 
 use_deprecated_feature = partial(
     Option,
-    '--use-deprecated',
-    dest='deprecated_features_enabled',
-    metavar='feature',
-    action='append',
+    "--use-deprecated",
+    dest="deprecated_features_enabled",
+    metavar="feature",
+    action="append",
     default=[],
     choices=[],
-    help=(
-        'Enable deprecated functionality, that will be removed in the future.'
-    ),
+    help=("Enable deprecated functionality, that will be removed in the future."),
 )  # type: Callable[..., Option]
 
 
@@ -937,8 +983,8 @@ def check_list_path_option(options):
 ##########
 
 general_group = {
-    'name': 'General Options',
-    'options': [
+    "name": "General Options",
+    "options": [
         help_,
         isolated_mode,
         require_virtualenv,
@@ -962,15 +1008,15 @@ def check_list_path_option(options):
         unstable_feature,
         use_new_feature,
         use_deprecated_feature,
-    ]
+    ],
 }  # type: Dict[str, Any]
 
 index_group = {
-    'name': 'Package Index Options',
-    'options': [
+    "name": "Package Index Options",
+    "options": [
         index_url,
         extra_index_url,
         no_index,
         find_links,
-    ]
+    ],
 }  # type: Dict[str, Any]
diff --git a/src/pip/_internal/cli/command_context.py b/src/pip/_internal/cli/command_context.py
index 669c777749d..c1696824bc1 100644
--- a/src/pip/_internal/cli/command_context.py
+++ b/src/pip/_internal/cli/command_context.py
@@ -7,7 +7,7 @@
 if MYPY_CHECK_RUNNING:
     from typing import ContextManager, Iterator, TypeVar
 
-    _T = TypeVar('_T', covariant=True)
+    _T = TypeVar("_T", covariant=True)
 
 
 class CommandContextMixIn(object):
diff --git a/src/pip/_internal/cli/main.py b/src/pip/_internal/cli/main.py
index 172f30dd5bf..9c853fb5c5e 100644
--- a/src/pip/_internal/cli/main.py
+++ b/src/pip/_internal/cli/main.py
@@ -46,6 +46,7 @@
 # call to main. As it is not safe to do any processing after calling
 # main, this should not be an issue in practice.
 
+
 def main(args=None):
     # type: (Optional[List[str]]) -> int
     if args is None:
@@ -66,7 +67,7 @@ def main(args=None):
     # Needed for locale.getpreferredencoding(False) to work
     # in pip._internal.utils.encoding.auto_decode
     try:
-        locale.setlocale(locale.LC_ALL, '')
+        locale.setlocale(locale.LC_ALL, "")
     except locale.Error as e:
         # setlocale can apparently crash if locale are uninitialized
         logger.debug("Ignoring error %s when setting locale", e)
diff --git a/src/pip/_internal/cli/main_parser.py b/src/pip/_internal/cli/main_parser.py
index 6356d831df1..ec1eec73f2e 100644
--- a/src/pip/_internal/cli/main_parser.py
+++ b/src/pip/_internal/cli/main_parser.py
@@ -5,10 +5,7 @@
 import sys
 
 from pip._internal.cli import cmdoptions
-from pip._internal.cli.parser import (
-    ConfigOptionParser,
-    UpdatingDefaultsHelpFormatter,
-)
+from pip._internal.cli.parser import ConfigOptionParser, UpdatingDefaultsHelpFormatter
 from pip._internal.commands import commands_dict, get_similar_commands
 from pip._internal.exceptions import CommandError
 from pip._internal.utils.misc import get_pip_version, get_prog
@@ -23,15 +20,14 @@
 
 def create_main_parser():
     # type: () -> ConfigOptionParser
-    """Creates and returns the main parser for pip's CLI
-    """
+    """Creates and returns the main parser for pip's CLI"""
 
     parser_kw = {
-        'usage': '\n%prog <command> [options]',
-        'add_help_option': False,
-        'formatter': UpdatingDefaultsHelpFormatter(),
-        'name': 'global',
-        'prog': get_prog(),
+        "usage": "\n%prog <command> [options]",
+        "add_help_option": False,
+        "formatter": UpdatingDefaultsHelpFormatter(),
+        "name": "global",
+        "prog": get_prog(),
     }
 
     parser = ConfigOptionParser(**parser_kw)
@@ -47,11 +43,11 @@ def create_main_parser():
     parser.main = True  # type: ignore
 
     # create command listing for description
-    description = [''] + [
-        '{name:27} {command_info.summary}'.format(**locals())
+    description = [""] + [
+        "{name:27} {command_info.summary}".format(**locals())
         for name, command_info in commands_dict.items()
     ]
-    parser.description = '\n'.join(description)
+    parser.description = "\n".join(description)
 
     return parser
 
@@ -76,7 +72,7 @@ def parse_command(args):
         sys.exit()
 
     # pip || pip help -> print_help()
-    if not args_else or (args_else[0] == 'help' and len(args_else) == 1):
+    if not args_else or (args_else[0] == "help" and len(args_else) == 1):
         parser.print_help()
         sys.exit()
 
@@ -90,7 +86,7 @@ def parse_command(args):
         if guess:
             msg.append('maybe you meant "{}"'.format(guess))
 
-        raise CommandError(' - '.join(msg))
+        raise CommandError(" - ".join(msg))
 
     # all the args without the subcommand
     cmd_args = args[:]
diff --git a/src/pip/_internal/cli/parser.py b/src/pip/_internal/cli/parser.py
index b6b78318a7a..6b6ffc3c147 100644
--- a/src/pip/_internal/cli/parser.py
+++ b/src/pip/_internal/cli/parser.py
@@ -26,15 +26,15 @@ class PrettyHelpFormatter(optparse.IndentedHelpFormatter):
 
     def __init__(self, *args, **kwargs):
         # help position must be aligned with __init__.parseopts.description
-        kwargs['max_help_position'] = 30
-        kwargs['indent_increment'] = 1
-        kwargs['width'] = get_terminal_size()[0] - 2
+        kwargs["max_help_position"] = 30
+        kwargs["indent_increment"] = 1
+        kwargs["width"] = get_terminal_size()[0] - 2
         optparse.IndentedHelpFormatter.__init__(self, *args, **kwargs)
 
     def format_option_strings(self, option):
         return self._format_option_strings(option)
 
-    def _format_option_strings(self, option, mvarfmt=' <{}>', optsep=', '):
+    def _format_option_strings(self, option, mvarfmt=" <{}>", optsep=", "):
         """
         Return a comma-separated list of option strings and metavars.
 
@@ -55,49 +55,48 @@ def _format_option_strings(self, option, mvarfmt=' <{}>', optsep=', '):
             metavar = option.metavar or option.dest.lower()
             opts.append(mvarfmt.format(metavar.lower()))
 
-        return ''.join(opts)
+        return "".join(opts)
 
     def format_heading(self, heading):
-        if heading == 'Options':
-            return ''
-        return heading + ':\n'
+        if heading == "Options":
+            return ""
+        return heading + ":\n"
 
     def format_usage(self, usage):
         """
         Ensure there is only one newline between usage and the first heading
         if there is no description.
         """
-        msg = '\nUsage: {}\n'.format(
-            self.indent_lines(textwrap.dedent(usage), "  "))
+        msg = "\nUsage: {}\n".format(self.indent_lines(textwrap.dedent(usage), "  "))
         return msg
 
     def format_description(self, description):
         # leave full control over description to us
         if description:
-            if hasattr(self.parser, 'main'):
-                label = 'Commands'
+            if hasattr(self.parser, "main"):
+                label = "Commands"
             else:
-                label = 'Description'
+                label = "Description"
             # some doc strings have initial newlines, some don't
-            description = description.lstrip('\n')
+            description = description.lstrip("\n")
             # some doc strings have final newlines and spaces, some don't
             description = description.rstrip()
             # dedent, then reindent
             description = self.indent_lines(textwrap.dedent(description), "  ")
-            description = '{}:\n{}\n'.format(label, description)
+            description = "{}:\n{}\n".format(label, description)
             return description
         else:
-            return ''
+            return ""
 
     def format_epilog(self, epilog):
         # leave full control over epilog to us
         if epilog:
             return epilog
         else:
-            return ''
+            return ""
 
     def indent_lines(self, text, indent):
-        new_lines = [indent + line for line in text.split('\n')]
+        new_lines = [indent + line for line in text.split("\n")]
         return "\n".join(new_lines)
 
 
@@ -115,7 +114,6 @@ def expand_default(self, option):
 
 
 class CustomOptionParser(optparse.OptionParser):
-
     def insert_option_group(self, idx, *args, **kwargs):
         """Insert an OptionGroup at a given position."""
         group = self.add_option_group(*args, **kwargs)
@@ -140,7 +138,7 @@ class ConfigOptionParser(CustomOptionParser):
     configuration files and environmental variables"""
 
     def __init__(self, *args, **kwargs):
-        self.name = kwargs.pop('name')
+        self.name = kwargs.pop("name")
 
         isolated = kwargs.pop("isolated", False)
         self.config = Configuration(isolated)
@@ -166,7 +164,7 @@ def _get_ordered_configuration_items(self):
             if not val:
                 logger.debug(
                     "Ignoring configuration key '%s' as it's value is empty.",
-                    section_key
+                    section_key,
                 )
                 continue
 
@@ -190,7 +188,7 @@ def _update_defaults(self, defaults):
         # Then set the options with those values
         for key, val in self._get_ordered_configuration_items():
             # '--' because configuration supports only long names
-            option = self.get_option('--' + key)
+            option = self.get_option("--" + key)
 
             # Ignore options not present in this parser. E.g. non-globals put
             # in [global] by users that want them to apply to all applicable
@@ -198,31 +196,31 @@ def _update_defaults(self, defaults):
             if option is None:
                 continue
 
-            if option.action in ('store_true', 'store_false'):
+            if option.action in ("store_true", "store_false"):
                 try:
                     val = strtobool(val)
                 except ValueError:
                     self.error(
-                        '{} is not a valid value for {} option, '  # noqa
-                        'please specify a boolean value like yes/no, '
-                        'true/false or 1/0 instead.'.format(val, key)
+                        "{} is not a valid value for {} option, "  # noqa
+                        "please specify a boolean value like yes/no, "
+                        "true/false or 1/0 instead.".format(val, key)
                     )
-            elif option.action == 'count':
+            elif option.action == "count":
                 with suppress(ValueError):
                     val = strtobool(val)
                 with suppress(ValueError):
                     val = int(val)
                 if not isinstance(val, int) or val < 0:
                     self.error(
-                        '{} is not a valid value for {} option, '  # noqa
-                        'please instead specify either a non-negative integer '
-                        'or a boolean value like yes/no or false/true '
-                        'which is equivalent to 1/0.'.format(val, key)
+                        "{} is not a valid value for {} option, "  # noqa
+                        "please instead specify either a non-negative integer "
+                        "or a boolean value like yes/no or false/true "
+                        "which is equivalent to 1/0.".format(val, key)
                     )
-            elif option.action == 'append':
+            elif option.action == "append":
                 val = val.split()
                 val = [self.check_default(option, key, v) for v in val]
-            elif option.action == 'callback':
+            elif option.action == "callback":
                 late_eval.add(option.dest)
                 opt_str = option.get_opt_string()
                 val = option.convert_value(opt_str, val)
diff --git a/src/pip/_internal/cli/progress_bars.py b/src/pip/_internal/cli/progress_bars.py
index 69338552f13..7177fb82670 100644
--- a/src/pip/_internal/cli/progress_bars.py
+++ b/src/pip/_internal/cli/progress_bars.py
@@ -79,10 +79,7 @@ def __init__(self, *args, **kwargs):
         Save the original SIGINT handler for later.
         """
         # https://github.com/python/mypy/issues/5887
-        super(InterruptibleMixin, self).__init__(  # type: ignore
-            *args,
-            **kwargs
-        )
+        super(InterruptibleMixin, self).__init__(*args, **kwargs)  # type: ignore
 
         self.original_handler = signal(SIGINT, self.handle_sigint)
 
@@ -117,7 +114,6 @@ def handle_sigint(self, signum, frame):  # type: ignore
 
 
 class SilentBar(Bar):
-
     def update(self):
         # type: () -> None
         pass
@@ -132,17 +128,11 @@ class BlueEmojiBar(IncrementalBar):
 
 
 class DownloadProgressMixin(object):
-
     def __init__(self, *args, **kwargs):
         # type: (List[Any], Dict[Any, Any]) -> None
         # https://github.com/python/mypy/issues/5887
-        super(DownloadProgressMixin, self).__init__(  # type: ignore
-            *args,
-            **kwargs
-        )
-        self.message = (" " * (
-            get_indentation() + 2
-        )) + self.message  # type: str
+        super(DownloadProgressMixin, self).__init__(*args, **kwargs)  # type: ignore
+        self.message = (" " * (get_indentation() + 2)) + self.message  # type: str
 
     @property
     def downloaded(self):
@@ -174,7 +164,6 @@ def iter(self, it):  # type: ignore
 
 
 class WindowsMixin(object):
-
     def __init__(self, *args, **kwargs):
         # type: (List[Any], Dict[Any, Any]) -> None
         # The Windows terminal does not support the hide/show cursor ANSI codes
@@ -204,16 +193,14 @@ def __init__(self, *args, **kwargs):
             self.file.flush = lambda: self.file.wrapped.flush()
 
 
-class BaseDownloadProgressBar(WindowsMixin, InterruptibleMixin,
-                              DownloadProgressMixin):
+class BaseDownloadProgressBar(WindowsMixin, InterruptibleMixin, DownloadProgressMixin):
 
     file = sys.stdout
     message = "%(percent)d%%"
     suffix = "%(downloaded)s %(download_speed)s %(pretty_eta)s"
 
 
-class DefaultDownloadProgressBar(BaseDownloadProgressBar,
-                                 _BaseBar):
+class DefaultDownloadProgressBar(BaseDownloadProgressBar, _BaseBar):
     pass
 
 
@@ -221,23 +208,21 @@ class DownloadSilentBar(BaseDownloadProgressBar, SilentBar):
     pass
 
 
-class DownloadBar(BaseDownloadProgressBar,
-                  Bar):
+class DownloadBar(BaseDownloadProgressBar, Bar):
     pass
 
 
-class DownloadFillingCirclesBar(BaseDownloadProgressBar,
-                                FillingCirclesBar):
+class DownloadFillingCirclesBar(BaseDownloadProgressBar, FillingCirclesBar):
     pass
 
 
-class DownloadBlueEmojiProgressBar(BaseDownloadProgressBar,
-                                   BlueEmojiBar):
+class DownloadBlueEmojiProgressBar(BaseDownloadProgressBar, BlueEmojiBar):
     pass
 
 
-class DownloadProgressSpinner(WindowsMixin, InterruptibleMixin,
-                              DownloadProgressMixin, Spinner):
+class DownloadProgressSpinner(
+    WindowsMixin, InterruptibleMixin, DownloadProgressMixin, Spinner
+):
 
     file = sys.stdout
     suffix = "%(downloaded)s %(download_speed)s"
@@ -253,13 +238,15 @@ def update(self):
         message = self.message % self
         phase = self.next_phase()
         suffix = self.suffix % self
-        line = ''.join([
-            message,
-            " " if message else "",
-            phase,
-            " " if suffix else "",
-            suffix,
-        ])
+        line = "".join(
+            [
+                message,
+                " " if message else "",
+                phase,
+                " " if suffix else "",
+                suffix,
+            ]
+        )
 
         self.writeln(line)
 
@@ -269,7 +256,7 @@ def update(self):
     "on": (DefaultDownloadProgressBar, DownloadProgressSpinner),
     "ascii": (DownloadBar, DownloadProgressSpinner),
     "pretty": (DownloadFillingCirclesBar, DownloadProgressSpinner),
-    "emoji": (DownloadBlueEmojiProgressBar, DownloadProgressSpinner)
+    "emoji": (DownloadBlueEmojiProgressBar, DownloadProgressSpinner),
 }
 
 
diff --git a/src/pip/_internal/cli/req_command.py b/src/pip/_internal/cli/req_command.py
index 76abce5acdf..647c1d34f35 100644
--- a/src/pip/_internal/cli/req_command.py
+++ b/src/pip/_internal/cli/req_command.py
@@ -38,10 +38,7 @@
     from pip._internal.req.req_install import InstallRequirement
     from pip._internal.req.req_tracker import RequirementTracker
     from pip._internal.resolution.base import BaseResolver
-    from pip._internal.utils.temp_dir import (
-        TempDirectory,
-        TempDirectoryTypeRegistry,
-    )
+    from pip._internal.utils.temp_dir import TempDirectory, TempDirectoryTypeRegistry
 
 
 logger = logging.getLogger(__name__)
@@ -52,6 +49,7 @@ class SessionCommandMixin(CommandContextMixIn):
     """
     A class mixin for command classes needing _build_session().
     """
+
     def __init__(self):
         # type: () -> None
         super(SessionCommandMixin, self).__init__()
@@ -88,8 +86,7 @@ def _build_session(self, options, retries=None, timeout=None):
         assert not options.cache_dir or os.path.isabs(options.cache_dir)
         session = PipSession(
             cache=(
-                os.path.join(options.cache_dir, "http")
-                if options.cache_dir else None
+                os.path.join(options.cache_dir, "http") if options.cache_dir else None
             ),
             retries=retries if retries is not None else options.retries,
             trusted_hosts=options.trusted_hosts,
@@ -106,9 +103,7 @@ def _build_session(self, options, retries=None, timeout=None):
 
         # Handle timeouts
         if options.timeout or timeout:
-            session.timeout = (
-                timeout if timeout is not None else options.timeout
-            )
+            session.timeout = timeout if timeout is not None else options.timeout
 
         # Handle configured proxies
         if options.proxy:
@@ -139,16 +134,14 @@ def handle_pip_version_check(self, options):
         This overrides the default behavior of not doing the check.
         """
         # Make sure the index_group options are present.
-        assert hasattr(options, 'no_index')
+        assert hasattr(options, "no_index")
 
         if options.disable_pip_version_check or options.no_index:
             return
 
         # Otherwise, check if we're using the latest version of pip available.
         session = self._build_session(
-            options,
-            retries=0,
-            timeout=min(5, options.timeout)
+            options, retries=0, timeout=min(5, options.timeout)
         )
         with session:
             pip_self_version_check(session, options)
@@ -166,6 +159,7 @@ def with_cleanup(func):
     """Decorator for common logic related to managing temporary
     directories.
     """
+
     def configure_tempdir_registry(registry):
         # type: (TempDirectoryTypeRegistry) -> None
         for t in KEEPABLE_TEMPDIR_TYPES:
@@ -190,7 +184,6 @@ def wrapper(self, options, args):
 
 
 class RequirementCommand(IndexGroupCommand):
-
     def __init__(self, *args, **kw):
         # type: (Any, Any) -> None
         super(RequirementCommand, self).__init__(*args, **kw)
@@ -199,13 +192,13 @@ def __init__(self, *args, **kw):
 
     @staticmethod
     def make_requirement_preparer(
-        temp_build_dir,           # type: TempDirectory
-        options,                  # type: Values
-        req_tracker,              # type: RequirementTracker
-        session,                  # type: PipSession
-        finder,                   # type: PackageFinder
-        use_user_site,            # type: bool
-        download_dir=None,        # type: str
+        temp_build_dir,  # type: TempDirectory
+        options,  # type: Values
+        req_tracker,  # type: RequirementTracker
+        session,  # type: PipSession
+        finder,  # type: PackageFinder
+        use_user_site,  # type: bool
+        download_dir=None,  # type: str
         wheel_download_dir=None,  # type: str
     ):
         # type: (...) -> RequirementPreparer
@@ -215,15 +208,15 @@ def make_requirement_preparer(
         temp_build_dir_path = temp_build_dir.path
         assert temp_build_dir_path is not None
 
-        if '2020-resolver' in options.features_enabled:
-            lazy_wheel = 'fast-deps' in options.features_enabled
+        if "2020-resolver" in options.features_enabled:
+            lazy_wheel = "fast-deps" in options.features_enabled
             if lazy_wheel:
                 logger.warning(
-                    'pip is using lazily downloaded wheels using HTTP '
-                    'range requests to obtain dependency information. '
-                    'This experimental feature is enabled through '
-                    '--use-feature=fast-deps and it is not ready for '
-                    'production.'
+                    "pip is using lazily downloaded wheels using HTTP "
+                    "range requests to obtain dependency information. "
+                    "This experimental feature is enabled through "
+                    "--use-feature=fast-deps and it is not ready for "
+                    "production."
                 )
         else:
             lazy_wheel = False
@@ -245,17 +238,17 @@ def make_requirement_preparer(
 
     @staticmethod
     def make_resolver(
-        preparer,                            # type: RequirementPreparer
-        finder,                              # type: PackageFinder
-        options,                             # type: Values
-        wheel_cache=None,                    # type: Optional[WheelCache]
-        use_user_site=False,                 # type: bool
-        ignore_installed=True,               # type: bool
-        ignore_requires_python=False,        # type: bool
-        force_reinstall=False,               # type: bool
+        preparer,  # type: RequirementPreparer
+        finder,  # type: PackageFinder
+        options,  # type: Values
+        wheel_cache=None,  # type: Optional[WheelCache]
+        use_user_site=False,  # type: bool
+        ignore_installed=True,  # type: bool
+        ignore_requires_python=False,  # type: bool
+        force_reinstall=False,  # type: bool
         upgrade_strategy="to-satisfy-only",  # type: str
-        use_pep517=None,                     # type: Optional[bool]
-        py_version_info=None            # type: Optional[Tuple[int, ...]]
+        use_pep517=None,  # type: Optional[bool]
+        py_version_info=None,  # type: Optional[Tuple[int, ...]]
     ):
         # type: (...) -> BaseResolver
         """
@@ -269,7 +262,7 @@ def make_resolver(
         # The long import name and duplicated invocation is needed to convince
         # Mypy into correctly typechecking. Otherwise it would complain the
         # "Resolver" class being redefined.
-        if '2020-resolver' in options.features_enabled:
+        if "2020-resolver" in options.features_enabled:
             import pip._internal.resolution.resolvelib.resolver
 
             return pip._internal.resolution.resolvelib.resolver.Resolver(
@@ -286,6 +279,7 @@ def make_resolver(
                 py_version_info=py_version_info,
             )
         import pip._internal.resolution.legacy.resolver
+
         return pip._internal.resolution.legacy.resolver.Resolver(
             preparer=preparer,
             finder=finder,
@@ -302,10 +296,10 @@ def make_resolver(
 
     def get_requirements(
         self,
-        args,             # type: List[str]
-        options,          # type: Values
-        finder,           # type: PackageFinder
-        session,          # type: PipSession
+        args,  # type: List[str]
+        options,  # type: Values
+        finder,  # type: PackageFinder
+        session,  # type: PipSession
     ):
         # type: (...) -> List[InstallRequirement]
         """
@@ -314,9 +308,12 @@ def get_requirements(
         requirements = []  # type: List[InstallRequirement]
         for filename in options.constraints:
             for parsed_req in parse_requirements(
-                    filename,
-                    constraint=True, finder=finder, options=options,
-                    session=session):
+                filename,
+                constraint=True,
+                finder=finder,
+                options=options,
+                session=session,
+            ):
                 req_to_add = install_req_from_parsed_requirement(
                     parsed_req,
                     isolated=options.isolated_mode,
@@ -326,7 +323,9 @@ def get_requirements(
 
         for req in args:
             req_to_add = install_req_from_line(
-                req, None, isolated=options.isolated_mode,
+                req,
+                None,
+                isolated=options.isolated_mode,
                 use_pep517=options.use_pep517,
                 user_supplied=True,
             )
@@ -344,8 +343,8 @@ def get_requirements(
         # NOTE: options.require_hashes may be set if --require-hashes is True
         for filename in options.requirements:
             for parsed_req in parse_requirements(
-                    filename,
-                    finder=finder, options=options, session=session):
+                filename, finder=finder, options=options, session=session
+            ):
                 req_to_add = install_req_from_parsed_requirement(
                     parsed_req,
                     isolated=options.isolated_mode,
@@ -359,16 +358,19 @@ def get_requirements(
             options.require_hashes = True
 
         if not (args or options.editables or options.requirements):
-            opts = {'name': self.name}
+            opts = {"name": self.name}
             if options.find_links:
                 raise CommandError(
-                    'You must give at least one requirement to {name} '
+                    "You must give at least one requirement to {name} "
                     '(maybe you meant "pip {name} {links}"?)'.format(
-                        **dict(opts, links=' '.join(options.find_links))))
+                        **dict(opts, links=" ".join(options.find_links))
+                    )
+                )
             else:
                 raise CommandError(
-                    'You must give at least one requirement to {name} '
-                    '(see "pip help {name}")'.format(**opts))
+                    "You must give at least one requirement to {name} "
+                    '(see "pip help {name}")'.format(**opts)
+                )
 
         return requirements
 
@@ -386,9 +388,9 @@ def trace_basic_info(finder):
 
     def _build_package_finder(
         self,
-        options,               # type: Values
-        session,               # type: PipSession
-        target_python=None,    # type: Optional[TargetPython]
+        options,  # type: Values
+        session,  # type: PipSession
+        target_python=None,  # type: Optional[TargetPython]
         ignore_requires_python=None,  # type: Optional[bool]
     ):
         # type: (...) -> PackageFinder
diff --git a/src/pip/_internal/cli/spinners.py b/src/pip/_internal/cli/spinners.py
index 65c3c23d742..99cbd3fddc8 100644
--- a/src/pip/_internal/cli/spinners.py
+++ b/src/pip/_internal/cli/spinners.py
@@ -29,9 +29,14 @@ def finish(self, final_status):
 
 
 class InteractiveSpinner(SpinnerInterface):
-    def __init__(self, message, file=None, spin_chars="-\\|/",
-                 # Empirically, 8 updates/second looks nice
-                 min_update_interval_seconds=0.125):
+    def __init__(
+        self,
+        message,
+        file=None,
+        spin_chars="-\\|/",
+        # Empirically, 8 updates/second looks nice
+        min_update_interval_seconds=0.125,
+    ):
         # type: (str, IO[str], str, float) -> None
         self._message = message
         if file is None:
@@ -106,8 +111,7 @@ def finish(self, final_status):
         # type: (str) -> None
         if self._finished:
             return
-        self._update(
-            "finished with status '{final_status}'".format(**locals()))
+        self._update("finished with status '{final_status}'".format(**locals()))
         self._finished = True
 
 
diff --git a/src/pip/_internal/commands/__init__.py b/src/pip/_internal/commands/__init__.py
index 4f0c4ba3ab9..c6d9513d428 100644
--- a/src/pip/_internal/commands/__init__.py
+++ b/src/pip/_internal/commands/__init__.py
@@ -22,7 +22,7 @@
     from pip._internal.cli.base_command import Command
 
 
-CommandInfo = namedtuple('CommandInfo', 'module_path, class_name, summary')
+CommandInfo = namedtuple("CommandInfo", "module_path, class_name, summary")
 
 # The ordering matters for help display.
 #    Also, even though the module path starts with the same
@@ -32,68 +32,130 @@
 # in a test-related module).
 #    Finally, we need to pass an iterable of pairs here rather than a dict
 # so that the ordering won't be lost when using Python 2.7.
-commands_dict = OrderedDict([
-    ('install', CommandInfo(
-        'pip._internal.commands.install', 'InstallCommand',
-        'Install packages.',
-    )),
-    ('download', CommandInfo(
-        'pip._internal.commands.download', 'DownloadCommand',
-        'Download packages.',
-    )),
-    ('uninstall', CommandInfo(
-        'pip._internal.commands.uninstall', 'UninstallCommand',
-        'Uninstall packages.',
-    )),
-    ('freeze', CommandInfo(
-        'pip._internal.commands.freeze', 'FreezeCommand',
-        'Output installed packages in requirements format.',
-    )),
-    ('list', CommandInfo(
-        'pip._internal.commands.list', 'ListCommand',
-        'List installed packages.',
-    )),
-    ('show', CommandInfo(
-        'pip._internal.commands.show', 'ShowCommand',
-        'Show information about installed packages.',
-    )),
-    ('check', CommandInfo(
-        'pip._internal.commands.check', 'CheckCommand',
-        'Verify installed packages have compatible dependencies.',
-    )),
-    ('config', CommandInfo(
-        'pip._internal.commands.configuration', 'ConfigurationCommand',
-        'Manage local and global configuration.',
-    )),
-    ('search', CommandInfo(
-        'pip._internal.commands.search', 'SearchCommand',
-        'Search PyPI for packages.',
-    )),
-    ('cache', CommandInfo(
-        'pip._internal.commands.cache', 'CacheCommand',
-        "Inspect and manage pip's wheel cache.",
-    )),
-    ('wheel', CommandInfo(
-        'pip._internal.commands.wheel', 'WheelCommand',
-        'Build wheels from your requirements.',
-    )),
-    ('hash', CommandInfo(
-        'pip._internal.commands.hash', 'HashCommand',
-        'Compute hashes of package archives.',
-    )),
-    ('completion', CommandInfo(
-        'pip._internal.commands.completion', 'CompletionCommand',
-        'A helper command used for command completion.',
-    )),
-    ('debug', CommandInfo(
-        'pip._internal.commands.debug', 'DebugCommand',
-        'Show information useful for debugging.',
-    )),
-    ('help', CommandInfo(
-        'pip._internal.commands.help', 'HelpCommand',
-        'Show help for commands.',
-    )),
-])  # type: OrderedDict[str, CommandInfo]
+commands_dict = OrderedDict(
+    [
+        (
+            "install",
+            CommandInfo(
+                "pip._internal.commands.install",
+                "InstallCommand",
+                "Install packages.",
+            ),
+        ),
+        (
+            "download",
+            CommandInfo(
+                "pip._internal.commands.download",
+                "DownloadCommand",
+                "Download packages.",
+            ),
+        ),
+        (
+            "uninstall",
+            CommandInfo(
+                "pip._internal.commands.uninstall",
+                "UninstallCommand",
+                "Uninstall packages.",
+            ),
+        ),
+        (
+            "freeze",
+            CommandInfo(
+                "pip._internal.commands.freeze",
+                "FreezeCommand",
+                "Output installed packages in requirements format.",
+            ),
+        ),
+        (
+            "list",
+            CommandInfo(
+                "pip._internal.commands.list",
+                "ListCommand",
+                "List installed packages.",
+            ),
+        ),
+        (
+            "show",
+            CommandInfo(
+                "pip._internal.commands.show",
+                "ShowCommand",
+                "Show information about installed packages.",
+            ),
+        ),
+        (
+            "check",
+            CommandInfo(
+                "pip._internal.commands.check",
+                "CheckCommand",
+                "Verify installed packages have compatible dependencies.",
+            ),
+        ),
+        (
+            "config",
+            CommandInfo(
+                "pip._internal.commands.configuration",
+                "ConfigurationCommand",
+                "Manage local and global configuration.",
+            ),
+        ),
+        (
+            "search",
+            CommandInfo(
+                "pip._internal.commands.search",
+                "SearchCommand",
+                "Search PyPI for packages.",
+            ),
+        ),
+        (
+            "cache",
+            CommandInfo(
+                "pip._internal.commands.cache",
+                "CacheCommand",
+                "Inspect and manage pip's wheel cache.",
+            ),
+        ),
+        (
+            "wheel",
+            CommandInfo(
+                "pip._internal.commands.wheel",
+                "WheelCommand",
+                "Build wheels from your requirements.",
+            ),
+        ),
+        (
+            "hash",
+            CommandInfo(
+                "pip._internal.commands.hash",
+                "HashCommand",
+                "Compute hashes of package archives.",
+            ),
+        ),
+        (
+            "completion",
+            CommandInfo(
+                "pip._internal.commands.completion",
+                "CompletionCommand",
+                "A helper command used for command completion.",
+            ),
+        ),
+        (
+            "debug",
+            CommandInfo(
+                "pip._internal.commands.debug",
+                "DebugCommand",
+                "Show information useful for debugging.",
+            ),
+        ),
+        (
+            "help",
+            CommandInfo(
+                "pip._internal.commands.help",
+                "HelpCommand",
+                "Show help for commands.",
+            ),
+        ),
+    ]
+)  # type: OrderedDict[str, CommandInfo]
 
 
 def create_command(name, **kwargs):
diff --git a/src/pip/_internal/commands/cache.py b/src/pip/_internal/commands/cache.py
index b9d3ed410bc..cbdf9d687a4 100644
--- a/src/pip/_internal/commands/cache.py
+++ b/src/pip/_internal/commands/cache.py
@@ -46,12 +46,12 @@ def add_options(self):
         # type: () -> None
 
         self.cmd_opts.add_option(
-            '--format',
-            action='store',
-            dest='list_format',
+            "--format",
+            action="store",
+            dest="list_format",
             default="human",
-            choices=('human', 'abspath'),
-            help="Select the output format among: human (default) or abspath"
+            choices=("human", "abspath"),
+            help="Select the output format among: human (default) or abspath",
         )
 
         self.parser.insert_option_group(0, self.cmd_opts)
@@ -67,8 +67,9 @@ def run(self, options, args):
         }
 
         if not options.cache_dir:
-            logger.error("pip cache commands can not "
-                         "function since cache is disabled.")
+            logger.error(
+                "pip cache commands can not " "function since cache is disabled."
+            )
             return ERROR
 
         # Determine action
@@ -93,44 +94,50 @@ def run(self, options, args):
     def get_cache_dir(self, options, args):
         # type: (Values, List[Any]) -> None
         if args:
-            raise CommandError('Too many arguments')
+            raise CommandError("Too many arguments")
 
         logger.info(options.cache_dir)
 
     def get_cache_info(self, options, args):
         # type: (Values, List[Any]) -> None
         if args:
-            raise CommandError('Too many arguments')
+            raise CommandError("Too many arguments")
 
-        num_packages = len(self._find_wheels(options, '*'))
+        num_packages = len(self._find_wheels(options, "*"))
 
         cache_location = self._wheels_cache_dir(options)
         cache_size = filesystem.format_directory_size(cache_location)
 
-        message = textwrap.dedent("""
+        message = (
+            textwrap.dedent(
+                """
             Location: {location}
             Size: {size}
             Number of wheels: {package_count}
-        """).format(
-            location=cache_location,
-            package_count=num_packages,
-            size=cache_size,
-        ).strip()
+        """
+            )
+            .format(
+                location=cache_location,
+                package_count=num_packages,
+                size=cache_size,
+            )
+            .strip()
+        )
 
         logger.info(message)
 
     def list_cache_items(self, options, args):
         # type: (Values, List[Any]) -> None
         if len(args) > 1:
-            raise CommandError('Too many arguments')
+            raise CommandError("Too many arguments")
 
         if args:
             pattern = args[0]
         else:
-            pattern = '*'
+            pattern = "*"
 
         files = self._find_wheels(options, pattern)
-        if options.list_format == 'human':
+        if options.list_format == "human":
             self.format_for_human(files)
         else:
             self.format_for_abspath(files)
@@ -138,16 +145,16 @@ def list_cache_items(self, options, args):
     def format_for_human(self, files):
         # type: (List[str]) -> None
         if not files:
-            logger.info('Nothing cached.')
+            logger.info("Nothing cached.")
             return
 
         results = []
         for filename in files:
             wheel = os.path.basename(filename)
             size = filesystem.format_file_size(filename)
-            results.append(' - {} ({})'.format(wheel, size))
-        logger.info('Cache contents:\n')
-        logger.info('\n'.join(sorted(results)))
+            results.append(" - {} ({})".format(wheel, size))
+        logger.info("Cache contents:\n")
+        logger.info("\n".join(sorted(results)))
 
     def format_for_abspath(self, files):
         # type: (List[str]) -> None
@@ -158,35 +165,35 @@ def format_for_abspath(self, files):
         for filename in files:
             results.append(filename)
 
-        logger.info('\n'.join(sorted(results)))
+        logger.info("\n".join(sorted(results)))
 
     def remove_cache_items(self, options, args):
         # type: (Values, List[Any]) -> None
         if len(args) > 1:
-            raise CommandError('Too many arguments')
+            raise CommandError("Too many arguments")
 
         if not args:
-            raise CommandError('Please provide a pattern')
+            raise CommandError("Please provide a pattern")
 
         files = self._find_wheels(options, args[0])
         if not files:
-            raise CommandError('No matching packages')
+            raise CommandError("No matching packages")
 
         for filename in files:
             os.unlink(filename)
-            logger.debug('Removed %s', filename)
-        logger.info('Files removed: %s', len(files))
+            logger.debug("Removed %s", filename)
+        logger.info("Files removed: %s", len(files))
 
     def purge_cache(self, options, args):
         # type: (Values, List[Any]) -> None
         if args:
-            raise CommandError('Too many arguments')
+            raise CommandError("Too many arguments")
 
-        return self.remove_cache_items(options, ['*'])
+        return self.remove_cache_items(options, ["*"])
 
     def _wheels_cache_dir(self, options):
         # type: (Values) -> str
-        return os.path.join(options.cache_dir, 'wheels')
+        return os.path.join(options.cache_dir, "wheels")
 
     def _find_wheels(self, options, pattern):
         # type: (Values, str) -> List[str]
diff --git a/src/pip/_internal/commands/check.py b/src/pip/_internal/commands/check.py
index e066bb63c74..decb4489066 100644
--- a/src/pip/_internal/commands/check.py
+++ b/src/pip/_internal/commands/check.py
@@ -33,7 +33,9 @@ def run(self, options, args):
             for dependency in missing[project_name]:
                 write_output(
                     "%s %s requires %s, which is not installed.",
-                    project_name, version, dependency[0],
+                    project_name,
+                    version,
+                    dependency[0],
                 )
 
         for project_name in conflicting:
@@ -41,7 +43,11 @@ def run(self, options, args):
             for dep_name, dep_version, req in conflicting[project_name]:
                 write_output(
                     "%s %s has requirement %s, but you have %s %s.",
-                    project_name, version, req, dep_name, dep_version,
+                    project_name,
+                    version,
+                    req,
+                    dep_name,
+                    dep_version,
                 )
 
         if missing or conflicting or parsing_probs:
diff --git a/src/pip/_internal/commands/completion.py b/src/pip/_internal/commands/completion.py
index b19f1ed1a56..99155af7c92 100644
--- a/src/pip/_internal/commands/completion.py
+++ b/src/pip/_internal/commands/completion.py
@@ -17,7 +17,7 @@
 """
 
 COMPLETION_SCRIPTS = {
-    'bash': """
+    "bash": """
         _pip_completion()
         {{
             COMPREPLY=( $( COMP_WORDS="${{COMP_WORDS[*]}}" \\
@@ -26,7 +26,7 @@
         }}
         complete -o default -F _pip_completion {prog}
     """,
-    'zsh': """
+    "zsh": """
         function _pip_completion {{
           local words cword
           read -Ac words
@@ -37,7 +37,7 @@
         }}
         compctl -K _pip_completion {prog}
     """,
-    'fish': """
+    "fish": """
         function __fish_complete_pip
             set -lx COMP_WORDS (commandline -o) ""
             set -lx COMP_CWORD ( \\
@@ -59,23 +59,29 @@ class CompletionCommand(Command):
     def add_options(self):
         # type: () -> None
         self.cmd_opts.add_option(
-            '--bash', '-b',
-            action='store_const',
-            const='bash',
-            dest='shell',
-            help='Emit completion code for bash')
+            "--bash",
+            "-b",
+            action="store_const",
+            const="bash",
+            dest="shell",
+            help="Emit completion code for bash",
+        )
         self.cmd_opts.add_option(
-            '--zsh', '-z',
-            action='store_const',
-            const='zsh',
-            dest='shell',
-            help='Emit completion code for zsh')
+            "--zsh",
+            "-z",
+            action="store_const",
+            const="zsh",
+            dest="shell",
+            help="Emit completion code for zsh",
+        )
         self.cmd_opts.add_option(
-            '--fish', '-f',
-            action='store_const',
-            const='fish',
-            dest='shell',
-            help='Emit completion code for fish')
+            "--fish",
+            "-f",
+            action="store_const",
+            const="fish",
+            dest="shell",
+            help="Emit completion code for fish",
+        )
 
         self.parser.insert_option_group(0, self.cmd_opts)
 
@@ -83,16 +89,15 @@ def run(self, options, args):
         #  type: (Values, List[str]) -> int
         """Prints the completion code of the given shell"""
         shells = COMPLETION_SCRIPTS.keys()
-        shell_options = ['--' + shell for shell in sorted(shells)]
+        shell_options = ["--" + shell for shell in sorted(shells)]
         if options.shell in shells:
             script = textwrap.dedent(
-                COMPLETION_SCRIPTS.get(options.shell, '').format(
-                    prog=get_prog())
+                COMPLETION_SCRIPTS.get(options.shell, "").format(prog=get_prog())
             )
             print(BASE_COMPLETION.format(script=script, shell=options.shell))
             return SUCCESS
         else:
             sys.stderr.write(
-                'ERROR: You must pass {}\n' .format(' or '.join(shell_options))
+                "ERROR: You must pass {}\n".format(" or ".join(shell_options))
             )
             return SUCCESS
diff --git a/src/pip/_internal/commands/configuration.py b/src/pip/_internal/commands/configuration.py
index 2a6311acd74..ddb10bb44a0 100644
--- a/src/pip/_internal/commands/configuration.py
+++ b/src/pip/_internal/commands/configuration.py
@@ -4,11 +4,7 @@
 
 from pip._internal.cli.base_command import Command
 from pip._internal.cli.status_codes import ERROR, SUCCESS
-from pip._internal.configuration import (
-    Configuration,
-    get_configuration_files,
-    kinds,
-)
+from pip._internal.configuration import Configuration, get_configuration_files, kinds
 from pip._internal.exceptions import PipError
 from pip._internal.utils.logging import indent_log
 from pip._internal.utils.misc import get_prog, write_output
@@ -56,38 +52,38 @@ class ConfigurationCommand(Command):
     def add_options(self):
         # type: () -> None
         self.cmd_opts.add_option(
-            '--editor',
-            dest='editor',
-            action='store',
+            "--editor",
+            dest="editor",
+            action="store",
             default=None,
             help=(
-                'Editor to use to edit the file. Uses VISUAL or EDITOR '
-                'environment variables if not provided.'
-            )
+                "Editor to use to edit the file. Uses VISUAL or EDITOR "
+                "environment variables if not provided."
+            ),
         )
 
         self.cmd_opts.add_option(
-            '--global',
-            dest='global_file',
-            action='store_true',
+            "--global",
+            dest="global_file",
+            action="store_true",
             default=False,
-            help='Use the system-wide configuration file only'
+            help="Use the system-wide configuration file only",
         )
 
         self.cmd_opts.add_option(
-            '--user',
-            dest='user_file',
-            action='store_true',
+            "--user",
+            dest="user_file",
+            action="store_true",
             default=False,
-            help='Use the user configuration file only'
+            help="Use the user configuration file only",
         )
 
         self.cmd_opts.add_option(
-            '--site',
-            dest='site_file',
-            action='store_true',
+            "--site",
+            dest="site_file",
+            action="store_true",
             default=False,
-            help='Use the current environment configuration file only'
+            help="Use the current environment configuration file only",
         )
 
         self.parser.insert_option_group(0, self.cmd_opts)
@@ -140,11 +136,15 @@ def run(self, options, args):
 
     def _determine_file(self, options, need_value):
         # type: (Values, bool) -> Optional[Kind]
-        file_options = [key for key, value in (
-            (kinds.USER, options.user_file),
-            (kinds.GLOBAL, options.global_file),
-            (kinds.SITE, options.site_file),
-        ) if value]
+        file_options = [
+            key
+            for key, value in (
+                (kinds.USER, options.user_file),
+                (kinds.GLOBAL, options.global_file),
+                (kinds.SITE, options.site_file),
+            )
+            if value
+        ]
 
         if not file_options:
             if not need_value:
@@ -206,26 +206,24 @@ def list_config_values(self, options, args):
             for fname in files:
                 with indent_log():
                     file_exists = os.path.exists(fname)
-                    write_output("%s, exists: %r",
-                                 fname, file_exists)
+                    write_output("%s, exists: %r", fname, file_exists)
                     if file_exists:
                         self.print_config_file_values(variant)
 
     def print_config_file_values(self, variant):
         # type: (Kind) -> None
         """Get key-value pairs from the file of a variant"""
-        for name, value in self.configuration.\
-                get_values_in_config(variant).items():
+        for name, value in self.configuration.get_values_in_config(variant).items():
             with indent_log():
                 write_output("%s: %s", name, value)
 
     def print_env_var_values(self):
         # type: () -> None
         """Get key-values pairs present as environment variables"""
-        write_output("%s:", 'env_var')
+        write_output("%s:", "env_var")
         with indent_log():
             for key, value in sorted(self.configuration.get_environ_vars()):
-                env_var = 'PIP_{}'.format(key.upper())
+                env_var = "PIP_{}".format(key.upper())
                 write_output("%s=%r", env_var, value)
 
     def open_in_editor(self, options, args):
@@ -240,17 +238,15 @@ def open_in_editor(self, options, args):
             subprocess.check_call([editor, fname])
         except subprocess.CalledProcessError as e:
             raise PipError(
-                "Editor Subprocess exited with exit code {}"
-                .format(e.returncode)
+                "Editor Subprocess exited with exit code {}".format(e.returncode)
             )
 
     def _get_n_args(self, args, example, n):
         # type: (List[str], str, int) -> Any
-        """Helper to make sure the command got the right number of arguments
-        """
+        """Helper to make sure the command got the right number of arguments"""
         if len(args) != n:
             msg = (
-                'Got unexpected number of arguments, expected {}. '
+                "Got unexpected number of arguments, expected {}. "
                 '(example: "{} config {}")'
             ).format(n, get_prog(), example)
             raise PipError(msg)
diff --git a/src/pip/_internal/commands/debug.py b/src/pip/_internal/commands/debug.py
index 1b65c43065b..0835766b620 100644
--- a/src/pip/_internal/commands/debug.py
+++ b/src/pip/_internal/commands/debug.py
@@ -30,38 +30,37 @@
 
 def show_value(name, value):
     # type: (str, Optional[str]) -> None
-    logger.info('%s: %s', name, value)
+    logger.info("%s: %s", name, value)
 
 
 def show_sys_implementation():
     # type: () -> None
-    logger.info('sys.implementation:')
-    if hasattr(sys, 'implementation'):
+    logger.info("sys.implementation:")
+    if hasattr(sys, "implementation"):
         implementation = sys.implementation  # type: ignore
         implementation_name = implementation.name
     else:
-        implementation_name = ''
+        implementation_name = ""
 
     with indent_log():
-        show_value('name', implementation_name)
+        show_value("name", implementation_name)
 
 
 def create_vendor_txt_map():
     # type: () -> Dict[str, str]
     vendor_txt_path = os.path.join(
-        os.path.dirname(pip_location),
-        '_vendor',
-        'vendor.txt'
+        os.path.dirname(pip_location), "_vendor", "vendor.txt"
     )
 
     with open(vendor_txt_path) as f:
         # Purge non version specifying lines.
         # Also, remove any space prefix or suffixes (including comments).
-        lines = [line.strip().split(' ', 1)[0]
-                 for line in f.readlines() if '==' in line]
+        lines = [
+            line.strip().split(" ", 1)[0] for line in f.readlines() if "==" in line
+        ]
 
     # Transform into "module" -> version dict.
-    return dict(line.split('==', 1) for line in lines)  # type: ignore
+    return dict(line.split("==", 1) for line in lines)  # type: ignore
 
 
 def get_module_from_module_name(module_name):
@@ -69,22 +68,17 @@ def get_module_from_module_name(module_name):
     # Module name can be uppercase in vendor.txt for some reason...
     module_name = module_name.lower()
     # PATCH: setuptools is actually only pkg_resources.
-    if module_name == 'setuptools':
-        module_name = 'pkg_resources'
-
-    __import__(
-        'pip._vendor.{}'.format(module_name),
-        globals(),
-        locals(),
-        level=0
-    )
+    if module_name == "setuptools":
+        module_name = "pkg_resources"
+
+    __import__("pip._vendor.{}".format(module_name), globals(), locals(), level=0)
     return getattr(pip._vendor, module_name)
 
 
 def get_vendor_version_from_module(module_name):
     # type: (str) -> Optional[str]
     module = get_module_from_module_name(module_name)
-    version = getattr(module, '__version__', None)
+    version = getattr(module, "__version__", None)
 
     if not version:
         # Try to find version in debundled module info
@@ -96,7 +90,7 @@ def get_vendor_version_from_module(module_name):
             [os.path.dirname(module.__file__)]  # type: ignore
         )
         package = pkg_set.find(pkg_resources.Requirement.parse(module_name))
-        version = getattr(package, 'version', None)
+        version = getattr(package, "version", None)
 
     return version
 
@@ -107,21 +101,25 @@ def show_actual_vendor_versions(vendor_txt_versions):
     a conflict or if the actual version could not be imported.
     """
     for module_name, expected_version in vendor_txt_versions.items():
-        extra_message = ''
+        extra_message = ""
         actual_version = get_vendor_version_from_module(module_name)
         if not actual_version:
-            extra_message = ' (Unable to locate actual module version, using'\
-                            ' vendor.txt specified version)'
+            extra_message = (
+                " (Unable to locate actual module version, using"
+                " vendor.txt specified version)"
+            )
             actual_version = expected_version
         elif actual_version != expected_version:
-            extra_message = ' (CONFLICT: vendor.txt suggests version should'\
-                            ' be {})'.format(expected_version)
-        logger.info('%s==%s%s', module_name, actual_version, extra_message)
+            extra_message = (
+                " (CONFLICT: vendor.txt suggests version should"
+                " be {})".format(expected_version)
+            )
+        logger.info("%s==%s%s", module_name, actual_version, extra_message)
 
 
 def show_vendor_versions():
     # type: () -> None
-    logger.info('vendored library versions:')
+    logger.info("vendored library versions:")
 
     vendor_txt_versions = create_vendor_txt_map()
     with indent_log():
@@ -137,11 +135,11 @@ def show_tags(options):
 
     # Display the target options that were explicitly provided.
     formatted_target = target_python.format_given()
-    suffix = ''
+    suffix = ""
     if formatted_target:
-        suffix = ' (target: {})'.format(formatted_target)
+        suffix = " (target: {})".format(formatted_target)
 
-    msg = 'Compatible tags: {}{}'.format(len(tags), suffix)
+    msg = "Compatible tags: {}{}".format(len(tags), suffix)
     logger.info(msg)
 
     if options.verbose < 1 and len(tags) > tag_limit:
@@ -156,8 +154,7 @@ def show_tags(options):
 
         if tags_limited:
             msg = (
-                '...\n'
-                '[First {tag_limit} tags shown. Pass --verbose to show all.]'
+                "...\n" "[First {tag_limit} tags shown. Pass --verbose to show all.]"
             ).format(tag_limit=tag_limit)
             logger.info(msg)
 
@@ -166,20 +163,20 @@ def ca_bundle_info(config):
     # type: (Configuration) -> str
     levels = set()
     for key, _ in config.items():
-        levels.add(key.split('.')[0])
+        levels.add(key.split(".")[0])
 
     if not levels:
         return "Not specified"
 
-    levels_that_override_global = ['install', 'wheel', 'download']
+    levels_that_override_global = ["install", "wheel", "download"]
     global_overriding_level = [
         level for level in levels if level in levels_that_override_global
     ]
     if not global_overriding_level:
-        return 'global'
+        return "global"
 
-    if 'global' in levels:
-        levels.remove('global')
+    if "global" in levels:
+        levels.remove("global")
     return ", ".join(levels)
 
 
@@ -206,20 +203,21 @@ def run(self, options, args):
             "details, since the output and options of this command may "
             "change without notice."
         )
-        show_value('pip version', get_pip_version())
-        show_value('sys.version', sys.version)
-        show_value('sys.executable', sys.executable)
-        show_value('sys.getdefaultencoding', sys.getdefaultencoding())
-        show_value('sys.getfilesystemencoding', sys.getfilesystemencoding())
+        show_value("pip version", get_pip_version())
+        show_value("sys.version", sys.version)
+        show_value("sys.executable", sys.executable)
+        show_value("sys.getdefaultencoding", sys.getdefaultencoding())
+        show_value("sys.getfilesystemencoding", sys.getfilesystemencoding())
         show_value(
-            'locale.getpreferredencoding', locale.getpreferredencoding(),
+            "locale.getpreferredencoding",
+            locale.getpreferredencoding(),
         )
-        show_value('sys.platform', sys.platform)
+        show_value("sys.platform", sys.platform)
         show_sys_implementation()
 
         show_value("'cert' config value", ca_bundle_info(self.parser.config))
-        show_value("REQUESTS_CA_BUNDLE", os.environ.get('REQUESTS_CA_BUNDLE'))
-        show_value("CURL_CA_BUNDLE", os.environ.get('CURL_CA_BUNDLE'))
+        show_value("REQUESTS_CA_BUNDLE", os.environ.get("REQUESTS_CA_BUNDLE"))
+        show_value("CURL_CA_BUNDLE", os.environ.get("CURL_CA_BUNDLE"))
         show_value("pip._vendor.certifi.where()", where())
         show_value("pip._vendor.DEBUNDLED", pip._vendor.DEBUNDLED)
 
diff --git a/src/pip/_internal/commands/download.py b/src/pip/_internal/commands/download.py
index 0861d9e67b2..0971ed3df77 100644
--- a/src/pip/_internal/commands/download.py
+++ b/src/pip/_internal/commands/download.py
@@ -58,9 +58,12 @@ def add_options(self):
         self.cmd_opts.add_option(cmdoptions.no_use_pep517())
 
         self.cmd_opts.add_option(
-            '-d', '--dest', '--destination-dir', '--destination-directory',
-            dest='download_dir',
-            metavar='dir',
+            "-d",
+            "--dest",
+            "--destination-dir",
+            "--destination-directory",
+            dest="download_dir",
+            metavar="dir",
             default=os.curdir,
             help=("Download packages into <dir>."),
         )
@@ -98,7 +101,7 @@ def run(self, options, args):
             session=session,
             target_python=target_python,
         )
-        build_delete = (not (options.no_clean or options.build_dir))
+        build_delete = not (options.no_clean or options.build_dir)
 
         req_tracker = self.enter_context(get_requirement_tracker())
 
@@ -130,9 +133,7 @@ def run(self, options, args):
 
         self.trace_basic_info(finder)
 
-        requirement_set = resolver.resolve(
-            reqs, check_supported_wheels=True
-        )
+        requirement_set = resolver.resolve(reqs, check_supported_wheels=True)
 
         downloaded = []  # type: List[str]
         for req in requirement_set.requirements.values():
@@ -140,6 +141,6 @@ def run(self, options, args):
                 assert req.name is not None
                 downloaded.append(req.name)
         if downloaded:
-            write_output('Successfully downloaded %s', ' '.join(downloaded))
+            write_output("Successfully downloaded %s", " ".join(downloaded))
 
         return SUCCESS
diff --git a/src/pip/_internal/commands/freeze.py b/src/pip/_internal/commands/freeze.py
index 2071fbabd61..cc4dc27cfc0 100644
--- a/src/pip/_internal/commands/freeze.py
+++ b/src/pip/_internal/commands/freeze.py
@@ -11,7 +11,7 @@
 from pip._internal.utils.compat import stdlib_pkgs
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 
-DEV_PKGS = {'pip', 'setuptools', 'distribute', 'wheel'}
+DEV_PKGS = {"pip", "setuptools", "distribute", "wheel"}
 
 if MYPY_CHECK_RUNNING:
     from optparse import Values
@@ -32,47 +32,55 @@ class FreezeCommand(Command):
     def add_options(self):
         # type: () -> None
         self.cmd_opts.add_option(
-            '-r', '--requirement',
-            dest='requirements',
-            action='append',
+            "-r",
+            "--requirement",
+            dest="requirements",
+            action="append",
             default=[],
-            metavar='file',
+            metavar="file",
             help="Use the order in the given requirements file and its "
-                 "comments when generating output. This option can be "
-                 "used multiple times.")
+            "comments when generating output. This option can be "
+            "used multiple times.",
+        )
         self.cmd_opts.add_option(
-            '-f', '--find-links',
-            dest='find_links',
-            action='append',
+            "-f",
+            "--find-links",
+            dest="find_links",
+            action="append",
             default=[],
-            metavar='URL',
-            help='URL for finding packages, which will be added to the '
-                 'output.')
+            metavar="URL",
+            help="URL for finding packages, which will be added to the " "output.",
+        )
         self.cmd_opts.add_option(
-            '-l', '--local',
-            dest='local',
-            action='store_true',
+            "-l",
+            "--local",
+            dest="local",
+            action="store_true",
             default=False,
-            help='If in a virtualenv that has global access, do not output '
-                 'globally-installed packages.')
+            help="If in a virtualenv that has global access, do not output "
+            "globally-installed packages.",
+        )
         self.cmd_opts.add_option(
-            '--user',
-            dest='user',
-            action='store_true',
+            "--user",
+            dest="user",
+            action="store_true",
             default=False,
-            help='Only output packages installed in user-site.')
+            help="Only output packages installed in user-site.",
+        )
         self.cmd_opts.add_option(cmdoptions.list_path())
         self.cmd_opts.add_option(
-            '--all',
-            dest='freeze_all',
-            action='store_true',
-            help='Do not skip these packages in the output:'
-                 ' {}'.format(', '.join(DEV_PKGS)))
+            "--all",
+            dest="freeze_all",
+            action="store_true",
+            help="Do not skip these packages in the output:"
+            " {}".format(", ".join(DEV_PKGS)),
+        )
         self.cmd_opts.add_option(
-            '--exclude-editable',
-            dest='exclude_editable',
-            action='store_true',
-            help='Exclude editable package from output.')
+            "--exclude-editable",
+            dest="exclude_editable",
+            action="store_true",
+            help="Exclude editable package from output.",
+        )
 
         self.parser.insert_option_group(0, self.cmd_opts)
 
@@ -99,5 +107,5 @@ def run(self, options, args):
         )
 
         for line in freeze(**freeze_kwargs):
-            sys.stdout.write(line + '\n')
+            sys.stdout.write(line + "\n")
         return SUCCESS
diff --git a/src/pip/_internal/commands/hash.py b/src/pip/_internal/commands/hash.py
index 37831c39522..d8f345ee991 100644
--- a/src/pip/_internal/commands/hash.py
+++ b/src/pip/_internal/commands/hash.py
@@ -25,19 +25,22 @@ class HashCommand(Command):
     installs.
     """
 
-    usage = '%prog [options] <file> ...'
+    usage = "%prog [options] <file> ..."
     ignore_require_venv = True
 
     def add_options(self):
         # type: () -> None
         self.cmd_opts.add_option(
-            '-a', '--algorithm',
-            dest='algorithm',
+            "-a",
+            "--algorithm",
+            dest="algorithm",
             choices=STRONG_HASHES,
-            action='store',
+            action="store",
             default=FAVORITE_HASH,
-            help='The hash algorithm to use: one of {}'.format(
-                 ', '.join(STRONG_HASHES)))
+            help="The hash algorithm to use: one of {}".format(
+                ", ".join(STRONG_HASHES)
+            ),
+        )
         self.parser.insert_option_group(0, self.cmd_opts)
 
     def run(self, options, args):
@@ -48,15 +51,16 @@ def run(self, options, args):
 
         algorithm = options.algorithm
         for path in args:
-            write_output('%s:\n--hash=%s:%s',
-                         path, algorithm, _hash_of_file(path, algorithm))
+            write_output(
+                "%s:\n--hash=%s:%s", path, algorithm, _hash_of_file(path, algorithm)
+            )
         return SUCCESS
 
 
 def _hash_of_file(path, algorithm):
     # type: (str, str) -> str
     """Return the hash digest of a file."""
-    with open(path, 'rb') as archive:
+    with open(path, "rb") as archive:
         hash = hashlib.new(algorithm)
         for chunk in read_chunks(archive):
             hash.update(chunk)
diff --git a/src/pip/_internal/commands/help.py b/src/pip/_internal/commands/help.py
index 2ab2b6d8f25..de4f6229328 100644
--- a/src/pip/_internal/commands/help.py
+++ b/src/pip/_internal/commands/help.py
@@ -38,7 +38,7 @@ def run(self, options, args):
             if guess:
                 msg.append('maybe you meant "{}"'.format(guess))
 
-            raise CommandError(' - '.join(msg))
+            raise CommandError(" - ".join(msg))
 
         command = create_command(cmd_name)
         command.parser.print_help()
diff --git a/src/pip/_internal/commands/install.py b/src/pip/_internal/commands/install.py
index e41660070a0..9ebbcf03541 100644
--- a/src/pip/_internal/commands/install.py
+++ b/src/pip/_internal/commands/install.py
@@ -90,87 +90,90 @@ def add_options(self):
 
         self.cmd_opts.add_option(cmdoptions.editable())
         self.cmd_opts.add_option(
-            '-t', '--target',
-            dest='target_dir',
-            metavar='dir',
+            "-t",
+            "--target",
+            dest="target_dir",
+            metavar="dir",
             default=None,
-            help='Install packages into <dir>. '
-                 'By default this will not replace existing files/folders in '
-                 '<dir>. Use --upgrade to replace existing packages in <dir> '
-                 'with new versions.'
+            help="Install packages into <dir>. "
+            "By default this will not replace existing files/folders in "
+            "<dir>. Use --upgrade to replace existing packages in <dir> "
+            "with new versions.",
         )
         cmdoptions.add_target_python_options(self.cmd_opts)
 
         self.cmd_opts.add_option(
-            '--user',
-            dest='use_user_site',
-            action='store_true',
+            "--user",
+            dest="use_user_site",
+            action="store_true",
             help="Install to the Python user install directory for your "
-                 "platform. Typically ~/.local/, or %APPDATA%\\Python on "
-                 "Windows. (See the Python documentation for site.USER_BASE "
-                 "for full details.)")
+            "platform. Typically ~/.local/, or %APPDATA%\\Python on "
+            "Windows. (See the Python documentation for site.USER_BASE "
+            "for full details.)",
+        )
         self.cmd_opts.add_option(
-            '--no-user',
-            dest='use_user_site',
-            action='store_false',
-            help=SUPPRESS_HELP)
+            "--no-user", dest="use_user_site", action="store_false", help=SUPPRESS_HELP
+        )
         self.cmd_opts.add_option(
-            '--root',
-            dest='root_path',
-            metavar='dir',
+            "--root",
+            dest="root_path",
+            metavar="dir",
             default=None,
-            help="Install everything relative to this alternate root "
-                 "directory.")
+            help="Install everything relative to this alternate root " "directory.",
+        )
         self.cmd_opts.add_option(
-            '--prefix',
-            dest='prefix_path',
-            metavar='dir',
+            "--prefix",
+            dest="prefix_path",
+            metavar="dir",
             default=None,
             help="Installation prefix where lib, bin and other top-level "
-                 "folders are placed")
+            "folders are placed",
+        )
 
         self.cmd_opts.add_option(cmdoptions.build_dir())
 
         self.cmd_opts.add_option(cmdoptions.src())
 
         self.cmd_opts.add_option(
-            '-U', '--upgrade',
-            dest='upgrade',
-            action='store_true',
-            help='Upgrade all specified packages to the newest available '
-                 'version. The handling of dependencies depends on the '
-                 'upgrade-strategy used.'
+            "-U",
+            "--upgrade",
+            dest="upgrade",
+            action="store_true",
+            help="Upgrade all specified packages to the newest available "
+            "version. The handling of dependencies depends on the "
+            "upgrade-strategy used.",
         )
 
         self.cmd_opts.add_option(
-            '--upgrade-strategy',
-            dest='upgrade_strategy',
-            default='only-if-needed',
-            choices=['only-if-needed', 'eager'],
-            help='Determines how dependency upgrading should be handled '
-                 '[default: %default]. '
-                 '"eager" - dependencies are upgraded regardless of '
-                 'whether the currently installed version satisfies the '
-                 'requirements of the upgraded package(s). '
-                 '"only-if-needed" -  are upgraded only when they do not '
-                 'satisfy the requirements of the upgraded package(s).'
+            "--upgrade-strategy",
+            dest="upgrade_strategy",
+            default="only-if-needed",
+            choices=["only-if-needed", "eager"],
+            help="Determines how dependency upgrading should be handled "
+            "[default: %default]. "
+            '"eager" - dependencies are upgraded regardless of '
+            "whether the currently installed version satisfies the "
+            "requirements of the upgraded package(s). "
+            '"only-if-needed" -  are upgraded only when they do not '
+            "satisfy the requirements of the upgraded package(s).",
         )
 
         self.cmd_opts.add_option(
-            '--force-reinstall',
-            dest='force_reinstall',
-            action='store_true',
-            help='Reinstall all packages even if they are already '
-                 'up-to-date.')
+            "--force-reinstall",
+            dest="force_reinstall",
+            action="store_true",
+            help="Reinstall all packages even if they are already " "up-to-date.",
+        )
 
         self.cmd_opts.add_option(
-            '-I', '--ignore-installed',
-            dest='ignore_installed',
-            action='store_true',
-            help='Ignore the installed packages, overwriting them. '
-                 'This can break your system if the existing package '
-                 'is of a different version or was installed '
-                 'with a different package manager!'
+            "-I",
+            "--ignore-installed",
+            dest="ignore_installed",
+            action="store_true",
+            help="Ignore the installed packages, overwriting them. "
+            "This can break your system if the existing package "
+            "is of a different version or was installed "
+            "with a different package manager!",
         )
 
         self.cmd_opts.add_option(cmdoptions.ignore_requires_python())
@@ -254,11 +257,11 @@ def run(self, options, args):
         if options.target_dir:
             options.ignore_installed = True
             options.target_dir = os.path.abspath(options.target_dir)
-            if (os.path.exists(options.target_dir) and not
-                    os.path.isdir(options.target_dir)):
+            if os.path.exists(options.target_dir) and not os.path.isdir(
+                options.target_dir
+            ):
                 raise CommandError(
-                    "Target path exists but is not a directory, will not "
-                    "continue."
+                    "Target path exists but is not a directory, will not " "continue."
                 )
 
             # Create a target directory for using with the target option
@@ -277,7 +280,7 @@ def run(self, options, args):
             target_python=target_python,
             ignore_requires_python=options.ignore_requires_python,
         )
-        build_delete = (not (options.no_clean or options.build_dir))
+        build_delete = not (options.no_clean or options.build_dir)
         wheel_cache = WheelCache(options.cache_dir, options.format_control)
 
         req_tracker = self.enter_context(get_requirement_tracker())
@@ -292,9 +295,7 @@ def run(self, options, args):
         try:
             reqs = self.get_requirements(args, options, finder, session)
 
-            reject_location_related_install_options(
-                reqs, options.install_options
-            )
+            reject_location_related_install_options(reqs, options.install_options)
 
             preparer = self.make_requirement_preparer(
                 temp_build_dir=directory,
@@ -331,19 +332,14 @@ def run(self, options, args):
                 # If we're not replacing an already installed pip,
                 # we're not modifying it.
                 modifying_pip = pip_req.satisfied_by is None
-            protect_pip_from_modification_on_windows(
-                modifying_pip=modifying_pip
-            )
+            protect_pip_from_modification_on_windows(modifying_pip=modifying_pip)
 
-            check_binary_allowed = get_check_binary_allowed(
-                finder.format_control
-            )
+            check_binary_allowed = get_check_binary_allowed(finder.format_control)
 
             reqs_to_build = [
-                r for r in requirement_set.requirements.values()
-                if should_build_for_install_command(
-                    r, check_binary_allowed
-                )
+                r
+                for r in requirement_set.requirements.values()
+                if should_build_for_install_command(r, check_binary_allowed)
             ]
 
             _, build_failures = build(
@@ -356,8 +352,7 @@ def run(self, options, args):
             # If we're using PEP 517, we cannot do a direct install
             # so we fail here.
             pep517_build_failure_names = [
-                r.name   # type: ignore
-                for r in build_failures if r.use_pep517
+                r.name for r in build_failures if r.use_pep517  # type: ignore
             ]  # type: List[str]
             if pep517_build_failure_names:
                 raise InstallationError(
@@ -374,15 +369,12 @@ def run(self, options, args):
                 if not r.use_pep517:
                     r.legacy_install_reason = 8368
 
-            to_install = resolver.get_installation_order(
-                requirement_set
-            )
+            to_install = resolver.get_installation_order(requirement_set)
 
             # Check for conflicts in the package set we're installing.
             conflicts = None  # type: Optional[ConflictDetails]
             should_warn_about_conflicts = (
-                not options.ignore_dependencies and
-                options.warn_about_conflicts
+                not options.ignore_dependencies and options.warn_about_conflicts
             )
             if should_warn_about_conflicts:
                 conflicts = self._determine_conflicts(to_install)
@@ -414,7 +406,7 @@ def run(self, options, args):
             )
             working_set = pkg_resources.WorkingSet(lib_locations)
 
-            installed.sort(key=operator.attrgetter('name'))
+            installed.sort(key=operator.attrgetter("name"))
             items = []
             for result in installed:
                 item = result.name
@@ -423,7 +415,7 @@ def run(self, options, args):
                         result.name, working_set=working_set
                     )
                     if installed_version:
-                        item += '-' + installed_version
+                        item += "-" + installed_version
                 except Exception:
                     pass
                 items.append(item)
@@ -431,19 +423,22 @@ def run(self, options, args):
             if conflicts is not None:
                 self._warn_about_conflicts(
                     conflicts,
-                    new_resolver='2020-resolver' in options.features_enabled,
+                    new_resolver="2020-resolver" in options.features_enabled,
                 )
 
-            installed_desc = ' '.join(items)
+            installed_desc = " ".join(items)
             if installed_desc:
                 write_output(
-                    'Successfully installed %s', installed_desc,
+                    "Successfully installed %s",
+                    installed_desc,
                 )
         except EnvironmentError as error:
-            show_traceback = (self.verbosity >= 1)
+            show_traceback = self.verbosity >= 1
 
             message = create_env_error_message(
-                error, show_traceback, options.use_user_site,
+                error,
+                show_traceback,
+                options.use_user_site,
             )
             logger.error(message, exc_info=show_traceback)  # noqa
 
@@ -467,10 +462,10 @@ def _handle_target_dir(self, target_dir, target_temp_dir, upgrade):
 
         # Checking both purelib and platlib directories for installed
         # packages to be moved to target directory
-        scheme = distutils_scheme('', home=target_temp_dir.path)
-        purelib_dir = scheme['purelib']
-        platlib_dir = scheme['platlib']
-        data_dir = scheme['data']
+        scheme = distutils_scheme("", home=target_temp_dir.path)
+        purelib_dir = scheme["purelib"]
+        platlib_dir = scheme["platlib"]
+        data_dir = scheme["data"]
 
         if os.path.exists(purelib_dir):
             lib_dir_list.append(purelib_dir)
@@ -489,18 +484,18 @@ def _handle_target_dir(self, target_dir, target_temp_dir, upgrade):
                 if os.path.exists(target_item_dir):
                     if not upgrade:
                         logger.warning(
-                            'Target directory %s already exists. Specify '
-                            '--upgrade to force replacement.',
-                            target_item_dir
+                            "Target directory %s already exists. Specify "
+                            "--upgrade to force replacement.",
+                            target_item_dir,
                         )
                         continue
                     if os.path.islink(target_item_dir):
                         logger.warning(
-                            'Target directory %s already exists and is '
-                            'a link. pip will not automatically replace '
-                            'links, please remove if replacement is '
-                            'desired.',
-                            target_item_dir
+                            "Target directory %s already exists and is "
+                            "a link. pip will not automatically replace "
+                            "links, please remove if replacement is "
+                            "desired.",
+                            target_item_dir,
                         )
                         continue
                     if os.path.isdir(target_item_dir):
@@ -508,10 +503,7 @@ def _handle_target_dir(self, target_dir, target_temp_dir, upgrade):
                     else:
                         os.remove(target_item_dir)
 
-                shutil.move(
-                    os.path.join(lib_dir, item),
-                    target_item_dir
-                )
+                shutil.move(os.path.join(lib_dir, item), target_item_dir)
 
     def _determine_conflicts(self, to_install):
         # type: (List[InstallRequirement]) -> Optional[ConflictDetails]
@@ -576,23 +568,24 @@ def _warn_about_conflicts(self, conflict_details, new_resolver):
 
 
 def get_lib_location_guesses(
-        user=False,  # type: bool
-        home=None,  # type: Optional[str]
-        root=None,  # type: Optional[str]
-        isolated=False,  # type: bool
-        prefix=None  # type: Optional[str]
+    user=False,  # type: bool
+    home=None,  # type: Optional[str]
+    root=None,  # type: Optional[str]
+    isolated=False,  # type: bool
+    prefix=None,  # type: Optional[str]
 ):
     # type:(...) -> List[str]
-    scheme = distutils_scheme('', user=user, home=home, root=root,
-                              isolated=isolated, prefix=prefix)
-    return [scheme['purelib'], scheme['platlib']]
+    scheme = distutils_scheme(
+        "", user=user, home=home, root=root, isolated=isolated, prefix=prefix
+    )
+    return [scheme["purelib"], scheme["platlib"]]
 
 
 def site_packages_writable(root, isolated):
     # type: (Optional[str], bool) -> bool
     return all(
-        test_writable_dir(d) for d in set(
-            get_lib_location_guesses(root=root, isolated=isolated))
+        test_writable_dir(d)
+        for d in set(get_lib_location_guesses(root=root, isolated=isolated))
     )
 
 
@@ -651,8 +644,10 @@ def decide_user_install(
         logger.debug("Non-user install because site-packages writeable")
         return False
 
-    logger.info("Defaulting to user installation because normal site-packages "
-                "is not writeable")
+    logger.info(
+        "Defaulting to user installation because normal site-packages "
+        "is not writeable"
+    )
     return True
 
 
@@ -661,6 +656,7 @@ def reject_location_related_install_options(requirements, options):
     """If any location-changing --install-option arguments were passed for
     requirements or on the command-line, then show a deprecation warning.
     """
+
     def format_options(option_names):
         # type: (Iterable[str]) -> List[str]
         return ["--{}".format(name.replace("_", "-")) for name in option_names]
@@ -681,9 +677,7 @@ def format_options(option_names):
         location_options = parse_distutils_args(options)
         if location_options:
             offenders.append(
-                "{!r} from command line".format(
-                    format_options(location_options.keys())
-                )
+                "{!r} from command line".format(format_options(location_options.keys()))
             )
 
     if not offenders:
@@ -692,9 +686,7 @@ def format_options(option_names):
     raise CommandError(
         "Location-changing options found in --install-option: {}."
         " This is unsupported, use pip-level options like --user,"
-        " --prefix, --root, and --target instead.".format(
-            "; ".join(offenders)
-        )
+        " --prefix, --root, and --target instead.".format("; ".join(offenders))
     )
 
 
@@ -724,10 +716,13 @@ def create_env_error_message(error, show_traceback, using_user_site):
         permissions_part = "Check the permissions"
 
         if not using_user_site:
-            parts.extend([
-                user_option_part, " or ",
-                permissions_part.lower(),
-            ])
+            parts.extend(
+                [
+                    user_option_part,
+                    " or ",
+                    permissions_part.lower(),
+                ]
+            )
         else:
             parts.append(permissions_part)
         parts.append(".\n")
diff --git a/src/pip/_internal/commands/list.py b/src/pip/_internal/commands/list.py
index a6dfa5fd578..1d9d13f52bf 100644
--- a/src/pip/_internal/commands/list.py
+++ b/src/pip/_internal/commands/list.py
@@ -47,76 +47,85 @@ class ListCommand(IndexGroupCommand):
     def add_options(self):
         # type: () -> None
         self.cmd_opts.add_option(
-            '-o', '--outdated',
-            action='store_true',
+            "-o",
+            "--outdated",
+            action="store_true",
             default=False,
-            help='List outdated packages')
+            help="List outdated packages",
+        )
         self.cmd_opts.add_option(
-            '-u', '--uptodate',
-            action='store_true',
+            "-u",
+            "--uptodate",
+            action="store_true",
             default=False,
-            help='List uptodate packages')
+            help="List uptodate packages",
+        )
         self.cmd_opts.add_option(
-            '-e', '--editable',
-            action='store_true',
+            "-e",
+            "--editable",
+            action="store_true",
             default=False,
-            help='List editable projects.')
+            help="List editable projects.",
+        )
         self.cmd_opts.add_option(
-            '-l', '--local',
-            action='store_true',
+            "-l",
+            "--local",
+            action="store_true",
             default=False,
-            help=('If in a virtualenv that has global access, do not list '
-                  'globally-installed packages.'),
+            help=(
+                "If in a virtualenv that has global access, do not list "
+                "globally-installed packages."
+            ),
         )
         self.cmd_opts.add_option(
-            '--user',
-            dest='user',
-            action='store_true',
+            "--user",
+            dest="user",
+            action="store_true",
             default=False,
-            help='Only output packages installed in user-site.')
+            help="Only output packages installed in user-site.",
+        )
         self.cmd_opts.add_option(cmdoptions.list_path())
         self.cmd_opts.add_option(
-            '--pre',
-            action='store_true',
+            "--pre",
+            action="store_true",
             default=False,
-            help=("Include pre-release and development versions. By default, "
-                  "pip only finds stable versions."),
+            help=(
+                "Include pre-release and development versions. By default, "
+                "pip only finds stable versions."
+            ),
         )
 
         self.cmd_opts.add_option(
-            '--format',
-            action='store',
-            dest='list_format',
+            "--format",
+            action="store",
+            dest="list_format",
             default="columns",
-            choices=('columns', 'freeze', 'json'),
+            choices=("columns", "freeze", "json"),
             help="Select the output format among: columns (default), freeze, "
-                 "or json",
+            "or json",
         )
 
         self.cmd_opts.add_option(
-            '--not-required',
-            action='store_true',
-            dest='not_required',
-            help="List packages that are not dependencies of "
-                 "installed packages.",
+            "--not-required",
+            action="store_true",
+            dest="not_required",
+            help="List packages that are not dependencies of " "installed packages.",
         )
 
         self.cmd_opts.add_option(
-            '--exclude-editable',
-            action='store_false',
-            dest='include_editable',
-            help='Exclude editable package from output.',
+            "--exclude-editable",
+            action="store_false",
+            dest="include_editable",
+            help="Exclude editable package from output.",
         )
         self.cmd_opts.add_option(
-            '--include-editable',
-            action='store_true',
-            dest='include_editable',
-            help='Include editable package from output.',
+            "--include-editable",
+            action="store_true",
+            dest="include_editable",
+            help="Include editable package from output.",
             default=True,
         )
-        index_opts = cmdoptions.make_option_group(
-            cmdoptions.index_group, self.parser
-        )
+        index_opts = cmdoptions.make_option_group(cmdoptions.index_group, self.parser)
 
         self.parser.insert_option_group(0, index_opts)
         self.parser.insert_option_group(0, self.cmd_opts)
@@ -142,8 +151,7 @@ def _build_package_finder(self, options, session):
     def run(self, options, args):
         # type: (Values, List[str]) -> int
         if options.outdated and options.uptodate:
-            raise CommandError(
-                "Options --outdated and --uptodate cannot be combined.")
+            raise CommandError("Options --outdated and --uptodate cannot be combined.")
 
         cmdoptions.check_list_path_option(options)
 
@@ -173,14 +181,16 @@ def run(self, options, args):
     def get_outdated(self, packages, options):
         # type: (List[Distribution], Values) -> List[Distribution]
         return [
-            dist for dist in self.iter_packages_latest_infos(packages, options)
+            dist
+            for dist in self.iter_packages_latest_infos(packages, options)
             if dist.latest_version > dist.parsed_version
         ]
 
     def get_uptodate(self, packages, options):
         # type: (List[Distribution], Values) -> List[Distribution]
         return [
-            dist for dist in self.iter_packages_latest_infos(packages, options)
+            dist
+            for dist in self.iter_packages_latest_infos(packages, options)
             if dist.latest_version == dist.parsed_version
         ]
 
@@ -205,8 +215,11 @@ def latest_info(dist):
                 all_candidates = finder.find_all_candidates(dist.key)
                 if not options.pre:
                     # Remove prereleases
-                    all_candidates = [candidate for candidate in all_candidates
-                                      if not candidate.version.is_prerelease]
+                    all_candidates = [
+                        candidate
+                        for candidate in all_candidates
+                        if not candidate.version.is_prerelease
+                    ]
 
                 evaluator = finder.make_candidate_evaluator(
                     project_name=dist.project_name,
@@ -217,9 +230,9 @@ def latest_info(dist):
 
                 remote_version = best_candidate.version
                 if best_candidate.link.is_wheel:
-                    typ = 'wheel'
+                    typ = "wheel"
                 else:
-                    typ = 'sdist'
+                    typ = "sdist"
                 # This is dirty but makes the rest of the code much cleaner
                 dist.latest_version = remote_version
                 dist.latest_filetype = typ
@@ -235,17 +248,18 @@ def output_package_listing(self, packages, options):
             packages,
             key=lambda dist: dist.project_name.lower(),
         )
-        if options.list_format == 'columns' and packages:
+        if options.list_format == "columns" and packages:
             data, header = format_for_columns(packages, options)
             self.output_package_listing_columns(data, header)
-        elif options.list_format == 'freeze':
+        elif options.list_format == "freeze":
             for dist in packages:
                 if options.verbose >= 1:
-                    write_output("%s==%s (%s)", dist.project_name,
-                                 dist.version, dist.location)
+                    write_output(
+                        "%s==%s (%s)", dist.project_name, dist.version, dist.location
+                    )
                 else:
                     write_output("%s==%s", dist.project_name, dist.version)
-        elif options.list_format == 'json':
+        elif options.list_format == "json":
             write_output(format_for_json(packages, options))
 
     def output_package_listing_columns(self, data, header):
@@ -258,7 +272,7 @@ def output_package_listing_columns(self, data, header):
 
         # Create and add a separator.
         if len(data) > 0:
-            pkg_strings.insert(1, " ".join(map(lambda x: '-' * x, sizes)))
+            pkg_strings.insert(1, " ".join(map(lambda x: "-" * x, sizes)))
 
         for val in pkg_strings:
             write_output(val)
@@ -307,14 +321,14 @@ def format_for_json(packages, options):
     data = []
     for dist in packages:
         info = {
-            'name': dist.project_name,
-            'version': six.text_type(dist.version),
+            "name": dist.project_name,
+            "version": six.text_type(dist.version),
         }
         if options.verbose >= 1:
-            info['location'] = dist.location
-            info['installer'] = get_installer(dist)
+            info["location"] = dist.location
+            info["installer"] = get_installer(dist)
         if options.outdated:
-            info['latest_version'] = six.text_type(dist.latest_version)
-            info['latest_filetype'] = dist.latest_filetype
+            info["latest_version"] = six.text_type(dist.latest_version)
+            info["latest_filetype"] = dist.latest_filetype
         data.append(info)
     return json.dumps(data)
diff --git a/src/pip/_internal/commands/search.py b/src/pip/_internal/commands/search.py
index ea4f47db5b5..2557efc8a73 100644
--- a/src/pip/_internal/commands/search.py
+++ b/src/pip/_internal/commands/search.py
@@ -7,6 +7,7 @@
 
 from pip._vendor import pkg_resources
 from pip._vendor.packaging.version import parse as parse_version
+
 # NOTE: XMLRPC Client is not annotated in typeshed as on 2017-07-17, which is
 #       why we ignore the type on this import
 from pip._vendor.six.moves import xmlrpc_client  # type: ignore
@@ -27,9 +28,10 @@
     from typing import Dict, List, Optional
 
     from typing_extensions import TypedDict
+
     TransformedHit = TypedDict(
-        'TransformedHit',
-        {'name': str, 'summary': str, 'versions': List[str]},
+        "TransformedHit",
+        {"name": str, "summary": str, "versions": List[str]},
     )
 
 logger = logging.getLogger(__name__)
@@ -45,18 +47,20 @@ class SearchCommand(Command, SessionCommandMixin):
     def add_options(self):
         # type: () -> None
         self.cmd_opts.add_option(
-            '-i', '--index',
-            dest='index',
-            metavar='URL',
+            "-i",
+            "--index",
+            dest="index",
+            metavar="URL",
             default=PyPI.pypi_url,
-            help='Base URL of Python Package Index (default %default)')
+            help="Base URL of Python Package Index (default %default)",
+        )
 
         self.parser.insert_option_group(0, self.cmd_opts)
 
     def run(self, options, args):
         # type: (Values, List[str]) -> int
         if not args:
-            raise CommandError('Missing required argument (search query).')
+            raise CommandError("Missing required argument (search query).")
         query = args
         pypi_hits = self.search(query, options)
         hits = transform_hits(pypi_hits)
@@ -78,7 +82,7 @@ def search(self, query, options):
 
         transport = PipXmlrpcTransport(index_url, session)
         pypi = xmlrpc_client.ServerProxy(index_url, transport)
-        hits = pypi.search({'name': query, 'summary': query}, 'or')
+        hits = pypi.search({"name": query, "summary": query}, "or")
         return hits
 
 
@@ -91,22 +95,22 @@ def transform_hits(hits):
     """
     packages = OrderedDict()  # type: OrderedDict[str, TransformedHit]
     for hit in hits:
-        name = hit['name']
-        summary = hit['summary']
-        version = hit['version']
+        name = hit["name"]
+        summary = hit["summary"]
+        version = hit["version"]
 
         if name not in packages.keys():
             packages[name] = {
-                'name': name,
-                'summary': summary,
-                'versions': [version],
+                "name": name,
+                "summary": summary,
+                "versions": [version],
             }
         else:
-            packages[name]['versions'].append(version)
+            packages[name]["versions"].append(version)
 
             # if this is the highest version, replace summary and score
-            if version == highest_version(packages[name]['versions']):
-                packages[name]['summary'] = summary
+            if version == highest_version(packages[name]["versions"]):
+                packages[name]["summary"] = summary
 
     return list(packages.values())
 
@@ -116,27 +120,31 @@ def print_results(hits, name_column_width=None, terminal_width=None):
     if not hits:
         return
     if name_column_width is None:
-        name_column_width = max([
-            len(hit['name']) + len(highest_version(hit.get('versions', ['-'])))
-            for hit in hits
-        ]) + 4
+        name_column_width = (
+            max(
+                [
+                    len(hit["name"]) + len(highest_version(hit.get("versions", ["-"])))
+                    for hit in hits
+                ]
+            )
+            + 4
+        )
 
     installed_packages = [p.project_name for p in pkg_resources.working_set]
     for hit in hits:
-        name = hit['name']
-        summary = hit['summary'] or ''
-        latest = highest_version(hit.get('versions', ['-']))
+        name = hit["name"]
+        summary = hit["summary"] or ""
+        latest = highest_version(hit.get("versions", ["-"]))
         if terminal_width is not None:
             target_width = terminal_width - name_column_width - 5
             if target_width > 10:
                 # wrap and indent summary to fit terminal
                 summary_lines = textwrap.wrap(summary, target_width)
-                summary = ('\n' + ' ' * (name_column_width + 3)).join(
-                    summary_lines)
+                summary = ("\n" + " " * (name_column_width + 3)).join(summary_lines)
 
-        line = '{name_latest:{name_column_width}} - {summary}'.format(
-            name_latest='{name} ({latest})'.format(**locals()),
-            **locals())
+        line = "{name_latest:{name_column_width}} - {summary}".format(
+            name_latest="{name} ({latest})".format(**locals()), **locals()
+        )
         try:
             write_output(line)
             if name in installed_packages:
@@ -144,14 +152,17 @@ def print_results(hits, name_column_width=None, terminal_width=None):
                 assert dist is not None
                 with indent_log():
                     if dist.version == latest:
-                        write_output('INSTALLED: %s (latest)', dist.version)
+                        write_output("INSTALLED: %s (latest)", dist.version)
                     else:
-                        write_output('INSTALLED: %s', dist.version)
+                        write_output("INSTALLED: %s", dist.version)
                         if parse_version(latest).pre:
-                            write_output('LATEST:    %s (pre-release; install'
-                                         ' with "pip install --pre")', latest)
+                            write_output(
+                                "LATEST:    %s (pre-release; install"
+                                ' with "pip install --pre")',
+                                latest,
+                            )
                         else:
-                            write_output('LATEST:    %s', latest)
+                            write_output("LATEST:    %s", latest)
         except UnicodeEncodeError:
             pass
 
diff --git a/src/pip/_internal/commands/show.py b/src/pip/_internal/commands/show.py
index b0b3f3abdcc..e40c0f4c53a 100644
--- a/src/pip/_internal/commands/show.py
+++ b/src/pip/_internal/commands/show.py
@@ -33,24 +33,27 @@ class ShowCommand(Command):
     def add_options(self):
         # type: () -> None
         self.cmd_opts.add_option(
-            '-f', '--files',
-            dest='files',
-            action='store_true',
+            "-f",
+            "--files",
+            dest="files",
+            action="store_true",
             default=False,
-            help='Show the full list of installed files for each package.')
+            help="Show the full list of installed files for each package.",
+        )
 
         self.parser.insert_option_group(0, self.cmd_opts)
 
     def run(self, options, args):
         # type: (Values, List[str]) -> int
         if not args:
-            logger.warning('ERROR: Please provide a package name or names.')
+            logger.warning("ERROR: Please provide a package name or names.")
             return ERROR
         query = args
 
         results = search_packages_info(query)
         if not print_results(
-                results, list_files=options.files, verbose=options.verbose):
+            results, list_files=options.files, verbose=options.verbose
+        ):
             return ERROR
         return SUCCESS
 
@@ -72,56 +75,56 @@ def search_packages_info(query):
         [name for name, pkg in zip(query, query_names) if pkg not in installed]
     )
     if missing:
-        logger.warning('Package(s) not found: %s', ', '.join(missing))
+        logger.warning("Package(s) not found: %s", ", ".join(missing))
 
     def get_requiring_packages(package_name):
         # type: (str) -> List[str]
         canonical_name = canonicalize_name(package_name)
         return [
-            pkg.project_name for pkg in pkg_resources.working_set
-            if canonical_name in
-               [canonicalize_name(required.name) for required in
-                pkg.requires()]
+            pkg.project_name
+            for pkg in pkg_resources.working_set
+            if canonical_name
+            in [canonicalize_name(required.name) for required in pkg.requires()]
         ]
 
     for dist in [installed[pkg] for pkg in query_names if pkg in installed]:
         package = {
-            'name': dist.project_name,
-            'version': dist.version,
-            'location': dist.location,
-            'requires': [dep.project_name for dep in dist.requires()],
-            'required_by': get_requiring_packages(dist.project_name)
+            "name": dist.project_name,
+            "version": dist.version,
+            "location": dist.location,
+            "requires": [dep.project_name for dep in dist.requires()],
+            "required_by": get_requiring_packages(dist.project_name),
         }
         file_list = None
-        metadata = ''
+        metadata = ""
         if isinstance(dist, pkg_resources.DistInfoDistribution):
             # RECORDs should be part of .dist-info metadatas
-            if dist.has_metadata('RECORD'):
-                lines = dist.get_metadata_lines('RECORD')
-                paths = [line.split(',')[0] for line in lines]
+            if dist.has_metadata("RECORD"):
+                lines = dist.get_metadata_lines("RECORD")
+                paths = [line.split(",")[0] for line in lines]
                 paths = [os.path.join(dist.location, p) for p in paths]
                 file_list = [os.path.relpath(p, dist.location) for p in paths]
 
-            if dist.has_metadata('METADATA'):
-                metadata = dist.get_metadata('METADATA')
+            if dist.has_metadata("METADATA"):
+                metadata = dist.get_metadata("METADATA")
         else:
             # Otherwise use pip's log for .egg-info's
-            if dist.has_metadata('installed-files.txt'):
-                paths = dist.get_metadata_lines('installed-files.txt')
+            if dist.has_metadata("installed-files.txt"):
+                paths = dist.get_metadata_lines("installed-files.txt")
                 paths = [os.path.join(dist.egg_info, p) for p in paths]
                 file_list = [os.path.relpath(p, dist.location) for p in paths]
 
-            if dist.has_metadata('PKG-INFO'):
-                metadata = dist.get_metadata('PKG-INFO')
+            if dist.has_metadata("PKG-INFO"):
+                metadata = dist.get_metadata("PKG-INFO")
 
-        if dist.has_metadata('entry_points.txt'):
-            entry_points = dist.get_metadata_lines('entry_points.txt')
-            package['entry_points'] = entry_points
+        if dist.has_metadata("entry_points.txt"):
+            entry_points = dist.get_metadata_lines("entry_points.txt")
+            package["entry_points"] = entry_points
 
-        if dist.has_metadata('INSTALLER'):
-            for line in dist.get_metadata_lines('INSTALLER'):
+        if dist.has_metadata("INSTALLER"):
+            for line in dist.get_metadata_lines("INSTALLER"):
                 if line.strip():
-                    package['installer'] = line.strip()
+                    package["installer"] = line.strip()
                     break
 
         # @todo: Should pkg_resources.Distribution have a
@@ -129,19 +132,25 @@ def get_requiring_packages(package_name):
         feed_parser = FeedParser()
         feed_parser.feed(metadata)
         pkg_info_dict = feed_parser.close()
-        for key in ('metadata-version', 'summary',
-                    'home-page', 'author', 'author-email', 'license'):
+        for key in (
+            "metadata-version",
+            "summary",
+            "home-page",
+            "author",
+            "author-email",
+            "license",
+        ):
             package[key] = pkg_info_dict.get(key)
 
         # It looks like FeedParser cannot deal with repeated headers
         classifiers = []
         for line in metadata.splitlines():
-            if line.startswith('Classifier: '):
-                classifiers.append(line[len('Classifier: '):])
-        package['classifiers'] = classifiers
+            if line.startswith("Classifier: "):
+                classifiers.append(line[len("Classifier: ") :])
+        package["classifiers"] = classifiers
 
         if file_list:
-            package['files'] = sorted(file_list)
+            package["files"] = sorted(file_list)
         yield package
 
 
@@ -156,30 +165,29 @@ def print_results(distributions, list_files=False, verbose=False):
         if i > 0:
             write_output("---")
 
-        write_output("Name: %s", dist.get('name', ''))
-        write_output("Version: %s", dist.get('version', ''))
-        write_output("Summary: %s", dist.get('summary', ''))
-        write_output("Home-page: %s", dist.get('home-page', ''))
-        write_output("Author: %s", dist.get('author', ''))
-        write_output("Author-email: %s", dist.get('author-email', ''))
-        write_output("License: %s", dist.get('license', ''))
-        write_output("Location: %s", dist.get('location', ''))
-        write_output("Requires: %s", ', '.join(dist.get('requires', [])))
-        write_output("Required-by: %s", ', '.join(dist.get('required_by', [])))
+        write_output("Name: %s", dist.get("name", ""))
+        write_output("Version: %s", dist.get("version", ""))
+        write_output("Summary: %s", dist.get("summary", ""))
+        write_output("Home-page: %s", dist.get("home-page", ""))
+        write_output("Author: %s", dist.get("author", ""))
+        write_output("Author-email: %s", dist.get("author-email", ""))
+        write_output("License: %s", dist.get("license", ""))
+        write_output("Location: %s", dist.get("location", ""))
+        write_output("Requires: %s", ", ".join(dist.get("requires", [])))
+        write_output("Required-by: %s", ", ".join(dist.get("required_by", [])))
 
         if verbose:
-            write_output("Metadata-Version: %s",
-                         dist.get('metadata-version', ''))
-            write_output("Installer: %s", dist.get('installer', ''))
+            write_output("Metadata-Version: %s", dist.get("metadata-version", ""))
+            write_output("Installer: %s", dist.get("installer", ""))
             write_output("Classifiers:")
-            for classifier in dist.get('classifiers', []):
+            for classifier in dist.get("classifiers", []):
                 write_output("  %s", classifier)
             write_output("Entry-points:")
-            for entry in dist.get('entry_points', []):
+            for entry in dist.get("entry_points", []):
                 write_output("  %s", entry.strip())
         if list_files:
             write_output("Files:")
-            for line in dist.get('files', []):
+            for line in dist.get("files", []):
                 write_output("  %s", line.strip())
             if "files" not in dist:
                 write_output("Cannot locate installed-files.txt")
diff --git a/src/pip/_internal/commands/uninstall.py b/src/pip/_internal/commands/uninstall.py
index 3371fe47ff1..97f045f629b 100644
--- a/src/pip/_internal/commands/uninstall.py
+++ b/src/pip/_internal/commands/uninstall.py
@@ -37,19 +37,22 @@ class UninstallCommand(Command, SessionCommandMixin):
     def add_options(self):
         # type: () -> None
         self.cmd_opts.add_option(
-            '-r', '--requirement',
-            dest='requirements',
-            action='append',
+            "-r",
+            "--requirement",
+            dest="requirements",
+            action="append",
             default=[],
-            metavar='file',
-            help='Uninstall all the packages listed in the given requirements '
-                 'file.  This option can be used multiple times.',
+            metavar="file",
+            help="Uninstall all the packages listed in the given requirements "
+            "file.  This option can be used multiple times.",
         )
         self.cmd_opts.add_option(
-            '-y', '--yes',
-            dest='yes',
-            action='store_true',
-            help="Don't ask for confirmation of uninstall deletions.")
+            "-y",
+            "--yes",
+            dest="yes",
+            action="store_true",
+            help="Don't ask for confirmation of uninstall deletions.",
+        )
 
         self.parser.insert_option_group(0, self.cmd_opts)
 
@@ -60,24 +63,23 @@ def run(self, options, args):
         reqs_to_uninstall = {}
         for name in args:
             req = install_req_from_line(
-                name, isolated=options.isolated_mode,
+                name,
+                isolated=options.isolated_mode,
             )
             if req.name:
                 reqs_to_uninstall[canonicalize_name(req.name)] = req
         for filename in options.requirements:
             for parsed_req in parse_requirements(
-                    filename,
-                    options=options,
-                    session=session):
+                filename, options=options, session=session
+            ):
                 req = install_req_from_parsed_requirement(
-                    parsed_req,
-                    isolated=options.isolated_mode
+                    parsed_req, isolated=options.isolated_mode
                 )
                 if req.name:
                     reqs_to_uninstall[canonicalize_name(req.name)] = req
         if not reqs_to_uninstall:
             raise InstallationError(
-                'You must give at least one requirement to {self.name} (see '
+                "You must give at least one requirement to {self.name} (see "
                 '"pip help {self.name}")'.format(**locals())
             )
 
@@ -87,7 +89,8 @@ def run(self, options, args):
 
         for req in reqs_to_uninstall.values():
             uninstall_pathset = req.uninstall(
-                auto_confirm=options.yes, verbose=self.verbosity > 0,
+                auto_confirm=options.yes,
+                verbose=self.verbosity > 0,
             )
             if uninstall_pathset:
                 uninstall_pathset.commit()
diff --git a/src/pip/_internal/commands/wheel.py b/src/pip/_internal/commands/wheel.py
index 0f718566bd0..7a0e484d514 100644
--- a/src/pip/_internal/commands/wheel.py
+++ b/src/pip/_internal/commands/wheel.py
@@ -51,21 +51,24 @@ def add_options(self):
         # type: () -> None
 
         self.cmd_opts.add_option(
-            '-w', '--wheel-dir',
-            dest='wheel_dir',
-            metavar='dir',
+            "-w",
+            "--wheel-dir",
+            dest="wheel_dir",
+            metavar="dir",
             default=os.curdir,
-            help=("Build wheels into <dir>, where the default is the "
-                  "current working directory."),
+            help=(
+                "Build wheels into <dir>, where the default is the "
+                "current working directory."
+            ),
         )
         self.cmd_opts.add_option(cmdoptions.no_binary())
         self.cmd_opts.add_option(cmdoptions.only_binary())
         self.cmd_opts.add_option(cmdoptions.prefer_binary())
         self.cmd_opts.add_option(
-            '--build-option',
-            dest='build_options',
-            metavar='options',
-            action='append',
+            "--build-option",
+            dest="build_options",
+            metavar="options",
+            action="append",
             help="Extra arguments to be supplied to 'setup.py bdist_wheel'.",
         )
         self.cmd_opts.add_option(cmdoptions.no_build_isolation())
@@ -81,19 +84,22 @@ def add_options(self):
         self.cmd_opts.add_option(cmdoptions.progress_bar())
 
         self.cmd_opts.add_option(
-            '--global-option',
-            dest='global_options',
-            action='append',
-            metavar='options',
+            "--global-option",
+            dest="global_options",
+            action="append",
+            metavar="options",
             help="Extra global options to be supplied to the setup.py "
-            "call before the 'bdist_wheel' command.")
+            "call before the 'bdist_wheel' command.",
+        )
 
         self.cmd_opts.add_option(
-            '--pre',
-            action='store_true',
+            "--pre",
+            action="store_true",
             default=False,
-            help=("Include pre-release and development versions. By default, "
-                  "pip only finds stable versions."),
+            help=(
+                "Include pre-release and development versions. By default, "
+                "pip only finds stable versions."
+            ),
         )
 
         self.cmd_opts.add_option(cmdoptions.require_hashes())
@@ -114,7 +120,7 @@ def run(self, options, args):
         session = self.get_default_session(options)
 
         finder = self._build_package_finder(options, session)
-        build_delete = (not (options.no_clean or options.build_dir))
+        build_delete = not (options.no_clean or options.build_dir)
         wheel_cache = WheelCache(options.cache_dir, options.format_control)
 
         options.wheel_dir = normalize_path(options.wheel_dir)
@@ -152,12 +158,11 @@ def run(self, options, args):
 
         self.trace_basic_info(finder)
 
-        requirement_set = resolver.resolve(
-            reqs, check_supported_wheels=True
-        )
+        requirement_set = resolver.resolve(reqs, check_supported_wheels=True)
 
         reqs_to_build = [
-            r for r in requirement_set.requirements.values()
+            r
+            for r in requirement_set.requirements.values()
             if should_build_for_wheel_command(r)
         ]
 
@@ -177,12 +182,11 @@ def run(self, options, args):
             except OSError as e:
                 logger.warning(
                     "Building wheel for %s failed: %s",
-                    req.name, e,
+                    req.name,
+                    e,
                 )
                 build_failures.append(req)
         if len(build_failures) != 0:
-            raise CommandError(
-                "Failed to build one or more wheels"
-            )
+            raise CommandError("Failed to build one or more wheels")
 
         return SUCCESS
diff --git a/src/pip/_internal/configuration.py b/src/pip/_internal/configuration.py
index 23614fd2bbe..6c2a57d86c6 100644
--- a/src/pip/_internal/configuration.py
+++ b/src/pip/_internal/configuration.py
@@ -33,15 +33,15 @@
     RawConfigParser = configparser.RawConfigParser  # Shorthand
     Kind = NewType("Kind", str)
 
-CONFIG_BASENAME = 'pip.ini' if WINDOWS else 'pip.conf'
+CONFIG_BASENAME = "pip.ini" if WINDOWS else "pip.conf"
 ENV_NAMES_IGNORED = "version", "help"
 
 # The kinds of configurations there are.
 kinds = enum(
-    USER="user",        # User Specific
-    GLOBAL="global",    # System Wide
-    SITE="site",        # [Virtual] Environment Specific
-    ENV="env",          # from PIP_CONFIG_FILE
+    USER="user",  # User Specific
+    GLOBAL="global",  # System Wide
+    SITE="site",  # [Virtual] Environment Specific
+    ENV="env",  # from PIP_CONFIG_FILE
     ENV_VAR="env-var",  # from Environment Variables
 )
 OVERRIDE_ORDER = kinds.GLOBAL, kinds.USER, kinds.SITE, kinds.ENV, kinds.ENV_VAR
@@ -53,10 +53,9 @@
 # NOTE: Maybe use the optionx attribute to normalize keynames.
 def _normalize_name(name):
     # type: (str) -> str
-    """Make a name consistent regardless of source (environment or file)
-    """
-    name = name.lower().replace('_', '-')
-    if name.startswith('--'):
+    """Make a name consistent regardless of source (environment or file)"""
+    name = name.lower().replace("_", "-")
+    if name.startswith("--"):
         name = name[2:]  # only prefer long opts
     return name
 
@@ -75,19 +74,16 @@ def _disassemble_key(name):
 def get_configuration_files():
     # type: () -> Dict[Kind, List[str]]
     global_config_files = [
-        os.path.join(path, CONFIG_BASENAME)
-        for path in appdirs.site_config_dirs('pip')
+        os.path.join(path, CONFIG_BASENAME) for path in appdirs.site_config_dirs("pip")
     ]
 
     site_config_file = os.path.join(sys.prefix, CONFIG_BASENAME)
     legacy_config_file = os.path.join(
-        expanduser('~'),
-        'pip' if WINDOWS else '.pip',
+        expanduser("~"),
+        "pip" if WINDOWS else ".pip",
         CONFIG_BASENAME,
     )
-    new_config_file = os.path.join(
-        appdirs.user_config_dir("pip"), CONFIG_BASENAME
-    )
+    new_config_file = os.path.join(appdirs.user_config_dir("pip"), CONFIG_BASENAME)
     return {
         kinds.GLOBAL: global_config_files,
         kinds.SITE: [site_config_file],
@@ -133,18 +129,15 @@ def __init__(self, isolated, load_only=None):
 
     def load(self):
         # type: () -> None
-        """Loads configuration from configuration files and environment
-        """
+        """Loads configuration from configuration files and environment"""
         self._load_config_files()
         if not self.isolated:
             self._load_environment_vars()
 
     def get_file_to_edit(self):
         # type: () -> Optional[str]
-        """Returns the file with highest priority in configuration
-        """
-        assert self.load_only is not None, \
-            "Need to be specified a file to be editing"
+        """Returns the file with highest priority in configuration"""
+        assert self.load_only is not None, "Need to be specified a file to be editing"
 
         try:
             return self._get_parser_to_modify()[0]
@@ -160,8 +153,7 @@ def items(self):
 
     def get_value(self, key):
         # type: (str) -> Any
-        """Get a value from the configuration.
-        """
+        """Get a value from the configuration."""
         try:
             return self._dictionary[key]
         except KeyError:
@@ -169,8 +161,7 @@ def get_value(self, key):
 
     def set_value(self, key, value):
         # type: (str, Any) -> None
-        """Modify a value in the configuration.
-        """
+        """Modify a value in the configuration."""
         self._ensure_have_load_only()
 
         assert self.load_only
@@ -200,8 +191,9 @@ def unset_value(self, key):
 
         if parser is not None:
             section, name = _disassemble_key(key)
-            if not (parser.has_section(section)
-                    and parser.remove_option(section, name)):
+            if not (
+                parser.has_section(section) and parser.remove_option(section, name)
+            ):
                 # The option was not removed.
                 raise ConfigurationError(
                     "Fatal Internal error [id=1]. Please report as a bug."
@@ -216,8 +208,7 @@ def unset_value(self, key):
 
     def save(self):
         # type: () -> None
-        """Save the current in-memory state.
-        """
+        """Save the current in-memory state."""
         self._ensure_have_load_only()
 
         for fname, parser in self._modified_parsers:
@@ -242,8 +233,7 @@ def _ensure_have_load_only(self):
     @property
     def _dictionary(self):
         # type: () -> Dict[str, Any]
-        """A dictionary representing the loaded configuration.
-        """
+        """A dictionary representing the loaded configuration."""
         # NOTE: Dictionaries are not populated if not loaded. So, conditionals
         #       are not needed here.
         retval = {}
@@ -255,8 +245,7 @@ def _dictionary(self):
 
     def _load_config_files(self):
         # type: () -> None
-        """Loads configuration from configuration files
-        """
+        """Loads configuration from configuration files"""
         config_files = dict(self.iter_config_files())
         if config_files[kinds.ENV][0:1] == [os.devnull]:
             logger.debug(
@@ -270,9 +259,7 @@ def _load_config_files(self):
                 # If there's specific variant set in `load_only`, load only
                 # that variant, not the others.
                 if self.load_only is not None and variant != self.load_only:
-                    logger.debug(
-                        "Skipping file '%s' (variant: %s)", fname, variant
-                    )
+                    logger.debug("Skipping file '%s' (variant: %s)", fname, variant)
                     continue
 
                 parser = self._load_file(variant, fname)
@@ -316,8 +303,7 @@ def _construct_parser(self, fname):
 
     def _load_environment_vars(self):
         # type: () -> None
-        """Loads configuration from environment variables
-        """
+        """Loads configuration from environment variables"""
         self._config[kinds.ENV_VAR].update(
             self._normalized_keys(":env:", self.get_environ_vars())
         )
@@ -354,7 +340,7 @@ def iter_config_files(self):
         # SMELL: Move the conditions out of this function
 
         # environment variables have the lowest priority
-        config_file = os.environ.get('PIP_CONFIG_FILE', None)
+        config_file = os.environ.get("PIP_CONFIG_FILE", None)
         if config_file is not None:
             yield kinds.ENV, [config_file]
         else:
diff --git a/src/pip/_internal/distributions/__init__.py b/src/pip/_internal/distributions/__init__.py
index d5c1afc5bc1..a2fece38bfe 100644
--- a/src/pip/_internal/distributions/__init__.py
+++ b/src/pip/_internal/distributions/__init__.py
@@ -9,8 +9,7 @@
 
 def make_distribution_for_install_requirement(install_req):
     # type: (InstallRequirement) -> AbstractDistribution
-    """Returns a Distribution for the given InstallRequirement
-    """
+    """Returns a Distribution for the given InstallRequirement"""
     # Editable requirements will always be source distributions. They use the
     # legacy logic until we create a modern standard for them.
     if install_req.editable:
diff --git a/src/pip/_internal/distributions/sdist.py b/src/pip/_internal/distributions/sdist.py
index 06b9df09cbe..426816269d3 100644
--- a/src/pip/_internal/distributions/sdist.py
+++ b/src/pip/_internal/distributions/sdist.py
@@ -51,10 +51,10 @@ def _raise_conflicts(conflicting_with, conflicting_reqs):
             error_message = format_string.format(
                 requirement=self.req,
                 conflicting_with=conflicting_with,
-                description=', '.join(
-                    '{} is incompatible with {}'.format(installed, wanted)
+                description=", ".join(
+                    "{} is incompatible with {}".format(installed, wanted)
                     for installed, wanted in sorted(conflicting)
-                )
+                ),
             )
             raise InstallationError(error_message)
 
@@ -65,15 +65,13 @@ def _raise_conflicts(conflicting_with, conflicting_reqs):
 
         self.req.build_env = BuildEnvironment()
         self.req.build_env.install_requirements(
-            finder, pyproject_requires, 'overlay',
-            "Installing build dependencies"
+            finder, pyproject_requires, "overlay", "Installing build dependencies"
         )
         conflicting, missing = self.req.build_env.check_requirements(
             self.req.requirements_to_check
         )
         if conflicting:
-            _raise_conflicts("PEP 517/518 supported requirements",
-                             conflicting)
+            _raise_conflicts("PEP 517/518 supported requirements", conflicting)
         if missing:
             logger.warning(
                 "Missing build requirements in pyproject.toml for %s.",
@@ -82,15 +80,13 @@ def _raise_conflicts(conflicting_with, conflicting_reqs):
             logger.warning(
                 "The project does not specify a build backend, and "
                 "pip cannot fall back to setuptools without %s.",
-                " and ".join(map(repr, sorted(missing)))
+                " and ".join(map(repr, sorted(missing))),
             )
         # Install any extra build dependencies that the backend requests.
         # This must be done in a second pass, as the pyproject.toml
         # dependencies must be installed before we can call the backend.
         with self.req.build_env:
-            runner = runner_with_spinner_message(
-                "Getting requirements to build wheel"
-            )
+            runner = runner_with_spinner_message("Getting requirements to build wheel")
             backend = self.req.pep517_backend
             assert backend is not None
             with backend.subprocess_runner(runner):
@@ -100,6 +96,5 @@ def _raise_conflicts(conflicting_with, conflicting_reqs):
         if conflicting:
             _raise_conflicts("the backend dependencies", conflicting)
         self.req.build_env.install_requirements(
-            finder, missing, 'normal',
-            "Installing backend dependencies"
+            finder, missing, "normal", "Installing backend dependencies"
         )
diff --git a/src/pip/_internal/exceptions.py b/src/pip/_internal/exceptions.py
index 62bde1eeda4..067bc4b8cb9 100644
--- a/src/pip/_internal/exceptions.py
+++ b/src/pip/_internal/exceptions.py
@@ -63,10 +63,9 @@ def __str__(self):
         # type: () -> str
         # Use `dist` in the error message because its stringification
         # includes more information, like the version and location.
-        return (
-            'None {} metadata found for distribution: {}'.format(
-                self.metadata_name, self.dist,
-            )
+        return "None {} metadata found for distribution: {}".format(
+            self.metadata_name,
+            self.dist,
         )
 
 
@@ -112,11 +111,13 @@ def __init__(self, error_msg, response=None, request=None):
         self.response = response
         self.request = request
         self.error_msg = error_msg
-        if (self.response is not None and not self.request and
-                hasattr(response, 'request')):
+        if (
+            self.response is not None
+            and not self.request
+            and hasattr(response, "request")
+        ):
             self.request = self.response.request
-        super(NetworkConnectionError, self).__init__(
-            error_msg, response, request)
+        super(NetworkConnectionError, self).__init__(error_msg, response, request)
 
     def __str__(self):
         # type: () -> str
@@ -138,6 +139,7 @@ class MetadataInconsistent(InstallationError):
     that do not match the information previously obtained from sdist filename
     or user-supplied ``#egg=`` value.
     """
+
     def __init__(self, ireq, field, built):
         # type: (InstallRequirement, str, Any) -> None
         self.ireq = ireq
@@ -147,7 +149,9 @@ def __init__(self, ireq, field, built):
     def __str__(self):
         # type: () -> str
         return "Requested {} has different {} in metadata: {!r}".format(
-            self.ireq, self.field, self.built,
+            self.ireq,
+            self.field,
+            self.built,
         )
 
 
@@ -170,8 +174,8 @@ def __str__(self):
             lines.append(cls.head)
             lines.extend(e.body() for e in errors_of_cls)
         if lines:
-            return '\n'.join(lines)
-        return ''
+            return "\n".join(lines)
+        return ""
 
     def __nonzero__(self):
         # type: () -> bool
@@ -198,8 +202,9 @@ class HashError(InstallationError):
         typically available earlier.
 
     """
+
     req = None  # type: Optional[InstallRequirement]
-    head = ''
+    head = ""
     order = None  # type: Optional[int]
 
     def body(self):
@@ -213,11 +218,11 @@ def body(self):
             its link already populated by the resolver's _populate_link().
 
         """
-        return '    {}'.format(self._requirement_name())
+        return "    {}".format(self._requirement_name())
 
     def __str__(self):
         # type: () -> str
-        return '{}\n{}'.format(self.head, self.body())
+        return "{}\n{}".format(self.head, self.body())
 
     def _requirement_name(self):
         # type: () -> str
@@ -227,7 +232,7 @@ def _requirement_name(self):
         line numbers
 
         """
-        return str(self.req) if self.req else 'unknown package'
+        return str(self.req) if self.req else "unknown package"
 
 
 class VcsHashUnsupported(HashError):
@@ -235,8 +240,10 @@ class VcsHashUnsupported(HashError):
     we don't have a method for hashing those."""
 
     order = 0
-    head = ("Can't verify hashes for these requirements because we don't "
-            "have a way to hash version control repositories:")
+    head = (
+        "Can't verify hashes for these requirements because we don't "
+        "have a way to hash version control repositories:"
+    )
 
 
 class DirectoryUrlHashUnsupported(HashError):
@@ -244,21 +251,25 @@ class DirectoryUrlHashUnsupported(HashError):
     we don't have a method for hashing those."""
 
     order = 1
-    head = ("Can't verify hashes for these file:// requirements because they "
-            "point to directories:")
+    head = (
+        "Can't verify hashes for these file:// requirements because they "
+        "point to directories:"
+    )
 
 
 class HashMissing(HashError):
     """A hash was needed for a requirement but is absent."""
 
     order = 2
-    head = ('Hashes are required in --require-hashes mode, but they are '
-            'missing from some requirements. Here is a list of those '
-            'requirements along with the hashes their downloaded archives '
-            'actually had. Add lines like these to your requirements files to '
-            'prevent tampering. (If you did not enable --require-hashes '
-            'manually, note that it turns on automatically when any package '
-            'has a hash.)')
+    head = (
+        "Hashes are required in --require-hashes mode, but they are "
+        "missing from some requirements. Here is a list of those "
+        "requirements along with the hashes their downloaded archives "
+        "actually had. Add lines like these to your requirements files to "
+        "prevent tampering. (If you did not enable --require-hashes "
+        "manually, note that it turns on automatically when any package "
+        "has a hash.)"
+    )
 
     def __init__(self, gotten_hash):
         # type: (str) -> None
@@ -278,13 +289,16 @@ def body(self):
             # In the case of URL-based requirements, display the original URL
             # seen in the requirements file rather than the package name,
             # so the output can be directly copied into the requirements file.
-            package = (self.req.original_link if self.req.original_link
-                       # In case someone feeds something downright stupid
-                       # to InstallRequirement's constructor.
-                       else getattr(self.req, 'req', None))
-        return '    {} --hash={}:{}'.format(package or 'unknown package',
-                                            FAVORITE_HASH,
-                                            self.gotten_hash)
+            package = (
+                self.req.original_link
+                if self.req.original_link
+                # In case someone feeds something downright stupid
+                # to InstallRequirement's constructor.
+                else getattr(self.req, "req", None)
+            )
+        return "    {} --hash={}:{}".format(
+            package or "unknown package", FAVORITE_HASH, self.gotten_hash
+        )
 
 
 class HashUnpinned(HashError):
@@ -292,8 +306,10 @@ class HashUnpinned(HashError):
     version."""
 
     order = 3
-    head = ('In --require-hashes mode, all requirements must have their '
-            'versions pinned with ==. These do not:')
+    head = (
+        "In --require-hashes mode, all requirements must have their "
+        "versions pinned with ==. These do not:"
+    )
 
 
 class HashMismatch(HashError):
@@ -305,11 +321,14 @@ class HashMismatch(HashError):
         improve its error message.
 
     """
+
     order = 4
-    head = ('THESE PACKAGES DO NOT MATCH THE HASHES FROM THE REQUIREMENTS '
-            'FILE. If you have updated the package versions, please update '
-            'the hashes. Otherwise, examine the package contents carefully; '
-            'someone may have tampered with them.')
+    head = (
+        "THESE PACKAGES DO NOT MATCH THE HASHES FROM THE REQUIREMENTS "
+        "FILE. If you have updated the package versions, please update "
+        "the hashes. Otherwise, examine the package contents carefully; "
+        "someone may have tampered with them."
+    )
 
     def __init__(self, allowed, gots):
         # type: (Dict[str, List[str]], Dict[str, _Hash]) -> None
@@ -324,8 +343,7 @@ def __init__(self, allowed, gots):
 
     def body(self):
         # type: () -> str
-        return '    {}:\n{}'.format(self._requirement_name(),
-                                    self._hash_comparison())
+        return "    {}:\n{}".format(self._requirement_name(), self._hash_comparison())
 
     def _hash_comparison(self):
         # type: () -> str
@@ -339,20 +357,23 @@ def _hash_comparison(self):
                     Got        bcdefbcdefbcdefbcdefbcdefbcdefbcdefbcdefbcdef
 
         """
+
         def hash_then_or(hash_name):
             # type: (str) -> chain[str]
             # For now, all the decent hashes have 6-char names, so we can get
             # away with hard-coding space literals.
-            return chain([hash_name], repeat('    or'))
+            return chain([hash_name], repeat("    or"))
 
         lines = []  # type: List[str]
         for hash_name, expecteds in iteritems(self.allowed):
             prefix = hash_then_or(hash_name)
-            lines.extend(('        Expected {} {}'.format(next(prefix), e))
-                         for e in expecteds)
-            lines.append('             Got        {}\n'.format(
-                         self.gots[hash_name].hexdigest()))
-        return '\n'.join(lines)
+            lines.extend(
+                ("        Expected {} {}".format(next(prefix), e)) for e in expecteds
+            )
+            lines.append(
+                "             Got        {}\n".format(self.gots[hash_name].hexdigest())
+            )
+        return "\n".join(lines)
 
 
 class UnsupportedPythonVersion(InstallationError):
@@ -361,8 +382,7 @@ class UnsupportedPythonVersion(InstallationError):
 
 
 class ConfigurationFileCouldNotBeLoaded(ConfigurationError):
-    """When there are errors while loading a configuration file
-    """
+    """When there are errors while loading a configuration file"""
 
     def __init__(self, reason="could not be loaded", fname=None, error=None):
         # type: (str, Optional[str], Optional[configparser.Error]) -> None
diff --git a/src/pip/_internal/index/collector.py b/src/pip/_internal/index/collector.py
index e6230c76734..cb84985cd30 100644
--- a/src/pip/_internal/index/collector.py
+++ b/src/pip/_internal/index/collector.py
@@ -51,7 +51,7 @@
     ResponseHeaders = MutableMapping[str, str]
 
     # Used in the @lru_cache polyfill.
-    F = TypeVar('F')
+    F = TypeVar("F")
 
     class LruCache(Protocol):
         def __call__(self, maxsize=None):
@@ -69,6 +69,7 @@ def noop_lru_cache(maxsize=None):
     def _wrapper(f):
         # type: (F) -> F
         return f
+
     return _wrapper
 
 
@@ -82,15 +83,14 @@ def _match_vcs_scheme(url):
     Returns the matched VCS scheme, or None if there's no match.
     """
     for scheme in vcs.schemes:
-        if url.lower().startswith(scheme) and url[len(scheme)] in '+:':
+        if url.lower().startswith(scheme) and url[len(scheme)] in "+:":
             return scheme
     return None
 
 
 def _is_url_like_archive(url):
     # type: (str) -> bool
-    """Return whether the URL looks like an archive.
-    """
+    """Return whether the URL looks like an archive."""
     filename = Link(url).filename
     for bad_ext in ARCHIVE_EXTENSIONS:
         if filename.endswith(bad_ext):
@@ -129,7 +129,7 @@ def _ensure_html_response(url, session):
     `_NotHTML` if the content type is not text/html.
     """
     scheme, netloc, path, query, fragment = urllib_parse.urlsplit(url)
-    if scheme not in {'http', 'https'}:
+    if scheme not in {"http", "https"}:
         raise _NotHTTP()
 
     resp = session.head(url, allow_redirects=True)
@@ -155,7 +155,7 @@ def _get_html_response(url, session):
     if _is_url_like_archive(url):
         _ensure_html_response(url, session=session)
 
-    logger.debug('Getting page %s', redact_auth_from_url(url))
+    logger.debug("Getting page %s", redact_auth_from_url(url))
 
     resp = session.get(
         url,
@@ -191,12 +191,11 @@ def _get_html_response(url, session):
 
 def _get_encoding_from_headers(headers):
     # type: (ResponseHeaders) -> Optional[str]
-    """Determine if we have any encoding information in our headers.
-    """
+    """Determine if we have any encoding information in our headers."""
     if headers and "Content-Type" in headers:
         content_type, params = cgi.parse_header(headers["Content-Type"])
         if "charset" in params:
-            return params['charset']
+            return params["charset"]
     return None
 
 
@@ -244,7 +243,7 @@ def _clean_file_url_path(part):
 
 
 # percent-encoded:                   /
-_reserved_chars_re = re.compile('(@|%2F)', re.IGNORECASE)
+_reserved_chars_re = re.compile("(@|%2F)", re.IGNORECASE)
 
 
 def _clean_url_path(path, is_local_path):
@@ -262,12 +261,12 @@ def _clean_url_path(path, is_local_path):
     parts = _reserved_chars_re.split(path)
 
     cleaned_parts = []
-    for to_clean, reserved in pairwise(itertools.chain(parts, [''])):
+    for to_clean, reserved in pairwise(itertools.chain(parts, [""])):
         cleaned_parts.append(clean_func(to_clean))
         # Normalize %xx escapes (e.g. %2f -> %2F)
         cleaned_parts.append(reserved.upper())
 
-    return ''.join(cleaned_parts)
+    return "".join(cleaned_parts)
 
 
 def _clean_link(url):
@@ -287,7 +286,7 @@ def _clean_link(url):
 
 
 def _create_link_from_element(
-    anchor,    # type: HTMLElement
+    anchor,  # type: HTMLElement
     page_url,  # type: str
     base_url,  # type: str
 ):
@@ -300,10 +299,10 @@ def _create_link_from_element(
         return None
 
     url = _clean_link(urllib_parse.urljoin(base_url, href))
-    pyrequire = anchor.get('data-requires-python')
+    pyrequire = anchor.get("data-requires-python")
     pyrequire = unescape(pyrequire) if pyrequire else None
 
-    yanked_reason = anchor.get('data-yanked')
+    yanked_reason = anchor.get("data-yanked")
     if yanked_reason:
         # This is a unicode string in Python 2 (and 3).
         yanked_reason = unescape(yanked_reason)
@@ -326,8 +325,7 @@ def __init__(self, page):
 
     def __eq__(self, other):
         # type: (object) -> bool
-        return (isinstance(other, type(self)) and
-                self.page.url == other.page.url)
+        return isinstance(other, type(self)) and self.page.url == other.page.url
 
     def __hash__(self):
         # type: () -> int
@@ -335,7 +333,7 @@ def __hash__(self):
 
 
 def with_cached_html_pages(
-    fn,    # type: Callable[[HTMLPage], Iterable[Link]]
+    fn,  # type: Callable[[HTMLPage], Iterable[Link]]
 ):
     # type: (...) -> Callable[[HTMLPage], List[Link]]
     """
@@ -389,9 +387,9 @@ class HTMLPage(object):
 
     def __init__(
         self,
-        content,                  # type: bytes
-        encoding,                 # type: Optional[str]
-        url,                      # type: str
+        content,  # type: bytes
+        encoding,  # type: Optional[str]
+        url,  # type: str
         cache_link_parsing=True,  # type: bool
     ):
         # type: (...) -> None
@@ -415,7 +413,7 @@ def __str__(self):
 def _handle_get_page_fail(
     link,  # type: Link
     reason,  # type: Union[str, Exception]
-    meth=None  # type: Optional[Callable[..., None]]
+    meth=None,  # type: Optional[Callable[..., None]]
 ):
     # type: (...) -> None
     if meth is None:
@@ -430,7 +428,8 @@ def _make_html_page(response, cache_link_parsing=True):
         response.content,
         encoding=encoding,
         url=response.url,
-        cache_link_parsing=cache_link_parsing)
+        cache_link_parsing=cache_link_parsing,
+    )
 
 
 def _get_html_page(link, session=None):
@@ -440,37 +439,44 @@ def _get_html_page(link, session=None):
             "_get_html_page() missing 1 required keyword argument: 'session'"
         )
 
-    url = link.url.split('#', 1)[0]
+    url = link.url.split("#", 1)[0]
 
     # Check for VCS schemes that do not support lookup as web pages.
     vcs_scheme = _match_vcs_scheme(url)
     if vcs_scheme:
-        logger.warning('Cannot look at %s URL %s because it does not support '
-                       'lookup as web pages.', vcs_scheme, link)
+        logger.warning(
+            "Cannot look at %s URL %s because it does not support "
+            "lookup as web pages.",
+            vcs_scheme,
+            link,
+        )
         return None
 
     # Tack index.html onto file:// URLs that point to directories
     scheme, _, path, _, _, _ = urllib_parse.urlparse(url)
-    if (scheme == 'file' and os.path.isdir(urllib_request.url2pathname(path))):
+    if scheme == "file" and os.path.isdir(urllib_request.url2pathname(path)):
         # add trailing slash if not present so urljoin doesn't trim
         # final segment
-        if not url.endswith('/'):
-            url += '/'
-        url = urllib_parse.urljoin(url, 'index.html')
-        logger.debug(' file: URL is directory, getting %s', url)
+        if not url.endswith("/"):
+            url += "/"
+        url = urllib_parse.urljoin(url, "index.html")
+        logger.debug(" file: URL is directory, getting %s", url)
 
     try:
         resp = _get_html_response(url, session=session)
     except _NotHTTP:
         logger.warning(
-            'Skipping page %s because it looks like an archive, and cannot '
-            'be checked by a HTTP HEAD request.', link,
+            "Skipping page %s because it looks like an archive, and cannot "
+            "be checked by a HTTP HEAD request.",
+            link,
         )
     except _NotHTML as exc:
         logger.warning(
-            'Skipping page %s because the %s request got Content-Type: %s.'
-            'The only supported Content-Type is text/html',
-            link, exc.request_desc, exc.content_type,
+            "Skipping page %s because the %s request got Content-Type: %s."
+            "The only supported Content-Type is text/html",
+            link,
+            exc.request_desc,
+            exc.content_type,
         )
     except NetworkConnectionError as exc:
         _handle_get_page_fail(link, exc)
@@ -485,8 +491,7 @@ def _get_html_page(link, session=None):
     except requests.Timeout:
         _handle_get_page_fail(link, "timed out")
     else:
-        return _make_html_page(resp,
-                               cache_link_parsing=link.cache_link_parsing)
+        return _make_html_page(resp, cache_link_parsing=link.cache_link_parsing)
     return None
 
 
@@ -513,7 +518,7 @@ def group_locations(locations, expand_dir=False):
     def sort_path(path):
         # type: (str) -> None
         url = path_to_url(path)
-        if mimetypes.guess_type(url, strict=False)[0] == 'text/html':
+        if mimetypes.guess_type(url, strict=False)[0] == "text/html":
             urls.append(url)
         else:
             files.append(url)
@@ -521,7 +526,7 @@ def sort_path(path):
     for url in locations:
 
         is_local_path = os.path.exists(url)
-        is_file_url = url.startswith('file:')
+        is_file_url = url.startswith("file:")
 
         if is_local_path or is_file_url:
             if is_local_path:
@@ -537,14 +542,15 @@ def sort_path(path):
                     urls.append(url)
                 else:
                     logger.warning(
-                        "Path '%s' is ignored: it is a directory.", path,
+                        "Path '%s' is ignored: it is a directory.",
+                        path,
                     )
             elif os.path.isfile(path):
                 sort_path(path)
             else:
                 logger.warning(
-                    "Url '%s' is ignored: it is neither a file "
-                    "nor a directory.", url,
+                    "Url '%s' is ignored: it is neither a file " "nor a directory.",
+                    url,
                 )
         elif is_url(url):
             # Only add url with clear scheme
@@ -552,7 +558,8 @@ def sort_path(path):
         else:
             logger.warning(
                 "Url '%s' is ignored. It is either a non-existing "
-                "path or lacks a specific scheme.", url,
+                "path or lacks a specific scheme.",
+                url,
             )
 
     return files, urls
@@ -577,8 +584,8 @@ class CollectedLinks(object):
 
     def __init__(
         self,
-        files,         # type: List[Link]
-        find_links,    # type: List[Link]
+        files,  # type: List[Link]
+        find_links,  # type: List[Link]
         project_urls,  # type: List[Link]
     ):
         # type: (...) -> None
@@ -604,7 +611,7 @@ class LinkCollector(object):
 
     def __init__(
         self,
-        session,       # type: PipSession
+        session,  # type: PipSession
         search_scope,  # type: SearchScope
     ):
         # type: (...) -> None
@@ -622,8 +629,8 @@ def create(cls, session, options, suppress_no_index=False):
         index_urls = [options.index_url] + options.extra_index_urls
         if options.no_index and not suppress_no_index:
             logger.debug(
-                'Ignoring indexes: %s',
-                ','.join(redact_auth_from_url(url) for url in index_urls),
+                "Ignoring indexes: %s",
+                ",".join(redact_auth_from_url(url) for url in index_urls),
             )
             index_urls = []
 
@@ -631,10 +638,12 @@ def create(cls, session, options, suppress_no_index=False):
         find_links = options.find_links or []
 
         search_scope = SearchScope.create(
-            find_links=find_links, index_urls=index_urls,
+            find_links=find_links,
+            index_urls=index_urls,
         )
         link_collector = LinkCollector(
-            session=session, search_scope=search_scope,
+            session=session,
+            search_scope=search_scope,
         )
         return link_collector
 
@@ -660,21 +669,21 @@ def collect_links(self, project_name):
         index_locations = search_scope.get_index_urls_locations(project_name)
         index_file_loc, index_url_loc = group_locations(index_locations)
         fl_file_loc, fl_url_loc = group_locations(
-            self.find_links, expand_dir=True,
+            self.find_links,
+            expand_dir=True,
         )
 
-        file_links = [
-            Link(url) for url in itertools.chain(index_file_loc, fl_file_loc)
-        ]
+        file_links = [Link(url) for url in itertools.chain(index_file_loc, fl_file_loc)]
 
         # We trust every directly linked archive in find_links
-        find_link_links = [Link(url, '-f') for url in self.find_links]
+        find_link_links = [Link(url, "-f") for url in self.find_links]
 
         # We trust every url that the user has given us whether it was given
         # via --index-url or --find-links.
         # We want to filter out anything that does not have a secure origin.
         url_locations = [
-            link for link in itertools.chain(
+            link
+            for link in itertools.chain(
                 # Mark PyPI indices as "cache_link_parsing == False" -- this
                 # will avoid caching the result of parsing the page for links.
                 (Link(url, cache_link_parsing=False) for url in index_url_loc),
@@ -685,13 +694,14 @@ def collect_links(self, project_name):
 
         url_locations = _remove_duplicate_links(url_locations)
         lines = [
-            '{} location(s) to search for versions of {}:'.format(
-                len(url_locations), project_name,
+            "{} location(s) to search for versions of {}:".format(
+                len(url_locations),
+                project_name,
             ),
         ]
         for link in url_locations:
-            lines.append('* {}'.format(link))
-        logger.debug('\n'.join(lines))
+            lines.append("* {}".format(link))
+        logger.debug("\n".join(lines))
 
         return CollectedLinks(
             files=file_links,
diff --git a/src/pip/_internal/index/package_finder.py b/src/pip/_internal/index/package_finder.py
index 19a9c2c1370..713286ac193 100644
--- a/src/pip/_internal/index/package_finder.py
+++ b/src/pip/_internal/index/package_finder.py
@@ -34,16 +34,7 @@
 from pip._internal.utils.urls import url_to_path
 
 if MYPY_CHECK_RUNNING:
-    from typing import (
-        FrozenSet,
-        Iterable,
-        List,
-        Optional,
-        Set,
-        Text,
-        Tuple,
-        Union,
-    )
+    from typing import FrozenSet, Iterable, List, Optional, Set, Text, Tuple, Union
 
     from pip._vendor.packaging.tags import Tag
     from pip._vendor.packaging.version import _BaseVersion
@@ -54,12 +45,10 @@
     from pip._internal.utils.hashes import Hashes
 
     BuildTag = Union[Tuple[()], Tuple[int, str]]
-    CandidateSortingKey = (
-        Tuple[int, int, int, _BaseVersion, BuildTag, Optional[int]]
-    )
+    CandidateSortingKey = Tuple[int, int, int, _BaseVersion, BuildTag, Optional[int]]
 
 
-__all__ = ['FormatControl', 'BestCandidateResult', 'PackageFinder']
+__all__ = ["FormatControl", "BestCandidateResult", "PackageFinder"]
 
 
 logger = logging.getLogger(__name__)
@@ -82,27 +71,32 @@ def _check_link_requires_python(
     """
     try:
         is_compatible = check_requires_python(
-            link.requires_python, version_info=version_info,
+            link.requires_python,
+            version_info=version_info,
         )
     except specifiers.InvalidSpecifier:
         logger.debug(
             "Ignoring invalid Requires-Python (%r) for link: %s",
-            link.requires_python, link,
+            link.requires_python,
+            link,
         )
     else:
         if not is_compatible:
-            version = '.'.join(map(str, version_info))
+            version = ".".join(map(str, version_info))
             if not ignore_requires_python:
                 logger.debug(
-                    'Link requires a different Python (%s not in: %r): %s',
-                    version, link.requires_python, link,
+                    "Link requires a different Python (%s not in: %r): %s",
+                    version,
+                    link.requires_python,
+                    link,
                 )
                 return False
 
             logger.debug(
-                'Ignoring failed Requires-Python check (%s not in: %r) '
-                'for link: %s',
-                version, link.requires_python, link,
+                "Ignoring failed Requires-Python check (%s not in: %r) " "for link: %s",
+                version,
+                link.requires_python,
+                link,
             )
 
     return True
@@ -114,7 +108,7 @@ class LinkEvaluator(object):
     Responsible for evaluating links for a particular project.
     """
 
-    _py_version_re = re.compile(r'-py([123]\.?[0-9]?)$')
+    _py_version_re = re.compile(r"-py([123]\.?[0-9]?)$")
 
     # Don't include an allow_yanked default value to make sure each call
     # site considers whether yanked releases are allowed. This also causes
@@ -122,11 +116,11 @@ class LinkEvaluator(object):
     # people when reading the code.
     def __init__(
         self,
-        project_name,    # type: str
+        project_name,  # type: str
         canonical_name,  # type: str
-        formats,         # type: FrozenSet[str]
-        target_python,   # type: TargetPython
-        allow_yanked,    # type: bool
+        formats,  # type: FrozenSet[str]
+        target_python,  # type: TargetPython
+        allow_yanked,  # type: bool
         ignore_requires_python=None,  # type: Optional[bool]
     ):
         # type: (...) -> None
@@ -170,11 +164,11 @@ def evaluate_link(self, link):
         """
         version = None
         if link.is_yanked and not self._allow_yanked:
-            reason = link.yanked_reason or '<none given>'
+            reason = link.yanked_reason or "<none given>"
             # Mark this as a unicode string to prevent "UnicodeEncodeError:
             # 'ascii' codec can't encode character" in Python 2 when
             # the reason contains non-ascii characters.
-            return (False, u'yanked for reason: {}'.format(reason))
+            return (False, u"yanked for reason: {}".format(reason))
 
         if link.egg_fragment:
             egg_info = link.egg_fragment
@@ -182,23 +176,21 @@ def evaluate_link(self, link):
         else:
             egg_info, ext = link.splitext()
             if not ext:
-                return (False, 'not a file')
+                return (False, "not a file")
             if ext not in SUPPORTED_EXTENSIONS:
-                return (False, 'unsupported archive format: {}'.format(ext))
+                return (False, "unsupported archive format: {}".format(ext))
             if "binary" not in self._formats and ext == WHEEL_EXTENSION:
-                reason = 'No binaries permitted for {}'.format(
-                    self.project_name)
+                reason = "No binaries permitted for {}".format(self.project_name)
                 return (False, reason)
-            if "macosx10" in link.path and ext == '.zip':
-                return (False, 'macosx10 one')
+            if "macosx10" in link.path and ext == ".zip":
+                return (False, "macosx10 one")
             if ext == WHEEL_EXTENSION:
                 try:
                     wheel = Wheel(link.filename)
                 except InvalidWheelFilename:
-                    return (False, 'invalid wheel filename')
+                    return (False, "invalid wheel filename")
                 if canonicalize_name(wheel.name) != self._canonical_name:
-                    reason = 'wrong project name (not {})'.format(
-                        self.project_name)
+                    reason = "wrong project name (not {})".format(self.project_name)
                     return (False, reason)
 
                 supported_tags = self._target_python.get_tags()
@@ -206,10 +198,8 @@ def evaluate_link(self, link):
                     # Include the wheel's tags in the reason string to
                     # simplify troubleshooting compatibility issues.
                     file_tags = wheel.get_formatted_file_tags()
-                    reason = (
-                        "none of the wheel's tags match: {}".format(
-                            ', '.join(file_tags)
-                        )
+                    reason = "none of the wheel's tags match: {}".format(
+                        ", ".join(file_tags)
                     )
                     return (False, reason)
 
@@ -217,26 +207,28 @@ def evaluate_link(self, link):
 
         # This should be up by the self.ok_binary check, but see issue 2700.
         if "source" not in self._formats and ext != WHEEL_EXTENSION:
-            reason = 'No sources permitted for {}'.format(self.project_name)
+            reason = "No sources permitted for {}".format(self.project_name)
             return (False, reason)
 
         if not version:
             version = _extract_version_from_fragment(
-                egg_info, self._canonical_name,
+                egg_info,
+                self._canonical_name,
             )
         if not version:
-            reason = 'Missing project version for {}'.format(self.project_name)
+            reason = "Missing project version for {}".format(self.project_name)
             return (False, reason)
 
         match = self._py_version_re.search(version)
         if match:
-            version = version[:match.start()]
+            version = version[: match.start()]
             py_version = match.group(1)
             if py_version != self._target_python.py_version:
-                return (False, 'Python version is incorrect')
+                return (False, "Python version is incorrect")
 
         supports_python = _check_link_requires_python(
-            link, version_info=self._target_python.py_version_info,
+            link,
+            version_info=self._target_python.py_version_info,
             ignore_requires_python=self._ignore_requires_python,
         )
         if not supports_python:
@@ -244,14 +236,14 @@ def evaluate_link(self, link):
             # _log_skipped_link().
             return (False, None)
 
-        logger.debug('Found link %s, version: %s', link, version)
+        logger.debug("Found link %s, version: %s", link, version)
 
         return (True, version)
 
 
 def filter_unallowed_hashes(
-    candidates,    # type: List[InstallationCandidate]
-    hashes,        # type: Hashes
+    candidates,  # type: List[InstallationCandidate]
+    hashes,  # type: Hashes
     project_name,  # type: str
 ):
     # type: (...) -> List[InstallationCandidate]
@@ -272,8 +264,8 @@ def filter_unallowed_hashes(
     """
     if not hashes:
         logger.debug(
-            'Given no hashes to check %s links for project %r: '
-            'discarding no candidates',
+            "Given no hashes to check %s links for project %r: "
+            "discarding no candidates",
             len(candidates),
             project_name,
         )
@@ -303,22 +295,22 @@ def filter_unallowed_hashes(
         filtered = list(candidates)
 
     if len(filtered) == len(candidates):
-        discard_message = 'discarding no candidates'
+        discard_message = "discarding no candidates"
     else:
-        discard_message = 'discarding {} non-matches:\n  {}'.format(
+        discard_message = "discarding {} non-matches:\n  {}".format(
             len(non_matches),
-            '\n  '.join(str(candidate.link) for candidate in non_matches)
+            "\n  ".join(str(candidate.link) for candidate in non_matches),
         )
 
     logger.debug(
-        'Checked %s links for project %r against %s hashes '
-        '(%s matches, %s no digest): %s',
+        "Checked %s links for project %r against %s hashes "
+        "(%s matches, %s no digest): %s",
         len(candidates),
         project_name,
         hashes.digest_count,
         match_count,
         len(matches_or_no_digest) - match_count,
-        discard_message
+        discard_message,
     )
 
     return filtered
@@ -353,9 +345,9 @@ class BestCandidateResult(object):
 
     def __init__(
         self,
-        candidates,             # type: List[InstallationCandidate]
+        candidates,  # type: List[InstallationCandidate]
         applicable_candidates,  # type: List[InstallationCandidate]
-        best_candidate,         # type: Optional[InstallationCandidate]
+        best_candidate,  # type: Optional[InstallationCandidate]
     ):
         # type: (...) -> None
         """
@@ -378,14 +370,12 @@ def __init__(
 
     def iter_all(self):
         # type: () -> Iterable[InstallationCandidate]
-        """Iterate through all candidates.
-        """
+        """Iterate through all candidates."""
         return iter(self._candidates)
 
     def iter_applicable(self):
         # type: () -> Iterable[InstallationCandidate]
-        """Iterate through the applicable candidates.
-        """
+        """Iterate through the applicable candidates."""
         return iter(self._applicable_candidates)
 
 
@@ -399,12 +389,12 @@ class CandidateEvaluator(object):
     @classmethod
     def create(
         cls,
-        project_name,         # type: str
-        target_python=None,   # type: Optional[TargetPython]
+        project_name,  # type: str
+        target_python=None,  # type: Optional[TargetPython]
         prefer_binary=False,  # type: bool
         allow_all_prereleases=False,  # type: bool
-        specifier=None,       # type: Optional[specifiers.BaseSpecifier]
-        hashes=None,          # type: Optional[Hashes]
+        specifier=None,  # type: Optional[specifiers.BaseSpecifier]
+        hashes=None,  # type: Optional[Hashes]
     ):
         # type: (...) -> CandidateEvaluator
         """Create a CandidateEvaluator object.
@@ -435,12 +425,12 @@ def create(
 
     def __init__(
         self,
-        project_name,         # type: str
-        supported_tags,       # type: List[Tag]
-        specifier,            # type: specifiers.BaseSpecifier
+        project_name,  # type: str
+        supported_tags,  # type: List[Tag]
+        specifier,  # type: specifiers.BaseSpecifier
         prefer_binary=False,  # type: bool
         allow_all_prereleases=False,  # type: bool
-        hashes=None,                  # type: Optional[Hashes]
+        hashes=None,  # type: Optional[Hashes]
     ):
         # type: (...) -> None
         """
@@ -466,7 +456,8 @@ def get_applicable_candidates(
         allow_prereleases = self._allow_all_prereleases or None
         specifier = self._specifier
         versions = {
-            str(v) for v in specifier.filter(
+            str(v)
+            for v in specifier.filter(
                 # We turn the version object into a str here because otherwise
                 # when we're debundled but setuptools isn't, Python will see
                 # packaging.version.Version and
@@ -480,9 +471,7 @@ def get_applicable_candidates(
         }
 
         # Again, converting version to str to deal with debundling.
-        applicable_candidates = [
-            c for c in candidates if str(c.version) in versions
-        ]
+        applicable_candidates = [c for c in candidates if str(c.version) in versions]
 
         filtered_applicable_candidates = filter_unallowed_hashes(
             candidates=applicable_candidates,
@@ -540,7 +529,7 @@ def _sort_key(self, candidate):
                 binary_preference = 1
             pri = -(wheel.support_index_min(valid_tags))
             if wheel.build_tag is not None:
-                match = re.match(r'^(\d+)(.*)$', wheel.build_tag)
+                match = re.match(r"^(\d+)(.*)$", wheel.build_tag)
                 build_tag_groups = match.groups()
                 build_tag = (int(build_tag_groups[0]), build_tag_groups[1])
         else:  # sdist
@@ -548,13 +537,17 @@ def _sort_key(self, candidate):
         has_allowed_hash = int(link.is_hash_allowed(self._hashes))
         yank_value = -1 * int(link.is_yanked)  # -1 for yanked.
         return (
-            has_allowed_hash, yank_value, binary_preference, candidate.version,
-            build_tag, pri,
+            has_allowed_hash,
+            yank_value,
+            binary_preference,
+            candidate.version,
+            build_tag,
+            pri,
         )
 
     def sort_best_candidate(
         self,
-        candidates,    # type: List[InstallationCandidate]
+        candidates,  # type: List[InstallationCandidate]
     ):
         # type: (...) -> Optional[InstallationCandidate]
         """
@@ -568,7 +561,7 @@ def sort_best_candidate(
 
     def compute_best_candidate(
         self,
-        candidates,      # type: List[InstallationCandidate]
+        candidates,  # type: List[InstallationCandidate]
     ):
         # type: (...) -> BestCandidateResult
         """
@@ -594,11 +587,11 @@ class PackageFinder(object):
 
     def __init__(
         self,
-        link_collector,       # type: LinkCollector
-        target_python,        # type: TargetPython
-        allow_yanked,         # type: bool
+        link_collector,  # type: LinkCollector
+        target_python,  # type: TargetPython
+        allow_yanked,  # type: bool
         format_control=None,  # type: Optional[FormatControl]
-        candidate_prefs=None,         # type: CandidatePreferences
+        candidate_prefs=None,  # type: CandidatePreferences
         ignore_requires_python=None,  # type: Optional[bool]
     ):
         # type: (...) -> None
@@ -635,8 +628,8 @@ def __init__(
     @classmethod
     def create(
         cls,
-        link_collector,      # type: LinkCollector
-        selection_prefs,     # type: SelectionPreferences
+        link_collector,  # type: LinkCollector
+        selection_prefs,  # type: SelectionPreferences
         target_python=None,  # type: Optional[TargetPython]
     ):
         # type: (...) -> PackageFinder
@@ -753,7 +746,7 @@ def _log_skipped_link(self, link, reason):
             # the reason contains non-ascii characters.
             #   Also, put the link at the end so the reason is more visible
             # and because the link string is usually very long.
-            logger.debug(u'Skipping link: %s: %s', reason, link)
+            logger.debug(u"Skipping link: %s: %s", reason, link)
             self._logged_links.add(link)
 
     def get_install_candidate(self, link_evaluator, link):
@@ -792,7 +785,8 @@ def evaluate_links(self, link_evaluator, links):
     def process_project_url(self, project_url, link_evaluator):
         # type: (Link, LinkEvaluator) -> List[InstallationCandidate]
         logger.debug(
-            'Fetching project page and analyzing links: %s', project_url,
+            "Fetching project page and analyzing links: %s",
+            project_url,
         )
         html_page = self._link_collector.fetch_page(project_url)
         if html_page is None:
@@ -830,7 +824,8 @@ def find_all_candidates(self, project_name):
         page_versions = []
         for project_url in collected_links.project_urls:
             package_links = self.process_project_url(
-                project_url, link_evaluator=link_evaluator,
+                project_url,
+                link_evaluator=link_evaluator,
             )
             page_versions.extend(package_links)
 
@@ -841,11 +836,10 @@ def find_all_candidates(self, project_name):
         if file_versions:
             file_versions.sort(reverse=True)
             logger.debug(
-                'Local files found: %s',
-                ', '.join([
-                    url_to_path(candidate.link.url)
-                    for candidate in file_versions
-                ])
+                "Local files found: %s",
+                ", ".join(
+                    [url_to_path(candidate.link.url) for candidate in file_versions]
+                ),
             )
 
         # This is an intentional priority ordering
@@ -853,13 +847,12 @@ def find_all_candidates(self, project_name):
 
     def make_candidate_evaluator(
         self,
-        project_name,    # type: str
+        project_name,  # type: str
         specifier=None,  # type: Optional[specifiers.BaseSpecifier]
-        hashes=None,     # type: Optional[Hashes]
+        hashes=None,  # type: Optional[Hashes]
     ):
         # type: (...) -> CandidateEvaluator
-        """Create a CandidateEvaluator object to use.
-        """
+        """Create a CandidateEvaluator object to use."""
         candidate_prefs = self._candidate_prefs
         return CandidateEvaluator.create(
             project_name=project_name,
@@ -872,9 +865,9 @@ def make_candidate_evaluator(
 
     def find_best_candidate(
         self,
-        project_name,       # type: str
-        specifier=None,     # type: Optional[specifiers.BaseSpecifier]
-        hashes=None,        # type: Optional[Hashes]
+        project_name,  # type: str
+        specifier=None,  # type: Optional[specifiers.BaseSpecifier]
+        hashes=None,  # type: Optional[Hashes]
     ):
         # type: (...) -> BestCandidateResult
         """Find matches for the given project and specifier.
@@ -903,11 +896,13 @@ def find_requirement(self, req, upgrade):
         """
         hashes = req.hashes(trust_internet=False)
         best_candidate_result = self.find_best_candidate(
-            req.name, specifier=req.specifier, hashes=hashes,
+            req.name,
+            specifier=req.specifier,
+            hashes=hashes,
         )
         best_candidate = best_candidate_result.best_candidate
 
-        installed_version = None    # type: Optional[_BaseVersion]
+        installed_version = None  # type: Optional[_BaseVersion]
         if req.satisfied_by is not None:
             installed_version = parse_version(req.satisfied_by.version)
 
@@ -917,41 +912,45 @@ def _format_versions(cand_iter):
             # handle different vendoring sources from pip and pkg_resources.
             # If we stop using the pkg_resources provided specifier and start
             # using our own, we can drop the cast to str().
-            return ", ".join(sorted(
-                {str(c.version) for c in cand_iter},
-                key=parse_version,
-            )) or "none"
+            return (
+                ", ".join(
+                    sorted(
+                        {str(c.version) for c in cand_iter},
+                        key=parse_version,
+                    )
+                )
+                or "none"
+            )
 
         if installed_version is None and best_candidate is None:
             logger.critical(
-                'Could not find a version that satisfies the requirement %s '
-                '(from versions: %s)',
+                "Could not find a version that satisfies the requirement %s "
+                "(from versions: %s)",
                 req,
                 _format_versions(best_candidate_result.iter_all()),
             )
 
             raise DistributionNotFound(
-                'No matching distribution found for {}'.format(
-                    req)
+                "No matching distribution found for {}".format(req)
             )
 
         best_installed = False
         if installed_version and (
-                best_candidate is None or
-                best_candidate.version <= installed_version):
+            best_candidate is None or best_candidate.version <= installed_version
+        ):
             best_installed = True
 
         if not upgrade and installed_version is not None:
             if best_installed:
                 logger.debug(
-                    'Existing installed version (%s) is most up-to-date and '
-                    'satisfies requirement',
+                    "Existing installed version (%s) is most up-to-date and "
+                    "satisfies requirement",
                     installed_version,
                 )
             else:
                 logger.debug(
-                    'Existing installed version (%s) satisfies requirement '
-                    '(most up-to-date version is %s)',
+                    "Existing installed version (%s) satisfies requirement "
+                    "(most up-to-date version is %s)",
                     installed_version,
                     best_candidate.version,
                 )
@@ -960,15 +959,14 @@ def _format_versions(cand_iter):
         if best_installed:
             # We have an existing version, and its the best version
             logger.debug(
-                'Installed version (%s) is most up-to-date (past versions: '
-                '%s)',
+                "Installed version (%s) is most up-to-date (past versions: " "%s)",
                 installed_version,
                 _format_versions(best_candidate_result.iter_applicable()),
             )
             raise BestVersionAlreadyInstalled
 
         logger.debug(
-            'Using version %s (newest of versions: %s)',
+            "Using version %s (newest of versions: %s)",
             best_candidate.version,
             _format_versions(best_candidate_result.iter_applicable()),
         )
diff --git a/src/pip/_internal/locations.py b/src/pip/_internal/locations.py
index 35a4512b4b1..24fbf925c5e 100644
--- a/src/pip/_internal/locations.py
+++ b/src/pip/_internal/locations.py
@@ -36,22 +36,20 @@ def get_major_minor_version():
     Return the major-minor version of the current Python as a string, e.g.
     "3.7" or "3.10".
     """
-    return '{}.{}'.format(*sys.version_info)
+    return "{}.{}".format(*sys.version_info)
 
 
 def get_src_prefix():
     # type: () -> str
     if running_under_virtualenv():
-        src_prefix = os.path.join(sys.prefix, 'src')
+        src_prefix = os.path.join(sys.prefix, "src")
     else:
         # FIXME: keep src in cwd for now (it is not a temporary folder)
         try:
-            src_prefix = os.path.join(os.getcwd(), 'src')
+            src_prefix = os.path.join(os.getcwd(), "src")
         except OSError:
             # In case the current working directory has been renamed or deleted
-            sys.exit(
-                "The folder you are executing pip from can no longer be found."
-            )
+            sys.exit("The folder you are executing pip from can no longer be found.")
 
     # under macOS + virtualenv sys.prefix is not properly resolved
     # it is something like /path/to/python/bin/..
@@ -75,20 +73,20 @@ def get_src_prefix():
     user_site = site.USER_SITE
 
 if WINDOWS:
-    bin_py = os.path.join(sys.prefix, 'Scripts')
-    bin_user = os.path.join(user_site, 'Scripts')
+    bin_py = os.path.join(sys.prefix, "Scripts")
+    bin_user = os.path.join(user_site, "Scripts")
     # buildout uses 'bin' on Windows too?
     if not os.path.exists(bin_py):
-        bin_py = os.path.join(sys.prefix, 'bin')
-        bin_user = os.path.join(user_site, 'bin')
+        bin_py = os.path.join(sys.prefix, "bin")
+        bin_user = os.path.join(user_site, "bin")
 else:
-    bin_py = os.path.join(sys.prefix, 'bin')
-    bin_user = os.path.join(user_site, 'bin')
+    bin_py = os.path.join(sys.prefix, "bin")
+    bin_user = os.path.join(user_site, "bin")
 
     # Forcing to use /usr/local/bin for standard macOS framework installs
     # Also log to ~/Library/Logs/ for use with the Console.app log viewer
-    if sys.platform[:6] == 'darwin' and sys.prefix[:16] == '/System/Library/':
-        bin_py = '/usr/local/bin'
+    if sys.platform[:6] == "darwin" and sys.prefix[:16] == "/System/Library/":
+        bin_py = "/usr/local/bin"
 
 
 def distutils_scheme(
@@ -100,14 +98,14 @@ def distutils_scheme(
     """
     from distutils.dist import Distribution
 
-    dist_args = {'name': dist_name}  # type: Dict[str, Union[str, List[str]]]
+    dist_args = {"name": dist_name}  # type: Dict[str, Union[str, List[str]]]
     if isolated:
         dist_args["script_args"] = ["--no-user-cfg"]
 
     d = Distribution(dist_args)
     d.parse_config_files()
     obj = None  # type: Optional[DistutilsCommand]
-    obj = d.get_command_obj('install', create=True)
+    obj = d.get_command_obj("install", create=True)
     assert obj is not None
     i = cast(distutils_install_command, obj)
     # NOTE: setting user or home has the side-effect of creating the home dir
@@ -125,28 +123,27 @@ def distutils_scheme(
 
     scheme = {}
     for key in SCHEME_KEYS:
-        scheme[key] = getattr(i, 'install_' + key)
+        scheme[key] = getattr(i, "install_" + key)
 
     # install_lib specified in setup.cfg should install *everything*
     # into there (i.e. it takes precedence over both purelib and
     # platlib).  Note, i.install_lib is *always* set after
     # finalize_options(); we only want to override here if the user
     # has explicitly requested it hence going back to the config
-    if 'install_lib' in d.get_option_dict('install'):
+    if "install_lib" in d.get_option_dict("install"):
         scheme.update(dict(purelib=i.install_lib, platlib=i.install_lib))
 
     if running_under_virtualenv():
-        scheme['headers'] = os.path.join(
+        scheme["headers"] = os.path.join(
             i.prefix,
-            'include',
-            'site',
-            'python{}'.format(get_major_minor_version()),
+            "include",
+            "site",
+            "python{}".format(get_major_minor_version()),
             dist_name,
         )
 
         if root is not None:
-            path_no_drive = os.path.splitdrive(
-                os.path.abspath(scheme["headers"]))[1]
+            path_no_drive = os.path.splitdrive(os.path.abspath(scheme["headers"]))[1]
             scheme["headers"] = os.path.join(
                 root,
                 path_no_drive[1:],
@@ -181,9 +178,7 @@ def get_scheme(
     :param prefix: indicates to use the "prefix" scheme and provides the
         base directory for the same
     """
-    scheme = distutils_scheme(
-        dist_name, user, home, root, isolated, prefix
-    )
+    scheme = distutils_scheme(dist_name, user, home, root, isolated, prefix)
     return Scheme(
         platlib=scheme["platlib"],
         purelib=scheme["purelib"],
diff --git a/src/pip/_internal/models/candidate.py b/src/pip/_internal/models/candidate.py
index 0d89a8c07da..c62071bd835 100644
--- a/src/pip/_internal/models/candidate.py
+++ b/src/pip/_internal/models/candidate.py
@@ -10,8 +10,7 @@
 
 
 class InstallationCandidate(KeyBasedCompareMixin):
-    """Represents a potential "candidate" for installation.
-    """
+    """Represents a potential "candidate" for installation."""
 
     __slots__ = ["name", "version", "link"]
 
@@ -23,17 +22,21 @@ def __init__(self, name, version, link):
 
         super(InstallationCandidate, self).__init__(
             key=(self.name, self.version, self.link),
-            defining_class=InstallationCandidate
+            defining_class=InstallationCandidate,
         )
 
     def __repr__(self):
         # type: () -> str
         return "<InstallationCandidate({!r}, {!r}, {!r})>".format(
-            self.name, self.version, self.link,
+            self.name,
+            self.version,
+            self.link,
         )
 
     def __str__(self):
         # type: () -> str
-        return '{!r} candidate (version {} at {})'.format(
-            self.name, self.version, self.link,
+        return "{!r} candidate (version {} at {})".format(
+            self.name,
+            self.version,
+            self.link,
         )
diff --git a/src/pip/_internal/models/direct_url.py b/src/pip/_internal/models/direct_url.py
index 99aa68d121b..f4f86db4f89 100644
--- a/src/pip/_internal/models/direct_url.py
+++ b/src/pip/_internal/models/direct_url.py
@@ -151,9 +151,7 @@ def _from_dict(cls, d):
         # type: (Optional[Dict[str, Any]]) -> Optional[DirInfo]
         if d is None:
             return None
-        return cls(
-            editable=_get_required(d, bool, "editable", default=False)
-        )
+        return cls(editable=_get_required(d, bool, "editable", default=False))
 
     def _to_dict(self):
         # type: () -> Dict[str, Any]
@@ -165,7 +163,6 @@ def _to_dict(self):
 
 
 class DirectUrl(object):
-
     def __init__(
         self,
         url,  # type: str
@@ -182,9 +179,9 @@ def _remove_auth_from_netloc(self, netloc):
             return netloc
         user_pass, netloc_no_user_pass = netloc.split("@", 1)
         if (
-            isinstance(self.info, VcsInfo) and
-            self.info.vcs == "git" and
-            user_pass == "git"
+            isinstance(self.info, VcsInfo)
+            and self.info.vcs == "git"
+            and user_pass == "git"
         ):
             return netloc
         if ENV_VAR_RE.match(user_pass):
diff --git a/src/pip/_internal/models/format_control.py b/src/pip/_internal/models/format_control.py
index adcf61e2854..b30729fe587 100644
--- a/src/pip/_internal/models/format_control.py
+++ b/src/pip/_internal/models/format_control.py
@@ -8,8 +8,7 @@
 
 
 class FormatControl(object):
-    """Helper for managing formats from which a package can be installed.
-    """
+    """Helper for managing formats from which a package can be installed."""
 
     __slots__ = ["no_binary", "only_binary"]
 
@@ -31,10 +30,7 @@ def __eq__(self, other):
         if self.__slots__ != other.__slots__:
             return False
 
-        return all(
-            getattr(self, k) == getattr(other, k)
-            for k in self.__slots__
-        )
+        return all(getattr(self, k) == getattr(other, k) for k in self.__slots__)
 
     def __ne__(self, other):
         # type: (object) -> bool
@@ -43,29 +39,27 @@ def __ne__(self, other):
     def __repr__(self):
         # type: () -> str
         return "{}({}, {})".format(
-            self.__class__.__name__,
-            self.no_binary,
-            self.only_binary
+            self.__class__.__name__, self.no_binary, self.only_binary
         )
 
     @staticmethod
     def handle_mutual_excludes(value, target, other):
         # type: (str, Set[str], Set[str]) -> None
-        if value.startswith('-'):
+        if value.startswith("-"):
             raise CommandError(
                 "--no-binary / --only-binary option requires 1 argument."
             )
-        new = value.split(',')
-        while ':all:' in new:
+        new = value.split(",")
+        while ":all:" in new:
             other.clear()
             target.clear()
-            target.add(':all:')
-            del new[:new.index(':all:') + 1]
+            target.add(":all:")
+            del new[: new.index(":all:") + 1]
             # Without a none, we want to discard everything as :all: covers it
-            if ':none:' not in new:
+            if ":none:" not in new:
                 return
         for name in new:
-            if name == ':none:':
+            if name == ":none:":
                 target.clear()
                 continue
             name = canonicalize_name(name)
@@ -76,17 +70,19 @@ def get_allowed_formats(self, canonical_name):
         # type: (str) -> FrozenSet[str]
         result = {"binary", "source"}
         if canonical_name in self.only_binary:
-            result.discard('source')
+            result.discard("source")
         elif canonical_name in self.no_binary:
-            result.discard('binary')
-        elif ':all:' in self.only_binary:
-            result.discard('source')
-        elif ':all:' in self.no_binary:
-            result.discard('binary')
+            result.discard("binary")
+        elif ":all:" in self.only_binary:
+            result.discard("source")
+        elif ":all:" in self.no_binary:
+            result.discard("binary")
         return frozenset(result)
 
     def disallow_binaries(self):
         # type: () -> None
         self.handle_mutual_excludes(
-            ':all:', self.no_binary, self.only_binary,
+            ":all:",
+            self.no_binary,
+            self.only_binary,
         )
diff --git a/src/pip/_internal/models/index.py b/src/pip/_internal/models/index.py
index 5b4a1fe2274..1c2052e0bd9 100644
--- a/src/pip/_internal/models/index.py
+++ b/src/pip/_internal/models/index.py
@@ -2,19 +2,17 @@
 
 
 class PackageIndex(object):
-    """Represents a Package Index and provides easier access to endpoints
-    """
+    """Represents a Package Index and provides easier access to endpoints"""
 
-    __slots__ = ['url', 'netloc', 'simple_url', 'pypi_url',
-                 'file_storage_domain']
+    __slots__ = ["url", "netloc", "simple_url", "pypi_url", "file_storage_domain"]
 
     def __init__(self, url, file_storage_domain):
         # type: (str, str) -> None
         super(PackageIndex, self).__init__()
         self.url = url
         self.netloc = urllib_parse.urlsplit(url).netloc
-        self.simple_url = self._url_for_path('simple')
-        self.pypi_url = self._url_for_path('pypi')
+        self.simple_url = self._url_for_path("simple")
+        self.pypi_url = self._url_for_path("pypi")
 
         # This is part of a temporary hack used to block installs of PyPI
         # packages which depend on external urls only necessary until PyPI can
@@ -26,9 +24,7 @@ def _url_for_path(self, path):
         return urllib_parse.urljoin(self.url, path)
 
 
-PyPI = PackageIndex(
-    'https://pypi.org/', file_storage_domain='files.pythonhosted.org'
-)
+PyPI = PackageIndex("https://pypi.org/", file_storage_domain="files.pythonhosted.org")
 TestPyPI = PackageIndex(
-    'https://test.pypi.org/', file_storage_domain='test-files.pythonhosted.org'
+    "https://test.pypi.org/", file_storage_domain="test-files.pythonhosted.org"
 )
diff --git a/src/pip/_internal/models/link.py b/src/pip/_internal/models/link.py
index 29ef402beef..56652fc6b89 100644
--- a/src/pip/_internal/models/link.py
+++ b/src/pip/_internal/models/link.py
@@ -22,8 +22,7 @@
 
 
 class Link(KeyBasedCompareMixin):
-    """Represents a parsed link from a Package Index's simple URL
-    """
+    """Represents a parsed link from a Package Index's simple URL"""
 
     __slots__ = [
         "_parsed_url",
@@ -36,10 +35,10 @@ class Link(KeyBasedCompareMixin):
 
     def __init__(
         self,
-        url,                   # type: str
-        comes_from=None,       # type: Optional[Union[str, HTMLPage]]
+        url,  # type: str
+        comes_from=None,  # type: Optional[Union[str, HTMLPage]]
         requires_python=None,  # type: Optional[str]
-        yanked_reason=None,    # type: Optional[Text]
+        yanked_reason=None,  # type: Optional[Text]
         cache_link_parsing=True,  # type: bool
     ):
         # type: (...) -> None
@@ -65,7 +64,7 @@ def __init__(
         """
 
         # url can be a UNC windows share
-        if url.startswith('\\\\'):
+        if url.startswith("\\\\"):
             url = path_to_url(url)
 
         self._parsed_url = urllib_parse.urlsplit(url)
@@ -84,18 +83,19 @@ def __init__(
     def __str__(self):
         # type: () -> str
         if self.requires_python:
-            rp = ' (requires-python:{})'.format(self.requires_python)
+            rp = " (requires-python:{})".format(self.requires_python)
         else:
-            rp = ''
+            rp = ""
         if self.comes_from:
-            return '{} (from {}){}'.format(
-                redact_auth_from_url(self._url), self.comes_from, rp)
+            return "{} (from {}){}".format(
+                redact_auth_from_url(self._url), self.comes_from, rp
+            )
         else:
             return redact_auth_from_url(str(self._url))
 
     def __repr__(self):
         # type: () -> str
-        return '<Link {}>'.format(self)
+        return "<Link {}>".format(self)
 
     @property
     def url(self):
@@ -105,7 +105,7 @@ def url(self):
     @property
     def filename(self):
         # type: () -> str
-        path = self.path.rstrip('/')
+        path = self.path.rstrip("/")
         name = posixpath.basename(path)
         if not name:
             # Make sure we don't leak auth information if the netloc
@@ -114,8 +114,7 @@ def filename(self):
             return netloc
 
         name = urllib_parse.unquote(name)
-        assert name, (
-            'URL {self._url!r} produced no filename'.format(**locals()))
+        assert name, "URL {self._url!r} produced no filename".format(**locals())
         return name
 
     @property
@@ -143,7 +142,7 @@ def path(self):
 
     def splitext(self):
         # type: () -> Tuple[str, str]
-        return splitext(posixpath.basename(self.path.rstrip('/')))
+        return splitext(posixpath.basename(self.path.rstrip("/")))
 
     @property
     def ext(self):
@@ -156,7 +155,7 @@ def url_without_fragment(self):
         scheme, netloc, path, query, fragment = self._parsed_url
         return urllib_parse.urlunsplit((scheme, netloc, path, query, None))
 
-    _egg_fragment_re = re.compile(r'[#&]egg=([^&]*)')
+    _egg_fragment_re = re.compile(r"[#&]egg=([^&]*)")
 
     @property
     def egg_fragment(self):
@@ -166,7 +165,7 @@ def egg_fragment(self):
             return None
         return match.group(1)
 
-    _subdirectory_fragment_re = re.compile(r'[#&]subdirectory=([^&]*)')
+    _subdirectory_fragment_re = re.compile(r"[#&]subdirectory=([^&]*)")
 
     @property
     def subdirectory_fragment(self):
@@ -176,9 +175,7 @@ def subdirectory_fragment(self):
             return None
         return match.group(1)
 
-    _hash_re = re.compile(
-        r'(sha1|sha224|sha384|sha256|sha512|md5)=([a-f0-9]+)'
-    )
+    _hash_re = re.compile(r"(sha1|sha224|sha384|sha256|sha512|md5)=([a-f0-9]+)")
 
     @property
     def hash(self):
@@ -199,12 +196,12 @@ def hash_name(self):
     @property
     def show_url(self):
         # type: () -> str
-        return posixpath.basename(self._url.split('#', 1)[0].split('?', 1)[0])
+        return posixpath.basename(self._url.split("#", 1)[0].split("?", 1)[0])
 
     @property
     def is_file(self):
         # type: () -> bool
-        return self.scheme == 'file'
+        return self.scheme == "file"
 
     def is_existing_dir(self):
         # type: () -> bool
diff --git a/src/pip/_internal/models/scheme.py b/src/pip/_internal/models/scheme.py
index 5040551eb0e..98ec415e1c9 100644
--- a/src/pip/_internal/models/scheme.py
+++ b/src/pip/_internal/models/scheme.py
@@ -6,7 +6,7 @@
 """
 
 
-SCHEME_KEYS = ['platlib', 'purelib', 'headers', 'scripts', 'data']
+SCHEME_KEYS = ["platlib", "purelib", "headers", "scripts", "data"]
 
 
 class Scheme(object):
diff --git a/src/pip/_internal/models/search_scope.py b/src/pip/_internal/models/search_scope.py
index d732504e6f5..0670976889f 100644
--- a/src/pip/_internal/models/search_scope.py
+++ b/src/pip/_internal/models/search_scope.py
@@ -43,7 +43,7 @@ def create(
         # blindly normalize anything starting with a ~...
         built_find_links = []  # type: List[str]
         for link in find_links:
-            if link.startswith('~'):
+            if link.startswith("~"):
                 new_link = normalize_path(link)
                 if os.path.exists(new_link):
                     link = new_link
@@ -54,11 +54,11 @@ def create(
         if not has_tls():
             for link in itertools.chain(index_urls, built_find_links):
                 parsed = urllib_parse.urlparse(link)
-                if parsed.scheme == 'https':
+                if parsed.scheme == "https":
                     logger.warning(
-                        'pip is configured with locations that require '
-                        'TLS/SSL, however the ssl module in Python is not '
-                        'available.'
+                        "pip is configured with locations that require "
+                        "TLS/SSL, however the ssl module in Python is not "
+                        "available."
                     )
                     break
 
@@ -95,20 +95,23 @@ def get_formatted_locations(self):
                 # exceptions for malformed URLs
                 if not purl.scheme and not purl.netloc:
                     logger.warning(
-                        'The index url "%s" seems invalid, '
-                        'please provide a scheme.', redacted_index_url)
+                        'The index url "%s" seems invalid, ' "please provide a scheme.",
+                        redacted_index_url,
+                    )
 
                 redacted_index_urls.append(redacted_index_url)
 
-            lines.append('Looking in indexes: {}'.format(
-                ', '.join(redacted_index_urls)))
+            lines.append(
+                "Looking in indexes: {}".format(", ".join(redacted_index_urls))
+            )
 
         if self.find_links:
             lines.append(
-                'Looking in links: {}'.format(', '.join(
-                    redact_auth_from_url(url) for url in self.find_links))
+                "Looking in links: {}".format(
+                    ", ".join(redact_auth_from_url(url) for url in self.find_links)
+                )
             )
-        return '\n'.join(lines)
+        return "\n".join(lines)
 
     def get_index_urls_locations(self, project_name):
         # type: (str) -> List[str]
@@ -121,15 +124,15 @@ def get_index_urls_locations(self, project_name):
         def mkurl_pypi_url(url):
             # type: (str) -> str
             loc = posixpath.join(
-                url,
-                urllib_parse.quote(canonicalize_name(project_name)))
+                url, urllib_parse.quote(canonicalize_name(project_name))
+            )
             # For maximum compatibility with easy_install, ensure the path
             # ends in a trailing slash.  Although this isn't in the spec
             # (and PyPI can handle it without the slash) some other index
             # implementations might break if they relied on easy_install's
             # behavior.
-            if not loc.endswith('/'):
-                loc = loc + '/'
+            if not loc.endswith("/"):
+                loc = loc + "/"
             return loc
 
         return [mkurl_pypi_url(url) for url in self.index_urls]
diff --git a/src/pip/_internal/models/selection_prefs.py b/src/pip/_internal/models/selection_prefs.py
index 83110dd8f90..427e3345d42 100644
--- a/src/pip/_internal/models/selection_prefs.py
+++ b/src/pip/_internal/models/selection_prefs.py
@@ -12,8 +12,13 @@ class SelectionPreferences(object):
     and installing files.
     """
 
-    __slots__ = ['allow_yanked', 'allow_all_prereleases', 'format_control',
-                 'prefer_binary', 'ignore_requires_python']
+    __slots__ = [
+        "allow_yanked",
+        "allow_all_prereleases",
+        "format_control",
+        "prefer_binary",
+        "ignore_requires_python",
+    ]
 
     # Don't include an allow_yanked default value to make sure each call
     # site considers whether yanked releases are allowed. This also causes
@@ -23,8 +28,8 @@ def __init__(
         self,
         allow_yanked,  # type: bool
         allow_all_prereleases=False,  # type: bool
-        format_control=None,          # type: Optional[FormatControl]
-        prefer_binary=False,          # type: bool
+        format_control=None,  # type: Optional[FormatControl]
+        prefer_binary=False,  # type: bool
         ignore_requires_python=None,  # type: Optional[bool]
     ):
         # type: (...) -> None
diff --git a/src/pip/_internal/models/target_python.py b/src/pip/_internal/models/target_python.py
index 6d1ca79645f..0ac6ab6dd19 100644
--- a/src/pip/_internal/models/target_python.py
+++ b/src/pip/_internal/models/target_python.py
@@ -1,9 +1,6 @@
 import sys
 
-from pip._internal.utils.compatibility_tags import (
-    get_supported,
-    version_info_to_nodot,
-)
+from pip._internal.utils.compatibility_tags import get_supported, version_info_to_nodot
 from pip._internal.utils.misc import normalize_version_info
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 
@@ -60,7 +57,7 @@ def __init__(
         else:
             py_version_info = normalize_version_info(py_version_info)
 
-        py_version = '.'.join(map(str, py_version_info[:2]))
+        py_version = ".".join(map(str, py_version_info[:2]))
 
         self.abi = abi
         self.implementation = implementation
@@ -78,18 +75,19 @@ def format_given(self):
         """
         display_version = None
         if self._given_py_version_info is not None:
-            display_version = '.'.join(
+            display_version = ".".join(
                 str(part) for part in self._given_py_version_info
             )
 
         key_values = [
-            ('platform', self.platform),
-            ('version_info', display_version),
-            ('abi', self.abi),
-            ('implementation', self.implementation),
+            ("platform", self.platform),
+            ("version_info", display_version),
+            ("abi", self.abi),
+            ("implementation", self.implementation),
         ]
-        return ' '.join(
-            '{}={!r}'.format(key, value) for key, value in key_values
+        return " ".join(
+            "{}={!r}".format(key, value)
+            for key, value in key_values
             if value is not None
         )
 
diff --git a/src/pip/_internal/models/wheel.py b/src/pip/_internal/models/wheel.py
index 4d4068f3b73..3a332c04601 100644
--- a/src/pip/_internal/models/wheel.py
+++ b/src/pip/_internal/models/wheel.py
@@ -19,7 +19,7 @@ class Wheel(object):
         r"""^(?P<namever>(?P<name>.+?)-(?P<ver>.*?))
         ((-(?P<build>\d[^-]*?))?-(?P<pyver>.+?)-(?P<abi>.+?)-(?P<plat>.+?)
         \.whl|\.dist-info)$""",
-        re.VERBOSE
+        re.VERBOSE,
     )
 
     def __init__(self, filename):
@@ -33,19 +33,18 @@ def __init__(self, filename):
                 "{} is not a valid wheel filename.".format(filename)
             )
         self.filename = filename
-        self.name = wheel_info.group('name').replace('_', '-')
+        self.name = wheel_info.group("name").replace("_", "-")
         # we'll assume "_" means "-" due to wheel naming scheme
         # (https://github.com/pypa/pip/issues/1150)
-        self.version = wheel_info.group('ver').replace('_', '-')
-        self.build_tag = wheel_info.group('build')
-        self.pyversions = wheel_info.group('pyver').split('.')
-        self.abis = wheel_info.group('abi').split('.')
-        self.plats = wheel_info.group('plat').split('.')
+        self.version = wheel_info.group("ver").replace("_", "-")
+        self.build_tag = wheel_info.group("build")
+        self.pyversions = wheel_info.group("pyver").split(".")
+        self.abis = wheel_info.group("abi").split(".")
+        self.plats = wheel_info.group("plat").split(".")
 
         # All the tag combinations from this file
         self.file_tags = {
-            Tag(x, y, z) for x in self.pyversions
-            for y in self.abis for z in self.plats
+            Tag(x, y, z) for x in self.pyversions for y in self.abis for z in self.plats
         }
 
     def get_formatted_file_tags(self):
diff --git a/src/pip/_internal/network/auth.py b/src/pip/_internal/network/auth.py
index 357811a16f1..1a34fbac1d5 100644
--- a/src/pip/_internal/network/auth.py
+++ b/src/pip/_internal/network/auth.py
@@ -36,7 +36,8 @@
     keyring = None
 except Exception as exc:
     logger.warning(
-        "Keyring is skipped due to an exception: %s", str(exc),
+        "Keyring is skipped due to an exception: %s",
+        str(exc),
     )
     keyring = None
 
@@ -68,14 +69,14 @@ def get_keyring_auth(url, username):
 
     except Exception as exc:
         logger.warning(
-            "Keyring is skipped due to an exception: %s", str(exc),
+            "Keyring is skipped due to an exception: %s",
+            str(exc),
         )
         keyring = None
     return None
 
 
 class MultiDomainBasicAuth(AuthBase):
-
     def __init__(self, prompting=True, index_urls=None):
         # type: (bool, Optional[List[str]]) -> None
         self.prompting = prompting
@@ -111,8 +112,7 @@ def _get_index_url(self, url):
                 return u
         return None
 
-    def _get_new_credentials(self, original_url, allow_netrc=True,
-                             allow_keyring=True):
+    def _get_new_credentials(self, original_url, allow_netrc=True, allow_keyring=True):
         # type: (str, bool, bool) -> AuthInfo
         """Find and return credentials for the specified URL."""
         # Split the credentials and netloc from the url.
@@ -152,9 +152,8 @@ def _get_new_credentials(self, original_url, allow_netrc=True,
         # If we don't have a password and keyring is available, use it.
         if allow_keyring:
             # The index url is more specific than the netloc, so try it first
-            kr_auth = (
-                get_keyring_auth(index_url, username) or
-                get_keyring_auth(netloc, username)
+            kr_auth = get_keyring_auth(index_url, username) or get_keyring_auth(
+                netloc, username
             )
             if kr_auth:
                 logger.debug("Found credentials in keyring for %s", netloc)
@@ -196,7 +195,8 @@ def _get_url_and_credentials(self, original_url):
 
         assert (
             # Credentials were found
-            (username is not None and password is not None) or
+            (username is not None and password is not None)
+            or
             # Credentials were not found
             (username is None and password is None)
         ), "Could not load credentials from url: {}".format(original_url)
@@ -290,7 +290,8 @@ def warn_on_401(self, resp, **kwargs):
         """Response callback to warn about incorrect credentials."""
         if resp.status_code == 401:
             logger.warning(
-                '401 Error, Credentials not correct for %s', resp.request.url,
+                "401 Error, Credentials not correct for %s",
+                resp.request.url,
             )
 
     def save_credentials(self, resp, **kwargs):
@@ -304,7 +305,7 @@ def save_credentials(self, resp, **kwargs):
         self._credentials_to_save = None
         if creds and resp.status_code < 400:
             try:
-                logger.info('Saving credentials to keyring')
+                logger.info("Saving credentials to keyring")
                 keyring.set_password(*creds)
             except Exception:
-                logger.exception('Failed to save credentials')
+                logger.exception("Failed to save credentials")
diff --git a/src/pip/_internal/network/cache.py b/src/pip/_internal/network/cache.py
index d2a1b7313f7..7344986786c 100644
--- a/src/pip/_internal/network/cache.py
+++ b/src/pip/_internal/network/cache.py
@@ -58,7 +58,7 @@ def get(self, key):
         # type: (str) -> Optional[bytes]
         path = self._get_cache_path(key)
         with suppressed_cache_errors():
-            with open(path, 'rb') as f:
+            with open(path, "rb") as f:
                 return f.read()
 
     def set(self, key, value):
diff --git a/src/pip/_internal/network/download.py b/src/pip/_internal/network/download.py
index 56feaabac10..365b3eb27f4 100644
--- a/src/pip/_internal/network/download.py
+++ b/src/pip/_internal/network/download.py
@@ -11,16 +11,8 @@
 from pip._internal.exceptions import NetworkConnectionError
 from pip._internal.models.index import PyPI
 from pip._internal.network.cache import is_from_cache
-from pip._internal.network.utils import (
-    HEADERS,
-    raise_for_status,
-    response_chunks,
-)
-from pip._internal.utils.misc import (
-    format_size,
-    redact_auth_from_url,
-    splitext,
-)
+from pip._internal.network.utils import HEADERS, raise_for_status, response_chunks
+from pip._internal.utils.misc import format_size, redact_auth_from_url, splitext
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 
 if MYPY_CHECK_RUNNING:
@@ -37,7 +29,7 @@
 def _get_http_response_size(resp):
     # type: (Response) -> Optional[int]
     try:
-        return int(resp.headers['content-length'])
+        return int(resp.headers["content-length"])
     except (ValueError, KeyError, TypeError):
         return None
 
@@ -45,7 +37,7 @@ def _get_http_response_size(resp):
 def _prepare_download(
     resp,  # type: Response
     link,  # type: Link
-    progress_bar  # type: str
+    progress_bar,  # type: str
 ):
     # type: (...) -> Iterable[bytes]
     total_length = _get_http_response_size(resp)
@@ -58,7 +50,7 @@ def _prepare_download(
     logged_url = redact_auth_from_url(url)
 
     if total_length:
-        logged_url = '{} ({})'.format(logged_url, format_size(total_length))
+        logged_url = "{} ({})".format(logged_url, format_size(total_length))
 
     if is_from_cache(resp):
         logger.info("Using cached %s", logged_url)
@@ -81,9 +73,7 @@ def _prepare_download(
     if not show_progress:
         return chunks
 
-    return DownloadProgressProvider(
-        progress_bar, max=total_length
-    )(chunks)
+    return DownloadProgressProvider(progress_bar, max=total_length)(chunks)
 
 
 def sanitize_content_filename(filename):
@@ -101,7 +91,7 @@ def parse_content_disposition(content_disposition, default_filename):
     return the default filename if the result is empty.
     """
     _type, params = cgi.parse_header(content_disposition)
-    filename = params.get('filename')
+    filename = params.get("filename")
     if filename:
         # We need to sanitize the filename to prevent directory traversal
         # in case the filename contains ".." path parts.
@@ -116,14 +106,12 @@ def _get_http_response_filename(resp, link):
     """
     filename = link.filename  # fallback
     # Have a look at the Content-Disposition header for a better guess
-    content_disposition = resp.headers.get('content-disposition')
+    content_disposition = resp.headers.get("content-disposition")
     if content_disposition:
         filename = parse_content_disposition(content_disposition, filename)
     ext = splitext(filename)[1]  # type: Optional[str]
     if not ext:
-        ext = mimetypes.guess_extension(
-            resp.headers.get('content-type', '')
-        )
+        ext = mimetypes.guess_extension(resp.headers.get("content-type", ""))
         if ext:
             filename += ext
     if not ext and link.url != resp.url:
@@ -135,7 +123,7 @@ def _get_http_response_filename(resp, link):
 
 def _http_get_download(session, link):
     # type: (PipSession, Link) -> Response
-    target_url = link.url.split('#', 1)[0]
+    target_url = link.url.split("#", 1)[0]
     resp = session.get(target_url, headers=HEADERS, stream=True)
     raise_for_status(resp)
     return resp
@@ -167,15 +155,14 @@ def __call__(self, link, location):
         filepath = os.path.join(location, filename)
 
         chunks = _prepare_download(resp, link, self._progress_bar)
-        with open(filepath, 'wb') as content_file:
+        with open(filepath, "wb") as content_file:
             for chunk in chunks:
                 content_file.write(chunk)
-        content_type = resp.headers.get('Content-Type', '')
+        content_type = resp.headers.get("Content-Type", "")
         return filepath, content_type
 
 
 class BatchDownloader(object):
-
     def __init__(
         self,
         session,  # type: PipSession
@@ -195,7 +182,8 @@ def __call__(self, links, location):
                 assert e.response is not None
                 logger.critical(
                     "HTTP error %s while getting %s",
-                    e.response.status_code, link,
+                    e.response.status_code,
+                    link,
                 )
                 raise
 
@@ -203,8 +191,8 @@ def __call__(self, links, location):
             filepath = os.path.join(location, filename)
 
             chunks = _prepare_download(resp, link, self._progress_bar)
-            with open(filepath, 'wb') as content_file:
+            with open(filepath, "wb") as content_file:
                 for chunk in chunks:
                     content_file.write(chunk)
-            content_type = resp.headers.get('Content-Type', '')
+            content_type = resp.headers.get("Content-Type", "")
             yield link.url, (filepath, content_type)
diff --git a/src/pip/_internal/network/lazy_wheel.py b/src/pip/_internal/network/lazy_wheel.py
index a0f9e151dd7..b09c37cbed0 100644
--- a/src/pip/_internal/network/lazy_wheel.py
+++ b/src/pip/_internal/network/lazy_wheel.py
@@ -1,6 +1,6 @@
 """Lazy ZIP over HTTP"""
 
-__all__ = ['HTTPRangeRequestUnsupported', 'dist_from_wheel_url']
+__all__ = ["HTTPRangeRequestUnsupported", "dist_from_wheel_url"]
 
 from bisect import bisect_left, bisect_right
 from contextlib import contextmanager
@@ -10,11 +10,7 @@
 from pip._vendor.requests.models import CONTENT_CHUNK_SIZE
 from pip._vendor.six.moves import range
 
-from pip._internal.network.utils import (
-    HEADERS,
-    raise_for_status,
-    response_chunks,
-)
+from pip._internal.network.utils import HEADERS, raise_for_status, response_chunks
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 from pip._internal.utils.wheel import pkg_resources_distribution_for_wheel
 
@@ -64,20 +60,20 @@ def __init__(self, url, session, chunk_size=CONTENT_CHUNK_SIZE):
         raise_for_status(head)
         assert head.status_code == 200
         self._session, self._url, self._chunk_size = session, url, chunk_size
-        self._length = int(head.headers['Content-Length'])
+        self._length = int(head.headers["Content-Length"])
         self._file = NamedTemporaryFile()
         self.truncate(self._length)
         self._left = []  # type: List[int]
         self._right = []  # type: List[int]
-        if 'bytes' not in head.headers.get('Accept-Ranges', 'none'):
-            raise HTTPRangeRequestUnsupported('range request is not supported')
+        if "bytes" not in head.headers.get("Accept-Ranges", "none"):
+            raise HTTPRangeRequestUnsupported("range request is not supported")
         self._check_zip()
 
     @property
     def mode(self):
         # type: () -> str
         """Opening mode, which is always rb."""
-        return 'rb'
+        return "rb"
 
     @property
     def name(self):
@@ -111,9 +107,9 @@ def read(self, size=-1):
         """
         download_size = max(size, self._chunk_size)
         start, length = self.tell(), self._length
-        stop = length if size < 0 else min(start+download_size, length)
-        start = max(0, stop-download_size)
-        self._download(start, stop-1)
+        stop = length if size < 0 else min(start + download_size, length)
+        start = max(0, stop - download_size)
+        self._download(start, stop - 1)
         return self._file.read(size)
 
     def readable(self):
@@ -195,9 +191,9 @@ def _stream_response(self, start, end, base_headers=HEADERS):
         # type: (int, int, Dict[str, str]) -> Response
         """Return HTTP response to a range request from start to end."""
         headers = base_headers.copy()
-        headers['Range'] = 'bytes={}-{}'.format(start, end)
+        headers["Range"] = "bytes={}-{}".format(start, end)
         # TODO: Get range requests to be correctly cached
-        headers['Cache-Control'] = 'no-cache'
+        headers["Cache-Control"] = "no-cache"
         return self._session.get(self._url, headers=headers, stream=True)
 
     def _merge(self, start, end, left, right):
@@ -211,11 +207,11 @@ def _merge(self, start, end, left, right):
             right (int): Index after last overlapping downloaded data
         """
         lslice, rslice = self._left[left:right], self._right[left:right]
-        i = start = min([start]+lslice[:1])
-        end = max([end]+rslice[-1:])
+        i = start = min([start] + lslice[:1])
+        end = max([end] + rslice[-1:])
         for j, k in zip(lslice, rslice):
             if j > i:
-                yield i, j-1
+                yield i, j - 1
             i = k + 1
         if i <= end:
             yield i, end
diff --git a/src/pip/_internal/network/session.py b/src/pip/_internal/network/session.py
index 176f0fb682c..2e988078720 100644
--- a/src/pip/_internal/network/session.py
+++ b/src/pip/_internal/network/session.py
@@ -25,6 +25,7 @@
 from pip import __version__
 from pip._internal.network.auth import MultiDomainBasicAuth
 from pip._internal.network.cache import SafeFileCache
+
 # Import ssl from compat so the initial import occurs in only one place.
 from pip._internal.utils.compat import has_tls, ipaddress
 from pip._internal.utils.glibc import libc_ver
@@ -73,13 +74,13 @@
 # For more background, see: https://github.com/pypa/pip/issues/5499
 CI_ENVIRONMENT_VARIABLES = (
     # Azure Pipelines
-    'BUILD_BUILDID',
+    "BUILD_BUILDID",
     # Jenkins
-    'BUILD_ID',
+    "BUILD_ID",
     # AppVeyor, CircleCI, Codeship, Gitlab CI, Shippable, Travis CI
-    'CI',
+    "CI",
     # Explicit environment variable.
-    'PIP_IS_CI',
+    "PIP_IS_CI",
 )
 
 
@@ -106,33 +107,38 @@ def user_agent():
         },
     }
 
-    if data["implementation"]["name"] == 'CPython':
+    if data["implementation"]["name"] == "CPython":
         data["implementation"]["version"] = platform.python_version()
-    elif data["implementation"]["name"] == 'PyPy':
-        if sys.pypy_version_info.releaselevel == 'final':
+    elif data["implementation"]["name"] == "PyPy":
+        if sys.pypy_version_info.releaselevel == "final":
             pypy_version_info = sys.pypy_version_info[:3]
         else:
             pypy_version_info = sys.pypy_version_info
         data["implementation"]["version"] = ".".join(
             [str(x) for x in pypy_version_info]
         )
-    elif data["implementation"]["name"] == 'Jython':
+    elif data["implementation"]["name"] == "Jython":
         # Complete Guess
         data["implementation"]["version"] = platform.python_version()
-    elif data["implementation"]["name"] == 'IronPython':
+    elif data["implementation"]["name"] == "IronPython":
         # Complete Guess
         data["implementation"]["version"] = platform.python_version()
 
     if sys.platform.startswith("linux"):
         from pip._vendor import distro
-        distro_infos = dict(filter(
-            lambda x: x[1],
-            zip(["name", "version", "id"], distro.linux_distribution()),
-        ))
-        libc = dict(filter(
-            lambda x: x[1],
-            zip(["lib", "version"], libc_ver()),
-        ))
+
+        distro_infos = dict(
+            filter(
+                lambda x: x[1],
+                zip(["name", "version", "id"], distro.linux_distribution()),
+            )
+        )
+        libc = dict(
+            filter(
+                lambda x: x[1],
+                zip(["lib", "version"], libc_ver()),
+            )
+        )
         if libc:
             distro_infos["libc"] = libc
         if distro_infos:
@@ -152,6 +158,7 @@ def user_agent():
 
     if has_tls():
         import _ssl as ssl
+
         data["openssl_version"] = ssl.OPENSSL_VERSION
 
     setuptools_version = get_installed_version("setuptools")
@@ -175,9 +182,9 @@ def user_agent():
 
 
 class LocalFSAdapter(BaseAdapter):
-
-    def send(self, request, stream=None, timeout=None, verify=None, cert=None,
-             proxies=None):
+    def send(
+        self, request, stream=None, timeout=None, verify=None, cert=None, proxies=None
+    ):
         pathname = url_to_path(request.url)
 
         resp = Response()
@@ -192,11 +199,13 @@ def send(self, request, stream=None, timeout=None, verify=None, cert=None,
         else:
             modified = email.utils.formatdate(stats.st_mtime, usegmt=True)
             content_type = mimetypes.guess_type(pathname)[0] or "text/plain"
-            resp.headers = CaseInsensitiveDict({
-                "Content-Type": content_type,
-                "Content-Length": stats.st_size,
-                "Last-Modified": modified,
-            })
+            resp.headers = CaseInsensitiveDict(
+                {
+                    "Content-Type": content_type,
+                    "Content-Length": stats.st_size,
+                    "Last-Modified": modified,
+                }
+            )
 
             resp.raw = open(pathname, "rb")
             resp.close = resp.raw.close
@@ -208,7 +217,6 @@ def close(self):
 
 
 class InsecureHTTPAdapter(HTTPAdapter):
-
     def cert_verify(self, conn, url, verify, cert):
         super(InsecureHTTPAdapter, self).cert_verify(
             conn=conn, url=url, verify=False, cert=cert
@@ -216,7 +224,6 @@ def cert_verify(self, conn, url, verify, cert):
 
 
 class InsecureCacheControlAdapter(CacheControlAdapter):
-
     def cert_verify(self, conn, url, verify, cert):
         super(InsecureCacheControlAdapter, self).cert_verify(
             conn=conn, url=url, verify=False, cert=cert
@@ -255,7 +262,6 @@ def __init__(self, *args, **kwargs):
             # Set the total number of retries that a particular request can
             # have.
             total=retries,
-
             # A 503 error from PyPI typically means that the Fastly -> Origin
             # connection got interrupted in some way. A 503 error in general
             # is typically considered a transient error so we'll go ahead and
@@ -263,7 +269,6 @@ def __init__(self, *args, **kwargs):
             # A 500 may indicate transient error in Amazon S3
             # A 520 or 527 - may indicate transient error in CloudFlare
             status_forcelist=[500, 503, 520, 527],
-
             # Add a small amount of back off between failed requests in
             # order to prevent hammering the service.
             backoff_factor=0.25,
@@ -320,46 +325,42 @@ def add_trusted_host(self, host, source=None, suppress_logging=False):
             string came from.
         """
         if not suppress_logging:
-            msg = 'adding trusted host: {!r}'.format(host)
+            msg = "adding trusted host: {!r}".format(host)
             if source is not None:
-                msg += ' (from {})'.format(source)
+                msg += " (from {})".format(source)
             logger.info(msg)
 
         host_port = parse_netloc(host)
         if host_port not in self.pip_trusted_origins:
             self.pip_trusted_origins.append(host_port)
 
-        self.mount(
-            build_url_from_netloc(host) + '/',
-            self._trusted_host_adapter
-        )
+        self.mount(build_url_from_netloc(host) + "/", self._trusted_host_adapter)
         if not host_port[1]:
             # Mount wildcard ports for the same host.
-            self.mount(
-                build_url_from_netloc(host) + ':',
-                self._trusted_host_adapter
-            )
+            self.mount(build_url_from_netloc(host) + ":", self._trusted_host_adapter)
 
     def iter_secure_origins(self):
         # type: () -> Iterator[SecureOrigin]
         for secure_origin in SECURE_ORIGINS:
             yield secure_origin
         for host, port in self.pip_trusted_origins:
-            yield ('*', host, '*' if port is None else port)
+            yield ("*", host, "*" if port is None else port)
 
     def is_secure_origin(self, location):
         # type: (Link) -> bool
         # Determine if this url used a secure transport mechanism
         parsed = urllib_parse.urlparse(str(location))
         origin_protocol, origin_host, origin_port = (
-            parsed.scheme, parsed.hostname, parsed.port,
+            parsed.scheme,
+            parsed.hostname,
+            parsed.port,
         )
 
         # The protocol to use to see if the protocol matches.
         # Don't count the repository type as part of the protocol: in
         # cases such as "git+ssh", only use "ssh". (I.e., Only verify against
         # the last scheme.)
-        origin_protocol = origin_protocol.rsplit('+', 1)[-1]
+        origin_protocol = origin_protocol.rsplit("+", 1)[-1]
 
         # Determine if our origin is a secure origin by looking through our
         # hardcoded list of secure origins, as well as any additional ones
@@ -371,20 +372,16 @@ def is_secure_origin(self, location):
 
             try:
                 addr = ipaddress.ip_address(
-                    None
-                    if origin_host is None
-                    else six.ensure_text(origin_host)
-                )
-                network = ipaddress.ip_network(
-                    six.ensure_text(secure_host)
+                    None if origin_host is None else six.ensure_text(origin_host)
                 )
+                network = ipaddress.ip_network(six.ensure_text(secure_host))
             except ValueError:
                 # We don't have both a valid address or a valid network, so
                 # we'll check this origin against hostnames.
                 if (
-                    origin_host and
-                    origin_host.lower() != secure_host.lower() and
-                    secure_host != "*"
+                    origin_host
+                    and origin_host.lower() != secure_host.lower()
+                    and secure_host != "*"
                 ):
                     continue
             else:
@@ -395,9 +392,9 @@ def is_secure_origin(self, location):
 
             # Check to see if the port matches.
             if (
-                origin_port != secure_port and
-                secure_port != "*" and
-                secure_port is not None
+                origin_port != secure_port
+                and secure_port != "*"
+                and secure_port is not None
             ):
                 continue
 
diff --git a/src/pip/_internal/network/utils.py b/src/pip/_internal/network/utils.py
index 907b3fed49a..f3fbbd47aa4 100644
--- a/src/pip/_internal/network/utils.py
+++ b/src/pip/_internal/network/utils.py
@@ -25,31 +25,37 @@
 # you're not asking for a compressed file and will then decompress it
 # before sending because if that's the case I don't think it'll ever be
 # possible to make this work.
-HEADERS = {'Accept-Encoding': 'identity'}  # type: Dict[str, str]
+HEADERS = {"Accept-Encoding": "identity"}  # type: Dict[str, str]
 
 
 def raise_for_status(resp):
     # type: (Response) -> None
-    http_error_msg = u''
+    http_error_msg = u""
     if isinstance(resp.reason, bytes):
         # We attempt to decode utf-8 first because some servers
         # choose to localize their reason strings. If the string
         # isn't utf-8, we fall back to iso-8859-1 for all other
         # encodings.
         try:
-            reason = resp.reason.decode('utf-8')
+            reason = resp.reason.decode("utf-8")
         except UnicodeDecodeError:
-            reason = resp.reason.decode('iso-8859-1')
+            reason = resp.reason.decode("iso-8859-1")
     else:
         reason = resp.reason
 
     if 400 <= resp.status_code < 500:
-        http_error_msg = u'%s Client Error: %s for url: %s' % (
-            resp.status_code, reason, resp.url)
+        http_error_msg = u"%s Client Error: %s for url: %s" % (
+            resp.status_code,
+            reason,
+            resp.url,
+        )
 
     elif 500 <= resp.status_code < 600:
-        http_error_msg = u'%s Server Error: %s for url: %s' % (
-            resp.status_code, reason, resp.url)
+        http_error_msg = u"%s Server Error: %s for url: %s" % (
+            resp.status_code,
+            reason,
+            resp.url,
+        )
 
     if http_error_msg:
         raise NetworkConnectionError(http_error_msg, response=resp)
@@ -57,8 +63,7 @@ def raise_for_status(resp):
 
 def response_chunks(response, chunk_size=CONTENT_CHUNK_SIZE):
     # type: (Response, int) -> Iterator[bytes]
-    """Given a requests Response, provide the data chunks.
-    """
+    """Given a requests Response, provide the data chunks."""
     try:
         # Special case for urllib3.
         for chunk in response.raw.stream(
diff --git a/src/pip/_internal/network/xmlrpc.py b/src/pip/_internal/network/xmlrpc.py
index 504018f28fe..1c60e671a13 100644
--- a/src/pip/_internal/network/xmlrpc.py
+++ b/src/pip/_internal/network/xmlrpc.py
@@ -38,9 +38,10 @@ def request(self, host, handler, request_body, verbose=False):
         parts = (self._scheme, host, handler, None, None, None)
         url = urllib_parse.urlunparse(parts)
         try:
-            headers = {'Content-Type': 'text/xml'}
-            response = self._session.post(url, data=request_body,
-                                          headers=headers, stream=True)
+            headers = {"Content-Type": "text/xml"}
+            response = self._session.post(
+                url, data=request_body, headers=headers, stream=True
+            )
             raise_for_status(response)
             self.verbose = verbose
             return self.parse_response(response.raw)
@@ -48,6 +49,7 @@ def request(self, host, handler, request_body, verbose=False):
             assert exc.response
             logger.critical(
                 "HTTP error %s while getting %s",
-                exc.response.status_code, url,
+                exc.response.status_code,
+                url,
             )
             raise
diff --git a/src/pip/_internal/operations/build/metadata.py b/src/pip/_internal/operations/build/metadata.py
index 5709962b09e..0c1ae5e7f54 100644
--- a/src/pip/_internal/operations/build/metadata.py
+++ b/src/pip/_internal/operations/build/metadata.py
@@ -19,9 +19,7 @@ def generate_metadata(build_env, backend):
 
     Returns the generated metadata directory.
     """
-    metadata_tmpdir = TempDirectory(
-        kind="modern-metadata", globally_managed=True
-    )
+    metadata_tmpdir = TempDirectory(kind="modern-metadata", globally_managed=True)
 
     metadata_dir = metadata_tmpdir.path
 
@@ -31,8 +29,6 @@ def generate_metadata(build_env, backend):
         # consider the possibility that this hook doesn't exist.
         runner = runner_with_spinner_message("Preparing wheel metadata")
         with backend.subprocess_runner(runner):
-            distinfo_dir = backend.prepare_metadata_for_build_wheel(
-                metadata_dir
-            )
+            distinfo_dir = backend.prepare_metadata_for_build_wheel(metadata_dir)
 
     return os.path.join(metadata_dir, distinfo_dir)
diff --git a/src/pip/_internal/operations/build/metadata_legacy.py b/src/pip/_internal/operations/build/metadata_legacy.py
index 14762aef3c0..b004ec4a9ed 100644
--- a/src/pip/_internal/operations/build/metadata_legacy.py
+++ b/src/pip/_internal/operations/build/metadata_legacy.py
@@ -18,22 +18,15 @@
 
 def _find_egg_info(directory):
     # type: (str) -> str
-    """Find an .egg-info subdirectory in `directory`.
-    """
-    filenames = [
-        f for f in os.listdir(directory) if f.endswith(".egg-info")
-    ]
+    """Find an .egg-info subdirectory in `directory`."""
+    filenames = [f for f in os.listdir(directory) if f.endswith(".egg-info")]
 
     if not filenames:
-        raise InstallationError(
-            "No .egg-info directory found in {}".format(directory)
-        )
+        raise InstallationError("No .egg-info directory found in {}".format(directory))
 
     if len(filenames) > 1:
         raise InstallationError(
-            "More than one .egg-info directory found in {}".format(
-                directory
-            )
+            "More than one .egg-info directory found in {}".format(directory)
         )
 
     return os.path.join(directory, filenames[0])
@@ -52,13 +45,12 @@ def generate_metadata(
     Returns the generated metadata directory.
     """
     logger.debug(
-        'Running setup.py (path:%s) egg_info for package %s',
-        setup_py_path, details,
+        "Running setup.py (path:%s) egg_info for package %s",
+        setup_py_path,
+        details,
     )
 
-    egg_info_dir = TempDirectory(
-        kind="pip-egg-info", globally_managed=True
-    ).path
+    egg_info_dir = TempDirectory(kind="pip-egg-info", globally_managed=True).path
 
     args = make_setuptools_egg_info_args(
         setup_py_path,
@@ -70,7 +62,7 @@ def generate_metadata(
         call_subprocess(
             args,
             cwd=source_dir,
-            command_desc='python setup.py egg_info',
+            command_desc="python setup.py egg_info",
         )
 
     # Return the .egg-info directory.
diff --git a/src/pip/_internal/operations/build/wheel.py b/src/pip/_internal/operations/build/wheel.py
index d16ee0966e1..8dc5babc76b 100644
--- a/src/pip/_internal/operations/build/wheel.py
+++ b/src/pip/_internal/operations/build/wheel.py
@@ -27,14 +27,16 @@ def build_wheel_pep517(
     assert metadata_directory is not None
     if build_options:
         # PEP 517 does not support --build-options
-        logger.error('Cannot build wheel for %s using PEP 517 when '
-                     '--build-option is present', name)
+        logger.error(
+            "Cannot build wheel for %s using PEP 517 when " "--build-option is present",
+            name,
+        )
         return None
     try:
-        logger.debug('Destination directory: %s', tempd)
+        logger.debug("Destination directory: %s", tempd)
 
         runner = runner_with_spinner_message(
-            'Building wheel for {} (PEP 517)'.format(name)
+            "Building wheel for {} (PEP 517)".format(name)
         )
         with backend.subprocess_runner(runner):
             wheel_name = backend.build_wheel(
@@ -42,6 +44,6 @@ def build_wheel_pep517(
                 metadata_directory=metadata_directory,
             )
     except Exception:
-        logger.error('Failed building wheel for %s', name)
+        logger.error("Failed building wheel for %s", name)
         return None
     return os.path.join(tempd, wheel_name)
diff --git a/src/pip/_internal/operations/build/wheel_legacy.py b/src/pip/_internal/operations/build/wheel_legacy.py
index 37dc876acbd..9ab4ef44256 100644
--- a/src/pip/_internal/operations/build/wheel_legacy.py
+++ b/src/pip/_internal/operations/build/wheel_legacy.py
@@ -2,9 +2,7 @@
 import os.path
 
 from pip._internal.cli.spinners import open_spinner
-from pip._internal.utils.setuptools_build import (
-    make_setuptools_bdist_wheel_args,
-)
+from pip._internal.utils.setuptools_build import make_setuptools_bdist_wheel_args
 from pip._internal.utils.subprocess import (
     LOG_DIVIDER,
     call_subprocess,
@@ -25,16 +23,16 @@ def format_command_result(
     # type: (...) -> str
     """Format command information for logging."""
     command_desc = format_command_args(command_args)
-    text = 'Command arguments: {}\n'.format(command_desc)
+    text = "Command arguments: {}\n".format(command_desc)
 
     if not command_output:
-        text += 'Command output: None'
+        text += "Command output: None"
     elif logger.getEffectiveLevel() > logging.DEBUG:
-        text += 'Command output: [use --verbose to show]'
+        text += "Command output: [use --verbose to show]"
     else:
-        if not command_output.endswith('\n'):
-            command_output += '\n'
-        text += 'Command output:\n{}{}'.format(command_output, LOG_DIVIDER)
+        if not command_output.endswith("\n"):
+            command_output += "\n"
+        text += "Command output:\n{}{}".format(command_output, LOG_DIVIDER)
 
     return text
 
@@ -51,17 +49,15 @@ def get_legacy_build_wheel_path(
     # Sort for determinism.
     names = sorted(names)
     if not names:
-        msg = (
-            'Legacy build of wheel for {!r} created no files.\n'
-        ).format(name)
+        msg = ("Legacy build of wheel for {!r} created no files.\n").format(name)
         msg += format_command_result(command_args, command_output)
         logger.warning(msg)
         return None
 
     if len(names) > 1:
         msg = (
-            'Legacy build of wheel for {!r} created more than one file.\n'
-            'Filenames (choosing first): {}\n'
+            "Legacy build of wheel for {!r} created more than one file.\n"
+            "Filenames (choosing first): {}\n"
         ).format(name, names)
         msg += format_command_result(command_args, command_output)
         logger.warning(msg)
@@ -89,9 +85,9 @@ def build_wheel_legacy(
         destination_dir=tempd,
     )
 
-    spin_message = 'Building wheel for {} (setup.py)'.format(name)
+    spin_message = "Building wheel for {} (setup.py)".format(name)
     with open_spinner(spin_message) as spinner:
-        logger.debug('Destination directory: %s', tempd)
+        logger.debug("Destination directory: %s", tempd)
 
         try:
             output = call_subprocess(
@@ -101,7 +97,7 @@ def build_wheel_legacy(
             )
         except Exception:
             spinner.finish("error")
-            logger.error('Failed building wheel for %s', name)
+            logger.error("Failed building wheel for %s", name)
             return None
 
         names = os.listdir(tempd)
diff --git a/src/pip/_internal/operations/check.py b/src/pip/_internal/operations/check.py
index 52e8116e199..5e4eb674c92 100644
--- a/src/pip/_internal/operations/check.py
+++ b/src/pip/_internal/operations/check.py
@@ -7,9 +7,7 @@
 from pip._vendor.packaging.utils import canonicalize_name
 from pip._vendor.pkg_resources import RequirementParseError
 
-from pip._internal.distributions import (
-    make_distribution_for_install_requirement,
-)
+from pip._internal.distributions import make_distribution_for_install_requirement
 from pip._internal.utils.misc import get_installed_distributions
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 
@@ -21,7 +19,7 @@
     from pip._internal.req.req_install import InstallRequirement
 
     # Shorthands
-    PackageSet = Dict[str, 'PackageDetails']
+    PackageSet = Dict[str, "PackageDetails"]
     Missing = Tuple[str, Any]
     Conflicting = Tuple[str, str, Any]
 
@@ -30,13 +28,12 @@
     CheckResult = Tuple[MissingDict, ConflictingDict]
     ConflictDetails = Tuple[PackageSet, CheckResult]
 
-PackageDetails = namedtuple('PackageDetails', ['version', 'requires'])
+PackageDetails = namedtuple("PackageDetails", ["version", "requires"])
 
 
 def create_package_set_from_installed(**kwargs):
     # type: (**Any) -> Tuple[PackageSet, bool]
-    """Converts a list of distributions into a PackageSet.
-    """
+    """Converts a list of distributions into a PackageSet."""
     # Default to using all packages installed on the system
     if kwargs == {}:
         kwargs = {"local_only": False, "skip": ()}
@@ -115,14 +112,13 @@ def check_install_conflicts(to_install):
         package_set,
         check_package_set(
             package_set, should_ignore=lambda name: name not in whitelist
-        )
+        ),
     )
 
 
 def _simulate_installation_of(to_install, package_set):
     # type: (List[InstallRequirement], PackageSet) -> Set[str]
-    """Computes the version of packages after installing to_install.
-    """
+    """Computes the version of packages after installing to_install."""
 
     # Keep track of packages that were installed
     installed = set()
diff --git a/src/pip/_internal/operations/freeze.py b/src/pip/_internal/operations/freeze.py
index b98b8cd79b5..b9088367dc1 100644
--- a/src/pip/_internal/operations/freeze.py
+++ b/src/pip/_internal/operations/freeze.py
@@ -18,10 +18,7 @@
     direct_url_as_pep440_direct_reference,
     dist_get_direct_url,
 )
-from pip._internal.utils.misc import (
-    dist_is_editable,
-    get_installed_distributions,
-)
+from pip._internal.utils.misc import dist_is_editable, get_installed_distributions
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 
 if MYPY_CHECK_RUNNING:
@@ -56,20 +53,17 @@ def freeze(
     isolated=False,  # type: bool
     wheel_cache=None,  # type: Optional[WheelCache]
     exclude_editable=False,  # type: bool
-    skip=()  # type: Container[str]
+    skip=(),  # type: Container[str]
 ):
     # type: (...) -> Iterator[str]
     find_links = find_links or []
 
     for link in find_links:
-        yield '-f {}'.format(link)
+        yield "-f {}".format(link)
     installations = {}  # type: Dict[str, FrozenRequirement]
 
     for dist in get_installed_distributions(
-            local_only=local_only,
-            skip=(),
-            user_only=user_only,
-            paths=paths
+        local_only=local_only, skip=(), user_only=user_only, paths=paths
     ):
         try:
             req = FrozenRequirement.from_dist(dist)
@@ -79,8 +73,7 @@ def freeze(
             # location. We also include the exception message to aid
             # troubleshooting.
             logger.warning(
-                'Could not generate requirement for distribution %r: %s',
-                dist, exc
+                "Could not generate requirement for distribution %r: %s", dist, exc
             )
             continue
         if exclude_editable and req.editable:
@@ -99,35 +92,43 @@ def freeze(
         for req_file_path in requirement:
             with open(req_file_path) as req_file:
                 for line in req_file:
-                    if (not line.strip() or
-                            line.strip().startswith('#') or
-                            line.startswith((
-                                '-r', '--requirement',
-                                '-f', '--find-links',
-                                '-i', '--index-url',
-                                '--pre',
-                                '--trusted-host',
-                                '--process-dependency-links',
-                                '--extra-index-url',
-                                '--use-feature'))):
+                    if (
+                        not line.strip()
+                        or line.strip().startswith("#")
+                        or line.startswith(
+                            (
+                                "-r",
+                                "--requirement",
+                                "-f",
+                                "--find-links",
+                                "-i",
+                                "--index-url",
+                                "--pre",
+                                "--trusted-host",
+                                "--process-dependency-links",
+                                "--extra-index-url",
+                                "--use-feature",
+                            )
+                        )
+                    ):
                         line = line.rstrip()
                         if line not in emitted_options:
                             emitted_options.add(line)
                             yield line
                         continue
 
-                    if line.startswith('-e') or line.startswith('--editable'):
-                        if line.startswith('-e'):
+                    if line.startswith("-e") or line.startswith("--editable"):
+                        if line.startswith("-e"):
                             line = line[2:].strip()
                         else:
-                            line = line[len('--editable'):].strip().lstrip('=')
+                            line = line[len("--editable") :].strip().lstrip("=")
                         line_req = install_req_from_editable(
                             line,
                             isolated=isolated,
                         )
                     else:
                         line_req = install_req_from_line(
-                            COMMENT_RE.sub('', line).strip(),
+                            COMMENT_RE.sub("", line).strip(),
                             isolated=isolated,
                         )
 
@@ -135,15 +136,15 @@ def freeze(
                         logger.info(
                             "Skipping line in requirement file [%s] because "
                             "it's not clear what it would install: %s",
-                            req_file_path, line.strip(),
+                            req_file_path,
+                            line.strip(),
                         )
                         logger.info(
                             "  (add #egg=PackageName to the URL to avoid"
                             " this warning)"
                         )
                     else:
-                        line_req_canonical_name = canonicalize_name(
-                            line_req.name)
+                        line_req_canonical_name = canonicalize_name(line_req.name)
                         if line_req_canonical_name not in installations:
                             # either it's not installed, or it is installed
                             # but has been processed already
@@ -152,14 +153,13 @@ def freeze(
                                     "Requirement file [%s] contains %s, but "
                                     "package %r is not installed",
                                     req_file_path,
-                                    COMMENT_RE.sub('', line).strip(),
-                                    line_req.name
+                                    COMMENT_RE.sub("", line).strip(),
+                                    line_req.name,
                                 )
                             else:
                                 req_files[line_req.name].append(req_file_path)
                         else:
-                            yield str(installations[
-                                line_req_canonical_name]).rstrip()
+                            yield str(installations[line_req_canonical_name]).rstrip()
                             del installations[line_req_canonical_name]
                             req_files[line_req.name].append(req_file_path)
 
@@ -167,15 +167,14 @@ def freeze(
         # single requirements file or in different requirements files).
         for name, files in six.iteritems(req_files):
             if len(files) > 1:
-                logger.warning("Requirement %s included multiple times [%s]",
-                               name, ', '.join(sorted(set(files))))
+                logger.warning(
+                    "Requirement %s included multiple times [%s]",
+                    name,
+                    ", ".join(sorted(set(files))),
+                )
 
-        yield(
-            '## The following requirements were added by '
-            'pip freeze:'
-        )
-    for installation in sorted(
-            installations.values(), key=lambda x: x.name.lower()):
+        yield ("## The following requirements were added by " "pip freeze:")
+    for installation in sorted(installations.values(), key=lambda x: x.name.lower()):
         if installation.canonical_name not in skip:
             yield str(installation).rstrip()
 
@@ -192,17 +191,17 @@ def get_requirement_info(dist):
     location = os.path.normcase(os.path.abspath(dist.location))
 
     from pip._internal.vcs import RemoteNotFoundError, vcs
+
     vcs_backend = vcs.get_backend_for_dir(location)
 
     if vcs_backend is None:
         req = dist.as_requirement()
         logger.debug(
-            'No VCS found for editable requirement "%s" in: %r', req,
+            'No VCS found for editable requirement "%s" in: %r',
+            req,
             location,
         )
-        comments = [
-            '# Editable install with no version control ({})'.format(req)
-        ]
+        comments = ["# Editable install with no version control ({})".format(req)]
         return (location, True, comments)
 
     try:
@@ -210,16 +209,17 @@ def get_requirement_info(dist):
     except RemoteNotFoundError:
         req = dist.as_requirement()
         comments = [
-            '# Editable {} install with no remote ({})'.format(
-                type(vcs_backend).__name__, req,
+            "# Editable {} install with no remote ({})".format(
+                type(vcs_backend).__name__,
+                req,
             )
         ]
         return (location, True, comments)
 
     except BadCommand:
         logger.warning(
-            'cannot determine version of editable source in %s '
-            '(%s command not found in path)',
+            "cannot determine version of editable source in %s "
+            "(%s command not found in path)",
             location,
             vcs_backend.name,
         )
@@ -228,16 +228,15 @@ def get_requirement_info(dist):
     except InstallationError as exc:
         logger.warning(
             "Error when trying to get requirement for VCS system %s, "
-            "falling back to uneditable format", exc
+            "falling back to uneditable format",
+            exc,
         )
     else:
         if req is not None:
             return (req, True, [])
 
-    logger.warning(
-        'Could not determine repository location of %s', location
-    )
-    comments = ['## !! Could not determine repository location']
+    logger.warning("Could not determine repository location of %s", location)
+    comments = ["## !! Could not determine repository location"]
 
     return (None, False, comments)
 
@@ -276,5 +275,5 @@ def __str__(self):
         # type: () -> str
         req = self.req
         if self.editable:
-            req = '-e {}'.format(req)
-        return '\n'.join(list(self.comments) + [str(req)]) + '\n'
+            req = "-e {}".format(req)
+        return "\n".join(list(self.comments) + [str(req)]) + "\n"
diff --git a/src/pip/_internal/operations/install/editable_legacy.py b/src/pip/_internal/operations/install/editable_legacy.py
index a668a61dc60..0990382d4ce 100644
--- a/src/pip/_internal/operations/install/editable_legacy.py
+++ b/src/pip/_internal/operations/install/editable_legacy.py
@@ -32,7 +32,7 @@ def install_editable(
     """Install a package in editable mode. Most arguments are pass-through
     to setuptools.
     """
-    logger.info('Running setup.py develop for %s', name)
+    logger.info("Running setup.py develop for %s", name)
 
     args = make_setuptools_develop_args(
         setup_py_path,
diff --git a/src/pip/_internal/operations/install/legacy.py b/src/pip/_internal/operations/install/legacy.py
index 87227d5fed6..0dc16615ac4 100644
--- a/src/pip/_internal/operations/install/legacy.py
+++ b/src/pip/_internal/operations/install/legacy.py
@@ -52,7 +52,7 @@ def install(
 
     with TempDirectory(kind="record") as temp_dir:
         try:
-            record_filename = os.path.join(temp_dir.path, 'install-record.txt')
+            record_filename = os.path.join(temp_dir.path, "install-record.txt")
             install_args = make_setuptools_install_args(
                 setup_py_path,
                 global_options=global_options,
@@ -77,7 +77,7 @@ def install(
                 )
 
             if not os.path.exists(record_filename):
-                logger.debug('Record file %s not found', record_filename)
+                logger.debug("Record file %s not found", record_filename)
                 # Signal to the caller that we didn't install the new package
                 return False
 
@@ -102,7 +102,7 @@ def prepend_root(path):
 
     for line in record_lines:
         directory = os.path.dirname(line)
-        if directory.endswith('.egg-info'):
+        if directory.endswith(".egg-info"):
             egg_info_dir = prepend_root(directory)
             break
     else:
@@ -118,13 +118,11 @@ def prepend_root(path):
         filename = line.strip()
         if os.path.isdir(filename):
             filename += os.path.sep
-        new_lines.append(
-            os.path.relpath(prepend_root(filename), egg_info_dir)
-        )
+        new_lines.append(os.path.relpath(prepend_root(filename), egg_info_dir))
     new_lines.sort()
     ensure_dir(egg_info_dir)
-    inst_files_path = os.path.join(egg_info_dir, 'installed-files.txt')
-    with open(inst_files_path, 'w') as f:
-        f.write('\n'.join(new_lines) + '\n')
+    inst_files_path = os.path.join(egg_info_dir, "installed-files.txt")
+    with open(inst_files_path, "w") as f:
+        f.write("\n".join(new_lines) + "\n")
 
     return True
diff --git a/src/pip/_internal/operations/install/wheel.py b/src/pip/_internal/operations/install/wheel.py
index af6b39052d9..c9f5967f70f 100644
--- a/src/pip/_internal/operations/install/wheel.py
+++ b/src/pip/_internal/operations/install/wheel.py
@@ -21,14 +21,7 @@
 from pip._vendor import pkg_resources
 from pip._vendor.distlib.scripts import ScriptMaker
 from pip._vendor.distlib.util import get_export_entry
-from pip._vendor.six import (
-    PY2,
-    ensure_str,
-    ensure_text,
-    itervalues,
-    reraise,
-    text_type,
-)
+from pip._vendor.six import PY2, ensure_str, ensure_text, itervalues, reraise, text_type
 from pip._vendor.six.moves import filterfalse, map
 
 from pip._internal.exceptions import InstallationError
@@ -36,12 +29,7 @@
 from pip._internal.models.direct_url import DIRECT_URL_METADATA_NAME, DirectUrl
 from pip._internal.models.scheme import SCHEME_KEYS
 from pip._internal.utils.filesystem import adjacent_tmp_file, replace
-from pip._internal.utils.misc import (
-    captured_stdout,
-    ensure_dir,
-    hash_file,
-    partition,
-)
+from pip._internal.utils.misc import captured_stdout, ensure_dir, hash_file, partition
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 from pip._internal.utils.unpacking import (
     current_umask,
@@ -49,10 +37,7 @@
     set_extracted_file_to_default_mode_plus_executable,
     zip_item_is_executable,
 )
-from pip._internal.utils.wheel import (
-    parse_wheel,
-    pkg_resources_distribution_for_wheel,
-)
+from pip._internal.utils.wheel import parse_wheel, pkg_resources_distribution_for_wheel
 
 # Use the custom cast function at runtime to make cast work,
 # and import typing.cast when performing pre-commit and type
@@ -85,7 +70,7 @@
     from pip._internal.models.scheme import Scheme
     from pip._internal.utils.filesystem import NamedTemporaryFileResult
 
-    RecordPath = NewType('RecordPath', text_type)
+    RecordPath = NewType("RecordPath", text_type)
     InstalledCSVRow = Tuple[RecordPath, str, Union[int, str]]
 
     class File(Protocol):
@@ -105,9 +90,7 @@ def rehash(path, blocksize=1 << 20):
     # type: (text_type, int) -> Tuple[str, str]
     """Return (encoded_digest, length) for path using hashlib.sha256()"""
     h, length = hash_file(path, blocksize)
-    digest = 'sha256=' + urlsafe_b64encode(
-        h.digest()
-    ).decode('latin1').rstrip('=')
+    digest = "sha256=" + urlsafe_b64encode(h.digest()).decode("latin1").rstrip("=")
     # unicode/str python2 issues
     return (digest, str(length))  # type: ignore
 
@@ -118,9 +101,9 @@ def csv_io_kwargs(mode):
     in the given mode.
     """
     if PY2:
-        return {'mode': '{}b'.format(mode)}
+        return {"mode": "{}b".format(mode)}
     else:
-        return {'mode': mode, 'newline': '', 'encoding': 'utf-8'}
+        return {"mode": mode, "newline": "", "encoding": "utf-8"}
 
 
 def fix_script(path):
@@ -131,14 +114,14 @@ def fix_script(path):
     # XXX RECORD hashes will need to be updated
     assert os.path.isfile(path)
 
-    with open(path, 'rb') as script:
+    with open(path, "rb") as script:
         firstline = script.readline()
-        if not firstline.startswith(b'#!python'):
+        if not firstline.startswith(b"#!python"):
             return False
         exename = sys.executable.encode(sys.getfilesystemencoding())
-        firstline = b'#!' + exename + os.linesep.encode("ascii")
+        firstline = b"#!" + exename + os.linesep.encode("ascii")
         rest = script.read()
-    with open(path, 'wb') as script:
+    with open(path, "wb") as script:
         script.write(firstline)
         script.write(rest)
     return True
@@ -153,8 +136,8 @@ def get_entrypoints(distribution):
     # type: (Distribution) -> Tuple[Dict[str, str], Dict[str, str]]
     # get the entry points and then the script names
     try:
-        console = distribution.get_entry_map('console_scripts')
-        gui = distribution.get_entry_map('gui_scripts')
+        console = distribution.get_entry_map("console_scripts")
+        gui = distribution.get_entry_map("gui_scripts")
     except KeyError:
         # Our dict-based Distribution raises KeyError if entry_points.txt
         # doesn't exist.
@@ -192,14 +175,15 @@ def message_about_scripts_not_on_PATH(scripts):
 
     # We don't want to warn for directories that are on PATH.
     not_warn_dirs = [
-        os.path.normcase(i).rstrip(os.sep) for i in
-        os.environ.get("PATH", "").split(os.pathsep)
+        os.path.normcase(i).rstrip(os.sep)
+        for i in os.environ.get("PATH", "").split(os.pathsep)
     ]
     # If an executable sits with sys.executable, we don't warn for it.
     #     This covers the case of venv invocations without activating the venv.
     not_warn_dirs.append(os.path.normcase(os.path.dirname(sys.executable)))
     warn_for = {
-        parent_dir: scripts for parent_dir, scripts in grouped_by_dir.items()
+        parent_dir: scripts
+        for parent_dir, scripts in grouped_by_dir.items()
         if os.path.normcase(parent_dir) not in not_warn_dirs
     }  # type: Dict[str, Set[str]]
     if not warn_for:
@@ -217,8 +201,9 @@ def message_about_scripts_not_on_PATH(scripts):
             )
 
         msg_lines.append(
-            "The {} installed in '{}' which is not on PATH."
-            .format(start_text, parent_dir)
+            "The {} installed in '{}' which is not on PATH.".format(
+                start_text, parent_dir
+            )
         )
 
     last_line_fmt = (
@@ -266,7 +251,7 @@ def _normalized_outrows(outrows):
     # For additional background, see--
     # https://github.com/pypa/pip/issues/5868
     return sorted(
-        (ensure_str(record_path, encoding='utf-8'), hash_, str(size))
+        (ensure_str(record_path, encoding="utf-8"), hash_, str(size))
         for record_path, hash_, size in outrows
     )
 
@@ -281,17 +266,19 @@ def _fs_to_record_path(path, relative_to=None):
     if relative_to is not None:
         # On Windows, do not handle relative paths if they belong to different
         # logical disks
-        if os.path.splitdrive(path)[0].lower() == \
-                os.path.splitdrive(relative_to)[0].lower():
+        if (
+            os.path.splitdrive(path)[0].lower()
+            == os.path.splitdrive(relative_to)[0].lower()
+        ):
             path = os.path.relpath(path, relative_to)
-    path = path.replace(os.path.sep, '/')
-    return cast('RecordPath', path)
+    path = path.replace(os.path.sep, "/")
+    return cast("RecordPath", path)
 
 
 def _parse_record_path(record_column):
     # type: (str) -> RecordPath
-    p = ensure_text(record_column, encoding='utf-8')
-    return cast('RecordPath', p)
+    p = ensure_text(record_column, encoding="utf-8")
+    return cast("RecordPath", p)
 
 
 def get_csv_rows_for_installed(
@@ -309,21 +296,21 @@ def get_csv_rows_for_installed(
     installed_rows = []  # type: List[InstalledCSVRow]
     for row in old_csv_rows:
         if len(row) > 3:
-            logger.warning('RECORD line has more than three elements: %s', row)
+            logger.warning("RECORD line has more than three elements: %s", row)
         old_record_path = _parse_record_path(row[0])
         new_record_path = installed.pop(old_record_path, old_record_path)
         if new_record_path in changed:
             digest, length = rehash(_record_to_fs_path(new_record_path))
         else:
-            digest = row[1] if len(row) > 1 else ''
-            length = row[2] if len(row) > 2 else ''
+            digest = row[1] if len(row) > 1 else ""
+            length = row[2] if len(row) > 2 else ""
         installed_rows.append((new_record_path, digest, length))
     for f in generated:
         path = _fs_to_record_path(f, lib_dir)
         digest, length = rehash(f)
         installed_rows.append((path, digest, length))
     for installed_record_path in itervalues(installed):
-        installed_rows.append((installed_record_path, '', ''))
+        installed_rows.append((installed_record_path, "", ""))
     return installed_rows
 
 
@@ -371,44 +358,42 @@ def get_console_script_specs(console):
     # DEFAULT
     #   - The default behavior is to install pip, pipX, pipX.Y, easy_install
     #     and easy_install-X.Y.
-    pip_script = console.pop('pip', None)
+    pip_script = console.pop("pip", None)
     if pip_script:
         if "ENSUREPIP_OPTIONS" not in os.environ:
-            scripts_to_generate.append('pip = ' + pip_script)
+            scripts_to_generate.append("pip = " + pip_script)
 
         if os.environ.get("ENSUREPIP_OPTIONS", "") != "altinstall":
             scripts_to_generate.append(
-                'pip{} = {}'.format(sys.version_info[0], pip_script)
+                "pip{} = {}".format(sys.version_info[0], pip_script)
             )
 
         scripts_to_generate.append(
-            'pip{} = {}'.format(get_major_minor_version(), pip_script)
+            "pip{} = {}".format(get_major_minor_version(), pip_script)
         )
         # Delete any other versioned pip entry points
-        pip_ep = [k for k in console if re.match(r'pip(\d(\.\d)?)?$', k)]
+        pip_ep = [k for k in console if re.match(r"pip(\d(\.\d)?)?$", k)]
         for k in pip_ep:
             del console[k]
-    easy_install_script = console.pop('easy_install', None)
+    easy_install_script = console.pop("easy_install", None)
     if easy_install_script:
         if "ENSUREPIP_OPTIONS" not in os.environ:
-            scripts_to_generate.append(
-                'easy_install = ' + easy_install_script
-            )
+            scripts_to_generate.append("easy_install = " + easy_install_script)
 
         scripts_to_generate.append(
-            'easy_install-{} = {}'.format(
+            "easy_install-{} = {}".format(
                 get_major_minor_version(), easy_install_script
             )
         )
         # Delete any other versioned easy_install entry points
         easy_install_ep = [
-            k for k in console if re.match(r'easy_install(-\d\.\d)?$', k)
+            k for k in console if re.match(r"easy_install(-\d\.\d)?$", k)
         ]
         for k in easy_install_ep:
             del console[k]
 
     # Generate the console entry points specified in the wheel
-    scripts_to_generate.extend(starmap('{} = {}'.format, console.items()))
+    scripts_to_generate.extend(starmap("{} = {}".format, console.items()))
 
     return scripts_to_generate
 
@@ -611,9 +596,7 @@ def make_data_scheme_file(record_path):
                     "Unknown scheme key used in {}: {} (for file {!r}). .data"
                     " directory contents should be in subdirectories named"
                     " with a valid scheme key ({})"
-                ).format(
-                    wheel_path, scheme_key, record_path, valid_scheme_keys
-                )
+                ).format(wheel_path, scheme_key, record_path, valid_scheme_keys)
                 raise InstallationError(message)
 
             dest_path = os.path.join(scheme_path, dest_subpath)
@@ -628,9 +611,7 @@ def is_data_scheme_path(path):
 
     paths = all_paths()
     file_paths = filterfalse(is_dir_path, paths)
-    root_scheme_paths, data_scheme_paths = partition(
-        is_data_scheme_path, file_paths
-    )
+    root_scheme_paths, data_scheme_paths = partition(is_data_scheme_path, file_paths)
 
     make_root_scheme_file = root_scheme_file_maker(
         wheel_zip,
@@ -641,11 +622,7 @@ def is_data_scheme_path(path):
     def is_script_scheme_path(path):
         # type: (RecordPath) -> bool
         parts = path.split("/", 2)
-        return (
-            len(parts) > 2 and
-            parts[0].endswith(".data") and
-            parts[1] == "scripts"
-        )
+        return len(parts) > 2 and parts[0].endswith(".data") and parts[1] == "scripts"
 
     other_scheme_paths, script_scheme_paths = partition(
         is_script_scheme_path, data_scheme_paths
@@ -656,9 +633,7 @@ def is_script_scheme_path(path):
     files = chain(files, other_scheme_files)
 
     # Get the defined entry points
-    distribution = pkg_resources_distribution_for_wheel(
-        wheel_zip, name, wheel_path
-    )
+    distribution = pkg_resources_distribution_for_wheel(wheel_zip, name, wheel_path)
     console, gui = get_entrypoints(distribution)
 
     def is_entrypoint_wrapper(file):
@@ -667,21 +642,19 @@ def is_entrypoint_wrapper(file):
         # entry point EP by setuptools
         path = file.dest_path
         name = os.path.basename(path)
-        if name.lower().endswith('.exe'):
+        if name.lower().endswith(".exe"):
             matchname = name[:-4]
-        elif name.lower().endswith('-script.py'):
+        elif name.lower().endswith("-script.py"):
             matchname = name[:-10]
         elif name.lower().endswith(".pya"):
             matchname = name[:-4]
         else:
             matchname = name
         # Ignore setuptools-generated scripts
-        return (matchname in console or matchname in gui)
+        return matchname in console or matchname in gui
 
     script_scheme_files = map(make_data_scheme_file, script_scheme_paths)
-    script_scheme_files = filterfalse(
-        is_entrypoint_wrapper, script_scheme_files
-    )
+    script_scheme_files = filterfalse(is_entrypoint_wrapper, script_scheme_files)
     script_scheme_files = map(ScriptFile, script_scheme_files)
     files = chain(files, script_scheme_files)
 
@@ -699,19 +672,18 @@ def pyc_source_file_paths():
             full_installed_path = os.path.join(lib_dir, installed_path)
             if not os.path.isfile(full_installed_path):
                 continue
-            if not full_installed_path.endswith('.py'):
+            if not full_installed_path.endswith(".py"):
                 continue
             yield full_installed_path
 
     def pyc_output_path(path):
         # type: (text_type) -> text_type
-        """Return the path the pyc file would have been written to.
-        """
+        """Return the path the pyc file would have been written to."""
         if PY2:
             if sys.flags.optimize:
-                return path + 'o'
+                return path + "o"
             else:
-                return path + 'c'
+                return path + "c"
         else:
             return importlib.util.cache_from_source(path)
 
@@ -719,16 +691,12 @@ def pyc_output_path(path):
     if pycompile:
         with captured_stdout() as stdout:
             with warnings.catch_warnings():
-                warnings.filterwarnings('ignore')
+                warnings.filterwarnings("ignore")
                 for path in pyc_source_file_paths():
                     # Python 2's `compileall.compile_file` requires a str in
                     # error cases, so we must convert to the native type.
-                    path_arg = ensure_str(
-                        path, encoding=sys.getfilesystemencoding()
-                    )
-                    success = compileall.compile_file(
-                        path_arg, force=True, quiet=True
-                    )
+                    path_arg = ensure_str(path, encoding=sys.getfilesystemencoding())
+                    success = compileall.compile_file(path_arg, force=True, quiet=True)
                     if success:
                         pyc_path = pyc_output_path(path)
                         assert os.path.exists(pyc_path)
@@ -747,7 +715,7 @@ def pyc_output_path(path):
     # Ensure we don't generate any variants for scripts because this is almost
     # never what somebody wants.
     # See https://bitbucket.org/pypa/distlib/issue/35/
-    maker.variants = {''}
+    maker.variants = {""}
 
     # This is required because otherwise distlib creates scripts that are not
     # executable.
@@ -757,14 +725,12 @@ def pyc_output_path(path):
     # Generate the console and GUI entry points specified in the wheel
     scripts_to_generate = get_console_script_specs(console)
 
-    gui_scripts_to_generate = list(starmap('{} = {}'.format, gui.items()))
+    gui_scripts_to_generate = list(starmap("{} = {}".format, gui.items()))
 
     generated_console_scripts = maker.make_multiple(scripts_to_generate)
     generated.extend(generated_console_scripts)
 
-    generated.extend(
-        maker.make_multiple(gui_scripts_to_generate, {'gui': True})
-    )
+    generated.extend(maker.make_multiple(gui_scripts_to_generate, {"gui": True}))
 
     if warn_script_location:
         msg = message_about_scripts_not_on_PATH(generated_console_scripts)
@@ -784,9 +750,9 @@ def _generate_file(path, **kwargs):
     dest_info_dir = os.path.join(lib_dir, info_dir)
 
     # Record pip as the installer
-    installer_path = os.path.join(dest_info_dir, 'INSTALLER')
+    installer_path = os.path.join(dest_info_dir, "INSTALLER")
     with _generate_file(installer_path) as installer_file:
-        installer_file.write(b'pip\n')
+        installer_file.write(b"pip\n")
     generated.append(installer_path)
 
     # Record the PEP 610 direct URL reference
@@ -798,12 +764,12 @@ def _generate_file(path, **kwargs):
 
     # Record the REQUESTED file
     if requested:
-        requested_path = os.path.join(dest_info_dir, 'REQUESTED')
+        requested_path = os.path.join(dest_info_dir, "REQUESTED")
         with open(requested_path, "w"):
             pass
         generated.append(requested_path)
 
-    record_text = distribution.get_metadata('RECORD')
+    record_text = distribution.get_metadata("RECORD")
     record_rows = list(csv.reader(record_text.splitlines()))
 
     rows = get_csv_rows_for_installed(
@@ -811,16 +777,17 @@ def _generate_file(path, **kwargs):
         installed=installed,
         changed=changed,
         generated=generated,
-        lib_dir=lib_dir)
+        lib_dir=lib_dir,
+    )
 
     # Record details of all files installed
-    record_path = os.path.join(dest_info_dir, 'RECORD')
+    record_path = os.path.join(dest_info_dir, "RECORD")
 
-    with _generate_file(record_path, **csv_io_kwargs('w')) as record_file:
+    with _generate_file(record_path, **csv_io_kwargs("w")) as record_file:
         # The type mypy infers for record_file is different for Python 3
         # (typing.IO[Any]) and Python 2 (typing.BinaryIO). We explicitly
         # cast to typing.IO[str] as a workaround.
-        writer = csv.writer(cast('IO[str]', record_file))
+        writer = csv.writer(cast("IO[str]", record_file))
         writer.writerows(_normalized_outrows(rows))
 
 
@@ -831,9 +798,7 @@ def req_error_context(req_description):
         yield
     except InstallationError as e:
         message = "For req: {}. {}".format(req_description, e.args[0])
-        reraise(
-            InstallationError, InstallationError(message), sys.exc_info()[2]
-        )
+        reraise(InstallationError, InstallationError(message), sys.exc_info()[2])
 
 
 def install_wheel(
diff --git a/src/pip/_internal/operations/prepare.py b/src/pip/_internal/operations/prepare.py
index acff7ffa1f7..7b5fb11fd01 100644
--- a/src/pip/_internal/operations/prepare.py
+++ b/src/pip/_internal/operations/prepare.py
@@ -12,9 +12,7 @@
 from pip._vendor.packaging.utils import canonicalize_name
 from pip._vendor.six import PY2
 
-from pip._internal.distributions import (
-    make_distribution_for_install_requirement,
-)
+from pip._internal.distributions import make_distribution_for_install_requirement
 from pip._internal.distributions.installed import InstalledDistribution
 from pip._internal.exceptions import (
     DirectoryUrlHashUnsupported,
@@ -34,12 +32,7 @@
 from pip._internal.utils.filesystem import copy2_fixed
 from pip._internal.utils.hashes import MissingHashes
 from pip._internal.utils.logging import indent_log
-from pip._internal.utils.misc import (
-    display_path,
-    hide_url,
-    path_to_display,
-    rmtree,
-)
+from pip._internal.utils.misc import display_path, hide_url, path_to_display, rmtree
 from pip._internal.utils.temp_dir import TempDirectory
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 from pip._internal.utils.unpacking import unpack_file
@@ -60,21 +53,21 @@
 
     if PY2:
         CopytreeKwargs = TypedDict(
-            'CopytreeKwargs',
+            "CopytreeKwargs",
             {
-                'ignore': Callable[[str, List[str]], List[str]],
-                'symlinks': bool,
+                "ignore": Callable[[str, List[str]], List[str]],
+                "symlinks": bool,
             },
             total=False,
         )
     else:
         CopytreeKwargs = TypedDict(
-            'CopytreeKwargs',
+            "CopytreeKwargs",
             {
-                'copy_function': Callable[[str, str], None],
-                'ignore': Callable[[str, List[str]], List[str]],
-                'ignore_dangling_symlinks': bool,
-                'symlinks': bool,
+                "copy_function": Callable[[str, str], None],
+                "ignore": Callable[[str, List[str]], List[str]],
+                "ignore_dangling_symlinks": bool,
+                "symlinks": bool,
             },
             total=False,
         )
@@ -104,7 +97,6 @@ def unpack_vcs_link(link, location):
 
 
 class File(object):
-
     def __init__(self, path, content_type):
         # type: (str, Optional[str]) -> None
         self.path = path
@@ -125,9 +117,7 @@ def get_http_url(
     # If a download dir is specified, is the file already downloaded there?
     already_downloaded_path = None
     if download_dir:
-        already_downloaded_path = _check_download_dir(
-            link, download_dir, hashes
-        )
+        already_downloaded_path = _check_download_dir(link, download_dir, hashes)
 
     if already_downloaded_path:
         from_path = already_downloaded_path
@@ -176,7 +166,7 @@ def ignore(d, names):
             # exclude the following directories if they appear in the top
             # level dir (and only it).
             # See discussion at https://github.com/pypa/pip/pull/6770
-            skipped += ['.tox', '.nox']
+            skipped += [".tox", ".nox"]
         if os.path.abspath(d) == target_dirname:
             # Prevent an infinite recursion if the target is in source.
             # This can happen when TMPDIR is set to ${PWD}/...
@@ -189,7 +179,7 @@ def ignore(d, names):
     if not PY2:
         # Python 2 does not support copy_function, so we only ignore
         # errors on special file copy in Python 3.
-        kwargs['copy_function'] = _copy2_ignoring_special_files
+        kwargs["copy_function"] = _copy2_ignoring_special_files
 
     shutil.copytree(source, target, **kwargs)
 
@@ -197,17 +187,14 @@ def ignore(d, names):
 def get_file_url(
     link,  # type: Link
     download_dir=None,  # type: Optional[str]
-    hashes=None  # type: Optional[Hashes]
+    hashes=None,  # type: Optional[Hashes]
 ):
     # type: (...) -> File
-    """Get file and optionally check its hash.
-    """
+    """Get file and optionally check its hash."""
     # If a download dir is specified, is the file already there and valid?
     already_downloaded_path = None
     if download_dir:
-        already_downloaded_path = _check_download_dir(
-            link, download_dir, hashes
-        )
+        already_downloaded_path = _check_download_dir(link, download_dir, hashes)
 
     if already_downloaded_path:
         from_path = already_downloaded_path
@@ -274,8 +261,8 @@ def unpack_url(
 
 def _check_download_dir(link, download_dir, hashes):
     # type: (Link, str, Optional[Hashes]) -> Optional[str]
-    """ Check download_dir for previously downloaded file with correct hash
-        If a correct file is found return its path else None
+    """Check download_dir for previously downloaded file with correct hash
+    If a correct file is found return its path else None
     """
     download_path = os.path.join(download_dir, link.filename)
 
@@ -283,15 +270,14 @@ def _check_download_dir(link, download_dir, hashes):
         return None
 
     # If already downloaded, does its hash match?
-    logger.info('File was already downloaded %s', download_path)
+    logger.info("File was already downloaded %s", download_path)
     if hashes:
         try:
             hashes.check_against_path(download_path)
         except HashMismatch:
             logger.warning(
-                'Previously-downloaded file %s has bad hash. '
-                'Re-downloading.',
-                download_path
+                "Previously-downloaded file %s has bad hash. " "Re-downloading.",
+                download_path,
             )
             os.unlink(download_path)
             return None
@@ -299,8 +285,7 @@ def _check_download_dir(link, download_dir, hashes):
 
 
 class RequirementPreparer(object):
-    """Prepares a Requirement
-    """
+    """Prepares a Requirement"""
 
     def __init__(
         self,
@@ -369,10 +354,10 @@ def _download_should_save(self):
         if os.path.exists(self.download_dir):
             return True
 
-        logger.critical('Could not find download directory')
+        logger.critical("Could not find download directory")
         raise InstallationError(
-            "Could not find or access download directory '{}'"
-            .format(self.download_dir))
+            "Could not find or access download directory '{}'".format(self.download_dir)
+        )
 
     def _log_preparing_link(self, req):
         # type: (InstallRequirement) -> None
@@ -420,7 +405,7 @@ def _ensure_link_req_src_dir(self, req, download_dir, parallel_builds):
         # installation.
         # FIXME: this won't upgrade when there's an existing
         # package unpacked in `req.source_dir`
-        if os.path.exists(os.path.join(req.source_dir, 'setup.py')):
+        if os.path.exists(os.path.join(req.source_dir, "setup.py")):
             raise PreviousBuildDirError(
                 "pip can't proceed with requirements '{}' due to a"
                 "pre-existing build directory ({}). This is likely "
@@ -468,12 +453,11 @@ def _fetch_metadata_using_lazy_wheel(self, link):
         if not self.use_lazy_wheel:
             return None
         if self.require_hashes:
-            logger.debug('Lazy wheel is not used as hash checking is required')
+            logger.debug("Lazy wheel is not used as hash checking is required")
             return None
         if link.is_file or not link.is_wheel:
             logger.debug(
-                'Lazy wheel is not used as '
-                '%r does not points to a remote wheel',
+                "Lazy wheel is not used as " "%r does not points to a remote wheel",
                 link,
             )
             return None
@@ -481,14 +465,15 @@ def _fetch_metadata_using_lazy_wheel(self, link):
         wheel = Wheel(link.filename)
         name = canonicalize_name(wheel.name)
         logger.info(
-            'Obtaining dependency information from %s %s',
-            name, wheel.version,
+            "Obtaining dependency information from %s %s",
+            name,
+            wheel.version,
         )
-        url = link.url.split('#', 1)[0]
+        url = link.url.split("#", 1)[0]
         try:
             return dist_from_wheel_url(name, url, self._session)
         except HTTPRangeRequestUnsupported:
-            logger.debug('%s does not support range requests', url)
+            logger.debug("%s does not support range requests", url)
             return None
 
     def prepare_linked_requirement(self, req, parallel_builds=False):
@@ -536,13 +521,16 @@ def _prepare_linked_requirement(self, req, parallel_builds):
         if link.url not in self._downloaded:
             try:
                 local_file = unpack_url(
-                    link, req.source_dir, self._download,
-                    download_dir, hashes,
+                    link,
+                    req.source_dir,
+                    self._download,
+                    download_dir,
+                    hashes,
                 )
             except NetworkConnectionError as exc:
                 raise InstallationError(
-                    'Could not install requirement {} because of HTTP '
-                    'error {} for URL {}'.format(req, exc, link)
+                    "Could not install requirement {} because of HTTP "
+                    "error {} for URL {}".format(req, exc, link)
                 )
         else:
             file_path, content_type = self._downloaded[link.url]
@@ -556,18 +544,21 @@ def _prepare_linked_requirement(self, req, parallel_builds):
             req.local_file_path = local_file.path
 
         dist = _get_prepared_distribution(
-            req, self.req_tracker, self.finder, self.build_isolation,
+            req,
+            self.req_tracker,
+            self.finder,
+            self.build_isolation,
         )
 
         if download_dir:
             if link.is_existing_dir():
-                logger.info('Link is a directory, ignoring download_dir')
+                logger.info("Link is a directory, ignoring download_dir")
             elif local_file:
                 download_location = os.path.join(download_dir, link.filename)
                 if not os.path.exists(download_location):
                     shutil.copy(local_file.path, download_location)
                     download_path = display_path(download_location)
-                    logger.info('Saved %s', download_path)
+                    logger.info("Saved %s", download_path)
 
         if self._download_should_save:
             # Make a .zip of the source_dir we already created.
@@ -580,24 +571,26 @@ def prepare_editable_requirement(
         req,  # type: InstallRequirement
     ):
         # type: (...) -> Distribution
-        """Prepare an editable requirement
-        """
+        """Prepare an editable requirement"""
         assert req.editable, "cannot prepare a non-editable req as editable"
 
-        logger.info('Obtaining %s', req)
+        logger.info("Obtaining %s", req)
 
         with indent_log():
             if self.require_hashes:
                 raise InstallationError(
-                    'The editable requirement {} cannot be installed when '
-                    'requiring hashes, because there is no single file to '
-                    'hash.'.format(req)
+                    "The editable requirement {} cannot be installed when "
+                    "requiring hashes, because there is no single file to "
+                    "hash.".format(req)
                 )
             req.ensure_has_source_dir(self.src_dir)
             req.update_editable(not self._download_should_save)
 
             dist = _get_prepared_distribution(
-                req, self.req_tracker, self.finder, self.build_isolation,
+                req,
+                self.req_tracker,
+                self.finder,
+                self.build_isolation,
             )
 
             if self._download_should_save:
@@ -609,26 +602,24 @@ def prepare_editable_requirement(
     def prepare_installed_requirement(
         self,
         req,  # type: InstallRequirement
-        skip_reason  # type: str
+        skip_reason,  # type: str
     ):
         # type: (...) -> Distribution
-        """Prepare an already-installed requirement
-        """
+        """Prepare an already-installed requirement"""
         assert req.satisfied_by, "req should have been satisfied but isn't"
         assert skip_reason is not None, (
             "did not get skip reason skipped but req.satisfied_by "
             "is set to {}".format(req.satisfied_by)
         )
         logger.info(
-            'Requirement %s: %s (%s)',
-            skip_reason, req, req.satisfied_by.version
+            "Requirement %s: %s (%s)", skip_reason, req, req.satisfied_by.version
         )
         with indent_log():
             if self.require_hashes:
                 logger.debug(
-                    'Since it is already installed, we are trusting this '
-                    'package without checking its hash. To ensure a '
-                    'completely repeatable environment, install into an '
-                    'empty virtualenv.'
+                    "Since it is already installed, we are trusting this "
+                    "package without checking its hash. To ensure a "
+                    "completely repeatable environment, install into an "
+                    "empty virtualenv."
                 )
             return InstalledDistribution(req).get_pkg_resources_distribution()
diff --git a/src/pip/_internal/pyproject.py b/src/pip/_internal/pyproject.py
index 4144a9ed60b..06dd4e86546 100644
--- a/src/pip/_internal/pyproject.py
+++ b/src/pip/_internal/pyproject.py
@@ -17,15 +17,14 @@
 
 def _is_list_of_str(obj):
     # type: (Any) -> bool
-    return (
-        isinstance(obj, list) and
-        all(isinstance(item, six.string_types) for item in obj)
+    return isinstance(obj, list) and all(
+        isinstance(item, six.string_types) for item in obj
     )
 
 
 def make_pyproject_path(unpacked_source_directory):
     # type: (str) -> str
-    path = os.path.join(unpacked_source_directory, 'pyproject.toml')
+    path = os.path.join(unpacked_source_directory, "pyproject.toml")
 
     # Python2 __file__ should not be unicode
     if six.PY2 and isinstance(path, six.text_type):
@@ -34,16 +33,16 @@ def make_pyproject_path(unpacked_source_directory):
     return path
 
 
-BuildSystemDetails = namedtuple('BuildSystemDetails', [
-    'requires', 'backend', 'check', 'backend_path'
-])
+BuildSystemDetails = namedtuple(
+    "BuildSystemDetails", ["requires", "backend", "check", "backend_path"]
+)
 
 
 def load_pyproject_toml(
     use_pep517,  # type: Optional[bool]
     pyproject_toml,  # type: str
     setup_py,  # type: str
-    req_name  # type: str
+    req_name,  # type: str
 ):
     # type: (...) -> Optional[BuildSystemDetails]
     """Load the pyproject.toml file.
@@ -95,9 +94,7 @@ def load_pyproject_toml(
             raise InstallationError(
                 "Disabling PEP 517 processing is invalid: "
                 "project specifies a build backend of {} "
-                "in pyproject.toml".format(
-                    build_system["build-backend"]
-                )
+                "in pyproject.toml".format(build_system["build-backend"])
             )
         use_pep517 = True
 
@@ -145,19 +142,24 @@ def load_pyproject_toml(
     # Specifying the build-system table but not the requires key is invalid
     if "requires" not in build_system:
         raise InstallationError(
-            error_template.format(package=req_name, reason=(
-                "it has a 'build-system' table but not "
-                "'build-system.requires' which is mandatory in the table"
-            ))
+            error_template.format(
+                package=req_name,
+                reason=(
+                    "it has a 'build-system' table but not "
+                    "'build-system.requires' which is mandatory in the table"
+                ),
+            )
         )
 
     # Error out if requires is not a list of strings
     requires = build_system["requires"]
     if not _is_list_of_str(requires):
-        raise InstallationError(error_template.format(
-            package=req_name,
-            reason="'build-system.requires' is not a list of strings.",
-        ))
+        raise InstallationError(
+            error_template.format(
+                package=req_name,
+                reason="'build-system.requires' is not a list of strings.",
+            )
+        )
 
     # Each requirement must be valid as per PEP 508
     for requirement in requires:
diff --git a/src/pip/_internal/req/__init__.py b/src/pip/_internal/req/__init__.py
index 8568d3f8b6e..17127f7785a 100644
--- a/src/pip/_internal/req/__init__.py
+++ b/src/pip/_internal/req/__init__.py
@@ -14,8 +14,10 @@
     from typing import Iterator, List, Optional, Sequence, Tuple
 
 __all__ = [
-    "RequirementSet", "InstallRequirement",
-    "parse_requirements", "install_given_reqs",
+    "RequirementSet",
+    "InstallRequirement",
+    "parse_requirements",
+    "install_given_reqs",
 ]
 
 logger = logging.getLogger(__name__)
@@ -61,8 +63,8 @@ def install_given_reqs(
 
     if to_install:
         logger.info(
-            'Installing collected packages: %s',
-            ', '.join(to_install.keys()),
+            "Installing collected packages: %s",
+            ", ".join(to_install.keys()),
         )
 
     installed = []
@@ -70,11 +72,9 @@ def install_given_reqs(
     with indent_log():
         for req_name, requirement in to_install.items():
             if requirement.should_reinstall:
-                logger.info('Attempting uninstall: %s', req_name)
+                logger.info("Attempting uninstall: %s", req_name)
                 with indent_log():
-                    uninstalled_pathset = requirement.uninstall(
-                        auto_confirm=True
-                    )
+                    uninstalled_pathset = requirement.uninstall(auto_confirm=True)
             else:
                 uninstalled_pathset = None
 
diff --git a/src/pip/_internal/req/constructors.py b/src/pip/_internal/req/constructors.py
index 97420af6c25..e1a54a4194e 100644
--- a/src/pip/_internal/req/constructors.py
+++ b/src/pip/_internal/req/constructors.py
@@ -36,10 +36,7 @@
     from pip._internal.req.req_file import ParsedRequirement
 
 
-__all__ = [
-    "install_req_from_editable", "install_req_from_line",
-    "parse_editable"
-]
+__all__ = ["install_req_from_editable", "install_req_from_line", "parse_editable"]
 
 logger = logging.getLogger(__name__)
 operators = Specifier._operators.keys()
@@ -56,7 +53,7 @@ def is_archive_file(name):
 
 def _strip_extras(path):
     # type: (str) -> Tuple[str, Optional[str]]
-    m = re.match(r'^(.+)(\[[^\]]+\])$', path)
+    m = re.match(r"^(.+)(\[[^\]]+\])$", path)
     extras = None
     if m:
         path_no_extras = m.group(1)
@@ -92,23 +89,23 @@ def parse_editable(editable_req):
     url_no_extras, extras = _strip_extras(url)
 
     if os.path.isdir(url_no_extras):
-        if not os.path.exists(os.path.join(url_no_extras, 'setup.py')):
+        if not os.path.exists(os.path.join(url_no_extras, "setup.py")):
             msg = (
                 'File "setup.py" not found. Directory cannot be installed '
-                'in editable mode: {}'.format(os.path.abspath(url_no_extras))
+                "in editable mode: {}".format(os.path.abspath(url_no_extras))
             )
             pyproject_path = make_pyproject_path(url_no_extras)
             if os.path.isfile(pyproject_path):
                 msg += (
                     '\n(A "pyproject.toml" file was found, but editable '
-                    'mode currently requires a setup.py based build.)'
+                    "mode currently requires a setup.py based build.)"
                 )
             raise InstallationError(msg)
 
         # Treating it as code that has already been checked out
         url_no_extras = path_to_url(url_no_extras)
 
-    if url_no_extras.lower().startswith('file:'):
+    if url_no_extras.lower().startswith("file:"):
         package_name = Link(url_no_extras).egg_fragment
         if extras:
             return (
@@ -120,24 +117,24 @@ def parse_editable(editable_req):
             return package_name, url_no_extras, set()
 
     for version_control in vcs:
-        if url.lower().startswith('{}:'.format(version_control)):
-            url = '{}+{}'.format(version_control, url)
+        if url.lower().startswith("{}:".format(version_control)):
+            url = "{}+{}".format(version_control, url)
             break
 
-    if '+' not in url:
+    if "+" not in url:
         raise InstallationError(
-            '{} is not a valid editable requirement. '
-            'It should either be a path to a local project or a VCS URL '
-            '(beginning with svn+, git+, hg+, or bzr+).'.format(editable_req)
+            "{} is not a valid editable requirement. "
+            "It should either be a path to a local project or a VCS URL "
+            "(beginning with svn+, git+, hg+, or bzr+).".format(editable_req)
         )
 
-    vc_type = url.split('+', 1)[0].lower()
+    vc_type = url.split("+", 1)[0].lower()
 
     if not vcs.get_backend(vc_type):
-        backends = ", ".join([bends.name + '+URL' for bends in vcs.backends])
-        error_message = "For --editable={}, " \
-                        "only {} are currently supported".format(
-                            editable_req, backends)
+        backends = ", ".join([bends.name + "+URL" for bends in vcs.backends])
+        error_message = "For --editable={}, " "only {} are currently supported".format(
+            editable_req, backends
+        )
         raise InstallationError(error_message)
 
     package_name = Link(url).egg_fragment
@@ -161,7 +158,7 @@ def deduce_helpful_msg(req):
         msg = " The path does exist. "
         # Try to parse and check if it is a requirements file.
         try:
-            with open(req, 'r') as fp:
+            with open(req, "r") as fp:
                 # parse first line only
                 next(parse_requirements(fp.read()))
                 msg += (
@@ -172,9 +169,7 @@ def deduce_helpful_msg(req):
                     " the packages specified within it."
                 ).format(req)
         except RequirementParseError:
-            logger.debug(
-                "Cannot parse '%s' as requirements file", req, exc_info=True
-            )
+            logger.debug("Cannot parse '%s' as requirements file", req, exc_info=True)
     else:
         msg += " File '{}' does not exist.".format(req)
     return msg
@@ -182,11 +177,11 @@ def deduce_helpful_msg(req):
 
 class RequirementParts(object):
     def __init__(
-            self,
-            requirement,  # type: Optional[Requirement]
-            link,         # type: Optional[Link]
-            markers,      # type: Optional[Marker]
-            extras,       # type: Set[str]
+        self,
+        requirement,  # type: Optional[Requirement]
+        link,  # type: Optional[Link]
+        markers,  # type: Optional[Marker]
+        extras,  # type: Set[str]
     ):
         self.requirement = requirement
         self.link = link
@@ -284,15 +279,13 @@ def _get_url_from_path(path, name):
         return None
     if os.path.isfile(path):
         return path_to_url(path)
-    urlreq_parts = name.split('@', 1)
+    urlreq_parts = name.split("@", 1)
     if len(urlreq_parts) >= 2 and not _looks_like_path(urlreq_parts[0]):
         # If the path contains '@' and the part before it does not look
         # like a path, try to treat it as a PEP 440 URL req instead.
         return None
     logger.warning(
-        'Requirement %r looks like a filename, but the '
-        'file does not exist',
-        name
+        "Requirement %r looks like a filename, but the " "file does not exist", name
     )
     return path_to_url(path)
 
@@ -300,9 +293,9 @@ def _get_url_from_path(path, name):
 def parse_req_from_line(name, line_source):
     # type: (str, Optional[str]) -> RequirementParts
     if is_url(name):
-        marker_sep = '; '
+        marker_sep = "; "
     else:
-        marker_sep = ';'
+        marker_sep = ";"
     if marker_sep in name:
         name, markers_as_string = name.split(marker_sep, 1)
         markers_as_string = markers_as_string.strip()
@@ -329,9 +322,8 @@ def parse_req_from_line(name, line_source):
     # it's a local file, dir, or url
     if link:
         # Handle relative file URLs
-        if link.scheme == 'file' and re.search(r'\.\./', link.url):
-            link = Link(
-                path_to_url(os.path.normpath(os.path.abspath(link.path))))
+        if link.scheme == "file" and re.search(r"\.\./", link.url):
+            link = Link(path_to_url(os.path.normpath(os.path.abspath(link.path))))
         # wheel file
         if link.is_wheel:
             wheel = Wheel(link.filename)  # can raise InvalidWheelFilename
@@ -351,7 +343,7 @@ def with_source(text):
         # type: (str) -> str
         if not line_source:
             return text
-        return '{} (from {})'.format(text, line_source)
+        return "{} (from {})".format(text, line_source)
 
     if req_as_string is not None:
         try:
@@ -360,16 +352,15 @@ def with_source(text):
             if os.path.sep in req_as_string:
                 add_msg = "It looks like a path."
                 add_msg += deduce_helpful_msg(req_as_string)
-            elif ('=' in req_as_string and
-                  not any(op in req_as_string for op in operators)):
+            elif "=" in req_as_string and not any(
+                op in req_as_string for op in operators
+            ):
                 add_msg = "= is not a valid operator. Did you mean == ?"
             else:
-                add_msg = ''
-            msg = with_source(
-                'Invalid requirement: {!r}'.format(req_as_string)
-            )
+                add_msg = ""
+            msg = with_source("Invalid requirement: {!r}".format(req_as_string))
             if add_msg:
-                msg += '\nHint: {}'.format(add_msg)
+                msg += "\nHint: {}".format(add_msg)
             raise InstallationError(msg)
         else:
             # Deprecate extras after specifiers: "name>=1.0[extras]"
@@ -378,7 +369,7 @@ def with_source(text):
             # RequirementParts
             for spec in req.specifier:
                 spec_str = str(spec)
-                if spec_str.endswith(']'):
+                if spec_str.endswith("]"):
                     msg = "Extras after version '{}'.".format(spec_str)
                     replace = "moving the extras before version specifiers"
                     deprecated(msg, replacement=replace, gone_in="21.0")
@@ -408,8 +399,12 @@ def install_req_from_line(
     parts = parse_req_from_line(name, line_source)
 
     return InstallRequirement(
-        parts.requirement, comes_from, link=parts.link, markers=parts.markers,
-        use_pep517=use_pep517, isolated=isolated,
+        parts.requirement,
+        comes_from,
+        link=parts.link,
+        markers=parts.markers,
+        use_pep517=use_pep517,
+        isolated=isolated,
         install_options=options.get("install_options", []) if options else [],
         global_options=options.get("global_options", []) if options else [],
         hash_options=options.get("hashes", {}) if options else {},
@@ -436,8 +431,12 @@ def install_req_from_req_string(
         PyPI.file_storage_domain,
         TestPyPI.file_storage_domain,
     ]
-    if (req.url and comes_from and comes_from.link and
-            comes_from.link.netloc in domains_not_allowed):
+    if (
+        req.url
+        and comes_from
+        and comes_from.link
+        and comes_from.link.netloc in domains_not_allowed
+    ):
         # Explicitly disallow pypi packages that depend on external urls
         raise InstallationError(
             "Packages installed from PyPI cannot depend on packages "
diff --git a/src/pip/_internal/req/req_file.py b/src/pip/_internal/req/req_file.py
index b070dc640da..512d94b9eb7 100644
--- a/src/pip/_internal/req/req_file.py
+++ b/src/pip/_internal/req/req_file.py
@@ -13,10 +13,7 @@
 from pip._vendor.six.moves.urllib import parse as urllib_parse
 
 from pip._internal.cli import cmdoptions
-from pip._internal.exceptions import (
-    InstallationError,
-    RequirementsFileParseError,
-)
+from pip._internal.exceptions import InstallationError, RequirementsFileParseError
 from pip._internal.models.search_scope import SearchScope
 from pip._internal.network.utils import raise_for_status
 from pip._internal.utils.encoding import auto_decode
@@ -45,16 +42,16 @@
     LineParser = Callable[[Text], Tuple[str, Values]]
 
 
-__all__ = ['parse_requirements']
+__all__ = ["parse_requirements"]
 
-SCHEME_RE = re.compile(r'^(http|https|file):', re.I)
-COMMENT_RE = re.compile(r'(^|\s+)#.*$')
+SCHEME_RE = re.compile(r"^(http|https|file):", re.I)
+COMMENT_RE = re.compile(r"(^|\s+)#.*$")
 
 # Matches environment variable-style values in '${MY_VARIABLE_1}' with the
 # variable name consisting of only uppercase letters, digits or the '_'
 # (underscore). This follows the POSIX standard defined in IEEE Std 1003.1,
 # 2013 Edition.
-ENV_VAR_RE = re.compile(r'(?P<var>\$\{(?P<name>[A-Z0-9_]+)\})')
+ENV_VAR_RE = re.compile(r"(?P<var>\$\{(?P<name>[A-Z0-9_]+)\})")
 
 SUPPORTED_OPTIONS = [
     cmdoptions.index_url,
@@ -157,10 +154,7 @@ def parse_requirements(
 
     for parsed_line in parser.parse(filename, constraint):
         parsed_req = handle_line(
-            parsed_line,
-            options=options,
-            finder=finder,
-            session=session
+            parsed_line, options=options, finder=finder, session=session
         )
         if parsed_req is not None:
             yield parsed_req
@@ -186,8 +180,10 @@ def handle_requirement_line(
     # type: (...) -> ParsedRequirement
 
     # preserve for the nested code path
-    line_comes_from = '{} {} (line {})'.format(
-        '-c' if line.constraint else '-r', line.filename, line.lineno,
+    line_comes_from = "{} {} (line {})".format(
+        "-c" if line.constraint else "-r",
+        line.filename,
+        line.lineno,
     )
 
     assert line.is_requirement
@@ -212,7 +208,7 @@ def handle_requirement_line(
             if dest in line.opts.__dict__ and line.opts.__dict__[dest]:
                 req_options[dest] = line.opts.__dict__[dest]
 
-        line_source = 'line {} of {}'.format(line.lineno, line.filename)
+        line_source = "line {} of {}".format(line.lineno, line.filename)
         return ParsedRequirement(
             requirement=line.requirement,
             is_editable=line.is_editable,
@@ -239,8 +235,7 @@ def handle_option_line(
             options.require_hashes = opts.require_hashes
         if opts.features_enabled:
             options.features_enabled.extend(
-                f for f in opts.features_enabled
-                if f not in options.features_enabled
+                f for f in opts.features_enabled if f not in options.features_enabled
             )
 
     # set finder options
@@ -282,7 +277,7 @@ def handle_option_line(
 
         if session:
             for host in opts.trusted_hosts or []:
-                source = 'line {} of {}'.format(lineno, filename)
+                source = "line {} of {}".format(lineno, filename)
                 session.add_trusted_host(host, source=source)
 
 
@@ -345,17 +340,15 @@ def __init__(
 
     def parse(self, filename, constraint):
         # type: (str, bool) -> Iterator[ParsedLine]
-        """Parse a given file, yielding parsed lines.
-        """
+        """Parse a given file, yielding parsed lines."""
         for line in self._parse_and_recurse(filename, constraint):
             yield line
 
     def _parse_and_recurse(self, filename, constraint):
         # type: (str, bool) -> Iterator[ParsedLine]
         for line in self._parse_file(filename, constraint):
-            if (
-                not line.is_requirement and
-                (line.opts.requirements or line.opts.constraints)
+            if not line.is_requirement and (
+                line.opts.requirements or line.opts.constraints
             ):
                 # parse a nested requirements file
                 if line.opts.requirements:
@@ -373,11 +366,13 @@ def _parse_and_recurse(self, filename, constraint):
                 elif not SCHEME_RE.search(req_path):
                     # do a join so relative paths work
                     req_path = os.path.join(
-                        os.path.dirname(filename), req_path,
+                        os.path.dirname(filename),
+                        req_path,
                     )
 
                 for inner_line in self._parse_and_recurse(
-                    req_path, nested_constraint,
+                    req_path,
+                    nested_constraint,
                 ):
                     yield inner_line
             else:
@@ -396,7 +391,7 @@ def _parse_file(self, filename, constraint):
                 args_str, opts = self._line_parser(line)
             except OptionParsingError as e:
                 # add offending line
-                msg = 'Invalid requirement: {}\n{}'.format(line, e.msg)
+                msg = "Invalid requirement: {}\n{}".format(line, e.msg)
                 raise RequirementsFileParseError(msg)
 
             yield ParsedLine(
@@ -425,11 +420,10 @@ def parse_line(line):
         # Prior to 2.7.3, shlex cannot deal with unicode entries
         if sys.version_info < (2, 7, 3):
             # https://github.com/python/mypy/issues/1174
-            options_str = options_str.encode('utf8')  # type: ignore
+            options_str = options_str.encode("utf8")  # type: ignore
 
         # https://github.com/python/mypy/issues/1174
-        opts, _ = parser.parse_args(
-            shlex.split(options_str), defaults)  # type: ignore
+        opts, _ = parser.parse_args(shlex.split(options_str), defaults)  # type: ignore
 
         return args_str, opts
 
@@ -442,16 +436,16 @@ def break_args_options(line):
     (and then optparse) the options, not the args.  args can contain markers
     which are corrupted by shlex.
     """
-    tokens = line.split(' ')
+    tokens = line.split(" ")
     args = []
     options = tokens[:]
     for token in tokens:
-        if token.startswith('-') or token.startswith('--'):
+        if token.startswith("-") or token.startswith("--"):
             break
         else:
             args.append(token)
             options.pop(0)
-    return ' '.join(args), ' '.join(options)  # type: ignore
+    return " ".join(args), " ".join(options)  # type: ignore
 
 
 class OptionParsingError(Exception):
@@ -477,6 +471,7 @@ def build_parser():
     def parser_exit(self, msg):
         # type: (Any, str) -> NoReturn
         raise OptionParsingError(msg)
+
     # NOTE: mypy disallows assigning to a method
     #       https://github.com/python/mypy/issues/2427
     parser.exit = parser_exit  # type: ignore
@@ -492,26 +487,26 @@ def join_lines(lines_enum):
     primary_line_number = None
     new_line = []  # type: List[Text]
     for line_number, line in lines_enum:
-        if not line.endswith('\\') or COMMENT_RE.match(line):
+        if not line.endswith("\\") or COMMENT_RE.match(line):
             if COMMENT_RE.match(line):
                 # this ensures comments are always matched later
-                line = ' ' + line
+                line = " " + line
             if new_line:
                 new_line.append(line)
                 assert primary_line_number is not None
-                yield primary_line_number, ''.join(new_line)
+                yield primary_line_number, "".join(new_line)
                 new_line = []
             else:
                 yield line_number, line
         else:
             if not new_line:
                 primary_line_number = line_number
-            new_line.append(line.strip('\\'))
+            new_line.append(line.strip("\\"))
 
     # last line contains \
     if new_line:
         assert primary_line_number is not None
-        yield primary_line_number, ''.join(new_line)
+        yield primary_line_number, "".join(new_line)
 
     # TODO: handle space after '\'.
 
@@ -522,7 +517,7 @@ def ignore_comments(lines_enum):
     Strips comments and filter empty lines.
     """
     for line_number, line in lines_enum:
-        line = COMMENT_RE.sub('', line)
+        line = COMMENT_RE.sub("", line)
         line = line.strip()
         if line:
             yield line_number, line
@@ -568,25 +563,23 @@ def get_file_content(url, session, comes_from=None):
     """
     scheme = get_url_scheme(url)
 
-    if scheme in ['http', 'https']:
+    if scheme in ["http", "https"]:
         # FIXME: catch some errors
         resp = session.get(url)
         raise_for_status(resp)
         return resp.url, resp.text
 
-    elif scheme == 'file':
-        if comes_from and comes_from.startswith('http'):
+    elif scheme == "file":
+        if comes_from and comes_from.startswith("http"):
             raise InstallationError(
-                'Requirements file {} references URL {}, '
-                'which is local'.format(comes_from, url)
+                "Requirements file {} references URL {}, "
+                "which is local".format(comes_from, url)
             )
         url = url_to_path(url)
 
     try:
-        with open(url, 'rb') as f:
+        with open(url, "rb") as f:
             content = auto_decode(f.read())
     except IOError as exc:
-        raise InstallationError(
-            'Could not open requirements file: {}'.format(exc)
-        )
+        raise InstallationError("Could not open requirements file: {}".format(exc))
     return url, content
diff --git a/src/pip/_internal/req/req_install.py b/src/pip/_internal/req/req_install.py
index 9a6763074a3..593381b2d36 100644
--- a/src/pip/_internal/req/req_install.py
+++ b/src/pip/_internal/req/req_install.py
@@ -22,10 +22,12 @@
 from pip._internal.locations import get_scheme
 from pip._internal.models.link import Link
 from pip._internal.operations.build.metadata import generate_metadata
-from pip._internal.operations.build.metadata_legacy import \
-    generate_metadata as generate_metadata_legacy
-from pip._internal.operations.install.editable_legacy import \
-    install_editable as install_editable_legacy
+from pip._internal.operations.build.metadata_legacy import (
+    generate_metadata as generate_metadata_legacy,
+)
+from pip._internal.operations.install.editable_legacy import (
+    install_editable as install_editable_legacy,
+)
 from pip._internal.operations.install.legacy import LegacyInstallFailure
 from pip._internal.operations.install.legacy import install as install_legacy
 from pip._internal.operations.install.wheel import install_wheel
@@ -132,9 +134,7 @@ def __init__(
         if self.editable:
             assert link
             if link.is_file:
-                self.source_dir = os.path.normpath(
-                    os.path.abspath(link.file_path)
-                )
+                self.source_dir = os.path.normpath(os.path.abspath(link.file_path))
 
         if link is None and req and req.url:
             # PEP 508 URL requirement
@@ -150,9 +150,7 @@ def __init__(
         if extras:
             self.extras = extras
         elif req:
-            self.extras = {
-                pkg_resources.safe_extra(extra) for extra in req.extras
-            }
+            self.extras = {pkg_resources.safe_extra(extra) for extra in req.extras}
         else:
             self.extras = set()
         if markers is None and req:
@@ -213,38 +211,36 @@ def __str__(self):
         if self.req:
             s = str(self.req)
             if self.link:
-                s += ' from {}'.format(redact_auth_from_url(self.link.url))
+                s += " from {}".format(redact_auth_from_url(self.link.url))
         elif self.link:
             s = redact_auth_from_url(self.link.url)
         else:
-            s = '<InstallRequirement>'
+            s = "<InstallRequirement>"
         if self.satisfied_by is not None:
-            s += ' in {}'.format(display_path(self.satisfied_by.location))
+            s += " in {}".format(display_path(self.satisfied_by.location))
         if self.comes_from:
             if isinstance(self.comes_from, six.string_types):
                 comes_from = self.comes_from  # type: Optional[str]
             else:
                 comes_from = self.comes_from.from_path()
             if comes_from:
-                s += ' (from {})'.format(comes_from)
+                s += " (from {})".format(comes_from)
         return s
 
     def __repr__(self):
         # type: () -> str
-        return '<{} object: {} editable={!r}>'.format(
-            self.__class__.__name__, str(self), self.editable)
+        return "<{} object: {} editable={!r}>".format(
+            self.__class__.__name__, str(self), self.editable
+        )
 
     def format_debug(self):
         # type: () -> str
-        """An un-tested helper for getting state, for debugging.
-        """
+        """An un-tested helper for getting state, for debugging."""
         attributes = vars(self)
         names = sorted(attributes)
 
-        state = (
-            "{}={!r}".format(attr, attributes[attr]) for attr in sorted(names)
-        )
-        return '<{name} object: {{{state}}}>'.format(
+        state = ("{}={!r}".format(attr, attributes[attr]) for attr in sorted(names))
+        return "<{name} object: {{{state}}}>".format(
             name=self.__class__.__name__,
             state=", ".join(state),
         )
@@ -270,8 +266,7 @@ def is_pinned(self):
         For example, some-package==1.2 is pinned; some-package>1.2 is not.
         """
         specifiers = self.specifier
-        return (len(specifiers) == 1 and
-                next(iter(specifiers)).operator in {'==', '==='})
+        return len(specifiers) == 1 and next(iter(specifiers)).operator in {"==", "==="}
 
     @property
     def installed_version(self):
@@ -283,11 +278,11 @@ def match_markers(self, extras_requested=None):
         if not extras_requested:
             # Provide an extra to safely evaluate the markers
             # without matching any extra
-            extras_requested = ('',)
+            extras_requested = ("",)
         if self.markers is not None:
             return any(
-                self.markers.evaluate({'extra': extra})
-                for extra in extras_requested)
+                self.markers.evaluate({"extra": extra}) for extra in extras_requested
+            )
         else:
             return True
 
@@ -326,8 +321,7 @@ def hashes(self, trust_internet=True):
 
     def from_path(self):
         # type: () -> Optional[str]
-        """Format a nice indicator to show where this "comes from"
-        """
+        """Format a nice indicator to show where this "comes from" """
         if self.req is None:
             return None
         s = str(self.req)
@@ -337,7 +331,7 @@ def from_path(self):
             else:
                 comes_from = self.comes_from.from_path()
             if comes_from:
-                s += '->' + comes_from
+                s += "->" + comes_from
         return s
 
     def ensure_build_location(self, build_dir, autodelete, parallel_builds):
@@ -365,7 +359,7 @@ def ensure_build_location(self, build_dir, autodelete, parallel_builds):
         # FIXME: Is there a better place to create the build_dir? (hg and bzr
         # need this)
         if not os.path.exists(build_dir):
-            logger.debug('Creating directory %s', build_dir)
+            logger.debug("Creating directory %s", build_dir)
             os.makedirs(build_dir)
         actual_build_dir = os.path.join(build_dir, dir_name)
         # `None` indicates that we respect the globally-configured deletion
@@ -380,8 +374,7 @@ def ensure_build_location(self, build_dir, autodelete, parallel_builds):
 
     def _set_requirement(self):
         # type: () -> None
-        """Set requirement after generating metadata.
-        """
+        """Set requirement after generating metadata."""
         assert self.req is None
         assert self.metadata is not None
         assert self.source_dir is not None
@@ -393,11 +386,13 @@ def _set_requirement(self):
             op = "==="
 
         self.req = Requirement(
-            "".join([
-                self.metadata["Name"],
-                op,
-                self.metadata["Version"],
-            ])
+            "".join(
+                [
+                    self.metadata["Name"],
+                    op,
+                    self.metadata["Version"],
+                ]
+            )
         )
 
     def warn_on_mismatching_name(self):
@@ -409,10 +404,12 @@ def warn_on_mismatching_name(self):
 
         # If we're here, there's a mismatch. Log a warning about it.
         logger.warning(
-            'Generating metadata for package %s '
-            'produced metadata for project name %s. Fix your '
-            '#egg=%s fragments.',
-            self.name, metadata_name, self.name
+            "Generating metadata for package %s "
+            "produced metadata for project name %s. Fix your "
+            "#egg=%s fragments.",
+            self.name,
+            metadata_name,
+            self.name,
         )
         self.req = Requirement(metadata_name)
 
@@ -434,12 +431,14 @@ def check_if_exists(self, use_user_site):
             if use_user_site:
                 if dist_in_usersite(existing_dist):
                     self.should_reinstall = True
-                elif (running_under_virtualenv() and
-                        dist_in_site_packages(existing_dist)):
+                elif running_under_virtualenv() and dist_in_site_packages(
+                    existing_dist
+                ):
                     raise InstallationError(
                         "Will not install to the user site because it will "
                         "lack sys.path precedence to {} in {}".format(
-                            existing_dist.project_name, existing_dist.location)
+                            existing_dist.project_name, existing_dist.location
+                        )
                     )
             else:
                 self.should_reinstall = True
@@ -465,14 +464,14 @@ def is_wheel(self):
     def unpacked_source_directory(self):
         # type: () -> str
         return os.path.join(
-            self.source_dir,
-            self.link and self.link.subdirectory_fragment or '')
+            self.source_dir, self.link and self.link.subdirectory_fragment or ""
+        )
 
     @property
     def setup_py_path(self):
         # type: () -> str
         assert self.source_dir, "No source dir for {}".format(self)
-        setup_py = os.path.join(self.unpacked_source_directory, 'setup.py')
+        setup_py = os.path.join(self.unpacked_source_directory, "setup.py")
 
         # Python2 __file__ should not be unicode
         if six.PY2 and isinstance(setup_py, six.text_type):
@@ -496,10 +495,7 @@ def load_pyproject_toml(self):
         follow the PEP 517 or legacy (setup.py) code path.
         """
         pyproject_toml_data = load_pyproject_toml(
-            self.use_pep517,
-            self.pyproject_toml_path,
-            self.setup_py_path,
-            str(self)
+            self.use_pep517, self.pyproject_toml_path, self.setup_py_path, str(self)
         )
 
         if pyproject_toml_data is None:
@@ -511,13 +507,14 @@ def load_pyproject_toml(self):
         self.requirements_to_check = check
         self.pyproject_requires = requires
         self.pep517_backend = Pep517HookCaller(
-            self.unpacked_source_directory, backend, backend_path=backend_path,
+            self.unpacked_source_directory,
+            backend,
+            backend_path=backend_path,
         )
 
     def _generate_metadata(self):
         # type: () -> str
-        """Invokes metadata generator functions, with the required arguments.
-        """
+        """Invokes metadata generator functions, with the required arguments."""
         if not self.use_pep517:
             assert self.unpacked_source_directory
 
@@ -526,7 +523,7 @@ def _generate_metadata(self):
                 setup_py_path=self.setup_py_path,
                 source_dir=self.unpacked_source_directory,
                 isolated=self.isolated,
-                details=self.name or "from {}".format(self.link)
+                details=self.name or "from {}".format(self.link),
             )
 
         assert self.pep517_backend is not None
@@ -559,7 +556,7 @@ def prepare_metadata(self):
     @property
     def metadata(self):
         # type: () -> Any
-        if not hasattr(self, '_metadata'):
+        if not hasattr(self, "_metadata"):
             self._metadata = get_metadata(self.get_dist())
 
         return self._metadata
@@ -571,16 +568,16 @@ def get_dist(self):
     def assert_source_matches_version(self):
         # type: () -> None
         assert self.source_dir
-        version = self.metadata['version']
+        version = self.metadata["version"]
         if self.req.specifier and version not in self.req.specifier:
             logger.warning(
-                'Requested %s, but installing version %s',
+                "Requested %s, but installing version %s",
                 self,
                 version,
             )
         else:
             logger.debug(
-                'Source in %s has version %s, which satisfies requirement %s',
+                "Source in %s has version %s, which satisfies requirement %s",
                 display_path(self.source_dir),
                 version,
                 self,
@@ -615,27 +612,23 @@ def update_editable(self, obtain=True):
         # type: (bool) -> None
         if not self.link:
             logger.debug(
-                "Cannot update repository at %s; repository location is "
-                "unknown",
+                "Cannot update repository at %s; repository location is " "unknown",
                 self.source_dir,
             )
             return
         assert self.editable
         assert self.source_dir
-        if self.link.scheme == 'file':
+        if self.link.scheme == "file":
             # Static paths don't get updated
             return
-        assert '+' in self.link.url, \
-            "bad url: {self.link.url!r}".format(**locals())
-        vc_type, url = self.link.url.split('+', 1)
+        assert "+" in self.link.url, "bad url: {self.link.url!r}".format(**locals())
+        vc_type, url = self.link.url.split("+", 1)
         vcs_backend = vcs.get_backend(vc_type)
         if vcs_backend:
             if not self.link.is_vcs:
                 reason = (
                     "This form of VCS requirement is being deprecated: {}."
-                ).format(
-                    self.link.url
-                )
+                ).format(self.link.url)
                 replacement = None
                 if self.link.url.startswith("git+git@"):
                     replacement = (
@@ -650,9 +643,9 @@ def update_editable(self, obtain=True):
             else:
                 vcs_backend.export(self.source_dir, url=hidden_url)
         else:
-            assert 0, (
-                'Unexpected version control type (in {}): {}'.format(
-                    self.link, vc_type))
+            assert 0, "Unexpected version control type (in {}): {}".format(
+                self.link, vc_type
+            )
 
     # Top-level Actions
     def uninstall(self, auto_confirm=False, verbose=False):
@@ -674,7 +667,7 @@ def uninstall(self, auto_confirm=False, verbose=False):
         if not dist:
             logger.warning("Skipping %s as it is not installed.", self.name)
             return None
-        logger.info('Found existing installation: %s', dist)
+        logger.info("Found existing installation: %s", dist)
 
         uninstalled_pathset = UninstallPathSet.from_dist(dist)
         uninstalled_pathset.remove(auto_confirm, verbose)
@@ -685,17 +678,16 @@ def _get_archive_name(self, path, parentdir, rootdir):
 
         def _clean_zip_name(name, prefix):
             # type: (str, str) -> str
-            assert name.startswith(prefix + os.path.sep), (
-                "name {name!r} doesn't start with prefix {prefix!r}"
-                .format(**locals())
-            )
-            name = name[len(prefix) + 1:]
-            name = name.replace(os.path.sep, '/')
+            assert name.startswith(
+                prefix + os.path.sep
+            ), "name {name!r} doesn't start with prefix {prefix!r}".format(**locals())
+            name = name[len(prefix) + 1 :]
+            name = name.replace(os.path.sep, "/")
             return name
 
         path = os.path.join(parentdir, path)
         name = _clean_zip_name(path, rootdir)
-        return self.name + '/' + name
+        return self.name + "/" + name
 
     def archive(self, build_dir):
         # type: (str) -> None
@@ -706,57 +698,62 @@ def archive(self, build_dir):
         assert self.source_dir
 
         create_archive = True
-        archive_name = '{}-{}.zip'.format(self.name, self.metadata["version"])
+        archive_name = "{}-{}.zip".format(self.name, self.metadata["version"])
         archive_path = os.path.join(build_dir, archive_name)
 
         if os.path.exists(archive_path):
             response = ask_path_exists(
-                'The file {} exists. (i)gnore, (w)ipe, '
-                '(b)ackup, (a)bort '.format(
-                    display_path(archive_path)),
-                ('i', 'w', 'b', 'a'))
-            if response == 'i':
+                "The file {} exists. (i)gnore, (w)ipe, "
+                "(b)ackup, (a)bort ".format(display_path(archive_path)),
+                ("i", "w", "b", "a"),
+            )
+            if response == "i":
                 create_archive = False
-            elif response == 'w':
-                logger.warning('Deleting %s', display_path(archive_path))
+            elif response == "w":
+                logger.warning("Deleting %s", display_path(archive_path))
                 os.remove(archive_path)
-            elif response == 'b':
+            elif response == "b":
                 dest_file = backup_dir(archive_path)
                 logger.warning(
-                    'Backing up %s to %s',
+                    "Backing up %s to %s",
                     display_path(archive_path),
                     display_path(dest_file),
                 )
                 shutil.move(archive_path, dest_file)
-            elif response == 'a':
+            elif response == "a":
                 sys.exit(-1)
 
         if not create_archive:
             return
 
         zip_output = zipfile.ZipFile(
-            archive_path, 'w', zipfile.ZIP_DEFLATED, allowZip64=True,
+            archive_path,
+            "w",
+            zipfile.ZIP_DEFLATED,
+            allowZip64=True,
         )
         with zip_output:
-            dir = os.path.normcase(
-                os.path.abspath(self.unpacked_source_directory)
-            )
+            dir = os.path.normcase(os.path.abspath(self.unpacked_source_directory))
             for dirpath, dirnames, filenames in os.walk(dir):
                 for dirname in dirnames:
                     dir_arcname = self._get_archive_name(
-                        dirname, parentdir=dirpath, rootdir=dir,
+                        dirname,
+                        parentdir=dirpath,
+                        rootdir=dir,
                     )
-                    zipdir = zipfile.ZipInfo(dir_arcname + '/')
+                    zipdir = zipfile.ZipInfo(dir_arcname + "/")
                     zipdir.external_attr = 0x1ED << 16  # 0o755
-                    zip_output.writestr(zipdir, '')
+                    zip_output.writestr(zipdir, "")
                 for filename in filenames:
                     file_arcname = self._get_archive_name(
-                        filename, parentdir=dirpath, rootdir=dir,
+                        filename,
+                        parentdir=dirpath,
+                        rootdir=dir,
                     )
                     filename = os.path.join(dirpath, filename)
                     zip_output.write(filename, file_arcname)
 
-        logger.info('Saved %s', display_path(archive_path))
+        logger.info("Saved %s", display_path(archive_path))
 
     def install(
         self,
@@ -767,7 +764,7 @@ def install(
         prefix=None,  # type: Optional[str]
         warn_script_location=True,  # type: bool
         use_user_site=False,  # type: bool
-        pycompile=True  # type: bool
+        pycompile=True,  # type: bool
     ):
         # type: (...) -> None
         scheme = get_scheme(
@@ -858,8 +855,9 @@ def install(
             deprecated(
                 reason=(
                     "{} was installed using the legacy 'setup.py install' "
-                    "method, because a wheel could not be built for it.".
-                    format(self.name)
+                    "method, because a wheel could not be built for it.".format(
+                        self.name
+                    )
                 ),
                 replacement="to fix the wheel build issue reported above",
                 gone_in="21.0",
@@ -888,12 +886,10 @@ def check_invalid_constraint_type(req):
                 "undocumented. The new implementation of the resolver no "
                 "longer supports these forms."
             ),
-            replacement=(
-                "replacing the constraint with a requirement."
-            ),
+            replacement=("replacing the constraint with a requirement."),
             # No plan yet for when the new resolver becomes default
             gone_in=None,
-            issue=8210
+            issue=8210,
         )
 
     return problem
diff --git a/src/pip/_internal/req/req_set.py b/src/pip/_internal/req/req_set.py
index c9ea3be5ddd..9becf32bb5a 100644
--- a/src/pip/_internal/req/req_set.py
+++ b/src/pip/_internal/req/req_set.py
@@ -20,13 +20,13 @@
 
 
 class RequirementSet(object):
-
     def __init__(self, check_supported_wheels=True):
         # type: (bool) -> None
-        """Create a RequirementSet.
-        """
+        """Create a RequirementSet."""
 
-        self.requirements = OrderedDict()  # type: Dict[str, InstallRequirement]  # noqa: E501
+        self.requirements = (
+            OrderedDict()
+        )  # type: Dict[str, InstallRequirement]  # noqa: E501
         self.check_supported_wheels = check_supported_wheels
 
         self.unnamed_requirements = []  # type: List[InstallRequirement]
@@ -37,7 +37,7 @@ def __str__(self):
             (req for req in self.requirements.values() if not req.comes_from),
             key=lambda req: canonicalize_name(req.name),
         )
-        return ' '.join(str(req.req) for req in requirements)
+        return " ".join(str(req.req) for req in requirements)
 
     def __repr__(self):
         # type: () -> str
@@ -46,11 +46,11 @@ def __repr__(self):
             key=lambda req: canonicalize_name(req.name),
         )
 
-        format_string = '<{classname} object; {count} requirement(s): {reqs}>'
+        format_string = "<{classname} object; {count} requirement(s): {reqs}>"
         return format_string.format(
             classname=self.__class__.__name__,
             count=len(requirements),
-            reqs=', '.join(str(req.req) for req in requirements),
+            reqs=", ".join(str(req.req) for req in requirements),
         )
 
     def add_unnamed_requirement(self, install_req):
@@ -69,7 +69,7 @@ def add_requirement(
         self,
         install_req,  # type: InstallRequirement
         parent_req_name=None,  # type: Optional[str]
-        extras_requested=None  # type: Optional[Iterable[str]]
+        extras_requested=None,  # type: Optional[Iterable[str]]
     ):
         # type: (...) -> Tuple[List[InstallRequirement], Optional[InstallRequirement]]  # noqa: E501
         """Add install_req as a requirement to install.
@@ -90,7 +90,8 @@ def add_requirement(
         if not install_req.match_markers(extras_requested):
             logger.info(
                 "Ignoring %s: markers '%s' don't match your environment",
-                install_req.name, install_req.markers,
+                install_req.name,
+                install_req.markers,
             )
             return [], None
 
@@ -101,16 +102,17 @@ def add_requirement(
         if install_req.link and install_req.link.is_wheel:
             wheel = Wheel(install_req.link.filename)
             tags = compatibility_tags.get_supported()
-            if (self.check_supported_wheels and not wheel.supported(tags)):
+            if self.check_supported_wheels and not wheel.supported(tags):
                 raise InstallationError(
                     "{} is not a supported wheel on this platform.".format(
-                        wheel.filename)
+                        wheel.filename
+                    )
                 )
 
         # This next bit is really a sanity check.
-        assert not install_req.user_supplied or parent_req_name is None, (
-            "a user supplied req shouldn't have a parent"
-        )
+        assert (
+            not install_req.user_supplied or parent_req_name is None
+        ), "a user supplied req shouldn't have a parent"
 
         # Unnamed requirements are scanned again and the requirement won't be
         # added as a dependency until after scanning.
@@ -120,21 +122,23 @@ def add_requirement(
 
         try:
             existing_req = self.get_requirement(
-                install_req.name)  # type: Optional[InstallRequirement]
+                install_req.name
+            )  # type: Optional[InstallRequirement]
         except KeyError:
             existing_req = None
 
         has_conflicting_requirement = (
-            parent_req_name is None and
-            existing_req and
-            not existing_req.constraint and
-            existing_req.extras == install_req.extras and
-            existing_req.req.specifier != install_req.req.specifier
+            parent_req_name is None
+            and existing_req
+            and not existing_req.constraint
+            and existing_req.extras == install_req.extras
+            and existing_req.req.specifier != install_req.req.specifier
         )
         if has_conflicting_requirement:
             raise InstallationError(
-                "Double requirement given: {} (already in {}, name={!r})"
-                .format(install_req, existing_req, install_req.name)
+                "Double requirement given: {} (already in {}, name={!r})".format(
+                    install_req, existing_req, install_req.name
+                )
             )
 
         # When no existing requirement exists, add the requirement as a
@@ -149,12 +153,8 @@ def add_requirement(
         if install_req.constraint or not existing_req.constraint:
             return [], existing_req
 
-        does_not_satisfy_constraint = (
-            install_req.link and
-            not (
-                existing_req.link and
-                install_req.link.path == existing_req.link.path
-            )
+        does_not_satisfy_constraint = install_req.link and not (
+            existing_req.link and install_req.link.path == existing_req.link.path
         )
         if does_not_satisfy_constraint:
             raise InstallationError(
@@ -169,12 +169,13 @@ def add_requirement(
         # mark the existing object as such.
         if install_req.user_supplied:
             existing_req.user_supplied = True
-        existing_req.extras = tuple(sorted(
-            set(existing_req.extras) | set(install_req.extras)
-        ))
+        existing_req.extras = tuple(
+            sorted(set(existing_req.extras) | set(install_req.extras))
+        )
         logger.debug(
             "Setting %s extras to: %s",
-            existing_req, existing_req.extras,
+            existing_req,
+            existing_req.extras,
         )
         # Return the existing requirement for addition to the parent and
         # scanning again.
@@ -185,8 +186,8 @@ def has_requirement(self, name):
         project_name = canonicalize_name(name)
 
         return (
-            project_name in self.requirements and
-            not self.requirements[project_name].constraint
+            project_name in self.requirements
+            and not self.requirements[project_name].constraint
         )
 
     def get_requirement(self, name):
diff --git a/src/pip/_internal/req/req_tracker.py b/src/pip/_internal/req/req_tracker.py
index 7379c307b31..b3e9a145b42 100644
--- a/src/pip/_internal/req/req_tracker.py
+++ b/src/pip/_internal/req/req_tracker.py
@@ -51,12 +51,10 @@ def update_env_context_manager(**changes):
 @contextlib.contextmanager
 def get_requirement_tracker():
     # type: () -> Iterator[RequirementTracker]
-    root = os.environ.get('PIP_REQ_TRACKER')
+    root = os.environ.get("PIP_REQ_TRACKER")
     with contextlib2.ExitStack() as ctx:
         if root is None:
-            root = ctx.enter_context(
-                TempDirectory(kind='req-tracker')
-            ).path
+            root = ctx.enter_context(TempDirectory(kind="req-tracker")).path
             ctx.enter_context(update_env_context_manager(PIP_REQ_TRACKER=root))
             logger.debug("Initialized build tracking at %s", root)
 
@@ -65,7 +63,6 @@ def get_requirement_tracker():
 
 
 class RequirementTracker(object):
-
     def __init__(self, root):
         # type: (str) -> None
         self._root = root
@@ -81,7 +78,7 @@ def __exit__(
         self,
         exc_type,  # type: Optional[Type[BaseException]]
         exc_val,  # type: Optional[BaseException]
-        exc_tb  # type: Optional[TracebackType]
+        exc_tb,  # type: Optional[TracebackType]
     ):
         # type: (...) -> None
         self.cleanup()
@@ -93,8 +90,7 @@ def _entry_path(self, link):
 
     def add(self, req):
         # type: (InstallRequirement) -> None
-        """Add an InstallRequirement to build tracking.
-        """
+        """Add an InstallRequirement to build tracking."""
 
         assert req.link
         # Get the file to write information about this requirement.
@@ -110,31 +106,29 @@ def add(self, req):
             if e.errno != errno.ENOENT:
                 raise
         else:
-            message = '{} is already being built: {}'.format(
-                req.link, contents)
+            message = "{} is already being built: {}".format(req.link, contents)
             raise LookupError(message)
 
         # If we're here, req should really not be building already.
         assert req not in self._entries
 
         # Start tracking this requirement.
-        with open(entry_path, 'w') as fp:
+        with open(entry_path, "w") as fp:
             fp.write(str(req))
         self._entries.add(req)
 
-        logger.debug('Added %s to build tracker %r', req, self._root)
+        logger.debug("Added %s to build tracker %r", req, self._root)
 
     def remove(self, req):
         # type: (InstallRequirement) -> None
-        """Remove an InstallRequirement from build tracking.
-        """
+        """Remove an InstallRequirement from build tracking."""
 
         assert req.link
         # Delete the created file and the corresponding entries.
         os.unlink(self._entry_path(req.link))
         self._entries.remove(req)
 
-        logger.debug('Removed %s from build tracker %r', req, self._root)
+        logger.debug("Removed %s from build tracker %r", req, self._root)
 
     def cleanup(self):
         # type: () -> None
diff --git a/src/pip/_internal/req/req_uninstall.py b/src/pip/_internal/req/req_uninstall.py
index 2e7dfcc7369..58461c4cde4 100644
--- a/src/pip/_internal/req/req_uninstall.py
+++ b/src/pip/_internal/req/req_uninstall.py
@@ -58,12 +58,12 @@ def _script_names(dist, script_name, is_gui):
     exe_name = os.path.join(bin_dir, script_name)
     paths_to_remove = [exe_name]
     if WINDOWS:
-        paths_to_remove.append(exe_name + '.exe')
-        paths_to_remove.append(exe_name + '.exe.manifest')
+        paths_to_remove.append(exe_name + ".exe")
+        paths_to_remove.append(exe_name + ".exe.manifest")
         if is_gui:
-            paths_to_remove.append(exe_name + '-script.pyw')
+            paths_to_remove.append(exe_name + "-script.pyw")
         else:
-            paths_to_remove.append(exe_name + '-script.py')
+            paths_to_remove.append(exe_name + "-script.py")
     return paths_to_remove
 
 
@@ -77,6 +77,7 @@ def unique(*args, **kw):
             if item not in seen:
                 seen.add(item)
                 yield item
+
     return unique
 
 
@@ -91,16 +92,16 @@ def uninstallation_paths(dist):
 
     UninstallPathSet.add() takes care of the __pycache__ .py[co].
     """
-    r = csv.reader(FakeFile(dist.get_metadata_lines('RECORD')))
+    r = csv.reader(FakeFile(dist.get_metadata_lines("RECORD")))
     for row in r:
         path = os.path.join(dist.location, row[0])
         yield path
-        if path.endswith('.py'):
+        if path.endswith(".py"):
             dn, fn = os.path.split(path)
             base = fn[:-3]
-            path = os.path.join(dn, base + '.pyc')
+            path = os.path.join(dn, base + ".pyc")
             yield path
-            path = os.path.join(dn, base + '.pyo')
+            path = os.path.join(dn, base + ".pyo")
             yield path
 
 
@@ -115,8 +116,8 @@ def compact(paths):
     short_paths = set()  # type: Set[str]
     for path in sorted(paths, key=len):
         should_skip = any(
-            path.startswith(shortpath.rstrip("*")) and
-            path[len(shortpath.rstrip("*").rstrip(sep))] == sep
+            path.startswith(shortpath.rstrip("*"))
+            and path[len(shortpath.rstrip("*").rstrip(sep))] == sep
             for shortpath in short_paths
         )
         if not should_skip:
@@ -133,8 +134,7 @@ def compress_for_rename(paths):
     """
     case_map = dict((os.path.normcase(p), p) for p in paths)
     remaining = set(case_map)
-    unchecked = sorted(set(os.path.split(p)[0]
-                           for p in case_map.values()), key=len)
+    unchecked = sorted(set(os.path.split(p)[0] for p in case_map.values()), key=len)
     wildcards = set()  # type: Set[str]
 
     def norm_join(*a):
@@ -142,18 +142,15 @@ def norm_join(*a):
         return os.path.normcase(os.path.join(*a))
 
     for root in unchecked:
-        if any(os.path.normcase(root).startswith(w)
-               for w in wildcards):
+        if any(os.path.normcase(root).startswith(w) for w in wildcards):
             # This directory has already been handled.
             continue
 
         all_files = set()  # type: Set[str]
         all_subdirs = set()  # type: Set[str]
         for dirname, subdirs, files in os.walk(root):
-            all_subdirs.update(norm_join(root, dirname, d)
-                               for d in subdirs)
-            all_files.update(norm_join(root, dirname, f)
-                             for f in files)
+            all_subdirs.update(norm_join(root, dirname, d) for d in subdirs)
+            all_files.update(norm_join(root, dirname, f) for f in files)
         # If all the files we found are in our remaining set of files to
         # remove, then remove them from the latter set and add a wildcard
         # for the directory.
@@ -203,14 +200,14 @@ def compress_for_output_listing(paths):
                     continue
 
                 file_ = os.path.join(dirpath, fname)
-                if (os.path.isfile(file_) and
-                        os.path.normcase(file_) not in _normcased_files):
+                if (
+                    os.path.isfile(file_)
+                    and os.path.normcase(file_) not in _normcased_files
+                ):
                     # We are skipping this file. Add it to the set.
                     will_skip.add(file_)
 
-    will_remove = files | {
-        os.path.join(folder, "*") for folder in folders
-    }
+    will_remove = files | {os.path.join(folder, "*") for folder in folders}
 
     return will_remove, will_skip
 
@@ -218,6 +215,7 @@ def compress_for_output_listing(paths):
 class StashedUninstallPathSet(object):
     """A set of file rename operations to stash files while
     tentatively uninstalling them."""
+
     def __init__(self):
         # type: () -> None
         # Mapping from source file root to [Adjacent]TempDirectory
@@ -262,7 +260,7 @@ def _get_file_stash(self, path):
         else:
             # Did not find any suitable root
             head = os.path.dirname(path)
-            save_dir = TempDirectory(kind='uninstall')
+            save_dir = TempDirectory(kind="uninstall")
             self._save_dirs[head] = save_dir
 
         relpath = os.path.relpath(path, head)
@@ -282,7 +280,7 @@ def stash(self, path):
             new_path = self._get_file_stash(path)
 
         self._moves.append((path, new_path))
-        if (path_is_dir and os.path.isdir(new_path)):
+        if path_is_dir and os.path.isdir(new_path):
             # If we're moving a directory, we need to
             # remove the destination first or else it will be
             # moved to inside the existing directory.
@@ -308,7 +306,7 @@ def rollback(self):
 
         for new_path, path in self._moves:
             try:
-                logger.debug('Replacing %s from %s', new_path, path)
+                logger.debug("Replacing %s from %s", new_path, path)
                 if os.path.isfile(new_path) or os.path.islink(new_path):
                     os.unlink(new_path)
                 elif os.path.isdir(new_path):
@@ -329,6 +327,7 @@ def can_rollback(self):
 class UninstallPathSet(object):
     """A set of file paths to be removed in the uninstallation of a
     requirement."""
+
     def __init__(self, dist):
         # type: (Distribution) -> None
         self.paths = set()  # type: Set[str]
@@ -363,7 +362,7 @@ def add(self, path):
 
         # __pycache__ files can show up after 'installed-files.txt' is created,
         # due to imports
-        if os.path.splitext(path)[1] == '.py' and uses_pycache:
+        if os.path.splitext(path)[1] == ".py" and uses_pycache:
             self.add(cache_from_source(path))
 
     def add_pth(self, pth_file, entry):
@@ -388,10 +387,8 @@ def remove(self, auto_confirm=False, verbose=False):
             )
             return
 
-        dist_name_version = (
-            self.dist.project_name + "-" + self.dist.version
-        )
-        logger.info('Uninstalling %s:', dist_name_version)
+        dist_name_version = self.dist.project_name + "-" + self.dist.version
+        logger.info("Uninstalling %s:", dist_name_version)
 
         with indent_log():
             if auto_confirm or self._allowed_to_proceed(verbose):
@@ -401,17 +398,16 @@ def remove(self, auto_confirm=False, verbose=False):
 
                 for path in sorted(compact(for_rename)):
                     moved.stash(path)
-                    logger.debug('Removing file or directory %s', path)
+                    logger.debug("Removing file or directory %s", path)
 
                 for pth in self.pth.values():
                     pth.remove()
 
-                logger.info('Successfully uninstalled %s', dist_name_version)
+                logger.info("Successfully uninstalled %s", dist_name_version)
 
     def _allowed_to_proceed(self, verbose):
         # type: (bool) -> bool
-        """Display which files would be deleted and prompt for confirmation
-        """
+        """Display which files would be deleted and prompt for confirmation"""
 
         def _display(msg, paths):
             # type: (str, Iterable[str]) -> None
@@ -431,13 +427,13 @@ def _display(msg, paths):
             will_remove = set(self.paths)
             will_skip = set()
 
-        _display('Would remove:', will_remove)
-        _display('Would not remove (might be manually added):', will_skip)
-        _display('Would not remove (outside of prefix):', self._refuse)
+        _display("Would remove:", will_remove)
+        _display("Would not remove (might be manually added):", will_skip)
+        _display("Would not remove (outside of prefix):", self._refuse)
         if verbose:
-            _display('Will actually move:', compress_for_rename(self.paths))
+            _display("Will actually move:", compress_for_rename(self.paths))
 
-        return ask('Proceed (y/n)? ', ('y', 'n')) == 'y'
+        return ask("Proceed (y/n)? ", ("y", "n")) == "y"
 
     def rollback(self):
         # type: () -> None
@@ -448,7 +444,7 @@ def rollback(self):
                 self.dist.project_name,
             )
             return
-        logger.info('Rolling back uninstall of %s', self.dist.project_name)
+        logger.info("Rolling back uninstall of %s", self.dist.project_name)
         self._moved_paths.rollback()
         for pth in self.pth.values():
             pth.rollback()
@@ -471,9 +467,11 @@ def from_dist(cls, dist):
             )
             return cls(dist)
 
-        if dist_path in {p for p in {sysconfig.get_path("stdlib"),
-                                     sysconfig.get_path("platstdlib")}
-                         if p}:
+        if dist_path in {
+            p
+            for p in {sysconfig.get_path("stdlib"), sysconfig.get_path("platstdlib")}
+            if p
+        }:
             logger.info(
                 "Not uninstalling %s at %s, as it is in the standard library.",
                 dist.key,
@@ -483,43 +481,47 @@ def from_dist(cls, dist):
 
         paths_to_remove = cls(dist)
         develop_egg_link = egg_link_path(dist)
-        develop_egg_link_egg_info = '{}.egg-info'.format(
-            pkg_resources.to_filename(dist.project_name))
+        develop_egg_link_egg_info = "{}.egg-info".format(
+            pkg_resources.to_filename(dist.project_name)
+        )
         egg_info_exists = dist.egg_info and os.path.exists(dist.egg_info)
         # Special case for distutils installed package
-        distutils_egg_info = getattr(dist._provider, 'path', None)
+        distutils_egg_info = getattr(dist._provider, "path", None)
 
         # Uninstall cases order do matter as in the case of 2 installs of the
         # same package, pip needs to uninstall the currently detected version
-        if (egg_info_exists and dist.egg_info.endswith('.egg-info') and
-                not dist.egg_info.endswith(develop_egg_link_egg_info)):
+        if (
+            egg_info_exists
+            and dist.egg_info.endswith(".egg-info")
+            and not dist.egg_info.endswith(develop_egg_link_egg_info)
+        ):
             # if dist.egg_info.endswith(develop_egg_link_egg_info), we
             # are in fact in the develop_egg_link case
             paths_to_remove.add(dist.egg_info)
-            if dist.has_metadata('installed-files.txt'):
+            if dist.has_metadata("installed-files.txt"):
                 for installed_file in dist.get_metadata(
-                        'installed-files.txt').splitlines():
-                    path = os.path.normpath(
-                        os.path.join(dist.egg_info, installed_file)
-                    )
+                    "installed-files.txt"
+                ).splitlines():
+                    path = os.path.normpath(os.path.join(dist.egg_info, installed_file))
                     paths_to_remove.add(path)
             # FIXME: need a test for this elif block
             # occurs with --single-version-externally-managed/--record outside
             # of pip
-            elif dist.has_metadata('top_level.txt'):
-                if dist.has_metadata('namespace_packages.txt'):
-                    namespaces = dist.get_metadata('namespace_packages.txt')
+            elif dist.has_metadata("top_level.txt"):
+                if dist.has_metadata("namespace_packages.txt"):
+                    namespaces = dist.get_metadata("namespace_packages.txt")
                 else:
                     namespaces = []
                 for top_level_pkg in [
-                        p for p
-                        in dist.get_metadata('top_level.txt').splitlines()
-                        if p and p not in namespaces]:
+                    p
+                    for p in dist.get_metadata("top_level.txt").splitlines()
+                    if p and p not in namespaces
+                ]:
                     path = os.path.join(dist.location, top_level_pkg)
                     paths_to_remove.add(path)
-                    paths_to_remove.add(path + '.py')
-                    paths_to_remove.add(path + '.pyc')
-                    paths_to_remove.add(path + '.pyo')
+                    paths_to_remove.add(path + ".py")
+                    paths_to_remove.add(path + ".pyc")
+                    paths_to_remove.add(path + ".pyo")
 
         elif distutils_egg_info:
             raise UninstallationError(
@@ -530,58 +532,61 @@ def from_dist(cls, dist):
                 )
             )
 
-        elif dist.location.endswith('.egg'):
+        elif dist.location.endswith(".egg"):
             # package installed by easy_install
             # We cannot match on dist.egg_name because it can slightly vary
             # i.e. setuptools-0.6c11-py2.6.egg vs setuptools-0.6rc11-py2.6.egg
             paths_to_remove.add(dist.location)
             easy_install_egg = os.path.split(dist.location)[1]
-            easy_install_pth = os.path.join(os.path.dirname(dist.location),
-                                            'easy-install.pth')
-            paths_to_remove.add_pth(easy_install_pth, './' + easy_install_egg)
+            easy_install_pth = os.path.join(
+                os.path.dirname(dist.location), "easy-install.pth"
+            )
+            paths_to_remove.add_pth(easy_install_pth, "./" + easy_install_egg)
 
-        elif egg_info_exists and dist.egg_info.endswith('.dist-info'):
+        elif egg_info_exists and dist.egg_info.endswith(".dist-info"):
             for path in uninstallation_paths(dist):
                 paths_to_remove.add(path)
 
         elif develop_egg_link:
             # develop egg
-            with open(develop_egg_link, 'r') as fh:
+            with open(develop_egg_link, "r") as fh:
                 link_pointer = os.path.normcase(fh.readline().strip())
-            assert (link_pointer == dist.location), (
-                'Egg-link {} does not match installed location of {} '
-                '(at {})'.format(
-                    link_pointer, dist.project_name, dist.location)
+            assert (
+                link_pointer == dist.location
+            ), "Egg-link {} does not match installed location of {} " "(at {})".format(
+                link_pointer, dist.project_name, dist.location
             )
             paths_to_remove.add(develop_egg_link)
-            easy_install_pth = os.path.join(os.path.dirname(develop_egg_link),
-                                            'easy-install.pth')
+            easy_install_pth = os.path.join(
+                os.path.dirname(develop_egg_link), "easy-install.pth"
+            )
             paths_to_remove.add_pth(easy_install_pth, dist.location)
 
         else:
             logger.debug(
-                'Not sure how to uninstall: %s - Check: %s',
-                dist, dist.location,
+                "Not sure how to uninstall: %s - Check: %s",
+                dist,
+                dist.location,
             )
 
         # find distutils scripts= scripts
-        if dist.has_metadata('scripts') and dist.metadata_isdir('scripts'):
-            for script in dist.metadata_listdir('scripts'):
+        if dist.has_metadata("scripts") and dist.metadata_isdir("scripts"):
+            for script in dist.metadata_listdir("scripts"):
                 if dist_in_usersite(dist):
                     bin_dir = bin_user
                 else:
                     bin_dir = bin_py
                 paths_to_remove.add(os.path.join(bin_dir, script))
                 if WINDOWS:
-                    paths_to_remove.add(os.path.join(bin_dir, script) + '.bat')
+                    paths_to_remove.add(os.path.join(bin_dir, script) + ".bat")
 
         # find console_scripts
         _scripts_to_remove = []
-        console_scripts = dist.get_entry_map(group='console_scripts')
+        console_scripts = dist.get_entry_map(group="console_scripts")
         for name in console_scripts.keys():
             _scripts_to_remove.extend(_script_names(dist, name, False))
         # find gui_scripts
-        gui_scripts = dist.get_entry_map(group='gui_scripts')
+        gui_scripts = dist.get_entry_map(group="gui_scripts")
         for name in gui_scripts.keys():
             _scripts_to_remove.extend(_script_names(dist, name, True))
 
@@ -611,47 +616,43 @@ def add(self, entry):
         # have more than "\\sever\share". Valid examples: "\\server\share\" or
         # "\\server\share\folder". Python 2.7.8+ support UNC in splitdrive.
         if WINDOWS and not os.path.splitdrive(entry)[0]:
-            entry = entry.replace('\\', '/')
+            entry = entry.replace("\\", "/")
         self.entries.add(entry)
 
     def remove(self):
         # type: () -> None
-        logger.debug('Removing pth entries from %s:', self.file)
+        logger.debug("Removing pth entries from %s:", self.file)
 
         # If the file doesn't exist, log a warning and return
         if not os.path.isfile(self.file):
-            logger.warning(
-                "Cannot remove entries from nonexistent file %s", self.file
-            )
+            logger.warning("Cannot remove entries from nonexistent file %s", self.file)
             return
-        with open(self.file, 'rb') as fh:
+        with open(self.file, "rb") as fh:
             # windows uses '\r\n' with py3k, but uses '\n' with py2.x
             lines = fh.readlines()
             self._saved_lines = lines
-        if any(b'\r\n' in line for line in lines):
-            endline = '\r\n'
+        if any(b"\r\n" in line for line in lines):
+            endline = "\r\n"
         else:
-            endline = '\n'
+            endline = "\n"
         # handle missing trailing newline
         if lines and not lines[-1].endswith(endline.encode("utf-8")):
             lines[-1] = lines[-1] + endline.encode("utf-8")
         for entry in self.entries:
             try:
-                logger.debug('Removing entry: %s', entry)
+                logger.debug("Removing entry: %s", entry)
                 lines.remove((entry + endline).encode("utf-8"))
             except ValueError:
                 pass
-        with open(self.file, 'wb') as fh:
+        with open(self.file, "wb") as fh:
             fh.writelines(lines)
 
     def rollback(self):
         # type: () -> bool
         if self._saved_lines is None:
-            logger.error(
-                'Cannot roll back changes to %s, none were made', self.file
-            )
+            logger.error("Cannot roll back changes to %s, none were made", self.file)
             return False
-        logger.debug('Rolling %s back to previous state', self.file)
-        with open(self.file, 'wb') as fh:
+        logger.debug("Rolling %s back to previous state", self.file)
+        with open(self.file, "wb") as fh:
             fh.writelines(self._saved_lines)
         return True
diff --git a/src/pip/_internal/resolution/base.py b/src/pip/_internal/resolution/base.py
index 6d50555e531..451212a4889 100644
--- a/src/pip/_internal/resolution/base.py
+++ b/src/pip/_internal/resolution/base.py
@@ -6,9 +6,7 @@
     from pip._internal.req.req_install import InstallRequirement
     from pip._internal.req.req_set import RequirementSet
 
-    InstallRequirementProvider = Callable[
-        [str, InstallRequirement], InstallRequirement
-    ]
+    InstallRequirementProvider = Callable[[str, InstallRequirement], InstallRequirement]
 
 
 class BaseResolver(object):
diff --git a/src/pip/_internal/resolution/legacy/resolver.py b/src/pip/_internal/resolution/legacy/resolver.py
index 6ef00bba19d..114e9d0a404 100644
--- a/src/pip/_internal/resolution/legacy/resolver.py
+++ b/src/pip/_internal/resolution/legacy/resolver.py
@@ -34,10 +34,7 @@
 from pip._internal.utils.compatibility_tags import get_supported
 from pip._internal.utils.logging import indent_log
 from pip._internal.utils.misc import dist_in_usersite, normalize_version_info
-from pip._internal.utils.packaging import (
-    check_requires_python,
-    get_requires_python,
-)
+from pip._internal.utils.packaging import check_requires_python, get_requires_python
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 
 if MYPY_CHECK_RUNNING:
@@ -78,31 +75,37 @@ def _check_dist_requires_python(
     requires_python = get_requires_python(dist)
     try:
         is_compatible = check_requires_python(
-            requires_python, version_info=version_info,
+            requires_python,
+            version_info=version_info,
         )
     except specifiers.InvalidSpecifier as exc:
         logger.warning(
             "Package %r has an invalid Requires-Python: %s",
-            dist.project_name, exc,
+            dist.project_name,
+            exc,
         )
         return
 
     if is_compatible:
         return
 
-    version = '.'.join(map(str, version_info))
+    version = ".".join(map(str, version_info))
     if ignore_requires_python:
         logger.debug(
-            'Ignoring failed Requires-Python check for package %r: '
-            '%s not in %r',
-            dist.project_name, version, requires_python,
+            "Ignoring failed Requires-Python check for package %r: " "%s not in %r",
+            dist.project_name,
+            version,
+            requires_python,
         )
         return
 
     raise UnsupportedPythonVersion(
-        'Package {!r} requires a different Python: {} not in {!r}'.format(
-            dist.project_name, version, requires_python,
-        ))
+        "Package {!r} requires a different Python: {} not in {!r}".format(
+            dist.project_name,
+            version,
+            requires_python,
+        )
+    )
 
 
 class Resolver(BaseResolver):
@@ -149,8 +152,9 @@ def __init__(
         self.use_user_site = use_user_site
         self._make_install_req = make_install_req
 
-        self._discovered_dependencies = \
-            defaultdict(list)  # type: DiscoveredDependencies
+        self._discovered_dependencies = defaultdict(
+            list
+        )  # type: DiscoveredDependencies
 
     def resolve(self, root_reqs, check_supported_wheels):
         # type: (List[InstallRequirement], bool) -> RequirementSet
@@ -164,9 +168,7 @@ def resolve(self, root_reqs, check_supported_wheels):
         possible to move the preparation to become a step separated from
         dependency resolution.
         """
-        requirement_set = RequirementSet(
-            check_supported_wheels=check_supported_wheels
-        )
+        requirement_set = RequirementSet(check_supported_wheels=check_supported_wheels)
         for req in root_reqs:
             if req.constraint:
                 check_invalid_constraint_type(req)
@@ -243,8 +245,8 @@ def _check_skip_installed(self, req_to_install):
 
         if not self._is_upgrade_allowed(req_to_install):
             if self.upgrade_strategy == "only-if-needed":
-                return 'already satisfied, skipping upgrade'
-            return 'already satisfied'
+                return "already satisfied, skipping upgrade"
+            return "already satisfied"
 
         # Check for the possibility of an upgrade.  For link-based
         # requirements we have to pull the tree down and inspect to assess
@@ -254,7 +256,7 @@ def _check_skip_installed(self, req_to_install):
                 self.finder.find_requirement(req_to_install, upgrade=True)
             except BestVersionAlreadyInstalled:
                 # Then the best version is installed.
-                return 'already up-to-date'
+                return "already up-to-date"
             except DistributionNotFound:
                 # No distribution found, so we squash the error.  It will
                 # be raised later when we re-try later to do the install.
@@ -274,14 +276,14 @@ def _find_requirement_link(self, req):
         # Log a warning per PEP 592 if necessary before returning.
         link = best_candidate.link
         if link.is_yanked:
-            reason = link.yanked_reason or '<none given>'
+            reason = link.yanked_reason or "<none given>"
             msg = (
                 # Mark this as a unicode string to prevent
                 # "UnicodeEncodeError: 'ascii' codec can't encode character"
                 # in Python 2 when the reason contains non-ascii characters.
-                u'The candidate selected for download or install is a '
-                'yanked version: {candidate}\n'
-                'Reason for being yanked: {reason}'
+                u"The candidate selected for download or install is a "
+                "yanked version: {candidate}\n"
+                "Reason for being yanked: {reason}"
             ).format(candidate=best_candidate, reason=reason)
             logger.warning(msg)
 
@@ -312,7 +314,7 @@ def _populate_link(self, req):
             supported_tags=get_supported(),
         )
         if cache_entry is not None:
-            logger.debug('Using cached wheel link: %s', cache_entry.link)
+            logger.debug("Using cached wheel link: %s", cache_entry.link)
             if req.link is req.original_link and cache_entry.persistent:
                 req.original_link_is_in_wheel_cache = True
             req.link = cache_entry.link
@@ -331,9 +333,7 @@ def _get_dist_for(self, req):
         skip_reason = self._check_skip_installed(req)
 
         if req.satisfied_by:
-            return self.preparer.prepare_installed_requirement(
-                req, skip_reason
-            )
+            return self.preparer.prepare_installed_requirement(req, skip_reason)
 
         # We eagerly populate the link, since that's our "legacy" behavior.
         self._populate_link(req)
@@ -352,17 +352,17 @@ def _get_dist_for(self, req):
 
         if req.satisfied_by:
             should_modify = (
-                self.upgrade_strategy != "to-satisfy-only" or
-                self.force_reinstall or
-                self.ignore_installed or
-                req.link.scheme == 'file'
+                self.upgrade_strategy != "to-satisfy-only"
+                or self.force_reinstall
+                or self.ignore_installed
+                or req.link.scheme == "file"
             )
             if should_modify:
                 self._set_req_to_reinstall(req)
             else:
                 logger.info(
-                    'Requirement already satisfied (use --upgrade to upgrade):'
-                    ' %s', req,
+                    "Requirement already satisfied (use --upgrade to upgrade):" " %s",
+                    req,
                 )
         return dist
 
@@ -389,7 +389,8 @@ def _resolve_one(
         # This will raise UnsupportedPythonVersion if the given Python
         # version isn't compatible with the distribution's Requires-Python.
         _check_dist_requires_python(
-            dist, version_info=self._py_version_info,
+            dist,
+            version_info=self._py_version_info,
             ignore_requires_python=self.ignore_requires_python,
         )
 
@@ -407,9 +408,7 @@ def add_req(subreq, extras_requested):
                 extras_requested=extras_requested,
             )
             if parent_req_name and add_to_parent:
-                self._discovered_dependencies[parent_req_name].append(
-                    add_to_parent
-                )
+                self._discovered_dependencies[parent_req_name].append(add_to_parent)
             more_reqs.extend(to_scan_again)
 
         with indent_log():
@@ -421,23 +420,21 @@ def add_req(subreq, extras_requested):
                 # provided by the user.
                 assert req_to_install.user_supplied
                 requirement_set.add_requirement(
-                    req_to_install, parent_req_name=None,
+                    req_to_install,
+                    parent_req_name=None,
                 )
 
             if not self.ignore_dependencies:
                 if req_to_install.extras:
                     logger.debug(
                         "Installing extra requirements: %r",
-                        ','.join(req_to_install.extras),
+                        ",".join(req_to_install.extras),
                     )
                 missing_requested = sorted(
                     set(req_to_install.extras) - set(dist.extras)
                 )
                 for missing in missing_requested:
-                    logger.warning(
-                        "%s does not provide the extra '%s'",
-                        dist, missing
-                    )
+                    logger.warning("%s does not provide the extra '%s'", dist, missing)
 
                 available_requested = sorted(
                     set(dist.extras) & set(req_to_install.extras)
diff --git a/src/pip/_internal/resolution/resolvelib/candidates.py b/src/pip/_internal/resolution/resolvelib/candidates.py
index ff2b336d9e0..3e6519e9fcf 100644
--- a/src/pip/_internal/resolution/resolvelib/candidates.py
+++ b/src/pip/_internal/resolution/resolvelib/candidates.py
@@ -56,7 +56,7 @@ def make_install_req_from_link(link, template):
         options=dict(
             install_options=template.install_options,
             global_options=template.global_options,
-            hashes=template.hash_options
+            hashes=template.hash_options,
         ),
     )
     ireq.original_link = template.original_link
@@ -77,7 +77,7 @@ def make_install_req_from_editable(link, template):
         options=dict(
             install_options=template.install_options,
             global_options=template.global_options,
-            hashes=template.hash_options
+            hashes=template.hash_options,
         ),
     )
 
@@ -101,7 +101,7 @@ def make_install_req_from_dist(dist, template):
         options=dict(
             install_options=template.install_options,
             global_options=template.global_options,
-            hashes=template.hash_options
+            hashes=template.hash_options,
         ),
     )
     ireq.satisfied_by = dist
@@ -123,15 +123,16 @@ class exposes appropriate information to the resolver.
         ``link`` would point to the wheel cache, while this points to the
         found remote link (e.g. from pypi.org).
     """
+
     is_installed = False
 
     def __init__(
         self,
-        link,          # type: Link
-        source_link,   # type: Link
-        ireq,          # type: InstallRequirement
-        factory,       # type: Factory
-        name=None,     # type: Optional[str]
+        link,  # type: Link
+        source_link,  # type: Link
+        ireq,  # type: InstallRequirement
+        factory,  # type: Factory
+        name=None,  # type: Optional[str]
         version=None,  # type: Optional[_BaseVersion]
     ):
         # type: (...) -> None
@@ -190,7 +191,7 @@ def format_for_error(self):
         return "{} {} (from {})".format(
             self.name,
             self.version,
-            self._link.file_path if self._link.is_file else self._link
+            self._link.file_path if self._link.is_file else self._link,
         )
 
     def _prepare_distribution(self):
@@ -261,10 +262,10 @@ class LinkCandidate(_InstallRequirementBackedCandidate):
 
     def __init__(
         self,
-        link,          # type: Link
-        template,        # type: InstallRequirement
-        factory,       # type: Factory
-        name=None,     # type: Optional[str]
+        link,  # type: Link
+        template,  # type: InstallRequirement
+        factory,  # type: Factory
+        name=None,  # type: Optional[str]
         version=None,  # type: Optional[_BaseVersion]
     ):
         # type: (...) -> None
@@ -278,20 +279,18 @@ def __init__(
         if ireq.link.is_wheel and not ireq.link.is_file:
             wheel = Wheel(ireq.link.filename)
             wheel_name = canonicalize_name(wheel.name)
-            assert name == wheel_name, (
-                "{!r} != {!r} for wheel".format(name, wheel_name)
-            )
+            assert name == wheel_name, "{!r} != {!r} for wheel".format(name, wheel_name)
             # Version may not be present for PEP 508 direct URLs
             if version is not None:
-                assert str(version) == wheel.version, (
-                    "{!r} != {!r} for wheel {}".format(
-                        version, wheel.version, name
-                    )
-                )
-
-        if (cache_entry is not None and
-                cache_entry.persistent and
-                template.link is template.original_link):
+                assert (
+                    str(version) == wheel.version
+                ), "{!r} != {!r} for wheel {}".format(version, wheel.version, name)
+
+        if (
+            cache_entry is not None
+            and cache_entry.persistent
+            and template.link is template.original_link
+        ):
             ireq.original_link_is_in_wheel_cache = True
 
         super(LinkCandidate, self).__init__(
@@ -306,7 +305,8 @@ def __init__(
     def _prepare_distribution(self):
         # type: () -> Distribution
         return self._factory.preparer.prepare_linked_requirement(
-            self._ireq, parallel_builds=True,
+            self._ireq,
+            parallel_builds=True,
         )
 
 
@@ -315,10 +315,10 @@ class EditableCandidate(_InstallRequirementBackedCandidate):
 
     def __init__(
         self,
-        link,          # type: Link
-        template,        # type: InstallRequirement
-        factory,       # type: Factory
-        name=None,     # type: Optional[str]
+        link,  # type: Link
+        template,  # type: InstallRequirement
+        factory,  # type: Factory
+        name=None,  # type: Optional[str]
         version=None,  # type: Optional[_BaseVersion]
     ):
         # type: (...) -> None
@@ -435,6 +435,7 @@ class ExtrasCandidate(Candidate):
     version 2.0. Having those candidates depend on foo=1.0 and foo=2.0
     respectively forces the resolver to recognise that this is a conflict.
     """
+
     def __init__(
         self,
         base,  # type: BaseCandidate
@@ -481,8 +482,7 @@ def version(self):
     def format_for_error(self):
         # type: () -> str
         return "{} [{}]".format(
-            self.base.format_for_error(),
-            ", ".join(sorted(self.extras))
+            self.base.format_for_error(), ", ".join(sorted(self.extras))
         )
 
     @property
@@ -519,12 +519,14 @@ def iter_dependencies(self, with_requires):
                 "%s %s does not provide the extra '%s'",
                 self.base.name,
                 self.version,
-                extra
+                extra,
             )
 
         for r in self.base.dist.requires(valid_extras):
             requirement = factory.make_requirement_from_spec(
-                str(r), self.base._ireq, valid_extras,
+                str(r),
+                self.base._ireq,
+                valid_extras,
             )
             if requirement:
                 yield requirement
diff --git a/src/pip/_internal/resolution/resolvelib/factory.py b/src/pip/_internal/resolution/resolvelib/factory.py
index 96e2d53314d..f55f4e14b41 100644
--- a/src/pip/_internal/resolution/resolvelib/factory.py
+++ b/src/pip/_internal/resolution/resolvelib/factory.py
@@ -136,13 +136,21 @@ def _make_candidate_from_link(
         if template.editable:
             if link not in self._editable_candidate_cache:
                 self._editable_candidate_cache[link] = EditableCandidate(
-                    link, template, factory=self, name=name, version=version,
+                    link,
+                    template,
+                    factory=self,
+                    name=name,
+                    version=version,
                 )
             base = self._editable_candidate_cache[link]  # type: BaseCandidate
         else:
             if link not in self._link_candidate_cache:
                 self._link_candidate_cache[link] = LinkCandidate(
-                    link, template, factory=self, name=name, version=version,
+                    link,
+                    template,
+                    factory=self,
+                    name=name,
+                    version=version,
                 )
             base = self._link_candidate_cache[link]
         if extras:
@@ -246,7 +254,8 @@ def find_candidates(self, requirements, constraint):
             )
 
         return (
-            c for c in explicit_candidates
+            c
+            for c in explicit_candidates
             if all(req.is_satisfied_by(c) for req in requirements)
         )
 
@@ -255,7 +264,8 @@ def make_requirement_from_install_req(self, ireq, requested_extras):
         if not ireq.match_markers(requested_extras):
             logger.info(
                 "Ignoring %s: markers '%s' don't match your environment",
-                ireq.name, ireq.markers,
+                ireq.name,
+                ireq.markers,
             )
             return None
         if not ireq.link:
@@ -339,7 +349,8 @@ def get_dist_to_uninstall(self, candidate):
             raise InstallationError(
                 "Will not install to the user site because it will "
                 "lack sys.path precedence to {} in {}".format(
-                    dist.project_name, dist.location,
+                    dist.project_name,
+                    dist.location,
                 )
             )
         return None
@@ -385,13 +396,13 @@ def get_installation_error(self, e):
             if parent is None:
                 req_disp = str(req)
             else:
-                req_disp = '{} (from {})'.format(req, parent.name)
+                req_disp = "{} (from {})".format(req, parent.name)
             logger.critical(
                 "Could not find a version that satisfies the requirement %s",
                 req_disp,
             )
             return DistributionNotFound(
-                'No matching distribution found for {}'.format(req)
+                "No matching distribution found for {}".format(req)
             )
 
         # OK, we now have a list of requirements that can't all be
@@ -428,26 +439,28 @@ def describe_trigger(parent):
         else:
             info = "the requested packages"
 
-        msg = "Cannot install {} because these package versions " \
+        msg = (
+            "Cannot install {} because these package versions "
             "have conflicting dependencies.".format(info)
+        )
         logger.critical(msg)
         msg = "\nThe conflict is caused by:"
         for req, parent in e.causes:
             msg = msg + "\n    "
             if parent:
-                msg = msg + "{} {} depends on ".format(
-                    parent.name,
-                    parent.version
-                )
+                msg = msg + "{} {} depends on ".format(parent.name, parent.version)
             else:
                 msg = msg + "The user requested "
             msg = msg + req.format_for_error()
 
-        msg = msg + "\n\n" + \
-            "To fix this you could try to:\n" + \
-            "1. loosen the range of package versions you've specified\n" + \
-            "2. remove package versions to allow pip attempt to solve " + \
-            "the dependency conflict\n"
+        msg = (
+            msg
+            + "\n\n"
+            + "To fix this you could try to:\n"
+            + "1. loosen the range of package versions you've specified\n"
+            + "2. remove package versions to allow pip attempt to solve "
+            + "the dependency conflict\n"
+        )
 
         logger.info(msg)
 
diff --git a/src/pip/_internal/resolution/resolvelib/provider.py b/src/pip/_internal/resolution/resolvelib/provider.py
index 99f99bfc212..e31481702f4 100644
--- a/src/pip/_internal/resolution/resolvelib/provider.py
+++ b/src/pip/_internal/resolution/resolvelib/provider.py
@@ -5,16 +5,7 @@
 from .base import Constraint
 
 if MYPY_CHECK_RUNNING:
-    from typing import (
-        Any,
-        Dict,
-        Iterable,
-        Optional,
-        Sequence,
-        Set,
-        Tuple,
-        Union,
-    )
+    from typing import Any, Dict, Iterable, Optional, Sequence, Set, Tuple, Union
 
     from .base import Candidate, Requirement
     from .factory import Factory
@@ -93,7 +84,7 @@ def _eligible_for_upgrade(name):
             if self._upgrade_strategy == "eager":
                 return True
             elif self._upgrade_strategy == "only-if-needed":
-                return (name in self.user_requested)
+                return name in self.user_requested
             return False
 
         def sort_key(c):
@@ -124,7 +115,7 @@ def get_preference(
         self,
         resolution,  # type: Optional[Candidate]
         candidates,  # type: Sequence[Candidate]
-        information  # type: Sequence[Tuple[Requirement, Candidate]]
+        information,  # type: Sequence[Tuple[Requirement, Candidate]]
     ):
         # type: (...) -> Any
         # Use the "usual" value for now
@@ -135,7 +126,8 @@ def find_matches(self, requirements):
         if not requirements:
             return []
         constraint = self._constraints.get(
-            requirements[0].name, Constraint.empty(),
+            requirements[0].name,
+            Constraint.empty(),
         )
         candidates = self._factory.find_candidates(requirements, constraint)
         return reversed(self._sort_matches(candidates))
@@ -147,8 +139,4 @@ def is_satisfied_by(self, requirement, candidate):
     def get_dependencies(self, candidate):
         # type: (Candidate) -> Sequence[Requirement]
         with_requires = not self._ignore_dependencies
-        return [
-            r
-            for r in candidate.iter_dependencies(with_requires)
-            if r is not None
-        ]
+        return [r for r in candidate.iter_dependencies(with_requires) if r is not None]
diff --git a/src/pip/_internal/resolution/resolvelib/requirements.py b/src/pip/_internal/resolution/resolvelib/requirements.py
index bc1061f4303..17d9a766ab1 100644
--- a/src/pip/_internal/resolution/resolvelib/requirements.py
+++ b/src/pip/_internal/resolution/resolvelib/requirements.py
@@ -88,9 +88,11 @@ def get_candidate_lookup(self):
 
     def is_satisfied_by(self, candidate):
         # type: (Candidate) -> bool
-        assert candidate.name == self.name, \
-            "Internal issue: Candidate is not for this requirement " \
-            " {} vs {}".format(candidate.name, self.name)
+        assert (
+            candidate.name == self.name
+        ), "Internal issue: Candidate is not for this requirement " " {} vs {}".format(
+            candidate.name, self.name
+        )
         # We can safely always allow prereleases here since PackageFinder
         # already implements the prerelease logic, and would have filtered out
         # prerelease candidates if the user does not expect them.
@@ -99,8 +101,8 @@ def is_satisfied_by(self, candidate):
 
 
 class RequiresPythonRequirement(Requirement):
-    """A requirement representing Requires-Python metadata.
-    """
+    """A requirement representing Requires-Python metadata."""
+
     def __init__(self, specifier, match):
         # type: (SpecifierSet, Candidate) -> None
         self.specifier = specifier
diff --git a/src/pip/_internal/resolution/resolvelib/resolver.py b/src/pip/_internal/resolution/resolvelib/resolver.py
index cb7d1ae8a59..81512189334 100644
--- a/src/pip/_internal/resolution/resolvelib/resolver.py
+++ b/src/pip/_internal/resolution/resolvelib/resolver.py
@@ -91,7 +91,8 @@ def resolve(self, root_reqs, check_supported_wheels):
                 if req.user_supplied and req.name:
                     user_requested.add(canonicalize_name(req.name))
                 r = self.factory.make_requirement_from_install_req(
-                    req, requested_extras=(),
+                    req,
+                    requested_extras=(),
                 )
                 if r is not None:
                     requirements.append(r)
@@ -109,7 +110,8 @@ def resolve(self, root_reqs, check_supported_wheels):
         try:
             try_to_avoid_resolution_too_deep = 2000000
             self._result = resolver.resolve(
-                requirements, max_rounds=try_to_avoid_resolution_too_deep,
+                requirements,
+                max_rounds=try_to_avoid_resolution_too_deep,
             )
 
         except ResolutionImpossible as e:
@@ -147,14 +149,14 @@ def resolve(self, root_reqs, check_supported_wheels):
                 # The reason can contain non-ASCII characters, Unicode
                 # is required for Python 2.
                 msg = (
-                    u'The candidate selected for download or install is a '
-                    u'yanked version: {name!r} candidate (version {version} '
-                    u'at {link})\nReason for being yanked: {reason}'
+                    u"The candidate selected for download or install is a "
+                    u"yanked version: {name!r} candidate (version {version} "
+                    u"at {link})\nReason for being yanked: {reason}"
                 ).format(
                     name=candidate.name,
                     version=candidate.version,
                     link=link,
-                    reason=link.yanked_reason or u'<none given>',
+                    reason=link.yanked_reason or u"<none given>",
                 )
                 logger.warning(msg)
 
@@ -237,7 +239,7 @@ def visit(node):
 
 
 def _req_set_item_sorter(
-    item,     # type: Tuple[str, InstallRequirement]
+    item,  # type: Tuple[str, InstallRequirement]
     weights,  # type: Dict[Optional[str], int]
 ):
     # type: (...) -> Tuple[int, str]
diff --git a/src/pip/_internal/self_outdated_check.py b/src/pip/_internal/self_outdated_check.py
index fbd9dfd48b7..2f7a57f74df 100644
--- a/src/pip/_internal/self_outdated_check.py
+++ b/src/pip/_internal/self_outdated_check.py
@@ -13,16 +13,8 @@
 from pip._internal.index.collector import LinkCollector
 from pip._internal.index.package_finder import PackageFinder
 from pip._internal.models.selection_prefs import SelectionPreferences
-from pip._internal.utils.filesystem import (
-    adjacent_tmp_file,
-    check_path_owner,
-    replace,
-)
-from pip._internal.utils.misc import (
-    ensure_dir,
-    get_distribution,
-    get_installed_version,
-)
+from pip._internal.utils.filesystem import adjacent_tmp_file, check_path_owner, replace
+from pip._internal.utils.misc import ensure_dir, get_distribution, get_installed_version
 from pip._internal.utils.packaging import get_installer
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 
@@ -141,8 +133,7 @@ def pip_self_version_check(session, options):
         # Determine if we need to refresh the state
         if "last_check" in state.state and "pypi_version" in state.state:
             last_check = datetime.datetime.strptime(
-                state.state["last_check"],
-                SELFCHECK_DATE_FMT
+                state.state["last_check"], SELFCHECK_DATE_FMT
             )
             if (current_time - last_check).total_seconds() < 7 * 24 * 60 * 60:
                 pypi_version = state.state["pypi_version"]
@@ -178,9 +169,9 @@ def pip_self_version_check(session, options):
         remote_version = packaging_version.parse(pypi_version)
 
         local_version_is_older = (
-            pip_version < remote_version and
-            pip_version.base_version != remote_version.base_version and
-            was_installed_by_pip('pip')
+            pip_version < remote_version
+            and pip_version.base_version != remote_version.base_version
+            and was_installed_by_pip("pip")
         )
 
         # Determine if our pypi_version is older
@@ -196,7 +187,9 @@ def pip_self_version_check(session, options):
             "You are using pip version %s; however, version %s is "
             "available.\nYou should consider upgrading via the "
             "'%s install --upgrade pip' command.",
-            pip_version, pypi_version, pip_cmd
+            pip_version,
+            pypi_version,
+            pip_cmd,
         )
     except Exception:
         logger.debug(
diff --git a/src/pip/_internal/utils/appdirs.py b/src/pip/_internal/utils/appdirs.py
index 3989ed31c3a..494d1681e62 100644
--- a/src/pip/_internal/utils/appdirs.py
+++ b/src/pip/_internal/utils/appdirs.py
@@ -27,7 +27,7 @@ def user_config_dir(appname, roaming=True):
     # type: (str, bool) -> str
     path = _appdirs.user_config_dir(appname, appauthor=False, roaming=roaming)
     if _appdirs.system == "darwin" and not os.path.isdir(path):
-        path = os.path.expanduser('~/.config/')
+        path = os.path.expanduser("~/.config/")
         if appname:
             path = os.path.join(path, appname)
     return path
@@ -40,5 +40,5 @@ def site_config_dirs(appname):
     dirval = _appdirs.site_config_dir(appname, appauthor=False, multipath=True)
     if _appdirs.system not in ["win32", "darwin"]:
         # always look in /etc directly as well
-        return dirval.split(os.pathsep) + ['/etc']
+        return dirval.split(os.pathsep) + ["/etc"]
     return [dirval]
diff --git a/src/pip/_internal/utils/compat.py b/src/pip/_internal/utils/compat.py
index cc63536783c..b25367710ee 100644
--- a/src/pip/_internal/utils/compat.py
+++ b/src/pip/_internal/utils/compat.py
@@ -27,13 +27,20 @@
         from pip._vendor import ipaddress  # type: ignore
     except ImportError:
         import ipaddr as ipaddress  # type: ignore
+
         ipaddress.ip_address = ipaddress.IPAddress  # type: ignore
         ipaddress.ip_network = ipaddress.IPNetwork  # type: ignore
 
 
 __all__ = [
-    "ipaddress", "uses_pycache", "console_to_str",
-    "get_path_uid", "stdlib_pkgs", "WINDOWS", "samefile", "get_terminal_size",
+    "ipaddress",
+    "uses_pycache",
+    "console_to_str",
+    "get_path_uid",
+    "stdlib_pkgs",
+    "WINDOWS",
+    "samefile",
+    "get_terminal_size",
 ]
 
 
@@ -65,6 +72,7 @@ def backslashreplace_decode_fn(err):
         # Python 2 gave us characters - convert to numeric bytes
         raw_bytes = (ord(b) for b in raw_bytes)
         return u"".join(map(u"\\x{:x}".format, raw_bytes)), err.end
+
     codecs.register_error(
         "backslashreplace_decode",
         backslashreplace_decode_fn,
@@ -78,11 +86,13 @@ def has_tls():
     # type: () -> bool
     try:
         import _ssl  # noqa: F401  # ignore unused
+
         return True
     except ImportError:
         pass
 
     from pip._vendor.urllib3.util import IS_PYOPENSSL
+
     return IS_PYOPENSSL
 
 
@@ -122,8 +132,8 @@ def str_to_display(data, desc=None):
         decoded_data = data.decode(encoding)
     except UnicodeDecodeError:
         logger.warning(
-            '%s does not appear to be encoded as %s',
-            desc or 'Bytes object',
+            "%s does not appear to be encoded as %s",
+            desc or "Bytes object",
             encoding,
         )
         decoded_data = data.decode(encoding, errors=backslashreplace_decode)
@@ -140,14 +150,10 @@ def str_to_display(data, desc=None):
     # or doesn't have an encoding attribute. Neither of these cases
     # should occur in normal pip use, but there's no harm in checking
     # in case people use pip in (unsupported) unusual situations.
-    output_encoding = getattr(getattr(sys, "__stderr__", None),
-                              "encoding", None)
+    output_encoding = getattr(getattr(sys, "__stderr__", None), "encoding", None)
 
     if output_encoding:
-        output_encoded = decoded_data.encode(
-            output_encoding,
-            errors="backslashreplace"
-        )
+        output_encoded = decoded_data.encode(output_encoding, errors="backslashreplace")
         decoded_data = output_encoded.decode(output_encoding)
 
     return decoded_data
@@ -155,9 +161,8 @@ def str_to_display(data, desc=None):
 
 def console_to_str(data):
     # type: (bytes) -> Text
-    """Return a string, safe for output, of subprocess output.
-    """
-    return str_to_display(data, desc='Subprocess output')
+    """Return a string, safe for output, of subprocess output."""
+    return str_to_display(data, desc="Subprocess output")
 
 
 def get_path_uid(path):
@@ -173,7 +178,7 @@ def get_path_uid(path):
 
     :raises OSError: When path is a symlink or can't be read.
     """
-    if hasattr(os, 'O_NOFOLLOW'):
+    if hasattr(os, "O_NOFOLLOW"):
         fd = os.open(path, os.O_RDONLY | os.O_NOFOLLOW)
         file_uid = os.fstat(fd).st_uid
         os.close(fd)
@@ -185,8 +190,7 @@ def get_path_uid(path):
         else:
             # raise OSError for parity with os.O_NOFOLLOW above
             raise OSError(
-                "{} is a symlink; Will not return uid for symlinks".format(
-                    path)
+                "{} is a symlink; Will not return uid for symlinks".format(path)
             )
     return file_uid
 
@@ -199,7 +203,7 @@ def expanduser(path):
     Includes a workaround for https://bugs.python.org/issue14768
     """
     expanded = os.path.expanduser(path)
-    if path.startswith('~/') and expanded.startswith('//'):
+    if path.startswith("~/") and expanded.startswith("//"):
         expanded = expanded[1:]
     return expanded
 
@@ -213,14 +217,13 @@ def expanduser(path):
 
 
 # windows detection, covers cpython and ironpython
-WINDOWS = (sys.platform.startswith("win") or
-           (sys.platform == 'cli' and os.name == 'nt'))
+WINDOWS = sys.platform.startswith("win") or (sys.platform == "cli" and os.name == "nt")
 
 
 def samefile(file1, file2):
     # type: (str, str) -> bool
     """Provide an alternative for os.path.samefile on Windows/Python2"""
-    if hasattr(os.path, 'samefile'):
+    if hasattr(os.path, "samefile"):
         return os.path.samefile(file1, file2)
     else:
         path1 = os.path.normcase(os.path.abspath(file1))
@@ -228,7 +231,8 @@ def samefile(file1, file2):
         return path1 == path2
 
 
-if hasattr(shutil, 'get_terminal_size'):
+if hasattr(shutil, "get_terminal_size"):
+
     def get_terminal_size():
         # type: () -> Tuple[int, int]
         """
@@ -236,27 +240,32 @@ def get_terminal_size():
         in characters of the terminal window.
         """
         return tuple(shutil.get_terminal_size())  # type: ignore
+
+
 else:
+
     def get_terminal_size():
         # type: () -> Tuple[int, int]
         """
         Returns a tuple (x, y) representing the width(x) and the height(y)
         in characters of the terminal window.
         """
+
         def ioctl_GWINSZ(fd):
             try:
                 import fcntl
                 import struct
                 import termios
+
                 cr = struct.unpack_from(
-                    'hh',
-                    fcntl.ioctl(fd, termios.TIOCGWINSZ, '12345678')
+                    "hh", fcntl.ioctl(fd, termios.TIOCGWINSZ, "12345678")
                 )
             except Exception:
                 return None
             if cr == (0, 0):
                 return None
             return cr
+
         cr = ioctl_GWINSZ(0) or ioctl_GWINSZ(1) or ioctl_GWINSZ(2)
         if not cr:
             if sys.platform != "win32":
@@ -267,5 +276,5 @@ def ioctl_GWINSZ(fd):
                 except Exception:
                     pass
         if not cr:
-            cr = (os.environ.get('LINES', 25), os.environ.get('COLUMNS', 80))
+            cr = (os.environ.get("LINES", 25), os.environ.get("COLUMNS", 80))
         return int(cr[1]), int(cr[0])
diff --git a/src/pip/_internal/utils/compatibility_tags.py b/src/pip/_internal/utils/compatibility_tags.py
index 4f21874ec6b..e0aa055abc3 100644
--- a/src/pip/_internal/utils/compatibility_tags.py
+++ b/src/pip/_internal/utils/compatibility_tags.py
@@ -22,13 +22,13 @@
 
     from pip._vendor.packaging.tags import PythonVersion
 
-_osx_arch_pat = re.compile(r'(.+)_(\d+)_(\d+)_(.+)')
+_osx_arch_pat = re.compile(r"(.+)_(\d+)_(\d+)_(.+)")
 
 
 def version_info_to_nodot(version_info):
     # type: (Tuple[int, ...]) -> str
     # Only use up to the first two numbers.
-    return ''.join(map(str, version_info[:2]))
+    return "".join(map(str, version_info[:2]))
 
 
 def _mac_platforms(arch):
@@ -43,7 +43,7 @@ def _mac_platforms(arch):
             # actual prefix provided by the user in case they provided
             # something like "macosxcustom_". It may be good to remove
             # this as undocumented or deprecate it in the future.
-            '{}_{}'.format(name, arch[len('macosx_'):])
+            "{}_{}".format(name, arch[len("macosx_") :])
             for arch in mac_platforms(mac_version, actual_arch)
         ]
     else:
@@ -55,31 +55,31 @@ def _mac_platforms(arch):
 def _custom_manylinux_platforms(arch):
     # type: (str) -> List[str]
     arches = [arch]
-    arch_prefix, arch_sep, arch_suffix = arch.partition('_')
-    if arch_prefix == 'manylinux2014':
+    arch_prefix, arch_sep, arch_suffix = arch.partition("_")
+    if arch_prefix == "manylinux2014":
         # manylinux1/manylinux2010 wheels run on most manylinux2014 systems
         # with the exception of wheels depending on ncurses. PEP 599 states
         # manylinux1/manylinux2010 wheels should be considered
         # manylinux2014 wheels:
         # https://www.python.org/dev/peps/pep-0599/#backwards-compatibility-with-manylinux2010-wheels
-        if arch_suffix in {'i686', 'x86_64'}:
-            arches.append('manylinux2010' + arch_sep + arch_suffix)
-            arches.append('manylinux1' + arch_sep + arch_suffix)
-    elif arch_prefix == 'manylinux2010':
+        if arch_suffix in {"i686", "x86_64"}:
+            arches.append("manylinux2010" + arch_sep + arch_suffix)
+            arches.append("manylinux1" + arch_sep + arch_suffix)
+    elif arch_prefix == "manylinux2010":
         # manylinux1 wheels run on most manylinux2010 systems with the
         # exception of wheels depending on ncurses. PEP 571 states
         # manylinux1 wheels should be considered manylinux2010 wheels:
         # https://www.python.org/dev/peps/pep-0571/#backwards-compatibility-with-manylinux1-wheels
-        arches.append('manylinux1' + arch_sep + arch_suffix)
+        arches.append("manylinux1" + arch_sep + arch_suffix)
     return arches
 
 
 def _get_custom_platforms(arch):
     # type: (str) -> List[str]
-    arch_prefix, arch_sep, arch_suffix = arch.partition('_')
-    if arch.startswith('macosx'):
+    arch_prefix, arch_sep, arch_suffix = arch.partition("_")
+    if arch.startswith("macosx"):
         arches = _mac_platforms(arch)
-    elif arch_prefix in ['manylinux2014', 'manylinux2010']:
+    elif arch_prefix in ["manylinux2014", "manylinux2010"]:
         arches = _custom_manylinux_platforms(arch)
     else:
         arches = [arch]
@@ -107,7 +107,7 @@ def get_supported(
     version=None,  # type: Optional[str]
     platform=None,  # type: Optional[str]
     impl=None,  # type: Optional[str]
-    abi=None  # type: Optional[str]
+    abi=None,  # type: Optional[str]
 ):
     # type: (...) -> List[Tag]
     """Return a list of supported tags for each version specified in
diff --git a/src/pip/_internal/utils/deprecation.py b/src/pip/_internal/utils/deprecation.py
index 2f20cfd49d3..c8a988a95b3 100644
--- a/src/pip/_internal/utils/deprecation.py
+++ b/src/pip/_internal/utils/deprecation.py
@@ -34,7 +34,12 @@ def _showwarning(message, category, filename, lineno, file=None, line=None):
     if file is not None:
         if _original_showwarning is not None:
             _original_showwarning(
-                message, category, filename, lineno, file, line,
+                message,
+                category,
+                filename,
+                lineno,
+                file,
+                line,
             )
     elif issubclass(category, PipDeprecationWarning):
         # We use a specially named logger which will handle all of the
@@ -43,7 +48,12 @@ def _showwarning(message, category, filename, lineno, file=None, line=None):
         logger.warning(message)
     else:
         _original_showwarning(
-            message, category, filename, lineno, file, line,
+            message,
+            category,
+            filename,
+            lineno,
+            file,
+            line,
         )
 
 
@@ -88,10 +98,13 @@ def deprecated(reason, replacement, gone_in, issue=None):
         (reason, DEPRECATION_MSG_PREFIX + "{}"),
         (gone_in, "pip {} will remove support for this functionality."),
         (replacement, "A possible replacement is {}."),
-        (issue, (
-            "You can find discussion regarding this at "
-            "https://github.com/pypa/pip/issues/{}."
-        )),
+        (
+            issue,
+            (
+                "You can find discussion regarding this at "
+                "https://github.com/pypa/pip/issues/{}."
+            ),
+        ),
     ]
     message = " ".join(
         template.format(val) for val, template in sentences if val is not None
diff --git a/src/pip/_internal/utils/direct_url_helpers.py b/src/pip/_internal/utils/direct_url_helpers.py
index a355a6c5ee4..1ef7c8fa47e 100644
--- a/src/pip/_internal/utils/direct_url_helpers.py
+++ b/src/pip/_internal/utils/direct_url_helpers.py
@@ -60,8 +60,8 @@ def direct_url_from_link(link, source_dir=None, link_is_in_wheel_cache=False):
     if link.is_vcs:
         vcs_backend = vcs.get_backend_for_scheme(link.scheme)
         assert vcs_backend
-        url, requested_revision, _ = (
-            vcs_backend.get_url_rev_and_auth(link.url_without_fragment)
+        url, requested_revision, _ = vcs_backend.get_url_rev_and_auth(
+            link.url_without_fragment
         )
         # For VCS links, we need to find out and add commit_id.
         if link_is_in_wheel_cache:
@@ -116,11 +116,7 @@ def dist_get_direct_url(dist):
         return None
     try:
         return DirectUrl.from_json(dist.get_metadata(DIRECT_URL_METADATA_NAME))
-    except (
-        DirectUrlValidationError,
-        JSONDecodeError,
-        UnicodeDecodeError
-    ) as e:
+    except (DirectUrlValidationError, JSONDecodeError, UnicodeDecodeError) as e:
         logger.warning(
             "Error parsing %s for %s: %s",
             DIRECT_URL_METADATA_NAME,
diff --git a/src/pip/_internal/utils/encoding.py b/src/pip/_internal/utils/encoding.py
index 42a57535af8..834c49b2407 100644
--- a/src/pip/_internal/utils/encoding.py
+++ b/src/pip/_internal/utils/encoding.py
@@ -9,16 +9,16 @@
     from typing import List, Text, Tuple
 
 BOMS = [
-    (codecs.BOM_UTF8, 'utf-8'),
-    (codecs.BOM_UTF16, 'utf-16'),
-    (codecs.BOM_UTF16_BE, 'utf-16-be'),
-    (codecs.BOM_UTF16_LE, 'utf-16-le'),
-    (codecs.BOM_UTF32, 'utf-32'),
-    (codecs.BOM_UTF32_BE, 'utf-32-be'),
-    (codecs.BOM_UTF32_LE, 'utf-32-le'),
+    (codecs.BOM_UTF8, "utf-8"),
+    (codecs.BOM_UTF16, "utf-16"),
+    (codecs.BOM_UTF16_BE, "utf-16-be"),
+    (codecs.BOM_UTF16_LE, "utf-16-le"),
+    (codecs.BOM_UTF32, "utf-32"),
+    (codecs.BOM_UTF32_BE, "utf-32-be"),
+    (codecs.BOM_UTF32_LE, "utf-32-le"),
 ]  # type: List[Tuple[bytes, Text]]
 
-ENCODING_RE = re.compile(br'coding[:=]\s*([-\w.]+)')
+ENCODING_RE = re.compile(br"coding[:=]\s*([-\w.]+)")
 
 
 def auto_decode(data):
@@ -28,13 +28,13 @@ def auto_decode(data):
     Fallback to locale.getpreferredencoding(False) like open() on Python3"""
     for bom, encoding in BOMS:
         if data.startswith(bom):
-            return data[len(bom):].decode(encoding)
+            return data[len(bom) :].decode(encoding)
     # Lets check the first two lines as in PEP263
-    for line in data.split(b'\n')[:2]:
-        if line[0:1] == b'#' and ENCODING_RE.search(line):
+    for line in data.split(b"\n")[:2]:
+        if line[0:1] == b"#" and ENCODING_RE.search(line):
             result = ENCODING_RE.search(line)
             assert result is not None
-            encoding = result.groups()[0].decode('ascii')
+            encoding = result.groups()[0].decode("ascii")
             return data.decode(encoding)
     return data.decode(
         locale.getpreferredencoding(False) or sys.getdefaultencoding(),
diff --git a/src/pip/_internal/utils/filesystem.py b/src/pip/_internal/utils/filesystem.py
index 303243fd22f..a679c191a51 100644
--- a/src/pip/_internal/utils/filesystem.py
+++ b/src/pip/_internal/utils/filesystem.py
@@ -76,7 +76,8 @@ def copy2_fixed(src, dest):
             else:
                 if is_socket_file:
                     raise shutil.SpecialFileError(
-                        "`{f}` is a socket".format(**locals()))
+                        "`{f}` is a socket".format(**locals())
+                    )
 
         raise
 
@@ -101,10 +102,10 @@ def adjacent_tmp_file(path, **kwargs):
         delete=False,
         dir=os.path.dirname(path),
         prefix=os.path.basename(path),
-        suffix='.tmp',
+        suffix=".tmp",
         **kwargs
     ) as f:
-        result = cast('NamedTemporaryFileResult', f)
+        result = cast("NamedTemporaryFileResult", f)
         try:
             yield result
         finally:
@@ -115,6 +116,7 @@ def adjacent_tmp_file(path, **kwargs):
 _replace_retry = retry(stop_max_delay=1000, wait_fixed=250)
 
 if PY2:
+
     @_replace_retry
     def replace(src, dest):
         # type: (str, str) -> None
@@ -124,6 +126,7 @@ def replace(src, dest):
             os.remove(dest)
             os.rename(src, dest)
 
+
 else:
     replace = _replace_retry(os.replace)
 
@@ -143,7 +146,7 @@ def test_writable_dir(path):
             break  # Should never get here, but infinite loops are bad
         path = parent
 
-    if os.name == 'posix':
+    if os.name == "posix":
         return os.access(path, os.W_OK)
 
     return _test_writable_dir_win(path)
@@ -153,10 +156,10 @@ def _test_writable_dir_win(path):
     # type: (str) -> bool
     # os.access doesn't work on Windows: http://bugs.python.org/issue2528
     # and we can't use tempfile: http://bugs.python.org/issue22107
-    basename = 'accesstest_deleteme_fishfingers_custard_'
-    alphabet = 'abcdefghijklmnopqrstuvwxyz0123456789'
+    basename = "accesstest_deleteme_fishfingers_custard_"
+    alphabet = "abcdefghijklmnopqrstuvwxyz0123456789"
     for _ in range(10):
-        name = basename + ''.join(random.choice(alphabet) for _ in range(6))
+        name = basename + "".join(random.choice(alphabet) for _ in range(6))
         file = os.path.join(path, name)
         try:
             fd = os.open(file, os.O_RDWR | os.O_CREAT | os.O_EXCL)
@@ -180,9 +183,7 @@ def _test_writable_dir_win(path):
             return True
 
     # This should never be reached
-    raise EnvironmentError(
-        'Unexpected condition testing for writable directory'
-    )
+    raise EnvironmentError("Unexpected condition testing for writable directory")
 
 
 def find_files(path, pattern):
diff --git a/src/pip/_internal/utils/filetypes.py b/src/pip/_internal/utils/filetypes.py
index daa0ca771b7..a0f9cf3b4fe 100644
--- a/src/pip/_internal/utils/filetypes.py
+++ b/src/pip/_internal/utils/filetypes.py
@@ -5,12 +5,15 @@
 if MYPY_CHECK_RUNNING:
     from typing import Tuple
 
-WHEEL_EXTENSION = '.whl'
-BZ2_EXTENSIONS = ('.tar.bz2', '.tbz')  # type: Tuple[str, ...]
-XZ_EXTENSIONS = ('.tar.xz', '.txz', '.tlz',
-                 '.tar.lz', '.tar.lzma')  # type: Tuple[str, ...]
-ZIP_EXTENSIONS = ('.zip', WHEEL_EXTENSION)  # type: Tuple[str, ...]
-TAR_EXTENSIONS = ('.tar.gz', '.tgz', '.tar')  # type: Tuple[str, ...]
-ARCHIVE_EXTENSIONS = (
-    ZIP_EXTENSIONS + BZ2_EXTENSIONS + TAR_EXTENSIONS + XZ_EXTENSIONS
-)
+WHEEL_EXTENSION = ".whl"
+BZ2_EXTENSIONS = (".tar.bz2", ".tbz")  # type: Tuple[str, ...]
+XZ_EXTENSIONS = (
+    ".tar.xz",
+    ".txz",
+    ".tlz",
+    ".tar.lz",
+    ".tar.lzma",
+)  # type: Tuple[str, ...]
+ZIP_EXTENSIONS = (".zip", WHEEL_EXTENSION)  # type: Tuple[str, ...]
+TAR_EXTENSIONS = (".tar.gz", ".tgz", ".tar")  # type: Tuple[str, ...]
+ARCHIVE_EXTENSIONS = ZIP_EXTENSIONS + BZ2_EXTENSIONS + TAR_EXTENSIONS + XZ_EXTENSIONS
diff --git a/src/pip/_internal/utils/hashes.py b/src/pip/_internal/utils/hashes.py
index 4d4e26b59f3..1eccaa417a1 100644
--- a/src/pip/_internal/utils/hashes.py
+++ b/src/pip/_internal/utils/hashes.py
@@ -4,11 +4,7 @@
 
 from pip._vendor.six import iteritems, iterkeys, itervalues
 
-from pip._internal.exceptions import (
-    HashMismatch,
-    HashMissing,
-    InstallationError,
-)
+from pip._internal.exceptions import HashMismatch, HashMissing, InstallationError
 from pip._internal.utils.misc import read_chunks
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 
@@ -16,6 +12,7 @@
     from typing import BinaryIO, Dict, Iterator, List, NoReturn
 
     from pip._vendor.six import PY3
+
     if PY3:
         from hashlib import _Hash
     else:
@@ -24,12 +21,12 @@
 
 # The recommended hash algo of the moment. Change this whenever the state of
 # the art changes; it won't hurt backward compatibility.
-FAVORITE_HASH = 'sha256'
+FAVORITE_HASH = "sha256"
 
 
 # Names of hashlib algorithms allowed by the --hash option and ``pip hash``
 # Currently, those are the ones at least as collision-resistant as sha256.
-STRONG_HASHES = ['sha256', 'sha384', 'sha512']
+STRONG_HASHES = ["sha256", "sha384", "sha512"]
 
 
 class Hashes(object):
@@ -37,6 +34,7 @@ class Hashes(object):
     known-good values
 
     """
+
     def __init__(self, hashes=None):
         # type: (Dict[str, List[str]]) -> None
         """
@@ -72,7 +70,7 @@ def digest_count(self):
 
     def is_hash_allowed(
         self,
-        hash_name,   # type: str
+        hash_name,  # type: str
         hex_digest,  # type: str
     ):
         # type: (...) -> bool
@@ -92,9 +90,7 @@ def check_against_chunks(self, chunks):
             try:
                 gots[hash_name] = hashlib.new(hash_name)
             except (ValueError, TypeError):
-                raise InstallationError(
-                    'Unknown hash name: {}'.format(hash_name)
-                )
+                raise InstallationError("Unknown hash name: {}".format(hash_name))
 
         for chunk in chunks:
             for hash in itervalues(gots):
@@ -120,7 +116,7 @@ def check_against_file(self, file):
 
     def check_against_path(self, path):
         # type: (str) -> None
-        with open(path, 'rb') as file:
+        with open(path, "rb") as file:
             return self.check_against_file(file)
 
     def __nonzero__(self):
@@ -140,6 +136,7 @@ class MissingHashes(Hashes):
     exception showing it to the user.
 
     """
+
     def __init__(self):
         # type: () -> None
         """Don't offer the ``hashes`` kwarg."""
diff --git a/src/pip/_internal/utils/inject_securetransport.py b/src/pip/_internal/utils/inject_securetransport.py
index 5b93b1d6730..b6863d93405 100644
--- a/src/pip/_internal/utils/inject_securetransport.py
+++ b/src/pip/_internal/utils/inject_securetransport.py
@@ -22,7 +22,7 @@ def inject_securetransport():
         return
 
     # Checks for OpenSSL 1.0.1
-    if ssl.OPENSSL_VERSION_NUMBER >= 0x1000100f:
+    if ssl.OPENSSL_VERSION_NUMBER >= 0x1000100F:
         return
 
     try:
diff --git a/src/pip/_internal/utils/logging.py b/src/pip/_internal/utils/logging.py
index 9a017cf7e33..639a388e71d 100644
--- a/src/pip/_internal/utils/logging.py
+++ b/src/pip/_internal/utils/logging.py
@@ -52,13 +52,14 @@
 
 
 _log_state = threading.local()
-subprocess_logger = getLogger('pip.subprocessor')
+subprocess_logger = getLogger("pip.subprocessor")
 
 
 class BrokenStdoutLoggingError(Exception):
     """
     Raised if BrokenPipeError occurs for the stdout stream while logging.
     """
+
     pass
 
 
@@ -69,21 +70,27 @@ class BrokenStdoutLoggingError(Exception):
     # https://bugs.python.org/issue19612
     # https://bugs.python.org/issue30418
     if PY2:
+
         def _is_broken_pipe_error(exc_class, exc):
             """See the docstring for non-Windows Python 3 below."""
-            return (exc_class is IOError and
-                    exc.errno in (errno.EINVAL, errno.EPIPE))
+            return exc_class is IOError and exc.errno in (errno.EINVAL, errno.EPIPE)
+
     else:
         # In Windows, a broken pipe IOError became OSError in Python 3.
         def _is_broken_pipe_error(exc_class, exc):
             """See the docstring for non-Windows Python 3 below."""
-            return ((exc_class is BrokenPipeError) or  # noqa: F821
-                    (exc_class is OSError and
-                     exc.errno in (errno.EINVAL, errno.EPIPE)))
+            return (exc_class is BrokenPipeError) or (  # noqa: F821
+                exc_class is OSError and exc.errno in (errno.EINVAL, errno.EPIPE)
+            )
+
+
 elif PY2:
+
     def _is_broken_pipe_error(exc_class, exc):
         """See the docstring for non-Windows Python 3 below."""
-        return (exc_class is IOError and exc.errno == errno.EPIPE)
+        return exc_class is IOError and exc.errno == errno.EPIPE
+
+
 else:
     # Then we are in the non-Windows Python 3 case.
     def _is_broken_pipe_error(exc_class, exc):
@@ -94,7 +101,7 @@ def _is_broken_pipe_error(exc_class, exc):
           exc_class: an exception class.
           exc: an exception instance.
         """
-        return (exc_class is BrokenPipeError)  # noqa: F821
+        return exc_class is BrokenPipeError  # noqa: F821
 
 
 @contextlib.contextmanager
@@ -113,11 +120,10 @@ def indent_log(num=2):
 
 
 def get_indentation():
-    return getattr(_log_state, 'indentation', 0)
+    return getattr(_log_state, "indentation", 0)
 
 
 class IndentingFormatter(logging.Formatter):
-
     def __init__(self, *args, **kwargs):
         """
         A logging.Formatter that obeys the indent_log() context manager.
@@ -134,15 +140,15 @@ def get_message_start(self, formatted, levelno):
         prefix to add to each line).
         """
         if levelno < logging.WARNING:
-            return ''
+            return ""
         if formatted.startswith(DEPRECATION_MSG_PREFIX):
             # Then the message already has a prefix.  We don't want it to
             # look like "WARNING: DEPRECATION: ...."
-            return ''
+            return ""
         if levelno < logging.ERROR:
-            return 'WARNING: '
+            return "WARNING: "
 
-        return 'ERROR: '
+        return "ERROR: "
 
     def format(self, record):
         """
@@ -153,22 +159,20 @@ def format(self, record):
         message_start = self.get_message_start(formatted, record.levelno)
         formatted = message_start + formatted
 
-        prefix = ''
+        prefix = ""
         if self.add_timestamp:
             # TODO: Use Formatter.default_time_format after dropping PY2.
             t = self.formatTime(record, "%Y-%m-%dT%H:%M:%S")
-            prefix = '{t},{record.msecs:03.0f} '.format(**locals())
+            prefix = "{t},{record.msecs:03.0f} ".format(**locals())
         prefix += " " * get_indentation()
-        formatted = "".join([
-            prefix + line
-            for line in formatted.splitlines(True)
-        ])
+        formatted = "".join([prefix + line for line in formatted.splitlines(True)])
         return formatted
 
 
 def _color_wrap(*colors):
     def wrapped(inp):
         return "".join(list(colors) + [inp, colorama.Style.RESET_ALL])
+
     return wrapped
 
 
@@ -207,7 +211,8 @@ def should_color(self):
             return False
 
         real_stream = (
-            self.stream if not isinstance(self.stream, colorama.AnsiToWin32)
+            self.stream
+            if not isinstance(self.stream, colorama.AnsiToWin32)
             else self.stream.wrapped
         )
 
@@ -240,22 +245,19 @@ def handleError(self, record):
         # stdout stream in logging's Handler.emit(), then raise our special
         # exception so we can handle it in main() instead of logging the
         # broken pipe error and continuing.
-        if (exc_class and self._using_stdout() and
-                _is_broken_pipe_error(exc_class, exc)):
+        if exc_class and self._using_stdout() and _is_broken_pipe_error(exc_class, exc):
             raise BrokenStdoutLoggingError()
 
         return super(ColorizedStreamHandler, self).handleError(record)
 
 
 class BetterRotatingFileHandler(logging.handlers.RotatingFileHandler):
-
     def _open(self):
         ensure_dir(os.path.dirname(self.baseFilename))
         return logging.handlers.RotatingFileHandler._open(self)
 
 
 class MaxLevelFilter(Filter):
-
     def __init__(self, level):
         self.level = level
 
@@ -322,78 +324,76 @@ def setup_logging(verbosity, no_color, user_log_file):
         ["user_log"] if include_user_log else []
     )
 
-    logging.config.dictConfig({
-        "version": 1,
-        "disable_existing_loggers": False,
-        "filters": {
-            "exclude_warnings": {
-                "()": "pip._internal.utils.logging.MaxLevelFilter",
-                "level": logging.WARNING,
-            },
-            "restrict_to_subprocess": {
-                "()": "logging.Filter",
-                "name": subprocess_logger.name,
-            },
-            "exclude_subprocess": {
-                "()": "pip._internal.utils.logging.ExcludeLoggerFilter",
-                "name": subprocess_logger.name,
+    logging.config.dictConfig(
+        {
+            "version": 1,
+            "disable_existing_loggers": False,
+            "filters": {
+                "exclude_warnings": {
+                    "()": "pip._internal.utils.logging.MaxLevelFilter",
+                    "level": logging.WARNING,
+                },
+                "restrict_to_subprocess": {
+                    "()": "logging.Filter",
+                    "name": subprocess_logger.name,
+                },
+                "exclude_subprocess": {
+                    "()": "pip._internal.utils.logging.ExcludeLoggerFilter",
+                    "name": subprocess_logger.name,
+                },
             },
-        },
-        "formatters": {
-            "indent": {
-                "()": IndentingFormatter,
-                "format": "%(message)s",
+            "formatters": {
+                "indent": {
+                    "()": IndentingFormatter,
+                    "format": "%(message)s",
+                },
+                "indent_with_timestamp": {
+                    "()": IndentingFormatter,
+                    "format": "%(message)s",
+                    "add_timestamp": True,
+                },
             },
-            "indent_with_timestamp": {
-                "()": IndentingFormatter,
-                "format": "%(message)s",
-                "add_timestamp": True,
+            "handlers": {
+                "console": {
+                    "level": level,
+                    "class": handler_classes["stream"],
+                    "no_color": no_color,
+                    "stream": log_streams["stdout"],
+                    "filters": ["exclude_subprocess", "exclude_warnings"],
+                    "formatter": "indent",
+                },
+                "console_errors": {
+                    "level": "WARNING",
+                    "class": handler_classes["stream"],
+                    "no_color": no_color,
+                    "stream": log_streams["stderr"],
+                    "filters": ["exclude_subprocess"],
+                    "formatter": "indent",
+                },
+                # A handler responsible for logging to the console messages
+                # from the "subprocessor" logger.
+                "console_subprocess": {
+                    "level": level,
+                    "class": handler_classes["stream"],
+                    "no_color": no_color,
+                    "stream": log_streams["stderr"],
+                    "filters": ["restrict_to_subprocess"],
+                    "formatter": "indent",
+                },
+                "user_log": {
+                    "level": "DEBUG",
+                    "class": handler_classes["file"],
+                    "filename": additional_log_file,
+                    "delay": True,
+                    "formatter": "indent_with_timestamp",
+                },
             },
-        },
-        "handlers": {
-            "console": {
-                "level": level,
-                "class": handler_classes["stream"],
-                "no_color": no_color,
-                "stream": log_streams["stdout"],
-                "filters": ["exclude_subprocess", "exclude_warnings"],
-                "formatter": "indent",
+            "root": {
+                "level": root_level,
+                "handlers": handlers,
             },
-            "console_errors": {
-                "level": "WARNING",
-                "class": handler_classes["stream"],
-                "no_color": no_color,
-                "stream": log_streams["stderr"],
-                "filters": ["exclude_subprocess"],
-                "formatter": "indent",
-            },
-            # A handler responsible for logging to the console messages
-            # from the "subprocessor" logger.
-            "console_subprocess": {
-                "level": level,
-                "class": handler_classes["stream"],
-                "no_color": no_color,
-                "stream": log_streams["stderr"],
-                "filters": ["restrict_to_subprocess"],
-                "formatter": "indent",
-            },
-            "user_log": {
-                "level": "DEBUG",
-                "class": handler_classes["file"],
-                "filename": additional_log_file,
-                "delay": True,
-                "formatter": "indent_with_timestamp",
-            },
-        },
-        "root": {
-            "level": root_level,
-            "handlers": handlers,
-        },
-        "loggers": {
-            "pip._vendor": {
-                "level": vendored_log_level
-            }
-        },
-    })
+            "loggers": {"pip._vendor": {"level": vendored_log_level}},
+        }
+    )
 
     return level_number
diff --git a/src/pip/_internal/utils/misc.py b/src/pip/_internal/utils/misc.py
index 289db0e39fd..c7e5cc3751d 100644
--- a/src/pip/_internal/utils/misc.py
+++ b/src/pip/_internal/utils/misc.py
@@ -20,6 +20,7 @@
 
 from pip._vendor import pkg_resources
 from pip._vendor.packaging.utils import canonicalize_name
+
 # NOTE: retrying is not annotated in typeshed as on 2017-07-17, which is
 #       why we ignore the type on this import.
 from pip._vendor.retrying import retry  # type: ignore
@@ -30,17 +31,8 @@
 
 from pip import __version__
 from pip._internal.exceptions import CommandError
-from pip._internal.locations import (
-    get_major_minor_version,
-    site_packages,
-    user_site,
-)
-from pip._internal.utils.compat import (
-    WINDOWS,
-    expanduser,
-    stdlib_pkgs,
-    str_to_display,
-)
+from pip._internal.locations import get_major_minor_version, site_packages, user_site
+from pip._internal.utils.compat import WINDOWS, expanduser, stdlib_pkgs, str_to_display
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING, cast
 from pip._internal.utils.virtualenv import (
     running_under_virtualenv,
@@ -74,13 +66,22 @@
     T = TypeVar("T")
 
 
-__all__ = ['rmtree', 'display_path', 'backup_dir',
-           'ask', 'splitext',
-           'format_size', 'is_installable_dir',
-           'normalize_path',
-           'renames', 'get_prog',
-           'captured_stdout', 'ensure_dir',
-           'get_installed_version', 'remove_auth_from_url']
+__all__ = [
+    "rmtree",
+    "display_path",
+    "backup_dir",
+    "ask",
+    "splitext",
+    "format_size",
+    "is_installable_dir",
+    "normalize_path",
+    "renames",
+    "get_prog",
+    "captured_stdout",
+    "ensure_dir",
+    "get_installed_version",
+    "remove_auth_from_url",
+]
 
 
 logger = logging.getLogger(__name__)
@@ -91,10 +92,10 @@ def get_pip_version():
     pip_pkg_dir = os.path.join(os.path.dirname(__file__), "..", "..")
     pip_pkg_dir = os.path.abspath(pip_pkg_dir)
 
-    return (
-        'pip {} from {} (python {})'.format(
-            __version__, pip_pkg_dir, get_major_minor_version(),
-        )
+    return "pip {} from {} (python {})".format(
+        __version__,
+        pip_pkg_dir,
+        get_major_minor_version(),
     )
 
 
@@ -115,7 +116,7 @@ def normalize_version_info(py_version_info):
     elif len(py_version_info) > 3:
         py_version_info = py_version_info[:3]
 
-    return cast('VersionInfo', py_version_info)
+    return cast("VersionInfo", py_version_info)
 
 
 def ensure_dir(path):
@@ -133,21 +134,20 @@ def get_prog():
     # type: () -> str
     try:
         prog = os.path.basename(sys.argv[0])
-        if prog in ('__main__.py', '-c'):
+        if prog in ("__main__.py", "-c"):
             return "{} -m pip".format(sys.executable)
         else:
             return prog
     except (AttributeError, TypeError, IndexError):
         pass
-    return 'pip'
+    return "pip"
 
 
 # Retry every half second for up to 3 seconds
 @retry(stop_max_delay=3000, wait_fixed=500)
 def rmtree(dir, ignore_errors=False):
     # type: (Text, bool) -> None
-    shutil.rmtree(dir, ignore_errors=ignore_errors,
-                  onerror=rmtree_errorhandler)
+    shutil.rmtree(dir, ignore_errors=ignore_errors, onerror=rmtree_errorhandler)
 
 
 def rmtree_errorhandler(func, path, exc_info):
@@ -185,7 +185,7 @@ def path_to_display(path):
         return path
     # Otherwise, path is a bytes object (str in Python 2).
     try:
-        display_path = path.decode(sys.getfilesystemencoding(), 'strict')
+        display_path = path.decode(sys.getfilesystemencoding(), "strict")
     except UnicodeDecodeError:
         # Include the full bytes to make troubleshooting easier, even though
         # it may not be very human readable.
@@ -195,7 +195,7 @@ def path_to_display(path):
             #   Also, we add the prefix "b" to the repr() return value both
             # to make the Python 2 output look like the Python 3 output, and
             # to signal to the user that this is a bytes representation.
-            display_path = str_to_display('b{!r}'.format(path))
+            display_path = str_to_display("b{!r}".format(path))
         else:
             # Silence the "F821 undefined name 'ascii'" flake8 error since
             # in Python 3 ascii() is a built-in.
@@ -210,14 +210,14 @@ def display_path(path):
     if possible."""
     path = os.path.normcase(os.path.abspath(path))
     if sys.version_info[0] == 2:
-        path = path.decode(sys.getfilesystemencoding(), 'replace')
-        path = path.encode(sys.getdefaultencoding(), 'replace')
+        path = path.decode(sys.getfilesystemencoding(), "replace")
+        path = path.encode(sys.getdefaultencoding(), "replace")
     if path.startswith(os.getcwd() + os.path.sep):
-        path = '.' + path[len(os.getcwd()):]
+        path = "." + path[len(os.getcwd()) :]
     return path
 
 
-def backup_dir(dir, ext='.bak'):
+def backup_dir(dir, ext=".bak"):
     # type: (str, str) -> str
     """Figure out the name of a directory to back up the given dir to
     (adding .bak, .bak2, etc)"""
@@ -231,7 +231,7 @@ def backup_dir(dir, ext='.bak'):
 
 def ask_path_exists(message, options):
     # type: (str, Iterable[str]) -> str
-    for action in os.environ.get('PIP_EXISTS_ACTION', '').split():
+    for action in os.environ.get("PIP_EXISTS_ACTION", "").split():
         if action in options:
             return action
     return ask(message, options)
@@ -240,10 +240,9 @@ def ask_path_exists(message, options):
 def _check_no_input(message):
     # type: (str) -> None
     """Raise an error if no input is allowed."""
-    if os.environ.get('PIP_NO_INPUT'):
+    if os.environ.get("PIP_NO_INPUT"):
         raise Exception(
-            'No input was expected ($PIP_NO_INPUT set); question: {}'.format(
-                message)
+            "No input was expected ($PIP_NO_INPUT set); question: {}".format(message)
         )
 
 
@@ -256,8 +255,8 @@ def ask(message, options):
         response = response.strip().lower()
         if response not in options:
             print(
-                'Your response ({!r}) was not one of the expected responses: '
-                '{}'.format(response, ', '.join(options))
+                "Your response ({!r}) was not one of the expected responses: "
+                "{}".format(response, ", ".join(options))
             )
         else:
             return response
@@ -280,13 +279,13 @@ def ask_password(message):
 def format_size(bytes):
     # type: (float) -> str
     if bytes > 1000 * 1000:
-        return '{:.1f} MB'.format(bytes / 1000.0 / 1000)
+        return "{:.1f} MB".format(bytes / 1000.0 / 1000)
     elif bytes > 10 * 1000:
-        return '{} kB'.format(int(bytes / 1000))
+        return "{} kB".format(int(bytes / 1000))
     elif bytes > 1000:
-        return '{:.1f} kB'.format(bytes / 1000.0)
+        return "{:.1f} kB".format(bytes / 1000.0)
     else:
-        return '{} bytes'.format(int(bytes))
+        return "{} bytes".format(int(bytes))
 
 
 def tabulate(rows):
@@ -299,21 +298,20 @@ def tabulate(rows):
     (['foobar     2000', '3735928559'], [10, 4])
     """
     rows = [tuple(map(str, row)) for row in rows]
-    sizes = [max(map(len, col)) for col in zip_longest(*rows, fillvalue='')]
+    sizes = [max(map(len, col)) for col in zip_longest(*rows, fillvalue="")]
     table = [" ".join(map(str.ljust, row, sizes)).rstrip() for row in rows]
     return table, sizes
 
 
 def is_installable_dir(path):
     # type: (str) -> bool
-    """Is path is a directory containing setup.py or pyproject.toml?
-    """
+    """Is path is a directory containing setup.py or pyproject.toml?"""
     if not os.path.isdir(path):
         return False
-    setup_py = os.path.join(path, 'setup.py')
+    setup_py = os.path.join(path, "setup.py")
     if os.path.isfile(setup_py):
         return True
-    pyproject_toml = os.path.join(path, 'pyproject.toml')
+    pyproject_toml = os.path.join(path, "pyproject.toml")
     if os.path.isfile(pyproject_toml):
         return True
     return False
@@ -346,7 +344,7 @@ def splitext(path):
     # type: (str) -> Tuple[str, str]
     """Like os.path.splitext, but take off .tar too"""
     base, ext = posixpath.splitext(path)
-    if base.lower().endswith('.tar'):
+    if base.lower().endswith(".tar"):
         ext = base[-4:] + ext
         base = base[:-4]
     return base, ext
@@ -420,19 +418,19 @@ def dist_is_editable(dist):
     Return True if given Distribution is an editable install.
     """
     for path_item in sys.path:
-        egg_link = os.path.join(path_item, dist.project_name + '.egg-link')
+        egg_link = os.path.join(path_item, dist.project_name + ".egg-link")
         if os.path.isfile(egg_link):
             return True
     return False
 
 
 def get_installed_distributions(
-        local_only=True,  # type: bool
-        skip=stdlib_pkgs,  # type: Container[str]
-        include_editables=True,  # type: bool
-        editables_only=False,  # type: bool
-        user_only=False,  # type: bool
-        paths=None  # type: Optional[List[str]]
+    local_only=True,  # type: bool
+    skip=stdlib_pkgs,  # type: Container[str]
+    include_editables=True,  # type: bool
+    editables_only=False,  # type: bool
+    user_only=False,  # type: bool
+    paths=None,  # type: Optional[List[str]]
 ):
     # type: (...) -> List[Distribution]
     """
@@ -462,36 +460,46 @@ def get_installed_distributions(
     if local_only:
         local_test = dist_is_local
     else:
+
         def local_test(d):
             return True
 
     if include_editables:
+
         def editable_test(d):
             return True
+
     else:
+
         def editable_test(d):
             return not dist_is_editable(d)
 
     if editables_only:
+
         def editables_only_test(d):
             return dist_is_editable(d)
+
     else:
+
         def editables_only_test(d):
             return True
 
     if user_only:
         user_test = dist_in_usersite
     else:
+
         def user_test(d):
             return True
 
-    return [d for d in working_set
-            if local_test(d) and
-            d.key not in skip and
-            editable_test(d) and
-            editables_only_test(d) and
-            user_test(d)
-            ]
+    return [
+        d
+        for d in working_set
+        if local_test(d)
+        and d.key not in skip
+        and editable_test(d)
+        and editables_only_test(d)
+        and user_test(d)
+    ]
 
 
 def _search_distribution(req_name):
@@ -575,7 +583,7 @@ def egg_link_path(dist):
         sites.append(site_packages)
 
     for site in sites:
-        egglink = os.path.join(site, dist.project_name) + '.egg-link'
+        egglink = os.path.join(site, dist.project_name) + ".egg-link"
         if os.path.isfile(egglink):
             return egglink
     return None
@@ -605,6 +613,7 @@ def write_output(msg, *args):
 class FakeFile(object):
     """Wrap a list of lines in an object with readline() to make
     ConfigParser happy."""
+
     def __init__(self, lines):
         self._gen = iter(lines)
 
@@ -612,14 +621,13 @@ def readline(self):
         try:
             return next(self._gen)
         except StopIteration:
-            return ''
+            return ""
 
     def __iter__(self):
         return self._gen
 
 
 class StreamWrapper(StringIO):
-
     @classmethod
     def from_stream(cls, orig_stream):
         cls.orig_stream = orig_stream
@@ -655,14 +663,14 @@ def captured_stdout():
 
     Taken from Lib/support/__init__.py in the CPython repo.
     """
-    return captured_output('stdout')
+    return captured_output("stdout")
 
 
 def captured_stderr():
     """
     See captured_stdout().
     """
-    return captured_output('stderr')
+    return captured_output("stderr")
 
 
 def get_installed_version(dist_name, working_set=None):
@@ -692,8 +700,8 @@ def consume(iterator):
 def enum(*sequential, **named):
     enums = dict(zip(sequential, range(len(sequential))), **named)
     reverse = {value: key for key, value in enums.items()}
-    enums['reverse_mapping'] = reverse
-    return type('Enum', (), enums)
+    enums["reverse_mapping"] = reverse
+    return type("Enum", (), enums)
 
 
 def build_netloc(host, port):
@@ -703,21 +711,21 @@ def build_netloc(host, port):
     """
     if port is None:
         return host
-    if ':' in host:
+    if ":" in host:
         # Only wrap host with square brackets when it is IPv6
-        host = '[{}]'.format(host)
-    return '{}:{}'.format(host, port)
+        host = "[{}]".format(host)
+    return "{}:{}".format(host, port)
 
 
-def build_url_from_netloc(netloc, scheme='https'):
+def build_url_from_netloc(netloc, scheme="https"):
     # type: (str, str) -> str
     """
     Build a full URL from a netloc.
     """
-    if netloc.count(':') >= 2 and '@' not in netloc and '[' not in netloc:
+    if netloc.count(":") >= 2 and "@" not in netloc and "[" not in netloc:
         # It must be a bare IPv6 address, so wrap it with brackets.
-        netloc = '[{}]'.format(netloc)
-    return '{}://{}'.format(scheme, netloc)
+        netloc = "[{}]".format(netloc)
+    return "{}://{}".format(scheme, netloc)
 
 
 def parse_netloc(netloc):
@@ -736,24 +744,22 @@ def split_auth_from_netloc(netloc):
 
     Returns: (netloc, (username, password)).
     """
-    if '@' not in netloc:
+    if "@" not in netloc:
         return netloc, (None, None)
 
     # Split from the right because that's how urllib.parse.urlsplit()
     # behaves if more than one @ is present (which can be checked using
     # the password attribute of urlsplit()'s return value).
-    auth, netloc = netloc.rsplit('@', 1)
-    if ':' in auth:
+    auth, netloc = netloc.rsplit("@", 1)
+    if ":" in auth:
         # Split from the left because that's how urllib.parse.urlsplit()
         # behaves if more than one : is present (which again can be checked
         # using the password attribute of the return value)
-        user_pass = auth.split(':', 1)
+        user_pass = auth.split(":", 1)
     else:
         user_pass = auth, None
 
-    user_pass = tuple(
-        None if x is None else urllib_unquote(x) for x in user_pass
-    )
+    user_pass = tuple(None if x is None else urllib_unquote(x) for x in user_pass)
 
     return netloc, user_pass
 
@@ -771,14 +777,14 @@ def redact_netloc(netloc):
     if user is None:
         return netloc
     if password is None:
-        user = '****'
-        password = ''
+        user = "****"
+        password = ""
     else:
         user = urllib_parse.quote(user)
-        password = ':****'
-    return '{user}{password}@{netloc}'.format(user=user,
-                                              password=password,
-                                              netloc=netloc)
+        password = ":****"
+    return "{user}{password}@{netloc}".format(
+        user=user, password=password, netloc=netloc
+    )
 
 
 def _transform_url(url, transform_netloc):
@@ -794,9 +800,7 @@ def _transform_url(url, transform_netloc):
     purl = urllib_parse.urlsplit(url)
     netloc_tuple = transform_netloc(purl.netloc)
     # stripped url
-    url_pieces = (
-        purl.scheme, netloc_tuple[0], purl.path, purl.query, purl.fragment
-    )
+    url_pieces = (purl.scheme, netloc_tuple[0], purl.path, purl.query, purl.fragment)
     surl = urllib_parse.urlunsplit(url_pieces)
     return surl, netloc_tuple
 
@@ -837,7 +841,7 @@ def redact_auth_from_url(url):
 class HiddenText(object):
     def __init__(
         self,
-        secret,    # type: str
+        secret,  # type: str
         redacted,  # type: str
     ):
         # type: (...) -> None
@@ -846,7 +850,7 @@ def __init__(
 
     def __repr__(self):
         # type: (...) -> str
-        return '<HiddenText {!r}>'.format(str(self))
+        return "<HiddenText {!r}>".format(str(self))
 
     def __str__(self):
         # type: (...) -> str
@@ -860,7 +864,7 @@ def __eq__(self, other):
 
         # The string being used for redaction doesn't also have to match,
         # just the raw, original string.
-        return (self.secret == other.secret)
+        return self.secret == other.secret
 
     # We need to provide an explicit __ne__ implementation for Python 2.
     # TODO: remove this when we drop PY2 support.
@@ -871,7 +875,7 @@ def __ne__(self, other):
 
 def hide_value(value):
     # type: (str) -> HiddenText
-    return HiddenText(value, redacted='****')
+    return HiddenText(value, redacted="****")
 
 
 def hide_url(url):
@@ -890,41 +894,36 @@ def protect_pip_from_modification_on_windows(modifying_pip):
     pip_names = [
         "pip.exe",
         "pip{}.exe".format(sys.version_info[0]),
-        "pip{}.{}.exe".format(*sys.version_info[:2])
+        "pip{}.{}.exe".format(*sys.version_info[:2]),
     ]
 
     # See https://github.com/pypa/pip/issues/1299 for more discussion
     should_show_use_python_msg = (
-        modifying_pip and
-        WINDOWS and
-        os.path.basename(sys.argv[0]) in pip_names
+        modifying_pip and WINDOWS and os.path.basename(sys.argv[0]) in pip_names
     )
 
     if should_show_use_python_msg:
-        new_command = [
-            sys.executable, "-m", "pip"
-        ] + sys.argv[1:]
+        new_command = [sys.executable, "-m", "pip"] + sys.argv[1:]
         raise CommandError(
-            'To modify pip, please run the following command:\n{}'
-            .format(" ".join(new_command))
+            "To modify pip, please run the following command:\n{}".format(
+                " ".join(new_command)
+            )
         )
 
 
 def is_console_interactive():
     # type: () -> bool
-    """Is this console interactive?
-    """
+    """Is this console interactive?"""
     return sys.stdin is not None and sys.stdin.isatty()
 
 
 def hash_file(path, blocksize=1 << 20):
     # type: (Text, int) -> Tuple[Any, int]
-    """Return (hash, length) for path using hashlib.sha256()
-    """
+    """Return (hash, length) for path using hashlib.sha256()"""
 
     h = hashlib.sha256()
     length = 0
-    with open(path, 'rb') as f:
+    with open(path, "rb") as f:
         for block in read_chunks(f, size=blocksize):
             length += len(block)
             h.update(block)
diff --git a/src/pip/_internal/utils/models.py b/src/pip/_internal/utils/models.py
index d1c2f226796..36ea1f48c49 100644
--- a/src/pip/_internal/utils/models.py
+++ b/src/pip/_internal/utils/models.py
@@ -7,10 +7,9 @@
 
 
 class KeyBasedCompareMixin(object):
-    """Provides comparison capabilities that is based on a key
-    """
+    """Provides comparison capabilities that is based on a key"""
 
-    __slots__ = ['_compare_key', '_defining_class']
+    __slots__ = ["_compare_key", "_defining_class"]
 
     def __init__(self, key, defining_class):
         self._compare_key = key
diff --git a/src/pip/_internal/utils/packaging.py b/src/pip/_internal/utils/packaging.py
index 27fd204234f..6c2f531609a 100644
--- a/src/pip/_internal/utils/packaging.py
+++ b/src/pip/_internal/utils/packaging.py
@@ -38,7 +38,7 @@ def check_requires_python(requires_python, version_info):
         return True
     requires_python_specifier = specifiers.SpecifierSet(requires_python)
 
-    python_version = version.parse('.'.join(map(str, version_info)))
+    python_version = version.parse(".".join(map(str, version_info)))
     return python_version in requires_python_specifier
 
 
@@ -48,16 +48,17 @@ def get_metadata(dist):
     :raises NoneMetadataError: if the distribution reports `has_metadata()`
         True but `get_metadata()` returns None.
     """
-    metadata_name = 'METADATA'
-    if (isinstance(dist, pkg_resources.DistInfoDistribution) and
-            dist.has_metadata(metadata_name)):
+    metadata_name = "METADATA"
+    if isinstance(dist, pkg_resources.DistInfoDistribution) and dist.has_metadata(
+        metadata_name
+    ):
         metadata = dist.get_metadata(metadata_name)
-    elif dist.has_metadata('PKG-INFO'):
-        metadata_name = 'PKG-INFO'
+    elif dist.has_metadata("PKG-INFO"):
+        metadata_name = "PKG-INFO"
         metadata = dist.get_metadata(metadata_name)
     else:
         logger.warning("No metadata found in %s", display_path(dist.location))
-        metadata = ''
+        metadata = ""
 
     if metadata is None:
         raise NoneMetadataError(dist, metadata_name)
@@ -76,7 +77,7 @@ def get_requires_python(dist):
     if not present.
     """
     pkg_info_dict = get_metadata(dist)
-    requires_python = pkg_info_dict.get('Requires-Python')
+    requires_python = pkg_info_dict.get("Requires-Python")
 
     if requires_python is not None:
         # Convert to a str to satisfy the type checker, since requires_python
@@ -88,8 +89,8 @@ def get_requires_python(dist):
 
 def get_installer(dist):
     # type: (Distribution) -> str
-    if dist.has_metadata('INSTALLER'):
-        for line in dist.get_metadata_lines('INSTALLER'):
+    if dist.has_metadata("INSTALLER"):
+        for line in dist.get_metadata_lines("INSTALLER"):
             if line.strip():
                 return line.strip()
-    return ''
+    return ""
diff --git a/src/pip/_internal/utils/parallel.py b/src/pip/_internal/utils/parallel.py
index d4113bdc285..6c7c9fee0cf 100644
--- a/src/pip/_internal/utils/parallel.py
+++ b/src/pip/_internal/utils/parallel.py
@@ -16,7 +16,7 @@
   than using the default value of 1.
 """
 
-__all__ = ['map_multiprocess', 'map_multithread']
+__all__ = ["map_multiprocess", "map_multithread"]
 
 from contextlib import contextmanager
 from multiprocessing import Pool as ProcessPool
@@ -33,8 +33,8 @@
     from typing import Callable, Iterable, Iterator, TypeVar, Union
 
     Pool = Union[pool.Pool, pool.ThreadPool]
-    S = TypeVar('S')
-    T = TypeVar('T')
+    S = TypeVar("S")
+    T = TypeVar("T")
 
 # On platforms without sem_open, multiprocessing[.dummy] Pool
 # cannot be created.
diff --git a/src/pip/_internal/utils/pkg_resources.py b/src/pip/_internal/utils/pkg_resources.py
index 0bc129acc6a..84fee79b0a4 100644
--- a/src/pip/_internal/utils/pkg_resources.py
+++ b/src/pip/_internal/utils/pkg_resources.py
@@ -8,8 +8,8 @@
 
 
 class DictMetadata(object):
-    """IMetadataProvider that reads metadata files from a dictionary.
-    """
+    """IMetadataProvider that reads metadata files from a dictionary."""
+
     def __init__(self, metadata):
         # type: (Dict[str, bytes]) -> None
         self._metadata = metadata
diff --git a/src/pip/_internal/utils/setuptools_build.py b/src/pip/_internal/utils/setuptools_build.py
index 2a664b00703..a5ddf57e9f6 100644
--- a/src/pip/_internal/utils/setuptools_build.py
+++ b/src/pip/_internal/utils/setuptools_build.py
@@ -24,7 +24,7 @@ def make_setuptools_shim_args(
     setup_py_path,  # type: str
     global_options=None,  # type: Sequence[str]
     no_user_config=False,  # type: bool
-    unbuffered_output=False  # type: bool
+    unbuffered_output=False,  # type: bool
 ):
     # type: (...) -> List[str]
     """
@@ -59,9 +59,7 @@ def make_setuptools_bdist_wheel_args(
     # relies on site.py to find parts of the standard library outside the
     # virtualenv.
     args = make_setuptools_shim_args(
-        setup_py_path,
-        global_options=global_options,
-        unbuffered_output=True
+        setup_py_path, global_options=global_options, unbuffered_output=True
     )
     args += ["bdist_wheel", "-d", destination_dir]
     args += build_options
@@ -74,9 +72,7 @@ def make_setuptools_clean_args(
 ):
     # type: (...) -> List[str]
     args = make_setuptools_shim_args(
-        setup_py_path,
-        global_options=global_options,
-        unbuffered_output=True
+        setup_py_path, global_options=global_options, unbuffered_output=True
     )
     args += ["clean", "--all"]
     return args
@@ -121,9 +117,7 @@ def make_setuptools_egg_info_args(
     no_user_config,  # type: bool
 ):
     # type: (...) -> List[str]
-    args = make_setuptools_shim_args(
-        setup_py_path, no_user_config=no_user_config
-    )
+    args = make_setuptools_shim_args(setup_py_path, no_user_config=no_user_config)
 
     args += ["egg_info"]
 
@@ -144,7 +138,7 @@ def make_setuptools_install_args(
     home,  # type: Optional[str]
     use_user_site,  # type: bool
     no_user_config,  # type: bool
-    pycompile  # type: bool
+    pycompile,  # type: bool
 ):
     # type: (...) -> List[str]
     assert not (use_user_site and prefix)
@@ -154,7 +148,7 @@ def make_setuptools_install_args(
         setup_py_path,
         global_options=global_options,
         no_user_config=no_user_config,
-        unbuffered_output=True
+        unbuffered_output=True,
     )
     args += ["install", "--record", record_filename]
     args += ["--single-version-externally-managed"]
diff --git a/src/pip/_internal/utils/subprocess.py b/src/pip/_internal/utils/subprocess.py
index 1dfe02fa0be..29b319fcdee 100644
--- a/src/pip/_internal/utils/subprocess.py
+++ b/src/pip/_internal/utils/subprocess.py
@@ -14,21 +14,12 @@
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 
 if MYPY_CHECK_RUNNING:
-    from typing import (
-        Any,
-        Callable,
-        Iterable,
-        List,
-        Mapping,
-        Optional,
-        Text,
-        Union,
-    )
+    from typing import Any, Callable, Iterable, List, Mapping, Optional, Text, Union
 
     CommandArgs = List[Union[str, HiddenText]]
 
 
-LOG_DIVIDER = '----------------------------------------'
+LOG_DIVIDER = "----------------------------------------"
 
 
 def make_command(*args):
@@ -59,9 +50,9 @@ def format_command_args(args):
     # this can trigger a UnicodeDecodeError in Python 2 if the argument
     # has type unicode and includes a non-ascii character.  (The type
     # checker doesn't ensure the annotations are correct in all cases.)
-    return ' '.join(
-        shlex_quote(str(arg)) if isinstance(arg, HiddenText)
-        else shlex_quote(arg) for arg in args
+    return " ".join(
+        shlex_quote(str(arg)) if isinstance(arg, HiddenText) else shlex_quote(arg)
+        for arg in args
     )
 
 
@@ -70,15 +61,13 @@ def reveal_command_args(args):
     """
     Return the arguments in their raw, unredacted form.
     """
-    return [
-        arg.secret if isinstance(arg, HiddenText) else arg for arg in args
-    ]
+    return [arg.secret if isinstance(arg, HiddenText) else arg for arg in args]
 
 
 def make_subprocess_output_error(
-    cmd_args,     # type: Union[List[str], CommandArgs]
-    cwd,          # type: Optional[str]
-    lines,        # type: List[Text]
+    cmd_args,  # type: Union[List[str], CommandArgs]
+    cwd,  # type: Optional[str]
+    lines,  # type: List[Text]
     exit_status,  # type: int
 ):
     # type: (...) -> Text
@@ -93,19 +82,19 @@ def make_subprocess_output_error(
     # them as arguments in the unicode format string below. This avoids
     # "UnicodeDecodeError: 'ascii' codec can't decode byte ..." in Python 2
     # if either contains a non-ascii character.
-    command_display = str_to_display(command, desc='command bytes')
+    command_display = str_to_display(command, desc="command bytes")
     cwd_display = path_to_display(cwd)
 
     # We know the joined output value ends in a newline.
-    output = ''.join(lines)
+    output = "".join(lines)
     msg = (
         # Use a unicode string to avoid "UnicodeEncodeError: 'ascii'
         # codec can't encode character ..." in Python 2 when a format
         # argument (e.g. `output`) has a non-ascii character.
-        u'Command errored out with exit status {exit_status}:\n'
-        ' command: {command_display}\n'
-        '     cwd: {cwd_display}\n'
-        'Complete output ({line_count} lines):\n{output}{divider}'
+        u"Command errored out with exit status {exit_status}:\n"
+        " command: {command_display}\n"
+        "     cwd: {cwd_display}\n"
+        "Complete output ({line_count} lines):\n{output}{divider}"
     ).format(
         exit_status=exit_status,
         command_display=command_display,
@@ -121,13 +110,13 @@ def call_subprocess(
     cmd,  # type: Union[List[str], CommandArgs]
     show_stdout=False,  # type: bool
     cwd=None,  # type: Optional[str]
-    on_returncode='raise',  # type: str
+    on_returncode="raise",  # type: str
     extra_ok_returncodes=None,  # type: Optional[Iterable[int]]
     command_desc=None,  # type: Optional[str]
     extra_environ=None,  # type: Optional[Mapping[str, Any]]
     unset_environ=None,  # type: Optional[Iterable[str]]
     spinner=None,  # type: Optional[SpinnerInterface]
-    log_failed_cmd=True  # type: Optional[bool]
+    log_failed_cmd=True,  # type: Optional[bool]
 ):
     # type: (...) -> Text
     """
@@ -189,8 +178,11 @@ def call_subprocess(
         proc = subprocess.Popen(
             # Convert HiddenText objects to the underlying str.
             reveal_command_args(cmd),
-            stderr=subprocess.STDOUT, stdin=subprocess.PIPE,
-            stdout=subprocess.PIPE, cwd=cwd, env=env,
+            stderr=subprocess.STDOUT,
+            stdin=subprocess.PIPE,
+            stdout=subprocess.PIPE,
+            cwd=cwd,
+            env=env,
         )
         assert proc.stdin
         assert proc.stdout
@@ -198,7 +190,9 @@ def call_subprocess(
     except Exception as exc:
         if log_failed_cmd:
             subprocess_logger.critical(
-                "Error %s while executing command %s", exc, command_desc,
+                "Error %s while executing command %s",
+                exc,
+                command_desc,
             )
         raise
     all_output = []
@@ -208,7 +202,7 @@ def call_subprocess(
         if not line:
             break
         line = line.rstrip()
-        all_output.append(line + '\n')
+        all_output.append(line + "\n")
 
         # Show the line immediately.
         log_subprocess(line)
@@ -221,9 +215,7 @@ def call_subprocess(
     finally:
         if proc.stdout:
             proc.stdout.close()
-    proc_had_error = (
-        proc.returncode and proc.returncode not in extra_ok_returncodes
-    )
+    proc_had_error = proc.returncode and proc.returncode not in extra_ok_returncodes
     if use_spinner:
         assert spinner
         if proc_had_error:
@@ -231,7 +223,7 @@ def call_subprocess(
         else:
             spinner.finish("done")
     if proc_had_error:
-        if on_returncode == 'raise':
+        if on_returncode == "raise":
             if not showing_subprocess and log_failed_cmd:
                 # Then the subprocess streams haven't been logged to the
                 # console yet.
@@ -243,23 +235,22 @@ def call_subprocess(
                 )
                 subprocess_logger.error(msg)
             exc_msg = (
-                'Command errored out with exit status {}: {} '
-                'Check the logs for full command output.'
+                "Command errored out with exit status {}: {} "
+                "Check the logs for full command output."
             ).format(proc.returncode, command_desc)
             raise InstallationError(exc_msg)
-        elif on_returncode == 'warn':
+        elif on_returncode == "warn":
             subprocess_logger.warning(
                 'Command "%s" had error code %s in %s',
                 command_desc,
                 proc.returncode,
                 cwd,
             )
-        elif on_returncode == 'ignore':
+        elif on_returncode == "ignore":
             pass
         else:
-            raise ValueError('Invalid value: on_returncode={!r}'.format(
-                             on_returncode))
-    return ''.join(all_output)
+            raise ValueError("Invalid value: on_returncode={!r}".format(on_returncode))
+    return "".join(all_output)
 
 
 def runner_with_spinner_message(message):
@@ -273,7 +264,7 @@ def runner_with_spinner_message(message):
     def runner(
         cmd,  # type: List[str]
         cwd=None,  # type: Optional[str]
-        extra_environ=None  # type: Optional[Mapping[str, Any]]
+        extra_environ=None,  # type: Optional[Mapping[str, Any]]
     ):
         # type: (...) -> None
         with open_spinner(message) as spinner:
diff --git a/src/pip/_internal/utils/temp_dir.py b/src/pip/_internal/utils/temp_dir.py
index 03aa8286670..0b3d9f7ed69 100644
--- a/src/pip/_internal/utils/temp_dir.py
+++ b/src/pip/_internal/utils/temp_dir.py
@@ -16,7 +16,7 @@
 if MYPY_CHECK_RUNNING:
     from typing import Any, Dict, Iterator, Optional, TypeVar, Union
 
-    _T = TypeVar('_T', bound='TempDirectory')
+    _T = TypeVar("_T", bound="TempDirectory")
 
 
 logger = logging.getLogger(__name__)
@@ -47,8 +47,7 @@ def global_tempdir_manager():
 
 
 class TempDirectoryTypeRegistry(object):
-    """Manages temp directory behavior
-    """
+    """Manages temp directory behavior"""
 
     def __init__(self):
         # type: () -> None
@@ -117,7 +116,7 @@ class TempDirectory(object):
 
     def __init__(
         self,
-        path=None,    # type: Optional[str]
+        path=None,  # type: Optional[str]
         delete=_default,  # type: Union[bool, None, _Default]
         kind="temp",  # type: str
         globally_managed=False,  # type: bool
@@ -149,8 +148,8 @@ def __init__(
     @property
     def path(self):
         # type: () -> str
-        assert not self._deleted, (
-            "Attempted to access deleted path: {}".format(self._path)
+        assert not self._deleted, "Attempted to access deleted path: {}".format(
+            self._path
         )
         return self._path
 
@@ -176,22 +175,18 @@ def __exit__(self, exc, value, tb):
 
     def _create(self, kind):
         # type: (str) -> str
-        """Create a temporary directory and store its path in self.path
-        """
+        """Create a temporary directory and store its path in self.path"""
         # We realpath here because some systems have their default tmpdir
         # symlinked to another directory.  This tends to confuse build
         # scripts, so we canonicalize the path by traversing potential
         # symlinks here.
-        path = os.path.realpath(
-            tempfile.mkdtemp(prefix="pip-{}-".format(kind))
-        )
+        path = os.path.realpath(tempfile.mkdtemp(prefix="pip-{}-".format(kind)))
         logger.debug("Created temporary directory: %s", path)
         return path
 
     def cleanup(self):
         # type: () -> None
-        """Remove the temporary directory created and reset state
-        """
+        """Remove the temporary directory created and reset state"""
         self._deleted = True
         if os.path.exists(self._path):
             # Make sure to pass unicode on Python 2 to make the contents also
@@ -213,6 +208,7 @@ class AdjacentTempDirectory(TempDirectory):
             (when used as a contextmanager)
 
     """
+
     # The characters that may be used to name the temp directory
     # We always prepend a ~ and then rotate through these until
     # a usable name is found.
@@ -222,7 +218,7 @@ class AdjacentTempDirectory(TempDirectory):
 
     def __init__(self, original, delete=None):
         # type: (str, Optional[bool]) -> None
-        self.original = original.rstrip('/\\')
+        self.original = original.rstrip("/\\")
         super(AdjacentTempDirectory, self).__init__(delete=delete)
 
     @classmethod
@@ -237,16 +233,18 @@ def _generate_names(cls, name):
         """
         for i in range(1, len(name)):
             for candidate in itertools.combinations_with_replacement(
-                    cls.LEADING_CHARS, i - 1):
-                new_name = '~' + ''.join(candidate) + name[i:]
+                cls.LEADING_CHARS, i - 1
+            ):
+                new_name = "~" + "".join(candidate) + name[i:]
                 if new_name != name:
                     yield new_name
 
         # If we make it this far, we will have to make a longer name
         for i in range(len(cls.LEADING_CHARS)):
             for candidate in itertools.combinations_with_replacement(
-                    cls.LEADING_CHARS, i):
-                new_name = '~' + ''.join(candidate) + name
+                cls.LEADING_CHARS, i
+            ):
+                new_name = "~" + "".join(candidate) + name
                 if new_name != name:
                     yield new_name
 
@@ -266,9 +264,7 @@ def _create(self, kind):
                 break
         else:
             # Final fallback on the default behavior.
-            path = os.path.realpath(
-                tempfile.mkdtemp(prefix="pip-{}-".format(kind))
-            )
+            path = os.path.realpath(tempfile.mkdtemp(prefix="pip-{}-".format(kind)))
 
         logger.debug("Created temporary directory: %s", path)
         return path
diff --git a/src/pip/_internal/utils/unpacking.py b/src/pip/_internal/utils/unpacking.py
index 620f31ebb74..56a7c1d99c4 100644
--- a/src/pip/_internal/utils/unpacking.py
+++ b/src/pip/_internal/utils/unpacking.py
@@ -32,16 +32,18 @@
 
 try:
     import bz2  # noqa
+
     SUPPORTED_EXTENSIONS += BZ2_EXTENSIONS
 except ImportError:
-    logger.debug('bz2 module is not available')
+    logger.debug("bz2 module is not available")
 
 try:
     # Only for Python 3.3+
     import lzma  # noqa
+
     SUPPORTED_EXTENSIONS += XZ_EXTENSIONS
 except ImportError:
-    logger.debug('lzma module is not available')
+    logger.debug("lzma module is not available")
 
 
 def current_umask():
@@ -54,18 +56,15 @@ def current_umask():
 
 def split_leading_dir(path):
     # type: (Union[str, Text]) -> List[Union[str, Text]]
-    path = path.lstrip('/').lstrip('\\')
-    if (
-        '/' in path and (
-            ('\\' in path and path.find('/') < path.find('\\')) or
-            '\\' not in path
-        )
+    path = path.lstrip("/").lstrip("\\")
+    if "/" in path and (
+        ("\\" in path and path.find("/") < path.find("\\")) or "\\" not in path
     ):
-        return path.split('/', 1)
-    elif '\\' in path:
-        return path.split('\\', 1)
+        return path.split("/", 1)
+    elif "\\" in path:
+        return path.split("\\", 1)
     else:
-        return [path, '']
+        return [path, ""]
 
 
 def has_leading_dir(paths):
@@ -124,7 +123,7 @@ def unzip_file(filename, location, flatten=True):
     no-ops per the python docs.
     """
     ensure_dir(location)
-    zipfp = open(filename, 'rb')
+    zipfp = open(filename, "rb")
     try:
         zip = zipfile.ZipFile(zipfp, allowZip64=True)
         leading = has_leading_dir(zip.namelist()) and flatten
@@ -137,11 +136,11 @@ def unzip_file(filename, location, flatten=True):
             dir = os.path.dirname(fn)
             if not is_within_directory(location, fn):
                 message = (
-                    'The zip file ({}) has a file ({}) trying to install '
-                    'outside target directory ({})'
+                    "The zip file ({}) has a file ({}) trying to install "
+                    "outside target directory ({})"
                 )
                 raise InstallationError(message.format(filename, fn, location))
-            if fn.endswith('/') or fn.endswith('\\'):
+            if fn.endswith("/") or fn.endswith("\\"):
                 # A directory
                 ensure_dir(fn)
             else:
@@ -150,7 +149,7 @@ def unzip_file(filename, location, flatten=True):
                 # chunk of memory for the file's content
                 fp = zip.open(name)
                 try:
-                    with open(fn, 'wb') as destfp:
+                    with open(fn, "wb") as destfp:
                         shutil.copyfileobj(fp, destfp)
                 finally:
                     fp.close()
@@ -171,24 +170,23 @@ def untar_file(filename, location):
     no-ops per the python docs.
     """
     ensure_dir(location)
-    if filename.lower().endswith('.gz') or filename.lower().endswith('.tgz'):
-        mode = 'r:gz'
+    if filename.lower().endswith(".gz") or filename.lower().endswith(".tgz"):
+        mode = "r:gz"
     elif filename.lower().endswith(BZ2_EXTENSIONS):
-        mode = 'r:bz2'
+        mode = "r:bz2"
     elif filename.lower().endswith(XZ_EXTENSIONS):
-        mode = 'r:xz'
-    elif filename.lower().endswith('.tar'):
-        mode = 'r'
+        mode = "r:xz"
+    elif filename.lower().endswith(".tar"):
+        mode = "r"
     else:
         logger.warning(
-            'Cannot determine compression type for file %s', filename,
+            "Cannot determine compression type for file %s",
+            filename,
         )
-        mode = 'r:*'
+        mode = "r:*"
     tar = tarfile.open(filename, mode)
     try:
-        leading = has_leading_dir([
-            member.name for member in tar.getmembers()
-        ])
+        leading = has_leading_dir([member.name for member in tar.getmembers()])
         for member in tar.getmembers():
             fn = member.name
             if leading:
@@ -197,12 +195,10 @@ def untar_file(filename, location):
             path = os.path.join(location, fn)
             if not is_within_directory(location, path):
                 message = (
-                    'The tar file ({}) has a file ({}) trying to install '
-                    'outside target directory ({})'
-                )
-                raise InstallationError(
-                    message.format(filename, path, location)
+                    "The tar file ({}) has a file ({}) trying to install "
+                    "outside target directory ({})"
                 )
+                raise InstallationError(message.format(filename, path, location))
             if member.isdir():
                 ensure_dir(path)
             elif member.issym():
@@ -213,8 +209,10 @@ def untar_file(filename, location):
                     # Some corrupt tar files seem to produce this
                     # (specifically bad symlinks)
                     logger.warning(
-                        'In the tar file %s the member %s is invalid: %s',
-                        filename, member.name, exc,
+                        "In the tar file %s the member %s is invalid: %s",
+                        filename,
+                        member.name,
+                        exc,
                     )
                     continue
             else:
@@ -224,13 +222,15 @@ def untar_file(filename, location):
                     # Some corrupt tar files seem to produce this
                     # (specifically bad symlinks)
                     logger.warning(
-                        'In the tar file %s the member %s is invalid: %s',
-                        filename, member.name, exc,
+                        "In the tar file %s the member %s is invalid: %s",
+                        filename,
+                        member.name,
+                        exc,
                     )
                     continue
                 ensure_dir(os.path.dirname(path))
                 assert fp is not None
-                with open(path, 'wb') as destfp:
+                with open(path, "wb") as destfp:
                     shutil.copyfileobj(fp, destfp)
                 fp.close()
                 # Update the timestamp (useful for cython compiled files)
@@ -244,38 +244,34 @@ def untar_file(filename, location):
 
 
 def unpack_file(
-        filename,  # type: str
-        location,  # type: str
-        content_type=None,  # type: Optional[str]
+    filename,  # type: str
+    location,  # type: str
+    content_type=None,  # type: Optional[str]
 ):
     # type: (...) -> None
     filename = os.path.realpath(filename)
     if (
-        content_type == 'application/zip' or
-        filename.lower().endswith(ZIP_EXTENSIONS) or
-        zipfile.is_zipfile(filename)
+        content_type == "application/zip"
+        or filename.lower().endswith(ZIP_EXTENSIONS)
+        or zipfile.is_zipfile(filename)
     ):
-        unzip_file(
-            filename,
-            location,
-            flatten=not filename.endswith('.whl')
-        )
+        unzip_file(filename, location, flatten=not filename.endswith(".whl"))
     elif (
-        content_type == 'application/x-gzip' or
-        tarfile.is_tarfile(filename) or
-        filename.lower().endswith(
-            TAR_EXTENSIONS + BZ2_EXTENSIONS + XZ_EXTENSIONS
-        )
+        content_type == "application/x-gzip"
+        or tarfile.is_tarfile(filename)
+        or filename.lower().endswith(TAR_EXTENSIONS + BZ2_EXTENSIONS + XZ_EXTENSIONS)
     ):
         untar_file(filename, location)
     else:
         # FIXME: handle?
         # FIXME: magic signatures?
         logger.critical(
-            'Cannot unpack file %s (downloaded from %s, content-type: %s); '
-            'cannot detect archive format',
-            filename, location, content_type,
+            "Cannot unpack file %s (downloaded from %s, content-type: %s); "
+            "cannot detect archive format",
+            filename,
+            location,
+            content_type,
         )
         raise InstallationError(
-            'Cannot determine archive format of {}'.format(location)
+            "Cannot determine archive format of {}".format(location)
         )
diff --git a/src/pip/_internal/utils/urls.py b/src/pip/_internal/utils/urls.py
index f37bc8f90b2..ff896fa951e 100644
--- a/src/pip/_internal/utils/urls.py
+++ b/src/pip/_internal/utils/urls.py
@@ -12,9 +12,9 @@
 
 def get_url_scheme(url):
     # type: (Union[str, Text]) -> Optional[Text]
-    if ':' not in url:
+    if ":" not in url:
         return None
-    return url.split(':', 1)[0].lower()
+    return url.split(":", 1)[0].lower()
 
 
 def path_to_url(path):
@@ -24,7 +24,7 @@ def path_to_url(path):
     quoted path parts.
     """
     path = os.path.normpath(os.path.abspath(path))
-    url = urllib_parse.urljoin('file:', urllib_request.pathname2url(path))
+    url = urllib_parse.urljoin("file:", urllib_request.pathname2url(path))
     return url
 
 
@@ -33,22 +33,23 @@ def url_to_path(url):
     """
     Convert a file: URL to a path.
     """
-    assert url.startswith('file:'), (
-        "You can only turn file: urls into filenames (not {url!r})"
-        .format(**locals()))
+    assert url.startswith(
+        "file:"
+    ), "You can only turn file: urls into filenames (not {url!r})".format(**locals())
 
     _, netloc, path, _, _ = urllib_parse.urlsplit(url)
 
-    if not netloc or netloc == 'localhost':
+    if not netloc or netloc == "localhost":
         # According to RFC 8089, same as empty authority.
-        netloc = ''
-    elif sys.platform == 'win32':
+        netloc = ""
+    elif sys.platform == "win32":
         # If we have a UNC path, prepend UNC share notation.
-        netloc = '\\\\' + netloc
+        netloc = "\\\\" + netloc
     else:
         raise ValueError(
-            'non-local file URIs are not supported on this platform: {url!r}'
-            .format(**locals())
+            "non-local file URIs are not supported on this platform: {url!r}".format(
+                **locals()
+            )
         )
 
     path = urllib_request.url2pathname(netloc + path)
diff --git a/src/pip/_internal/utils/virtualenv.py b/src/pip/_internal/utils/virtualenv.py
index 4a7812873b3..a978f4962d7 100644
--- a/src/pip/_internal/utils/virtualenv.py
+++ b/src/pip/_internal/utils/virtualenv.py
@@ -34,13 +34,12 @@ def _running_under_regular_virtualenv():
     This handles virtual environments created with pypa's virtualenv.
     """
     # pypa/virtualenv case
-    return hasattr(sys, 'real_prefix')
+    return hasattr(sys, "real_prefix")
 
 
 def running_under_virtualenv():
     # type: () -> bool
-    """Return True if we're running inside a virtualenv, False otherwise.
-    """
+    """Return True if we're running inside a virtualenv, False otherwise."""
     return _running_under_venv() or _running_under_regular_virtualenv()
 
 
@@ -50,11 +49,11 @@ def _get_pyvenv_cfg_lines():
 
     Returns None, if it could not read/access the file.
     """
-    pyvenv_cfg_file = os.path.join(sys.prefix, 'pyvenv.cfg')
+    pyvenv_cfg_file = os.path.join(sys.prefix, "pyvenv.cfg")
     try:
         # Although PEP 405 does not specify, the built-in venv module always
         # writes with UTF-8. (pypa/pip#8717)
-        with io.open(pyvenv_cfg_file, encoding='utf-8') as f:
+        with io.open(pyvenv_cfg_file, encoding="utf-8") as f:
             return f.read().splitlines()  # avoids trailing newlines
     except IOError:
         return None
@@ -85,7 +84,7 @@ def _no_global_under_venv():
 
     for line in cfg_lines:
         match = _INCLUDE_SYSTEM_SITE_PACKAGES_REGEX.match(line)
-        if match is not None and match.group('value') == 'false':
+        if match is not None and match.group("value") == "false":
             return True
     return False
 
@@ -99,15 +98,15 @@ def _no_global_under_regular_virtualenv():
     """
     site_mod_dir = os.path.dirname(os.path.abspath(site.__file__))
     no_global_site_packages_file = os.path.join(
-        site_mod_dir, 'no-global-site-packages.txt',
+        site_mod_dir,
+        "no-global-site-packages.txt",
     )
     return os.path.exists(no_global_site_packages_file)
 
 
 def virtualenv_no_global():
     # type: () -> bool
-    """Returns a boolean, whether running in venv with no system site-packages.
-    """
+    """Returns a boolean, whether running in venv with no system site-packages."""
     # PEP 405 compliance needs to be checked first since virtualenv >=20 would
     # return True for both checks, but is only able to use the PEP 405 config.
     if _running_under_venv():
diff --git a/src/pip/_internal/utils/wheel.py b/src/pip/_internal/utils/wheel.py
index 9ce371c76eb..04c51c8f5ae 100644
--- a/src/pip/_internal/utils/wheel.py
+++ b/src/pip/_internal/utils/wheel.py
@@ -37,6 +37,7 @@ class WheelMetadata(DictMetadata):
     """Metadata provider that maps metadata decoding exceptions to our
     internal exception type.
     """
+
     def __init__(self, metadata, wheel_name):
         # type: (Dict[str, bytes], str) -> None
         super(WheelMetadata, self).__init__(metadata)
@@ -49,9 +50,7 @@ def get_metadata(self, name):
         except UnicodeDecodeError as e:
             # Augment the default error with the origin of the file.
             raise UnsupportedWheel(
-                "Error decoding metadata for {}: {}".format(
-                    self._wheel_name, e
-                )
+                "Error decoding metadata for {}: {}".format(self._wheel_name, e)
             )
 
 
@@ -81,15 +80,11 @@ def pkg_resources_distribution_for_wheel(wheel_zip, name, location):
                 wheel_zip, full_path
             )
         except UnsupportedWheel as e:
-            raise UnsupportedWheel(
-                "{} has an invalid wheel, {}".format(name, str(e))
-            )
+            raise UnsupportedWheel("{} has an invalid wheel, {}".format(name, str(e)))
 
     metadata = WheelMetadata(metadata_text, location)
 
-    return DistInfoDistribution(
-        location=location, metadata=metadata, project_name=name
-    )
+    return DistInfoDistribution(location=location, metadata=metadata, project_name=name)
 
 
 def parse_wheel(wheel_zip, name):
@@ -104,9 +99,7 @@ def parse_wheel(wheel_zip, name):
         metadata = wheel_metadata(wheel_zip, info_dir)
         version = wheel_version(metadata)
     except UnsupportedWheel as e:
-        raise UnsupportedWheel(
-            "{} has an invalid wheel, {}".format(name, str(e))
-        )
+        raise UnsupportedWheel("{} has an invalid wheel, {}".format(name, str(e)))
 
     check_compatibility(version, name)
 
@@ -123,16 +116,14 @@ def wheel_dist_info_dir(source, name):
     # Zip file path separators must be /
     subdirs = set(p.split("/", 1)[0] for p in source.namelist())
 
-    info_dirs = [s for s in subdirs if s.endswith('.dist-info')]
+    info_dirs = [s for s in subdirs if s.endswith(".dist-info")]
 
     if not info_dirs:
         raise UnsupportedWheel(".dist-info directory not found")
 
     if len(info_dirs) > 1:
         raise UnsupportedWheel(
-            "multiple .dist-info directories found: {}".format(
-                ", ".join(info_dirs)
-            )
+            "multiple .dist-info directories found: {}".format(", ".join(info_dirs))
         )
 
     info_dir = info_dirs[0]
@@ -158,9 +149,7 @@ def read_wheel_metadata_file(source, path):
         # BadZipFile for general corruption, KeyError for missing entry,
         # and RuntimeError for password-protected files
     except (BadZipFile, KeyError, RuntimeError) as e:
-        raise UnsupportedWheel(
-            "could not read {!r} file: {!r}".format(path, e)
-        )
+        raise UnsupportedWheel("could not read {!r} file: {!r}".format(path, e))
 
 
 def wheel_metadata(source, dist_info_dir):
@@ -195,7 +184,7 @@ def wheel_version(wheel_data):
     version = version_text.strip()
 
     try:
-        return tuple(map(int, version.split('.')))
+        return tuple(map(int, version.split(".")))
     except ValueError:
         raise UnsupportedWheel("invalid Wheel-Version: {!r}".format(version))
 
@@ -216,10 +205,10 @@ def check_compatibility(version, name):
     if version[0] > VERSION_COMPATIBLE[0]:
         raise UnsupportedWheel(
             "{}'s Wheel-Version ({}) is not compatible with this version "
-            "of pip".format(name, '.'.join(map(str, version)))
+            "of pip".format(name, ".".join(map(str, version)))
         )
     elif version > VERSION_COMPATIBLE:
         logger.warning(
-            'Installing from a newer Wheel-Version (%s)',
-            '.'.join(map(str, version)),
+            "Installing from a newer Wheel-Version (%s)",
+            ".".join(map(str, version)),
         )
diff --git a/src/pip/_internal/vcs/bazaar.py b/src/pip/_internal/vcs/bazaar.py
index 3180713f7db..d9247157f23 100644
--- a/src/pip/_internal/vcs/bazaar.py
+++ b/src/pip/_internal/vcs/bazaar.py
@@ -25,24 +25,29 @@
 
 
 class Bazaar(VersionControl):
-    name = 'bzr'
-    dirname = '.bzr'
-    repo_name = 'branch'
+    name = "bzr"
+    dirname = ".bzr"
+    repo_name = "branch"
     schemes = (
-        'bzr', 'bzr+http', 'bzr+https', 'bzr+ssh', 'bzr+sftp', 'bzr+ftp',
-        'bzr+lp',
+        "bzr",
+        "bzr+http",
+        "bzr+https",
+        "bzr+ssh",
+        "bzr+sftp",
+        "bzr+ftp",
+        "bzr+lp",
     )
 
     def __init__(self, *args, **kwargs):
         super(Bazaar, self).__init__(*args, **kwargs)
         # This is only needed for python <2.7.5
         # Register lp but do not expose as a scheme to support bzr+lp.
-        if getattr(urllib_parse, 'uses_fragment', None):
-            urllib_parse.uses_fragment.extend(['lp'])
+        if getattr(urllib_parse, "uses_fragment", None):
+            urllib_parse.uses_fragment.extend(["lp"])
 
     @staticmethod
     def get_base_rev_args(rev):
-        return ['-r', rev]
+        return ["-r", rev]
 
     def export(self, location, url):
         # type: (str, HiddenText) -> None
@@ -54,31 +59,27 @@ def export(self, location, url):
             rmtree(location)
 
         url, rev_options = self.get_url_rev_options(url)
-        self.run_command(
-            make_command('export', location, url, rev_options.to_args())
-        )
+        self.run_command(make_command("export", location, url, rev_options.to_args()))
 
     def fetch_new(self, dest, url, rev_options):
         # type: (str, HiddenText, RevOptions) -> None
         rev_display = rev_options.to_display()
         logger.info(
-            'Checking out %s%s to %s',
+            "Checking out %s%s to %s",
             url,
             rev_display,
             display_path(dest),
         )
-        cmd_args = (
-            make_command('branch', '-q', rev_options.to_args(), url, dest)
-        )
+        cmd_args = make_command("branch", "-q", rev_options.to_args(), url, dest)
         self.run_command(cmd_args)
 
     def switch(self, dest, url, rev_options):
         # type: (str, HiddenText, RevOptions) -> None
-        self.run_command(make_command('switch', url), cwd=dest)
+        self.run_command(make_command("switch", url), cwd=dest)
 
     def update(self, dest, url, rev_options):
         # type: (str, HiddenText, RevOptions) -> None
-        cmd_args = make_command('pull', '-q', rev_options.to_args())
+        cmd_args = make_command("pull", "-q", rev_options.to_args())
         self.run_command(cmd_args, cwd=dest)
 
     @classmethod
@@ -86,17 +87,16 @@ def get_url_rev_and_auth(cls, url):
         # type: (str) -> Tuple[str, Optional[str], AuthInfo]
         # hotfix the URL scheme after removing bzr+ from bzr+ssh:// readd it
         url, rev, user_pass = super(Bazaar, cls).get_url_rev_and_auth(url)
-        if url.startswith('ssh://'):
-            url = 'bzr+' + url
+        if url.startswith("ssh://"):
+            url = "bzr+" + url
         return url, rev, user_pass
 
     @classmethod
     def get_remote_url(cls, location):
-        urls = cls.run_command(['info'], cwd=location)
+        urls = cls.run_command(["info"], cwd=location)
         for line in urls.splitlines():
             line = line.strip()
-            for x in ('checkout of branch: ',
-                      'parent branch: '):
+            for x in ("checkout of branch: ", "parent branch: "):
                 if line.startswith(x):
                     repo = line.split(x)[1]
                     if cls._is_local_repository(repo):
@@ -107,7 +107,8 @@ def get_remote_url(cls, location):
     @classmethod
     def get_revision(cls, location):
         revision = cls.run_command(
-            ['revno'], cwd=location,
+            ["revno"],
+            cwd=location,
         )
         return revision.splitlines()[-1]
 
diff --git a/src/pip/_internal/vcs/git.py b/src/pip/_internal/vcs/git.py
index 1831aede58a..ca880471c62 100644
--- a/src/pip/_internal/vcs/git.py
+++ b/src/pip/_internal/vcs/git.py
@@ -37,7 +37,7 @@
 logger = logging.getLogger(__name__)
 
 
-HASH_REGEX = re.compile('^[a-fA-F0-9]{40}$')
+HASH_REGEX = re.compile("^[a-fA-F0-9]{40}$")
 
 
 def looks_like_hash(sha):
@@ -45,16 +45,21 @@ def looks_like_hash(sha):
 
 
 class Git(VersionControl):
-    name = 'git'
-    dirname = '.git'
-    repo_name = 'clone'
+    name = "git"
+    dirname = ".git"
+    repo_name = "clone"
     schemes = (
-        'git', 'git+http', 'git+https', 'git+ssh', 'git+git', 'git+file',
+        "git",
+        "git+http",
+        "git+https",
+        "git+ssh",
+        "git+git",
+        "git+file",
     )
     # Prevent the user's environment variables from interfering with pip:
     # https://github.com/pypa/pip/issues/1130
-    unset_environ = ('GIT_DIR', 'GIT_WORK_TREE')
-    default_arg_rev = 'HEAD'
+    unset_environ = ("GIT_DIR", "GIT_WORK_TREE")
+    default_arg_rev = "HEAD"
 
     @staticmethod
     def get_base_rev_args(rev):
@@ -72,22 +77,20 @@ def is_immutable_rev_checkout(self, url, dest):
         # return False in the rare case rev is both a commit hash
         # and a tag or a branch; we don't want to cache in that case
         # because that branch/tag could point to something else in the future
-        is_tag_or_branch = bool(
-            self.get_revision_sha(dest, rev_options.rev)[0]
-        )
+        is_tag_or_branch = bool(self.get_revision_sha(dest, rev_options.rev)[0])
         return not is_tag_or_branch
 
     def get_git_version(self):
-        VERSION_PFX = 'git version '
-        version = self.run_command(['version'])
+        VERSION_PFX = "git version "
+        version = self.run_command(["version"])
         if version.startswith(VERSION_PFX):
-            version = version[len(VERSION_PFX):].split()[0]
+            version = version[len(VERSION_PFX) :].split()[0]
         else:
-            version = ''
+            version = ""
         # get first 3 positions of the git version because
         # on windows it is x.y.z.windows.t, and this parses as
         # LegacyVersion which always smaller than a Version.
-        version = '.'.join(version.split('.')[:3])
+        version = ".".join(version.split(".")[:3])
         return parse_version(version)
 
     @classmethod
@@ -100,28 +103,29 @@ def get_current_branch(cls, location):
         # HEAD rather than a symbolic ref.  In addition, the -q causes the
         # command to exit with status code 1 instead of 128 in this case
         # and to suppress the message to stderr.
-        args = ['symbolic-ref', '-q', 'HEAD']
+        args = ["symbolic-ref", "-q", "HEAD"]
         output = cls.run_command(
-            args, extra_ok_returncodes=(1, ), cwd=location,
+            args,
+            extra_ok_returncodes=(1,),
+            cwd=location,
         )
         ref = output.strip()
 
-        if ref.startswith('refs/heads/'):
-            return ref[len('refs/heads/'):]
+        if ref.startswith("refs/heads/"):
+            return ref[len("refs/heads/") :]
 
         return None
 
     def export(self, location, url):
         # type: (str, HiddenText) -> None
         """Export the Git repository at the url to the destination location"""
-        if not location.endswith('/'):
-            location = location + '/'
+        if not location.endswith("/"):
+            location = location + "/"
 
         with TempDirectory(kind="export") as temp_dir:
             self.unpack(temp_dir.path, url=url)
             self.run_command(
-                ['checkout-index', '-a', '-f', '--prefix', location],
-                cwd=temp_dir.path
+                ["checkout-index", "-a", "-f", "--prefix", location], cwd=temp_dir.path
             )
 
     @classmethod
@@ -136,9 +140,9 @@ def get_revision_sha(cls, dest, rev):
         """
         # Pass rev to pre-filter the list.
 
-        output = ''
+        output = ""
         try:
-            output = cls.run_command(['show-ref', rev], cwd=dest)
+            output = cls.run_command(["show-ref", rev], cwd=dest)
         except SubProcessError:
             pass
 
@@ -149,12 +153,12 @@ def get_revision_sha(cls, dest, rev):
             except ValueError:
                 # Include the offending line to simplify troubleshooting if
                 # this error ever occurs.
-                raise ValueError('unexpected show-ref line: {!r}'.format(line))
+                raise ValueError("unexpected show-ref line: {!r}".format(line))
 
             refs[ref] = sha
 
-        branch_ref = 'refs/remotes/origin/{}'.format(rev)
-        tag_ref = 'refs/tags/{}'.format(rev)
+        branch_ref = "refs/remotes/origin/{}".format(rev)
+        tag_ref = "refs/tags/{}".format(rev)
 
         sha = refs.get(branch_ref)
         if sha is not None:
@@ -223,11 +227,11 @@ def resolve_revision(cls, dest, url, rev_options):
 
         # fetch the requested revision
         cls.run_command(
-            make_command('fetch', '-q', url, rev_options.to_args()),
+            make_command("fetch", "-q", url, rev_options.to_args()),
             cwd=dest,
         )
         # Change the revision to the SHA of the ref we fetched
-        sha = cls.get_revision(dest, rev='FETCH_HEAD')
+        sha = cls.get_revision(dest, rev="FETCH_HEAD")
         rev_options = rev_options.make_new(sha)
 
         return rev_options
@@ -250,27 +254,33 @@ def is_commit_id_equal(cls, dest, name):
     def fetch_new(self, dest, url, rev_options):
         # type: (str, HiddenText, RevOptions) -> None
         rev_display = rev_options.to_display()
-        logger.info('Cloning %s%s to %s', url, rev_display, display_path(dest))
-        self.run_command(make_command('clone', '-q', url, dest))
+        logger.info("Cloning %s%s to %s", url, rev_display, display_path(dest))
+        self.run_command(make_command("clone", "-q", url, dest))
 
         if rev_options.rev:
             # Then a specific revision was requested.
             rev_options = self.resolve_revision(dest, url, rev_options)
-            branch_name = getattr(rev_options, 'branch_name', None)
+            branch_name = getattr(rev_options, "branch_name", None)
             if branch_name is None:
                 # Only do a checkout if the current commit id doesn't match
                 # the requested revision.
                 if not self.is_commit_id_equal(dest, rev_options.rev):
                     cmd_args = make_command(
-                        'checkout', '-q', rev_options.to_args(),
+                        "checkout",
+                        "-q",
+                        rev_options.to_args(),
                     )
                     self.run_command(cmd_args, cwd=dest)
             elif self.get_current_branch(dest) != branch_name:
                 # Then a specific branch was requested, and that branch
                 # is not yet checked out.
-                track_branch = 'origin/{}'.format(branch_name)
+                track_branch = "origin/{}".format(branch_name)
                 cmd_args = [
-                    'checkout', '-b', branch_name, '--track', track_branch,
+                    "checkout",
+                    "-b",
+                    branch_name,
+                    "--track",
+                    track_branch,
                 ]
                 self.run_command(cmd_args, cwd=dest)
 
@@ -280,10 +290,10 @@ def fetch_new(self, dest, url, rev_options):
     def switch(self, dest, url, rev_options):
         # type: (str, HiddenText, RevOptions) -> None
         self.run_command(
-            make_command('config', 'remote.origin.url', url),
+            make_command("config", "remote.origin.url", url),
             cwd=dest,
         )
-        cmd_args = make_command('checkout', '-q', rev_options.to_args())
+        cmd_args = make_command("checkout", "-q", rev_options.to_args())
         self.run_command(cmd_args, cwd=dest)
 
         self.update_submodules(dest)
@@ -291,14 +301,14 @@ def switch(self, dest, url, rev_options):
     def update(self, dest, url, rev_options):
         # type: (str, HiddenText, RevOptions) -> None
         # First fetch changes from the default remote
-        if self.get_git_version() >= parse_version('1.9.0'):
+        if self.get_git_version() >= parse_version("1.9.0"):
             # fetch tags in addition to everything else
-            self.run_command(['fetch', '-q', '--tags'], cwd=dest)
+            self.run_command(["fetch", "-q", "--tags"], cwd=dest)
         else:
-            self.run_command(['fetch', '-q'], cwd=dest)
+            self.run_command(["fetch", "-q"], cwd=dest)
         # Then reset to wanted revision (maybe even origin/master)
         rev_options = self.resolve_revision(dest, url, rev_options)
-        cmd_args = make_command('reset', '--hard', '-q', rev_options.to_args())
+        cmd_args = make_command("reset", "--hard", "-q", rev_options.to_args())
         self.run_command(cmd_args, cwd=dest)
         #: update submodules
         self.update_submodules(dest)
@@ -314,8 +324,9 @@ def get_remote_url(cls, location):
         # We need to pass 1 for extra_ok_returncodes since the command
         # exits with return code 1 if there are no matching lines.
         stdout = cls.run_command(
-            ['config', '--get-regexp', r'remote\..*\.url'],
-            extra_ok_returncodes=(1, ), cwd=location,
+            ["config", "--get-regexp", r"remote\..*\.url"],
+            extra_ok_returncodes=(1,),
+            cwd=location,
         )
         remotes = stdout.splitlines()
         try:
@@ -324,10 +335,10 @@ def get_remote_url(cls, location):
             raise RemoteNotFoundError
 
         for remote in remotes:
-            if remote.startswith('remote.origin.url '):
+            if remote.startswith("remote.origin.url "):
                 found_remote = remote
                 break
-        url = found_remote.split(' ')[1]
+        url = found_remote.split(" ")[1]
         return url.strip()
 
     @classmethod
@@ -336,9 +347,7 @@ def has_commit(cls, location, rev):
         Check if rev is a commit that is available in the local repository.
         """
         try:
-            cls.run_command(
-                ['rev-parse', '-q', '--verify', "sha^" + rev], cwd=location
-            )
+            cls.run_command(["rev-parse", "-q", "--verify", "sha^" + rev], cwd=location)
         except SubProcessError:
             return False
         else:
@@ -347,9 +356,10 @@ def has_commit(cls, location, rev):
     @classmethod
     def get_revision(cls, location, rev=None):
         if rev is None:
-            rev = 'HEAD'
+            rev = "HEAD"
         current_rev = cls.run_command(
-            ['rev-parse', rev], cwd=location,
+            ["rev-parse", rev],
+            cwd=location,
         )
         return current_rev.strip()
 
@@ -360,12 +370,10 @@ def get_subdirectory(cls, location):
         Return None if setup.py is in the repo root.
         """
         # find the repo root
-        git_dir = cls.run_command(
-            ['rev-parse', '--git-dir'],
-            cwd=location).strip()
+        git_dir = cls.run_command(["rev-parse", "--git-dir"], cwd=location).strip()
         if not os.path.isabs(git_dir):
             git_dir = os.path.join(location, git_dir)
-        repo_root = os.path.abspath(os.path.join(git_dir, '..'))
+        repo_root = os.path.abspath(os.path.join(git_dir, ".."))
         return find_path_to_setup_from_repo_root(location, repo_root)
 
     @classmethod
@@ -380,23 +388,21 @@ def get_url_rev_and_auth(cls, url):
         # Works around an apparent Git bug
         # (see https://article.gmane.org/gmane.comp.version-control.git/146500)
         scheme, netloc, path, query, fragment = urlsplit(url)
-        if scheme.endswith('file'):
-            initial_slashes = path[:-len(path.lstrip('/'))]
-            newpath = (
-                initial_slashes +
-                urllib_request.url2pathname(path)
-                .replace('\\', '/').lstrip('/')
-            )
-            after_plus = scheme.find('+') + 1
+        if scheme.endswith("file"):
+            initial_slashes = path[: -len(path.lstrip("/"))]
+            newpath = initial_slashes + urllib_request.url2pathname(path).replace(
+                "\\", "/"
+            ).lstrip("/")
+            after_plus = scheme.find("+") + 1
             url = scheme[:after_plus] + urlunsplit(
                 (scheme[after_plus:], netloc, newpath, query, fragment),
             )
 
-        if '://' not in url:
-            assert 'file:' not in url
-            url = url.replace('git+', 'git+ssh://')
+        if "://" not in url:
+            assert "file:" not in url
+            url = url.replace("git+", "git+ssh://")
             url, rev, user_pass = super(Git, cls).get_url_rev_and_auth(url)
-            url = url.replace('ssh://', '')
+            url = url.replace("ssh://", "")
         else:
             url, rev, user_pass = super(Git, cls).get_url_rev_and_auth(url)
 
@@ -404,10 +410,10 @@ def get_url_rev_and_auth(cls, url):
 
     @classmethod
     def update_submodules(cls, location):
-        if not os.path.exists(os.path.join(location, '.gitmodules')):
+        if not os.path.exists(os.path.join(location, ".gitmodules")):
             return
         cls.run_command(
-            ['submodule', 'update', '--init', '--recursive', '-q'],
+            ["submodule", "update", "--init", "--recursive", "-q"],
             cwd=location,
         )
 
@@ -418,17 +424,20 @@ def get_repository_root(cls, location):
             return loc
         try:
             r = cls.run_command(
-                ['rev-parse', '--show-toplevel'],
+                ["rev-parse", "--show-toplevel"],
                 cwd=location,
                 log_failed_cmd=False,
             )
         except BadCommand:
-            logger.debug("could not determine if %s is under git control "
-                         "because git is not available", location)
+            logger.debug(
+                "could not determine if %s is under git control "
+                "because git is not available",
+                location,
+            )
             return None
         except SubProcessError:
             return None
-        return os.path.normpath(r.rstrip('\r\n'))
+        return os.path.normpath(r.rstrip("\r\n"))
 
 
 vcs.register(Git)
diff --git a/src/pip/_internal/vcs/mercurial.py b/src/pip/_internal/vcs/mercurial.py
index 69763feaea4..55bdb31187c 100644
--- a/src/pip/_internal/vcs/mercurial.py
+++ b/src/pip/_internal/vcs/mercurial.py
@@ -29,11 +29,16 @@
 
 
 class Mercurial(VersionControl):
-    name = 'hg'
-    dirname = '.hg'
-    repo_name = 'clone'
+    name = "hg"
+    dirname = ".hg"
+    repo_name = "clone"
     schemes = (
-        'hg', 'hg+file', 'hg+http', 'hg+https', 'hg+ssh', 'hg+static-http',
+        "hg",
+        "hg+file",
+        "hg+http",
+        "hg+https",
+        "hg+ssh",
+        "hg+static-http",
     )
 
     @staticmethod
@@ -46,53 +51,51 @@ def export(self, location, url):
         with TempDirectory(kind="export") as temp_dir:
             self.unpack(temp_dir.path, url=url)
 
-            self.run_command(
-                ['archive', location], cwd=temp_dir.path
-            )
+            self.run_command(["archive", location], cwd=temp_dir.path)
 
     def fetch_new(self, dest, url, rev_options):
         # type: (str, HiddenText, RevOptions) -> None
         rev_display = rev_options.to_display()
         logger.info(
-            'Cloning hg %s%s to %s',
+            "Cloning hg %s%s to %s",
             url,
             rev_display,
             display_path(dest),
         )
-        self.run_command(make_command('clone', '--noupdate', '-q', url, dest))
+        self.run_command(make_command("clone", "--noupdate", "-q", url, dest))
         self.run_command(
-            make_command('update', '-q', rev_options.to_args()),
+            make_command("update", "-q", rev_options.to_args()),
             cwd=dest,
         )
 
     def switch(self, dest, url, rev_options):
         # type: (str, HiddenText, RevOptions) -> None
-        repo_config = os.path.join(dest, self.dirname, 'hgrc')
+        repo_config = os.path.join(dest, self.dirname, "hgrc")
         config = configparser.RawConfigParser()
         try:
             config.read(repo_config)
-            config.set('paths', 'default', url.secret)
-            with open(repo_config, 'w') as config_file:
+            config.set("paths", "default", url.secret)
+            with open(repo_config, "w") as config_file:
                 config.write(config_file)
         except (OSError, configparser.NoSectionError) as exc:
             logger.warning(
-                'Could not switch Mercurial repository to %s: %s', url, exc,
+                "Could not switch Mercurial repository to %s: %s",
+                url,
+                exc,
             )
         else:
-            cmd_args = make_command('update', '-q', rev_options.to_args())
+            cmd_args = make_command("update", "-q", rev_options.to_args())
             self.run_command(cmd_args, cwd=dest)
 
     def update(self, dest, url, rev_options):
         # type: (str, HiddenText, RevOptions) -> None
-        self.run_command(['pull', '-q'], cwd=dest)
-        cmd_args = make_command('update', '-q', rev_options.to_args())
+        self.run_command(["pull", "-q"], cwd=dest)
+        cmd_args = make_command("update", "-q", rev_options.to_args())
         self.run_command(cmd_args, cwd=dest)
 
     @classmethod
     def get_remote_url(cls, location):
-        url = cls.run_command(
-            ['showconfig', 'paths.default'],
-            cwd=location).strip()
+        url = cls.run_command(["showconfig", "paths.default"], cwd=location).strip()
         if cls._is_local_repository(url):
             url = path_to_url(url)
         return url.strip()
@@ -103,7 +106,8 @@ def get_revision(cls, location):
         Return the repository-local changeset revision number, as an integer.
         """
         current_revision = cls.run_command(
-            ['parents', '--template={rev}'], cwd=location).strip()
+            ["parents", "--template={rev}"], cwd=location
+        ).strip()
         return current_revision
 
     @classmethod
@@ -113,8 +117,8 @@ def get_requirement_revision(cls, location):
         hexadecimal string
         """
         current_rev_hash = cls.run_command(
-            ['parents', '--template={node}'],
-            cwd=location).strip()
+            ["parents", "--template={node}"], cwd=location
+        ).strip()
         return current_rev_hash
 
     @classmethod
@@ -129,8 +133,7 @@ def get_subdirectory(cls, location):
         Return None if setup.py is in the repo root.
         """
         # find the repo root
-        repo_root = cls.run_command(
-            ['root'], cwd=location).strip()
+        repo_root = cls.run_command(["root"], cwd=location).strip()
         if not os.path.isabs(repo_root):
             repo_root = os.path.abspath(os.path.join(location, repo_root))
         return find_path_to_setup_from_repo_root(location, repo_root)
@@ -142,17 +145,20 @@ def get_repository_root(cls, location):
             return loc
         try:
             r = cls.run_command(
-                ['root'],
+                ["root"],
                 cwd=location,
                 log_failed_cmd=False,
             )
         except BadCommand:
-            logger.debug("could not determine if %s is under hg control "
-                         "because hg is not available", location)
+            logger.debug(
+                "could not determine if %s is under hg control "
+                "because hg is not available",
+                location,
+            )
             return None
         except SubProcessError:
             return None
-        return os.path.normpath(r.rstrip('\r\n'))
+        return os.path.normpath(r.rstrip("\r\n"))
 
 
 vcs.register(Mercurial)
diff --git a/src/pip/_internal/vcs/subversion.py b/src/pip/_internal/vcs/subversion.py
index eae09c19610..f09b0aafd56 100644
--- a/src/pip/_internal/vcs/subversion.py
+++ b/src/pip/_internal/vcs/subversion.py
@@ -21,7 +21,7 @@
 _svn_xml_url_re = re.compile('url="([^"]+)"')
 _svn_rev_re = re.compile(r'committed-rev="(\d+)"')
 _svn_info_xml_rev_re = re.compile(r'\s*revision="(\d+)"')
-_svn_info_xml_url_re = re.compile(r'<url>(.*)</url>')
+_svn_info_xml_url_re = re.compile(r"<url>(.*)</url>")
 
 
 if MYPY_CHECK_RUNNING:
@@ -36,10 +36,10 @@
 
 
 class Subversion(VersionControl):
-    name = 'svn'
-    dirname = '.svn'
-    repo_name = 'checkout'
-    schemes = ('svn', 'svn+ssh', 'svn+http', 'svn+https', 'svn+svn')
+    name = "svn"
+    dirname = ".svn"
+    repo_name = "checkout"
+    schemes = ("svn", "svn+ssh", "svn+http", "svn+https", "svn+svn")
 
     @classmethod
     def should_add_vcs_url_prefix(cls, remote_url):
@@ -47,7 +47,7 @@ def should_add_vcs_url_prefix(cls, remote_url):
 
     @staticmethod
     def get_base_rev_args(rev):
-        return ['-r', rev]
+        return ["-r", rev]
 
     @classmethod
     def get_revision(cls, location):
@@ -60,9 +60,9 @@ def get_revision(cls, location):
         for base, dirs, _ in os.walk(location):
             if cls.dirname not in dirs:
                 dirs[:] = []
-                continue    # no sense walking uncontrolled subdirs
+                continue  # no sense walking uncontrolled subdirs
             dirs.remove(cls.dirname)
-            entries_fn = os.path.join(base, cls.dirname, 'entries')
+            entries_fn = os.path.join(base, cls.dirname, "entries")
             if not os.path.exists(entries_fn):
                 # FIXME: should we warn?
                 continue
@@ -70,10 +70,10 @@ def get_revision(cls, location):
             dirurl, localrev = cls._get_svn_url_rev(base)
 
             if base == location:
-                base = dirurl + '/'   # save the root url
+                base = dirurl + "/"  # save the root url
             elif not dirurl or not dirurl.startswith(base):
                 dirs[:] = []
-                continue    # not part of the same svn tree, skip it
+                continue  # not part of the same svn tree, skip it
             revision = max(revision, localrev)
         return revision
 
@@ -83,7 +83,7 @@ def get_netloc_and_auth(cls, netloc, scheme):
         This override allows the auth information to be passed to svn via the
         --username and --password options instead of via the URL.
         """
-        if scheme == 'ssh':
+        if scheme == "ssh":
             # The --username and --password options can't be used for
             # svn+ssh URLs, so keep the auth information in the URL.
             return super(Subversion, cls).get_netloc_and_auth(netloc, scheme)
@@ -95,8 +95,8 @@ def get_url_rev_and_auth(cls, url):
         # type: (str) -> Tuple[str, Optional[str], AuthInfo]
         # hotfix the URL scheme after removing svn+ from svn+ssh:// readd it
         url, rev, user_pass = super(Subversion, cls).get_url_rev_and_auth(url)
-        if url.startswith('ssh://'):
-            url = 'svn+' + url
+        if url.startswith("ssh://"):
+            url = "svn+" + url
         return url, rev, user_pass
 
     @staticmethod
@@ -104,9 +104,9 @@ def make_rev_args(username, password):
         # type: (Optional[str], Optional[HiddenText]) -> CommandArgs
         extra_args = []  # type: CommandArgs
         if username:
-            extra_args += ['--username', username]
+            extra_args += ["--username", username]
         if password:
-            extra_args += ['--password', password]
+            extra_args += ["--password", password]
 
         return extra_args
 
@@ -116,7 +116,7 @@ def get_remote_url(cls, location):
         # setup.py we have to look up in the location until we find a real
         # setup.py
         orig_location = location
-        while not os.path.exists(os.path.join(location, 'setup.py')):
+        while not os.path.exists(os.path.join(location, "setup.py")):
             last_location = location
             location = os.path.dirname(location)
             if location == last_location:
@@ -135,26 +135,23 @@ def get_remote_url(cls, location):
     def _get_svn_url_rev(cls, location):
         from pip._internal.exceptions import SubProcessError
 
-        entries_path = os.path.join(location, cls.dirname, 'entries')
+        entries_path = os.path.join(location, cls.dirname, "entries")
         if os.path.exists(entries_path):
             with open(entries_path) as f:
                 data = f.read()
         else:  # subversion >= 1.7 does not have the 'entries' file
-            data = ''
+            data = ""
 
-        if (data.startswith('8') or
-                data.startswith('9') or
-                data.startswith('10')):
-            data = list(map(str.splitlines, data.split('\n\x0c\n')))
+        if data.startswith("8") or data.startswith("9") or data.startswith("10"):
+            data = list(map(str.splitlines, data.split("\n\x0c\n")))
             del data[0][0]  # get rid of the '8'
             url = data[0][3]
             revs = [int(d[9]) for d in data if len(d) > 9 and d[9]] + [0]
-        elif data.startswith('<?xml'):
+        elif data.startswith("<?xml"):
             match = _svn_xml_url_re.search(data)
             if not match:
-                raise ValueError(
-                    'Badly formatted data: {data!r}'.format(**locals()))
-            url = match.group(1)    # get repository URL
+                raise ValueError("Badly formatted data: {data!r}".format(**locals()))
+            url = match.group(1)  # get repository URL
             revs = [int(m.group(1)) for m in _svn_rev_re.finditer(data)] + [0]
         else:
             try:
@@ -165,12 +162,10 @@ def _get_svn_url_rev(cls, location):
                 # is being used to prompt for passwords, because passwords
                 # are only potentially needed for remote server requests.
                 xml = cls.run_command(
-                    ['info', '--xml', location],
+                    ["info", "--xml", location],
                 )
                 url = _svn_info_xml_url_re.search(xml).group(1)
-                revs = [
-                    int(m.group(1)) for m in _svn_info_xml_rev_re.finditer(xml)
-                ]
+                revs = [int(m.group(1)) for m in _svn_info_xml_rev_re.finditer(xml)]
             except SubProcessError:
                 url, revs = None, []
 
@@ -216,14 +211,14 @@ def call_vcs_version(self):
         #      compiled Mar 28 2018, 08:49:13 on x86_64-pc-linux-gnu
         #   svn, version 1.12.0-SlikSvn (SlikSvn/1.12.0)
         #      compiled May 28 2019, 13:44:56 on x86_64-microsoft-windows6.2
-        version_prefix = 'svn, version '
-        version = self.run_command(['--version'])
+        version_prefix = "svn, version "
+        version = self.run_command(["--version"])
 
         if not version.startswith(version_prefix):
             return ()
 
-        version = version[len(version_prefix):].split()[0]
-        version_list = version.partition('-')[0].split('.')
+        version = version[len(version_prefix) :].split()[0]
+        version_list = version.partition("-")[0].split(".")
         try:
             parsed_version = tuple(map(int, version_list))
         except ValueError:
@@ -269,7 +264,7 @@ def get_remote_call_options(self):
         if not self.use_interactive:
             # --non-interactive switch is available since Subversion 0.14.4.
             # Subversion < 1.8 runs in interactive mode by default.
-            return ['--non-interactive']
+            return ["--non-interactive"]
 
         svn_version = self.get_vcs_version()
         # By default, Subversion >= 1.8 runs in non-interactive mode if
@@ -281,7 +276,7 @@ def get_remote_call_options(self):
         # SVN 1.7, pip should continue to support SVN 1.7. Therefore, pip
         # can't safely add the option if the SVN version is < 1.8 (or unknown).
         if svn_version >= (1, 8):
-            return ['--force-interactive']
+            return ["--force-interactive"]
 
         return []
 
@@ -290,15 +285,18 @@ def export(self, location, url):
         """Export the svn repository at the url to the destination location"""
         url, rev_options = self.get_url_rev_options(url)
 
-        logger.info('Exporting svn repository %s to %s', url, location)
+        logger.info("Exporting svn repository %s to %s", url, location)
         with indent_log():
             if os.path.exists(location):
                 # Subversion doesn't like to check out over an existing
                 # directory --force fixes this, but was only added in svn 1.5
                 rmtree(location)
             cmd_args = make_command(
-                'export', self.get_remote_call_options(),
-                rev_options.to_args(), url, location,
+                "export",
+                self.get_remote_call_options(),
+                rev_options.to_args(),
+                url,
+                location,
             )
             self.run_command(cmd_args)
 
@@ -306,29 +304,38 @@ def fetch_new(self, dest, url, rev_options):
         # type: (str, HiddenText, RevOptions) -> None
         rev_display = rev_options.to_display()
         logger.info(
-            'Checking out %s%s to %s',
+            "Checking out %s%s to %s",
             url,
             rev_display,
             display_path(dest),
         )
         cmd_args = make_command(
-            'checkout', '-q', self.get_remote_call_options(),
-            rev_options.to_args(), url, dest,
+            "checkout",
+            "-q",
+            self.get_remote_call_options(),
+            rev_options.to_args(),
+            url,
+            dest,
         )
         self.run_command(cmd_args)
 
     def switch(self, dest, url, rev_options):
         # type: (str, HiddenText, RevOptions) -> None
         cmd_args = make_command(
-            'switch', self.get_remote_call_options(), rev_options.to_args(),
-            url, dest,
+            "switch",
+            self.get_remote_call_options(),
+            rev_options.to_args(),
+            url,
+            dest,
         )
         self.run_command(cmd_args)
 
     def update(self, dest, url, rev_options):
         # type: (str, HiddenText, RevOptions) -> None
         cmd_args = make_command(
-            'update', self.get_remote_call_options(), rev_options.to_args(),
+            "update",
+            self.get_remote_call_options(),
+            rev_options.to_args(),
             dest,
         )
         self.run_command(cmd_args)
diff --git a/src/pip/_internal/vcs/versioncontrol.py b/src/pip/_internal/vcs/versioncontrol.py
index e4f61a99c12..108bafd71b3 100644
--- a/src/pip/_internal/vcs/versioncontrol.py
+++ b/src/pip/_internal/vcs/versioncontrol.py
@@ -12,11 +12,7 @@
 from pip._vendor import pkg_resources
 from pip._vendor.six.moves.urllib import parse as urllib_parse
 
-from pip._internal.exceptions import (
-    BadCommand,
-    InstallationError,
-    SubProcessError,
-)
+from pip._internal.exceptions import BadCommand, InstallationError, SubProcessError
 from pip._internal.utils.compat import console_to_str, samefile
 from pip._internal.utils.logging import subprocess_logger
 from pip._internal.utils.misc import (
@@ -57,7 +53,7 @@
     AuthInfo = Tuple[Optional[str], Optional[str]]
 
 
-__all__ = ['vcs']
+__all__ = ["vcs"]
 
 
 logger = logging.getLogger(__name__)
@@ -71,7 +67,7 @@ def is_url(name):
     scheme = get_url_scheme(name)
     if scheme is None:
         return False
-    return scheme in ['http', 'https', 'file', 'ftp'] + vcs.all_schemes
+    return scheme in ["http", "https", "file", "ftp"] + vcs.all_schemes
 
 
 def make_vcs_requirement_url(repo_url, rev, project_name, subdir=None):
@@ -84,9 +80,9 @@ def make_vcs_requirement_url(repo_url, rev, project_name, subdir=None):
       project_name: the (unescaped) project name.
     """
     egg_project_name = pkg_resources.to_filename(project_name)
-    req = '{}@{}#egg={}'.format(repo_url, rev, egg_project_name)
+    req = "{}@{}#egg={}".format(repo_url, rev, egg_project_name)
     if subdir:
-        req += '&subdirectory={}'.format(subdir)
+        req += "&subdirectory={}".format(subdir)
 
     return req
 
@@ -96,7 +92,7 @@ def call_subprocess(
     cwd=None,  # type: Optional[str]
     extra_environ=None,  # type: Optional[Mapping[str, Any]]
     extra_ok_returncodes=None,  # type: Optional[Iterable[int]]
-    log_failed_cmd=True  # type: Optional[bool]
+    log_failed_cmd=True,  # type: Optional[bool]
 ):
     # type: (...) -> Text
     """
@@ -126,14 +122,16 @@ def call_subprocess(
             reveal_command_args(cmd),
             stdout=subprocess.PIPE,
             stderr=subprocess.PIPE,
-            cwd=cwd
+            cwd=cwd,
         )
         if proc.stdin:
             proc.stdin.close()
     except Exception as exc:
         if log_failed_cmd:
             subprocess_logger.critical(
-                "Error %s while executing command %s", exc, command_desc,
+                "Error %s while executing command %s",
+                exc,
+                command_desc,
             )
         raise
     all_output = []
@@ -145,7 +143,7 @@ def call_subprocess(
         if not line:
             break
         line = line.rstrip()
-        all_output.append(line + '\n')
+        all_output.append(line + "\n")
 
         # Show the line immediately.
         log_subprocess(line)
@@ -155,9 +153,7 @@ def call_subprocess(
         if proc.stdout:
             proc.stdout.close()
 
-    proc_had_error = (
-        proc.returncode and proc.returncode not in extra_ok_returncodes
-    )
+    proc_had_error = proc.returncode and proc.returncode not in extra_ok_returncodes
     if proc_had_error:
         if not showing_subprocess and log_failed_cmd:
             # Then the subprocess streams haven't been logged to the
@@ -170,11 +166,11 @@ def call_subprocess(
             )
             subprocess_logger.error(msg)
         exc_msg = (
-            'Command errored out with exit status {}: {} '
-            'Check the logs for full command output.'
+            "Command errored out with exit status {}: {} "
+            "Check the logs for full command output."
         ).format(proc.returncode, command_desc)
         raise SubProcessError(exc_msg)
-    return ''.join(all_output)
+    return "".join(all_output)
 
 
 def find_path_to_setup_from_repo_root(location, repo_root):
@@ -186,7 +182,7 @@ def find_path_to_setup_from_repo_root(location, repo_root):
     """
     # find setup.py
     orig_location = location
-    while not os.path.exists(os.path.join(location, 'setup.py')):
+    while not os.path.exists(os.path.join(location, "setup.py")):
         last_location = location
         location = os.path.dirname(location)
         if location == last_location:
@@ -241,7 +237,7 @@ def __init__(
 
     def __repr__(self):
         # type: () -> str
-        return '<RevOptions {}: rev={!r}>'.format(self.vc_class.name, self.rev)
+        return "<RevOptions {}: rev={!r}>".format(self.vc_class.name, self.rev)
 
     @property
     def arg_rev(self):
@@ -267,9 +263,9 @@ def to_args(self):
     def to_display(self):
         # type: () -> str
         if not self.rev:
-            return ''
+            return ""
 
-        return ' (to revision {})'.format(self.rev)
+        return " (to revision {})".format(self.rev)
 
     def make_new(self, rev):
         # type: (str) -> RevOptions
@@ -284,7 +280,7 @@ def make_new(self, rev):
 
 class VcsSupport(object):
     _registry = {}  # type: Dict[str, VersionControl]
-    schemes = ['ssh', 'git', 'hg', 'bzr', 'sftp', 'svn']
+    schemes = ["ssh", "git", "hg", "bzr", "sftp", "svn"]
 
     def __init__(self):
         # type: () -> None
@@ -292,7 +288,7 @@ def __init__(self):
         # systems
         urllib_parse.uses_netloc.extend(self.schemes)
         # Python >= 2.7.4, 3.3 doesn't have uses_fragment
-        if getattr(urllib_parse, 'uses_fragment', None):
+        if getattr(urllib_parse, "uses_fragment", None):
             urllib_parse.uses_fragment.extend(self.schemes)
         super(VcsSupport, self).__init__()
 
@@ -320,12 +316,12 @@ def all_schemes(self):
 
     def register(self, cls):
         # type: (Type[VersionControl]) -> None
-        if not hasattr(cls, 'name'):
-            logger.warning('Cannot register VCS %s', cls.__name__)
+        if not hasattr(cls, "name"):
+            logger.warning("Cannot register VCS %s", cls.__name__)
             return
         if cls.name not in self._registry:
             self._registry[cls.name] = cls()
-            logger.debug('Registered VCS backend: %s', cls.name)
+            logger.debug("Registered VCS backend: %s", cls.name)
 
     def unregister(self, name):
         # type: (str) -> None
@@ -343,8 +339,7 @@ def get_backend_for_dir(self, location):
             repo_path = vcs_backend.get_repository_root(location)
             if not repo_path:
                 continue
-            logger.debug('Determine that %s uses VCS: %s',
-                         location, vcs_backend.name)
+            logger.debug("Determine that %s uses VCS: %s", location, vcs_backend.name)
             vcs_backends[repo_path] = vcs_backend
 
         if not vcs_backends:
@@ -380,9 +375,9 @@ def get_backend(self, name):
 
 
 class VersionControl(object):
-    name = ''
-    dirname = ''
-    repo_name = ''
+    name = ""
+    dirname = ""
+    repo_name = ""
     # List of supported schemes for this Version Control
     schemes = ()  # type: Tuple[str, ...]
     # Iterable of environment variable names to pass to call_subprocess().
@@ -396,7 +391,7 @@ def should_add_vcs_url_prefix(cls, remote_url):
         Return whether the vcs prefix (e.g. "git+") should be added to a
         repository's remote url when used in a requirement.
         """
-        return not remote_url.lower().startswith('{}:'.format(cls.name))
+        return not remote_url.lower().startswith("{}:".format(cls.name))
 
     @classmethod
     def get_subdirectory(cls, location):
@@ -434,12 +429,11 @@ def get_src_requirement(cls, repo_dir, project_name):
             return None
 
         if cls.should_add_vcs_url_prefix(repo_url):
-            repo_url = '{}+{}'.format(cls.name, repo_url)
+            repo_url = "{}+{}".format(cls.name, repo_url)
 
         revision = cls.get_requirement_revision(repo_dir)
         subdir = cls.get_subdirectory(repo_dir)
-        req = make_vcs_requirement_url(repo_url, revision, project_name,
-                                       subdir=subdir)
+        req = make_vcs_requirement_url(repo_url, revision, project_name, subdir=subdir)
 
         return req
 
@@ -484,8 +478,8 @@ def make_rev_options(cls, rev=None, extra_args=None):
     def _is_local_repository(cls, repo):
         # type: (str) -> bool
         """
-           posix absolute paths start with os.path.sep,
-           win32 ones start with drive (like c:\\folder)
+        posix absolute paths start with os.path.sep,
+        win32 ones start with drive (like c:\\folder)
         """
         drive, tail = os.path.splitdrive(repo)
         return repo.startswith(os.path.sep) or bool(drive)
@@ -530,25 +524,25 @@ def get_url_rev_and_auth(cls, url):
         Returns: (url, rev, (username, password)).
         """
         scheme, netloc, path, query, frag = urllib_parse.urlsplit(url)
-        if '+' not in scheme:
+        if "+" not in scheme:
             raise ValueError(
                 "Sorry, {!r} is a malformed VCS url. "
                 "The format is <vcs>+<protocol>://<url>, "
                 "e.g. svn+http://myrepo/svn/MyApp#egg=MyApp".format(url)
             )
         # Remove the vcs prefix.
-        scheme = scheme.split('+', 1)[1]
+        scheme = scheme.split("+", 1)[1]
         netloc, user_pass = cls.get_netloc_and_auth(netloc, scheme)
         rev = None
-        if '@' in path:
-            path, rev = path.rsplit('@', 1)
+        if "@" in path:
+            path, rev = path.rsplit("@", 1)
             if not rev:
                 raise InstallationError(
                     "The URL {!r} has an empty revision (after @) "
                     "which is not supported. Include a revision after @ "
                     "or remove @ from the URL.".format(url)
                 )
-        url = urllib_parse.urlunsplit((scheme, netloc, path, query, ''))
+        url = urllib_parse.urlunsplit((scheme, netloc, path, query, ""))
         return url, rev, user_pass
 
     @staticmethod
@@ -582,7 +576,7 @@ def normalize_url(url):
         Normalize a URL for comparison by unquoting it and removing any
         trailing slash.
         """
-        return urllib_parse.unquote(url).rstrip('/')
+        return urllib_parse.unquote(url).rstrip("/")
 
     @classmethod
     def compare_urls(cls, url1, url2):
@@ -590,7 +584,7 @@ def compare_urls(cls, url1, url2):
         """
         Compare two repo URLs for identity, ignoring incidental differences.
         """
-        return (cls.normalize_url(url1) == cls.normalize_url(url2))
+        return cls.normalize_url(url1) == cls.normalize_url(url2)
 
     def fetch_new(self, dest, url, rev_options):
         # type: (str, HiddenText, RevOptions) -> None
@@ -656,73 +650,72 @@ def obtain(self, dest, url):
             existing_url = self.get_remote_url(dest)
             if self.compare_urls(existing_url, url.secret):
                 logger.debug(
-                    '%s in %s exists, and has correct URL (%s)',
+                    "%s in %s exists, and has correct URL (%s)",
                     self.repo_name.title(),
                     display_path(dest),
                     url,
                 )
                 if not self.is_commit_id_equal(dest, rev_options.rev):
                     logger.info(
-                        'Updating %s %s%s',
+                        "Updating %s %s%s",
                         display_path(dest),
                         self.repo_name,
                         rev_display,
                     )
                     self.update(dest, url, rev_options)
                 else:
-                    logger.info('Skipping because already up-to-date.')
+                    logger.info("Skipping because already up-to-date.")
                 return
 
             logger.warning(
-                '%s %s in %s exists with URL %s',
+                "%s %s in %s exists with URL %s",
                 self.name,
                 self.repo_name,
                 display_path(dest),
                 existing_url,
             )
-            prompt = ('(s)witch, (i)gnore, (w)ipe, (b)ackup ',
-                      ('s', 'i', 'w', 'b'))
+            prompt = ("(s)witch, (i)gnore, (w)ipe, (b)ackup ", ("s", "i", "w", "b"))
         else:
             logger.warning(
-                'Directory %s already exists, and is not a %s %s.',
+                "Directory %s already exists, and is not a %s %s.",
                 dest,
                 self.name,
                 self.repo_name,
             )
             # https://github.com/python/mypy/issues/1174
-            prompt = ('(i)gnore, (w)ipe, (b)ackup ',  # type: ignore
-                      ('i', 'w', 'b'))
+            prompt = ("(i)gnore, (w)ipe, (b)ackup ", ("i", "w", "b"))  # type: ignore
 
         logger.warning(
-            'The plan is to install the %s repository %s',
+            "The plan is to install the %s repository %s",
             self.name,
             url,
         )
-        response = ask_path_exists('What to do?  {}'.format(
-            prompt[0]), prompt[1])
+        response = ask_path_exists("What to do?  {}".format(prompt[0]), prompt[1])
 
-        if response == 'a':
+        if response == "a":
             sys.exit(-1)
 
-        if response == 'w':
-            logger.warning('Deleting %s', display_path(dest))
+        if response == "w":
+            logger.warning("Deleting %s", display_path(dest))
             rmtree(dest)
             self.fetch_new(dest, url, rev_options)
             return
 
-        if response == 'b':
+        if response == "b":
             dest_dir = backup_dir(dest)
             logger.warning(
-                'Backing up %s to %s', display_path(dest), dest_dir,
+                "Backing up %s to %s",
+                display_path(dest),
+                dest_dir,
             )
             shutil.move(dest, dest_dir)
             self.fetch_new(dest, url, rev_options)
             return
 
         # Do nothing if the response is "i".
-        if response == 's':
+        if response == "s":
             logger.info(
-                'Switching %s %s to %s%s',
+                "Switching %s %s to %s%s",
                 self.repo_name,
                 display_path(dest),
                 url,
@@ -768,7 +761,7 @@ def run_command(
         cwd=None,  # type: Optional[str]
         extra_environ=None,  # type: Optional[Mapping[str, Any]]
         extra_ok_returncodes=None,  # type: Optional[Iterable[int]]
-        log_failed_cmd=True  # type: bool
+        log_failed_cmd=True,  # type: bool
     ):
         # type: (...) -> Text
         """
@@ -778,18 +771,22 @@ def run_command(
         """
         cmd = make_command(cls.name, *cmd)
         try:
-            return call_subprocess(cmd, cwd,
-                                   extra_environ=extra_environ,
-                                   extra_ok_returncodes=extra_ok_returncodes,
-                                   log_failed_cmd=log_failed_cmd)
+            return call_subprocess(
+                cmd,
+                cwd,
+                extra_environ=extra_environ,
+                extra_ok_returncodes=extra_ok_returncodes,
+                log_failed_cmd=log_failed_cmd,
+            )
         except OSError as e:
             # errno.ENOENT = no such file or directory
             # In other words, the VCS executable isn't available
             if e.errno == errno.ENOENT:
                 raise BadCommand(
-                    'Cannot find command {cls.name!r} - do you have '
-                    '{cls.name!r} installed and in your '
-                    'PATH?'.format(**locals()))
+                    "Cannot find command {cls.name!r} - do you have "
+                    "{cls.name!r} installed and in your "
+                    "PATH?".format(**locals())
+                )
             else:
                 raise  # re-raise exception if a different error occurred
 
@@ -799,8 +796,7 @@ def is_repository_directory(cls, path):
         """
         Return whether a directory path is a repository directory.
         """
-        logger.debug('Checking in %s for %s (%s)...',
-                     path, cls.dirname, cls.name)
+        logger.debug("Checking in %s for %s (%s)...", path, cls.dirname, cls.name)
         return os.path.exists(os.path.join(path, cls.dirname))
 
     @classmethod
diff --git a/src/pip/_internal/wheel_builder.py b/src/pip/_internal/wheel_builder.py
index 27fce66c264..f7d25070645 100644
--- a/src/pip/_internal/wheel_builder.py
+++ b/src/pip/_internal/wheel_builder.py
@@ -29,7 +29,7 @@
 
 logger = logging.getLogger(__name__)
 
-_egg_info_re = re.compile(r'([a-z0-9_.]+)-([a-z0-9_.!+-]+)', re.IGNORECASE)
+_egg_info_re = re.compile(r"([a-z0-9_.]+)-([a-z0-9_.!+-]+)", re.IGNORECASE)
 
 
 def _contains_egg_info(s):
@@ -54,7 +54,8 @@ def _should_build(
     if req.is_wheel:
         if need_wheel:
             logger.info(
-                'Skipping %s, due to already being wheel.', req.name,
+                "Skipping %s, due to already being wheel.",
+                req.name,
             )
         return False
 
@@ -70,8 +71,8 @@ def _should_build(
 
     if not check_binary_allowed(req):
         logger.info(
-            "Skipping wheel build for %s, due to binaries "
-            "being disabled for it.", req.name,
+            "Skipping wheel build for %s, due to binaries " "being disabled for it.",
+            req.name,
         )
         return False
 
@@ -79,7 +80,8 @@ def _should_build(
         # we don't build legacy requirements if wheel is not installed
         logger.info(
             "Using legacy 'setup.py install' for %s, "
-            "since package 'wheel' is not installed.", req.name,
+            "since package 'wheel' is not installed.",
+            req.name,
         )
         return False
 
@@ -90,9 +92,7 @@ def should_build_for_wheel_command(
     req,  # type: InstallRequirement
 ):
     # type: (...) -> bool
-    return _should_build(
-        req, need_wheel=True, check_binary_allowed=_always_true
-    )
+    return _should_build(req, need_wheel=True, check_binary_allowed=_always_true)
 
 
 def should_build_for_install_command(
@@ -176,15 +176,14 @@ def _build_one(
     except OSError as e:
         logger.warning(
             "Building wheel for %s failed: %s",
-            req.name, e,
+            req.name,
+            e,
         )
         return None
 
     # Install build deps into temporary directory (PEP 518)
     with req.build_env:
-        return _build_one_inside_env(
-            req, output_dir, build_options, global_options
-        )
+        return _build_one_inside_env(req, output_dir, build_options, global_options)
 
 
 def _build_one_inside_env(
@@ -221,16 +220,20 @@ def _build_one_inside_env(
             try:
                 wheel_hash, length = hash_file(wheel_path)
                 shutil.move(wheel_path, dest_path)
-                logger.info('Created wheel for %s: '
-                            'filename=%s size=%d sha256=%s',
-                            req.name, wheel_name, length,
-                            wheel_hash.hexdigest())
-                logger.info('Stored in directory: %s', output_dir)
+                logger.info(
+                    "Created wheel for %s: " "filename=%s size=%d sha256=%s",
+                    req.name,
+                    wheel_name,
+                    length,
+                    wheel_hash.hexdigest(),
+                )
+                logger.info("Stored in directory: %s", output_dir)
                 return dest_path
             except Exception as e:
                 logger.warning(
                     "Building wheel for %s failed: %s",
-                    req.name, e,
+                    req.name,
+                    e,
                 )
         # Ignore return, we can't do anything else useful.
         if not req.use_pep517:
@@ -245,12 +248,12 @@ def _clean_one_legacy(req, global_options):
         global_options=global_options,
     )
 
-    logger.info('Running setup.py clean for %s', req.name)
+    logger.info("Running setup.py clean for %s", req.name)
     try:
         call_subprocess(clean_args, cwd=req.source_dir)
         return True
     except Exception:
-        logger.error('Failed cleaning build dir for %s', req.name)
+        logger.error("Failed cleaning build dir for %s", req.name)
         return False
 
 
@@ -271,17 +274,15 @@ def build(
 
     # Build the wheels.
     logger.info(
-        'Building wheels for collected packages: %s',
-        ', '.join(req.name for req in requirements),  # type: ignore
+        "Building wheels for collected packages: %s",
+        ", ".join(req.name for req in requirements),  # type: ignore
     )
 
     with indent_log():
         build_successes, build_failures = [], []
         for req in requirements:
             cache_dir = _get_cache_dir(req, wheel_cache)
-            wheel_file = _build_one(
-                req, cache_dir, build_options, global_options
-            )
+            wheel_file = _build_one(req, cache_dir, build_options, global_options)
             if wheel_file:
                 # Update the link for this.
                 req.link = Link(path_to_url(wheel_file))
@@ -294,13 +295,13 @@ def build(
     # notify success/failure
     if build_successes:
         logger.info(
-            'Successfully built %s',
-            ' '.join([req.name for req in build_successes]),  # type: ignore
+            "Successfully built %s",
+            " ".join([req.name for req in build_successes]),  # type: ignore
         )
     if build_failures:
         logger.info(
-            'Failed to build %s',
-            ' '.join([req.name for req in build_failures]),  # type: ignore
+            "Failed to build %s",
+            " ".join([req.name for req in build_failures]),  # type: ignore
         )
     # Return a list of requirements that failed to build
     return build_successes, build_failures
diff --git a/tests/conftest.py b/tests/conftest.py
index ffd9f42158b..13b333541e8 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -60,29 +60,32 @@ def pytest_addoption(parser):
 
 def pytest_collection_modifyitems(config, items):
     for item in items:
-        if not hasattr(item, 'module'):  # e.g.: DoctestTextfile
+        if not hasattr(item, "module"):  # e.g.: DoctestTextfile
             continue
 
         # Mark network tests as flaky
-        if (item.get_closest_marker('network') is not None and
-                "CI" in os.environ):
+        if item.get_closest_marker("network") is not None and "CI" in os.environ:
             item.add_marker(pytest.mark.flaky(reruns=3))
 
-        if (item.get_closest_marker('fails_on_new_resolver') and
-                config.getoption("--new-resolver") and
-                not config.getoption("--new-resolver-runtests")):
-            item.add_marker(pytest.mark.skip(
-                'This test does not work with the new resolver'))
+        if (
+            item.get_closest_marker("fails_on_new_resolver")
+            and config.getoption("--new-resolver")
+            and not config.getoption("--new-resolver-runtests")
+        ):
+            item.add_marker(
+                pytest.mark.skip("This test does not work with the new resolver")
+            )
 
         if six.PY3:
-            if (item.get_closest_marker('incompatible_with_test_venv') and
-                    config.getoption("--use-venv")):
-                item.add_marker(pytest.mark.skip(
-                    'Incompatible with test venv'))
-            if (item.get_closest_marker('incompatible_with_venv') and
-                    sys.prefix != sys.base_prefix):
-                item.add_marker(pytest.mark.skip(
-                    'Incompatible with venv'))
+            if item.get_closest_marker(
+                "incompatible_with_test_venv"
+            ) and config.getoption("--use-venv"):
+                item.add_marker(pytest.mark.skip("Incompatible with test venv"))
+            if (
+                item.get_closest_marker("incompatible_with_venv")
+                and sys.prefix != sys.base_prefix
+            ):
+                item.add_marker(pytest.mark.skip("Incompatible with venv"))
 
         module_path = os.path.relpath(
             item.module.__file__,
@@ -90,22 +93,21 @@ def pytest_collection_modifyitems(config, items):
         )
 
         module_root_dir = module_path.split(os.pathsep)[0]
-        if (module_root_dir.startswith("functional") or
-                module_root_dir.startswith("integration") or
-                module_root_dir.startswith("lib")):
+        if (
+            module_root_dir.startswith("functional")
+            or module_root_dir.startswith("integration")
+            or module_root_dir.startswith("lib")
+        ):
             item.add_marker(pytest.mark.integration)
         elif module_root_dir.startswith("unit"):
             item.add_marker(pytest.mark.unit)
         else:
-            raise RuntimeError(
-                "Unknown test type (filename = {})".format(module_path)
-            )
+            raise RuntimeError("Unknown test type (filename = {})".format(module_path))
 
 
 @pytest.fixture(scope="session", autouse=True)
 def use_new_resolver(request):
-    """Set environment variable to make pip default to the new resolver.
-    """
+    """Set environment variable to make pip default to the new resolver."""
     new_resolver = request.config.getoption("--new-resolver")
     features = set(os.environ.get("PIP_USE_FEATURE", "").split())
     if new_resolver:
@@ -116,9 +118,9 @@ def use_new_resolver(request):
         yield new_resolver
 
 
-@pytest.fixture(scope='session')
+@pytest.fixture(scope="session")
 def tmpdir_factory(request, tmpdir_factory):
-    """ Modified `tmpdir_factory` session fixture
+    """Modified `tmpdir_factory` session fixture
     that will automatically cleanup after itself.
     """
     yield tmpdir_factory
@@ -176,17 +178,17 @@ def isolate(tmpdir, monkeypatch):
     fake_root = os.path.join(str(tmpdir), "fake-root")
     os.makedirs(fake_root)
 
-    if sys.platform == 'win32':
+    if sys.platform == "win32":
         # Note: this will only take effect in subprocesses...
         home_drive, home_path = os.path.splitdrive(home_dir)
-        monkeypatch.setenv('USERPROFILE', home_dir)
-        monkeypatch.setenv('HOMEDRIVE', home_drive)
-        monkeypatch.setenv('HOMEPATH', home_path)
+        monkeypatch.setenv("USERPROFILE", home_dir)
+        monkeypatch.setenv("HOMEDRIVE", home_drive)
+        monkeypatch.setenv("HOMEPATH", home_path)
         for env_var, sub_path in (
-            ('APPDATA', 'AppData/Roaming'),
-            ('LOCALAPPDATA', 'AppData/Local'),
+            ("APPDATA", "AppData/Roaming"),
+            ("LOCALAPPDATA", "AppData/Local"),
         ):
-            path = os.path.join(home_dir, *sub_path.split('/'))
+            path = os.path.join(home_dir, *sub_path.split("/"))
             monkeypatch.setenv(env_var, path)
             os.makedirs(path)
     else:
@@ -195,23 +197,46 @@ def isolate(tmpdir, monkeypatch):
         # of the user's actual $HOME directory.
         monkeypatch.setenv("HOME", home_dir)
         # Isolate ourselves from XDG directories
-        monkeypatch.setenv("XDG_DATA_HOME", os.path.join(
-            home_dir, ".local", "share",
-        ))
-        monkeypatch.setenv("XDG_CONFIG_HOME", os.path.join(
-            home_dir, ".config",
-        ))
+        monkeypatch.setenv(
+            "XDG_DATA_HOME",
+            os.path.join(
+                home_dir,
+                ".local",
+                "share",
+            ),
+        )
+        monkeypatch.setenv(
+            "XDG_CONFIG_HOME",
+            os.path.join(
+                home_dir,
+                ".config",
+            ),
+        )
         monkeypatch.setenv("XDG_CACHE_HOME", os.path.join(home_dir, ".cache"))
-        monkeypatch.setenv("XDG_RUNTIME_DIR", os.path.join(
-            home_dir, ".runtime",
-        ))
-        monkeypatch.setenv("XDG_DATA_DIRS", os.pathsep.join([
-            os.path.join(fake_root, "usr", "local", "share"),
-            os.path.join(fake_root, "usr", "share"),
-        ]))
-        monkeypatch.setenv("XDG_CONFIG_DIRS", os.path.join(
-            fake_root, "etc", "xdg",
-        ))
+        monkeypatch.setenv(
+            "XDG_RUNTIME_DIR",
+            os.path.join(
+                home_dir,
+                ".runtime",
+            ),
+        )
+        monkeypatch.setenv(
+            "XDG_DATA_DIRS",
+            os.pathsep.join(
+                [
+                    os.path.join(fake_root, "usr", "local", "share"),
+                    os.path.join(fake_root, "usr", "share"),
+                ]
+            ),
+        )
+        monkeypatch.setenv(
+            "XDG_CONFIG_DIRS",
+            os.path.join(
+                fake_root,
+                "etc",
+                "xdg",
+            ),
+        )
 
     # Configure git, because without an author name/email git will complain
     # and cause test failures.
@@ -228,9 +253,7 @@ def isolate(tmpdir, monkeypatch):
     # FIXME: Windows...
     os.makedirs(os.path.join(home_dir, ".config", "git"))
     with open(os.path.join(home_dir, ".config", "git", "config"), "wb") as fp:
-        fp.write(
-            b"[user]\n\tname = pip\n\temail = distutils-sig@python.org\n"
-        )
+        fp.write(b"[user]\n\tname = pip\n\temail = distutils-sig@python.org\n")
 
 
 @pytest.fixture(autouse=True)
@@ -249,7 +272,7 @@ def scoped_global_tempdir_manager(request):
         yield
 
 
-@pytest.fixture(scope='session')
+@pytest.fixture(scope="session")
 def pip_src(tmpdir_factory):
     def not_code_files_and_folders(path, names):
         # In the root directory...
@@ -269,7 +292,7 @@ def not_code_files_and_folders(path, names):
             ignored.update(fnmatch.filter(names, pattern))
         return ignored
 
-    pip_src = Path(str(tmpdir_factory.mktemp('pip_src'))).joinpath('pip_src')
+    pip_src = Path(str(tmpdir_factory.mktemp("pip_src"))).joinpath("pip_src")
     # Copy over our source tree so that each use is self contained
     shutil.copytree(
         SRC_DIR,
@@ -280,83 +303,79 @@ def not_code_files_and_folders(path, names):
 
 
 def _common_wheel_editable_install(tmpdir_factory, common_wheels, package):
-    wheel_candidates = list(
-        common_wheels.glob('{package}-*.whl'.format(**locals())))
+    wheel_candidates = list(common_wheels.glob("{package}-*.whl".format(**locals())))
     assert len(wheel_candidates) == 1, wheel_candidates
-    install_dir = Path(str(tmpdir_factory.mktemp(package))) / 'install'
+    install_dir = Path(str(tmpdir_factory.mktemp(package))) / "install"
     Wheel(wheel_candidates[0]).install_as_egg(install_dir)
-    (install_dir / 'EGG-INFO').rename(
-        install_dir / '{package}.egg-info'.format(**locals()))
+    (install_dir / "EGG-INFO").rename(
+        install_dir / "{package}.egg-info".format(**locals())
+    )
     assert compileall.compile_dir(str(install_dir), quiet=1)
     return install_dir
 
 
-@pytest.fixture(scope='session')
+@pytest.fixture(scope="session")
 def setuptools_install(tmpdir_factory, common_wheels):
-    return _common_wheel_editable_install(tmpdir_factory,
-                                          common_wheels,
-                                          'setuptools')
+    return _common_wheel_editable_install(tmpdir_factory, common_wheels, "setuptools")
 
 
-@pytest.fixture(scope='session')
+@pytest.fixture(scope="session")
 def wheel_install(tmpdir_factory, common_wheels):
-    return _common_wheel_editable_install(tmpdir_factory,
-                                          common_wheels,
-                                          'wheel')
+    return _common_wheel_editable_install(tmpdir_factory, common_wheels, "wheel")
 
 
-@pytest.fixture(scope='session')
+@pytest.fixture(scope="session")
 def coverage_install(tmpdir_factory, common_wheels):
-    return _common_wheel_editable_install(tmpdir_factory,
-                                          common_wheels,
-                                          'coverage')
+    return _common_wheel_editable_install(tmpdir_factory, common_wheels, "coverage")
 
 
 def install_egg_link(venv, project_name, egg_info_dir):
-    with open(venv.site / 'easy-install.pth', 'a') as fp:
-        fp.write(str(egg_info_dir.resolve()) + '\n')
-    with open(venv.site / (project_name + '.egg-link'), 'w') as fp:
-        fp.write(str(egg_info_dir) + '\n.')
+    with open(venv.site / "easy-install.pth", "a") as fp:
+        fp.write(str(egg_info_dir.resolve()) + "\n")
+    with open(venv.site / (project_name + ".egg-link"), "w") as fp:
+        fp.write(str(egg_info_dir) + "\n.")
 
 
-@pytest.fixture(scope='session')
-def virtualenv_template(request, tmpdir_factory, pip_src,
-                        setuptools_install, coverage_install):
+@pytest.fixture(scope="session")
+def virtualenv_template(
+    request, tmpdir_factory, pip_src, setuptools_install, coverage_install
+):
 
-    if six.PY3 and request.config.getoption('--use-venv'):
-        venv_type = 'venv'
+    if six.PY3 and request.config.getoption("--use-venv"):
+        venv_type = "venv"
     else:
-        venv_type = 'virtualenv'
+        venv_type = "virtualenv"
 
     # Create the virtual environment
-    tmpdir = Path(str(tmpdir_factory.mktemp('virtualenv')))
-    venv = VirtualEnvironment(
-        tmpdir.joinpath("venv_orig"), venv_type=venv_type
-    )
+    tmpdir = Path(str(tmpdir_factory.mktemp("virtualenv")))
+    venv = VirtualEnvironment(tmpdir.joinpath("venv_orig"), venv_type=venv_type)
 
     # Install setuptools and pip.
-    install_egg_link(venv, 'setuptools', setuptools_install)
-    pip_editable = Path(str(tmpdir_factory.mktemp('pip'))) / 'pip'
+    install_egg_link(venv, "setuptools", setuptools_install)
+    pip_editable = Path(str(tmpdir_factory.mktemp("pip"))) / "pip"
     shutil.copytree(pip_src, pip_editable, symlinks=True)
     # noxfile.py is Python 3 only
     assert compileall.compile_dir(
-        str(pip_editable), quiet=1, rx=re.compile("noxfile.py$"),
+        str(pip_editable),
+        quiet=1,
+        rx=re.compile("noxfile.py$"),
+    )
+    subprocess.check_call(
+        [venv.bin / "python", "setup.py", "-q", "develop"], cwd=pip_editable
     )
-    subprocess.check_call([venv.bin / 'python', 'setup.py', '-q', 'develop'],
-                          cwd=pip_editable)
 
     # Install coverage and pth file for executing it in any spawned processes
     # in this virtual environment.
-    install_egg_link(venv, 'coverage', coverage_install)
+    install_egg_link(venv, "coverage", coverage_install)
     # zz prefix ensures the file is after easy-install.pth.
-    with open(venv.site / 'zz-coverage-helper.pth', 'a') as f:
-        f.write('import coverage; coverage.process_startup()')
+    with open(venv.site / "zz-coverage-helper.pth", "a") as f:
+        f.write("import coverage; coverage.process_startup()")
 
     # Drop (non-relocatable) launchers.
     for exe in os.listdir(venv.bin):
         if not (
-            exe.startswith('python') or
-            exe.startswith('libpy')  # Don't remove libpypy-c.so...
+            exe.startswith("python")
+            or exe.startswith("libpy")  # Don't remove libpypy-c.so...
         ):
             (venv.bin / exe).unlink()
 
@@ -391,7 +410,7 @@ def virtualenv(virtualenv_factory, tmpdir):
 
 @pytest.fixture
 def with_wheel(virtualenv, wheel_install):
-    install_egg_link(virtualenv, 'wheel', wheel_install)
+    install_egg_link(virtualenv, "wheel", wheel_install)
 
 
 @pytest.fixture(scope="session")
@@ -402,21 +421,16 @@ def factory(tmpdir, virtualenv=None):
         return PipTestEnvironment(
             # The base location for our test environment
             tmpdir,
-
             # Tell the Test Environment where our virtualenv is located
             virtualenv=virtualenv,
-
             # Do not ignore hidden files, they need to be checked as well
             ignore_hidden=False,
-
             # We are starting with an already empty directory
             start_clear=False,
-
             # We want to ensure no temporary files are left behind, so the
             # PipTestEnvironment needs to capture and assert against temp
             capture_temp=True,
             assert_no_temp=True,
-
             # Deprecated python versions produce an extra deprecation warning
             pip_expect_warning=deprecated_python,
         )
@@ -438,7 +452,7 @@ def script(tmpdir, virtualenv, script_factory):
 @pytest.fixture(scope="session")
 def common_wheels():
     """Provide a directory with latest setuptools and wheel wheels"""
-    return DATA_DIR.joinpath('common_wheels')
+    return DATA_DIR.joinpath("common_wheels")
 
 
 @pytest.fixture(scope="session")
@@ -489,8 +503,7 @@ def deprecated_python():
 def cert_factory(tmpdir_factory):
     def factory():
         # type: () -> str
-        """Returns path to cert/key file.
-        """
+        """Returns path to cert/key file."""
         output_path = Path(str(tmpdir_factory.mktemp("certs"))) / "cert.pem"
         # Must be Text on PY2.
         cert, key = make_tls_cert(u"localhost")
@@ -544,12 +557,9 @@ def stop(self):
 
     def get_requests(self):
         # type: () -> Dict[str, str]
-        """Get environ for each received request.
-        """
+        """Get environ for each received request."""
         assert not self._running, "cannot get mock from running server"
-        return [
-            call.args[0] for call in self._server.mock.call_args_list
-        ]
+        return [call.args[0] for call in self._server.mock.call_args_list]
 
 
 @pytest.fixture
@@ -563,8 +573,8 @@ def mock_server():
 @pytest.fixture
 def utc():
     # time.tzset() is not implemented on some platforms, e.g. Windows.
-    tzset = getattr(time, 'tzset', lambda: None)
-    with patch.dict(os.environ, {'TZ': 'UTC'}):
+    tzset = getattr(time, "tzset", lambda: None)
+    with patch.dict(os.environ, {"TZ": "UTC"}):
         tzset()
         yield
     tzset()
diff --git a/tests/data/packages/BrokenEmitsUTF8/setup.py b/tests/data/packages/BrokenEmitsUTF8/setup.py
index 81c5baeadba..a40bc60c18f 100644
--- a/tests/data/packages/BrokenEmitsUTF8/setup.py
+++ b/tests/data/packages/BrokenEmitsUTF8/setup.py
@@ -7,20 +7,32 @@
 class FakeError(Exception):
     pass
 
-if sys.argv[1] == 'install':
-    if hasattr(sys.stdout, 'buffer'):
-        sys.stdout.buffer.write('\nThis package prints out UTF-8 stuff like:\n'.encode('utf-8'))
-        sys.stdout.buffer.write('* return type of ‘main’ is not ‘int’\n'.encode('utf-8'))
-        sys.stdout.buffer.write('* Björk Guðmundsdóttir [ˈpjœr̥k ˈkv�ðm�ntsˌtoʊhtɪr]'.encode('utf-8'))
+
+if sys.argv[1] == "install":
+    if hasattr(sys.stdout, "buffer"):
+        sys.stdout.buffer.write(
+            "\nThis package prints out UTF-8 stuff like:\n".encode("utf-8")
+        )
+        sys.stdout.buffer.write(
+            "* return type of ‘main’ is not ‘int’\n".encode("utf-8")
+        )
+        sys.stdout.buffer.write(
+            "* Björk Guðmundsdóttir [ˈpjœr̥k ˈkv�ðm�ntsˌtoʊhtɪr]".encode("utf-8")
+        )
     else:
         pass
-        sys.stdout.write('\nThis package prints out UTF-8 stuff like:\n')
-        sys.stdout.write('* return type of \xe2\x80\x98main\xe2\x80\x99 is not \xe2\x80\x98int\xe2\x80\x99\n')
-        sys.stdout.write('* Bj\xc3\xb6rk Gu\xc3\xb0mundsd\xc3\xb3ttir [\xcb\x88pj\xc5\x93r\xcc\xa5k \xcb\x88kv\xca\x8f\xc3\xb0m\xca\x8fnts\xcb\x8cto\xca\x8aht\xc9\xaar]\n')
+        sys.stdout.write("\nThis package prints out UTF-8 stuff like:\n")
+        sys.stdout.write(
+            "* return type of \xe2\x80\x98main\xe2\x80\x99 is not \xe2\x80\x98int\xe2\x80\x99\n"
+        )
+        sys.stdout.write(
+            "* Bj\xc3\xb6rk Gu\xc3\xb0mundsd\xc3\xb3ttir [\xcb\x88pj\xc5\x93r\xcc\xa5k \xcb\x88kv\xca\x8f\xc3\xb0m\xca\x8fnts\xcb\x8cto\xca\x8aht\xc9\xaar]\n"
+        )
 
-    raise FakeError('this package designed to fail on install')
+    raise FakeError("this package designed to fail on install")
 
-setup(name='broken',
-      version='0.2',
-      py_modules=['broken'],
-      )
+setup(
+    name="broken",
+    version="0.2",
+    py_modules=["broken"],
+)
diff --git a/tests/data/packages/FSPkg/setup.py b/tests/data/packages/FSPkg/setup.py
index d1b725e8cc4..58a78413339 100644
--- a/tests/data/packages/FSPkg/setup.py
+++ b/tests/data/packages/FSPkg/setup.py
@@ -1,25 +1,26 @@
 from setuptools import find_packages, setup
 
-version = '0.1dev'
+version = "0.1dev"
 
-setup(name='FSPkg',
-      version=version,
-      description="File system test package",
-      long_description="""\
+setup(
+    name="FSPkg",
+    version=version,
+    description="File system test package",
+    long_description="""\
 File system test package""",
-      classifiers=[], # Get strings from https://pypi.org/pypi?%3Aaction=list_classifiers
-      keywords='pip tests',
-      author='pip',
-      author_email='pip@openplans.org',
-      url='http://pip.openplans.org',
-      license='',
-      packages=find_packages(exclude=['ez_setup', 'examples', 'tests']),
-      include_package_data=True,
-      zip_safe=False,
-      install_requires=[
-          # -*- Extra requirements: -*-
-      ],
-      entry_points="""
+    classifiers=[],  # Get strings from https://pypi.org/pypi?%3Aaction=list_classifiers
+    keywords="pip tests",
+    author="pip",
+    author_email="pip@openplans.org",
+    url="http://pip.openplans.org",
+    license="",
+    packages=find_packages(exclude=["ez_setup", "examples", "tests"]),
+    include_package_data=True,
+    zip_safe=False,
+    install_requires=[
+        # -*- Extra requirements: -*-
+    ],
+    entry_points="""
       # -*- Entry points: -*-
       """,
-      )
+)
diff --git a/tests/data/packages/HackedEggInfo/setup.py b/tests/data/packages/HackedEggInfo/setup.py
index 171f5a2a34b..36201f79e1d 100644
--- a/tests/data/packages/HackedEggInfo/setup.py
+++ b/tests/data/packages/HackedEggInfo/setup.py
@@ -4,14 +4,14 @@
 from setuptools.command import egg_info as orig_egg_info
 
 
-class egg_info (orig_egg_info.egg_info):
+class egg_info(orig_egg_info.egg_info):
     def run(self):
         orig_egg_info.egg_info.run(self)
 
 
 setup(
     name="hackedegginfo",
-    version='0.0.0',
-    cmdclass={'egg_info':egg_info},
+    version="0.0.0",
+    cmdclass={"egg_info": egg_info},
     zip_safe=False,
 )
diff --git a/tests/data/packages/LocalEnvironMarker/setup.py b/tests/data/packages/LocalEnvironMarker/setup.py
index 36ceb214cf7..0ab6c8a5719 100644
--- a/tests/data/packages/LocalEnvironMarker/setup.py
+++ b/tests/data/packages/LocalEnvironMarker/setup.py
@@ -11,17 +11,17 @@ def path_to_url(path):
     path = os.path.normpath(os.path.abspath(path))
     drive, path = os.path.splitdrive(path)
     filepath = path.split(os.path.sep)
-    url = '/'.join(filepath)
+    url = "/".join(filepath)
     if drive:
-        return 'file:///' + drive + url
-    return 'file://' + url
+        return "file:///" + drive + url
+    return "file://" + url
 
 
 setup(
-    name='LocalEnvironMarker',
-    version='0.0.1',
+    name="LocalEnvironMarker",
+    version="0.0.1",
     packages=find_packages(),
     extras_require={
-        ":python_version == '2.7'": ['simple'],
-    }
+        ":python_version == '2.7'": ["simple"],
+    },
 )
diff --git a/tests/data/packages/LocalExtras-0.0.2/setup.py b/tests/data/packages/LocalExtras-0.0.2/setup.py
index cc5c832837f..6e910d1cbb2 100644
--- a/tests/data/packages/LocalExtras-0.0.2/setup.py
+++ b/tests/data/packages/LocalExtras-0.0.2/setup.py
@@ -11,16 +11,16 @@ def path_to_url(path):
     path = os.path.normpath(os.path.abspath(path))
     drive, path = os.path.splitdrive(path)
     filepath = path.split(os.path.sep)
-    url = '/'.join(filepath)
+    url = "/".join(filepath)
     if drive:
-        return 'file:///' + drive + url
-    return 'file://' + url
+        return "file:///" + drive + url
+    return "file://" + url
 
 
 setup(
-    name='LocalExtras',
-    version='0.0.2',
+    name="LocalExtras",
+    version="0.0.2",
     packages=find_packages(),
-    install_requires=['simple==1.0'],
-    extras_require={'bar': ['simple==2.0'], 'baz': ['singlemodule']}
+    install_requires=["simple==1.0"],
+    extras_require={"bar": ["simple==2.0"], "baz": ["singlemodule"]},
 )
diff --git a/tests/data/packages/LocalExtras/setup.py b/tests/data/packages/LocalExtras/setup.py
index eb390e32e89..4bf2179da78 100644
--- a/tests/data/packages/LocalExtras/setup.py
+++ b/tests/data/packages/LocalExtras/setup.py
@@ -11,15 +11,15 @@ def path_to_url(path):
     path = os.path.normpath(os.path.abspath(path))
     drive, path = os.path.splitdrive(path)
     filepath = path.split(os.path.sep)
-    url = '/'.join(filepath)
+    url = "/".join(filepath)
     if drive:
-        return 'file:///' + drive + url
-    return 'file://' + url
+        return "file:///" + drive + url
+    return "file://" + url
 
 
 setup(
-    name='LocalExtras',
-    version='0.0.1',
+    name="LocalExtras",
+    version="0.0.1",
     packages=find_packages(),
-    extras_require={'bar': ['simple'], 'baz': ['singlemodule']}
+    extras_require={"bar": ["simple"], "baz": ["singlemodule"]},
 )
diff --git a/tests/data/packages/SetupPyLatin1/setup.py b/tests/data/packages/SetupPyLatin1/setup.py
index 3ca77c00c96..bc8967c5199 100644
--- a/tests/data/packages/SetupPyLatin1/setup.py
+++ b/tests/data/packages/SetupPyLatin1/setup.py
@@ -2,6 +2,7 @@
 
 from distutils.core import setup
 
-setup(name="SetupPyUTF8",
-      author=u"Saúl Ibarra Corretgé",
-      )
+setup(
+    name="SetupPyUTF8",
+    author=u"Saúl Ibarra Corretgé",
+)
diff --git a/tests/data/packages/SetupPyUTF8/setup.py b/tests/data/packages/SetupPyUTF8/setup.py
index 9b65f5e79fc..e32aa438c5f 100644
--- a/tests/data/packages/SetupPyUTF8/setup.py
+++ b/tests/data/packages/SetupPyUTF8/setup.py
@@ -2,6 +2,7 @@
 
 from distutils.core import setup
 
-setup(name="SetupPyUTF8",
-      author="Saúl Ibarra Corretgé",
-      )
+setup(
+    name="SetupPyUTF8",
+    author="Saúl Ibarra Corretgé",
+)
diff --git a/tests/data/packages/pep517_wrapper_buildsys/mybuildsys.py b/tests/data/packages/pep517_wrapper_buildsys/mybuildsys.py
index e2f920ba3f5..08645e8bd5b 100644
--- a/tests/data/packages/pep517_wrapper_buildsys/mybuildsys.py
+++ b/tests/data/packages/pep517_wrapper_buildsys/mybuildsys.py
@@ -2,9 +2,11 @@
 
 from setuptools.build_meta import build_sdist
 from setuptools.build_meta import build_wheel as setuptools_build_wheel
-from setuptools.build_meta import (get_requires_for_build_sdist,
-                                   get_requires_for_build_wheel,
-                                   prepare_metadata_for_build_wheel)
+from setuptools.build_meta import (
+    get_requires_for_build_sdist,
+    get_requires_for_build_wheel,
+    prepare_metadata_for_build_wheel,
+)
 
 
 def build_wheel(*a, **kw):
@@ -12,7 +14,7 @@ def build_wheel(*a, **kw):
         raise RuntimeError("Failing build_wheel, as requested.")
 
     # Create the marker file to record that the hook was called
-    with open(os.environ['PIP_TEST_MARKER_FILE'], 'wb'):
+    with open(os.environ["PIP_TEST_MARKER_FILE"], "wb"):
         pass
 
     return setuptools_build_wheel(*a, **kw)
diff --git a/tests/data/packages/requiresPaste/requiresPaste.py b/tests/data/packages/requiresPaste/requiresPaste.py
index c74209e44fe..84d4ed536d3 100644
--- a/tests/data/packages/requiresPaste/requiresPaste.py
+++ b/tests/data/packages/requiresPaste/requiresPaste.py
@@ -1,3 +1,3 @@
 """Module requiring Paste to test dependencies download of pip wheel."""
 
-__version__ = '3.1.4'
+__version__ = "3.1.4"
diff --git a/tests/data/packages/requires_wheelbroken_upper/setup.py b/tests/data/packages/requires_wheelbroken_upper/setup.py
index 150f98dfbf7..210b7c67ad8 100644
--- a/tests/data/packages/requires_wheelbroken_upper/setup.py
+++ b/tests/data/packages/requires_wheelbroken_upper/setup.py
@@ -3,4 +3,5 @@
 setuptools.setup(
     name="requires_wheelbroken_upper",
     version="0",
-    install_requires=['wheelbroken', 'upper'])
+    install_requires=["wheelbroken", "upper"],
+)
diff --git a/tests/data/packages/symlinks/setup.py b/tests/data/packages/symlinks/setup.py
index b71e35f1e1e..8605b6fae95 100644
--- a/tests/data/packages/symlinks/setup.py
+++ b/tests/data/packages/symlinks/setup.py
@@ -1,8 +1,9 @@
 from setuptools import setup
 
-version = '0.1'
+version = "0.1"
 
-setup(name='symlinks',
-      version=version,
-      packages=["symlinks"],
-      )
+setup(
+    name="symlinks",
+    version=version,
+    packages=["symlinks"],
+)
diff --git a/tests/data/src/TopoRequires/setup.py b/tests/data/src/TopoRequires/setup.py
index 6cd29a7b656..c4b1029f55c 100644
--- a/tests/data/src/TopoRequires/setup.py
+++ b/tests/data/src/TopoRequires/setup.py
@@ -1,7 +1,7 @@
 from setuptools import setup
 
 setup(
-    name='TopoRequires',
-    version='0.0.1',
-    packages=['toporequires'],
+    name="TopoRequires",
+    version="0.0.1",
+    packages=["toporequires"],
 )
diff --git a/tests/data/src/TopoRequires2/setup.py b/tests/data/src/TopoRequires2/setup.py
index 019f43cb231..11d009c4175 100644
--- a/tests/data/src/TopoRequires2/setup.py
+++ b/tests/data/src/TopoRequires2/setup.py
@@ -1,8 +1,8 @@
 from setuptools import setup
 
 setup(
-    name='TopoRequires2',
-    version='0.0.1',
-    packages=['toporequires2'],
-    install_requires=['TopoRequires'],
+    name="TopoRequires2",
+    version="0.0.1",
+    packages=["toporequires2"],
+    install_requires=["TopoRequires"],
 )
diff --git a/tests/data/src/TopoRequires3/setup.py b/tests/data/src/TopoRequires3/setup.py
index 772ed618e3c..550bb008eb9 100644
--- a/tests/data/src/TopoRequires3/setup.py
+++ b/tests/data/src/TopoRequires3/setup.py
@@ -1,8 +1,8 @@
 from setuptools import setup
 
 setup(
-    name='TopoRequires3',
-    version='0.0.1',
-    packages=['toporequires3'],
-    install_requires=['TopoRequires'],
+    name="TopoRequires3",
+    version="0.0.1",
+    packages=["toporequires3"],
+    install_requires=["TopoRequires"],
 )
diff --git a/tests/data/src/TopoRequires4/setup.py b/tests/data/src/TopoRequires4/setup.py
index e276f55a240..077eec765a5 100644
--- a/tests/data/src/TopoRequires4/setup.py
+++ b/tests/data/src/TopoRequires4/setup.py
@@ -1,8 +1,8 @@
 from setuptools import setup
 
 setup(
-    name='TopoRequires4',
-    version='0.0.1',
-    packages=['toporequires4'],
-    install_requires=['TopoRequires2', 'TopoRequires', 'TopoRequires3'],
+    name="TopoRequires4",
+    version="0.0.1",
+    packages=["toporequires4"],
+    install_requires=["TopoRequires2", "TopoRequires", "TopoRequires3"],
 )
diff --git a/tests/data/src/chattymodule/setup.py b/tests/data/src/chattymodule/setup.py
index 01d7720765f..62d0111234e 100644
--- a/tests/data/src/chattymodule/setup.py
+++ b/tests/data/src/chattymodule/setup.py
@@ -14,7 +14,7 @@
 
 setup(
     name="chattymodule",
-    version='0.0.1',
+    version="0.0.1",
     description="A sample Python project with a single module",
-    py_modules=['chattymodule'],
+    py_modules=["chattymodule"],
 )
diff --git a/tests/data/src/compilewheel/setup.py b/tests/data/src/compilewheel/setup.py
index 8319a2a5c20..da994945048 100644
--- a/tests/data/src/compilewheel/setup.py
+++ b/tests/data/src/compilewheel/setup.py
@@ -1,7 +1,4 @@
 #!/usr/bin/env python
 from setuptools import find_packages, setup
 
-setup(name='compilewheel',
-      version='1.0',
-      packages=find_packages()
-      )
+setup(name="compilewheel", version="1.0", packages=find_packages())
diff --git a/tests/data/src/extension/setup.py b/tests/data/src/extension/setup.py
index b26302b0536..83624965de5 100644
--- a/tests/data/src/extension/setup.py
+++ b/tests/data/src/extension/setup.py
@@ -1,4 +1,4 @@
 from setuptools import Extension, setup
 
-module = Extension('extension', sources=['extension.c'])
-setup(name='extension', version='0.0.1', ext_modules = [module])
+module = Extension("extension", sources=["extension.c"])
+setup(name="extension", version="0.0.1", ext_modules=[module])
diff --git a/tests/data/src/pep518-3.0/pep518.py b/tests/data/src/pep518-3.0/pep518.py
index 7986d11379a..9ce06a81ea4 100644
--- a/tests/data/src/pep518-3.0/pep518.py
+++ b/tests/data/src/pep518-3.0/pep518.py
@@ -1 +1 @@
-#dummy
+# dummy
diff --git a/tests/data/src/pep518-3.0/setup.py b/tests/data/src/pep518-3.0/setup.py
index b63f59926f7..587c04fc07d 100644
--- a/tests/data/src/pep518-3.0/setup.py
+++ b/tests/data/src/pep518-3.0/setup.py
@@ -3,7 +3,8 @@
 
 import simplewheel  # ensure dependency is installed
 
-setup(name='pep518',
-      version='3.0',
-      py_modules=['pep518'],
-      )
+setup(
+    name="pep518",
+    version="3.0",
+    py_modules=["pep518"],
+)
diff --git a/tests/data/src/pep518_conflicting_requires/pep518.py b/tests/data/src/pep518_conflicting_requires/pep518.py
index 7986d11379a..9ce06a81ea4 100644
--- a/tests/data/src/pep518_conflicting_requires/pep518.py
+++ b/tests/data/src/pep518_conflicting_requires/pep518.py
@@ -1 +1 @@
-#dummy
+# dummy
diff --git a/tests/data/src/pep518_conflicting_requires/setup.py b/tests/data/src/pep518_conflicting_requires/setup.py
index 34bdc16b5aa..28f3db53d6e 100644
--- a/tests/data/src/pep518_conflicting_requires/setup.py
+++ b/tests/data/src/pep518_conflicting_requires/setup.py
@@ -2,7 +2,7 @@
 from setuptools import setup
 
 setup(
-    name='pep518_conflicting_requires',
-    version='1.0.0',
-    py_modules=['pep518'],
+    name="pep518_conflicting_requires",
+    version="1.0.0",
+    py_modules=["pep518"],
 )
diff --git a/tests/data/src/pep518_forkbomb-235/setup.py b/tests/data/src/pep518_forkbomb-235/setup.py
index c8bc29287c9..f69346cac82 100644
--- a/tests/data/src/pep518_forkbomb-235/setup.py
+++ b/tests/data/src/pep518_forkbomb-235/setup.py
@@ -1,5 +1,3 @@
 from setuptools import setup
 
-setup(name='pep518_forkbomb',
-      version='235',
-      py_modules=['pep518_forkbomb'])
+setup(name="pep518_forkbomb", version="235", py_modules=["pep518_forkbomb"])
diff --git a/tests/data/src/pep518_invalid_build_system/pep518.py b/tests/data/src/pep518_invalid_build_system/pep518.py
index 7986d11379a..9ce06a81ea4 100644
--- a/tests/data/src/pep518_invalid_build_system/pep518.py
+++ b/tests/data/src/pep518_invalid_build_system/pep518.py
@@ -1 +1 @@
-#dummy
+# dummy
diff --git a/tests/data/src/pep518_invalid_build_system/setup.py b/tests/data/src/pep518_invalid_build_system/setup.py
index ba23cf24ab2..de4161d3a04 100644
--- a/tests/data/src/pep518_invalid_build_system/setup.py
+++ b/tests/data/src/pep518_invalid_build_system/setup.py
@@ -2,7 +2,7 @@
 from setuptools import setup
 
 setup(
-    name='pep518_invalid_build_system',
-    version='1.0.0',
-    py_modules=['pep518'],
+    name="pep518_invalid_build_system",
+    version="1.0.0",
+    py_modules=["pep518"],
 )
diff --git a/tests/data/src/pep518_invalid_requires/pep518.py b/tests/data/src/pep518_invalid_requires/pep518.py
index 7986d11379a..9ce06a81ea4 100644
--- a/tests/data/src/pep518_invalid_requires/pep518.py
+++ b/tests/data/src/pep518_invalid_requires/pep518.py
@@ -1 +1 @@
-#dummy
+# dummy
diff --git a/tests/data/src/pep518_invalid_requires/setup.py b/tests/data/src/pep518_invalid_requires/setup.py
index e8a92da312a..ff6ac8b324d 100644
--- a/tests/data/src/pep518_invalid_requires/setup.py
+++ b/tests/data/src/pep518_invalid_requires/setup.py
@@ -2,7 +2,7 @@
 from setuptools import setup
 
 setup(
-    name='pep518_invalid_requires',
-    version='1.0.0',
-    py_modules=['pep518'],
+    name="pep518_invalid_requires",
+    version="1.0.0",
+    py_modules=["pep518"],
 )
diff --git a/tests/data/src/pep518_missing_requires/pep518.py b/tests/data/src/pep518_missing_requires/pep518.py
index 7986d11379a..9ce06a81ea4 100644
--- a/tests/data/src/pep518_missing_requires/pep518.py
+++ b/tests/data/src/pep518_missing_requires/pep518.py
@@ -1 +1 @@
-#dummy
+# dummy
diff --git a/tests/data/src/pep518_missing_requires/setup.py b/tests/data/src/pep518_missing_requires/setup.py
index cbc5d28af04..4d3c5f3e5f4 100644
--- a/tests/data/src/pep518_missing_requires/setup.py
+++ b/tests/data/src/pep518_missing_requires/setup.py
@@ -2,7 +2,7 @@
 from setuptools import setup
 
 setup(
-    name='pep518_missing_requires',
-    version='1.0.0',
-    py_modules=['pep518'],
+    name="pep518_missing_requires",
+    version="1.0.0",
+    py_modules=["pep518"],
 )
diff --git a/tests/data/src/pep518_twin_forkbombs_first-234/setup.py b/tests/data/src/pep518_twin_forkbombs_first-234/setup.py
index 55e9bbfb17d..acb97e18efc 100644
--- a/tests/data/src/pep518_twin_forkbombs_first-234/setup.py
+++ b/tests/data/src/pep518_twin_forkbombs_first-234/setup.py
@@ -1,5 +1,7 @@
 from setuptools import setup
 
-setup(name='pep518_twin_forkbombs_first',
-      version='234',
-      py_modules=['pep518_twin_forkbombs_first'])
+setup(
+    name="pep518_twin_forkbombs_first",
+    version="234",
+    py_modules=["pep518_twin_forkbombs_first"],
+)
diff --git a/tests/data/src/pep518_twin_forkbombs_second-238/setup.py b/tests/data/src/pep518_twin_forkbombs_second-238/setup.py
index 985af51df82..c14c1cfb025 100644
--- a/tests/data/src/pep518_twin_forkbombs_second-238/setup.py
+++ b/tests/data/src/pep518_twin_forkbombs_second-238/setup.py
@@ -1,5 +1,7 @@
 from setuptools import setup
 
-setup(name='pep518_twin_forkbombs_second',
-      version='238',
-      py_modules=['pep518_twin_forkbombs_second'])
+setup(
+    name="pep518_twin_forkbombs_second",
+    version="238",
+    py_modules=["pep518_twin_forkbombs_second"],
+)
diff --git a/tests/data/src/pep518_with_extra_and_markers-1.0/pep518_with_extra_and_markers.py b/tests/data/src/pep518_with_extra_and_markers-1.0/pep518_with_extra_and_markers.py
index 7986d11379a..9ce06a81ea4 100644
--- a/tests/data/src/pep518_with_extra_and_markers-1.0/pep518_with_extra_and_markers.py
+++ b/tests/data/src/pep518_with_extra_and_markers-1.0/pep518_with_extra_and_markers.py
@@ -1 +1 @@
-#dummy
+# dummy
diff --git a/tests/data/src/pep518_with_extra_and_markers-1.0/setup.py b/tests/data/src/pep518_with_extra_and_markers-1.0/setup.py
index 29a8175e4d1..08e6eceac1b 100644
--- a/tests/data/src/pep518_with_extra_and_markers-1.0/setup.py
+++ b/tests/data/src/pep518_with_extra_and_markers-1.0/setup.py
@@ -7,9 +7,10 @@
 import simple
 import simplewheel
 
-assert simplewheel.__version__ == '1.0' if sys.version_info < (3,) else '2.0'
+assert simplewheel.__version__ == "1.0" if sys.version_info < (3,) else "2.0"
 
-setup(name='pep518_with_extra_and_markers',
-      version='1.0',
-      py_modules=['pep518_with_extra_and_markers'],
-      )
+setup(
+    name="pep518_with_extra_and_markers",
+    version="1.0",
+    py_modules=["pep518_with_extra_and_markers"],
+)
diff --git a/tests/data/src/pep518_with_namespace_package-1.0/setup.py b/tests/data/src/pep518_with_namespace_package-1.0/setup.py
index 540ede4cf43..263ba19880e 100644
--- a/tests/data/src/pep518_with_namespace_package-1.0/setup.py
+++ b/tests/data/src/pep518_with_namespace_package-1.0/setup.py
@@ -3,7 +3,7 @@
 import simple_namespace.module
 
 setup(
-    name='pep518_with_namespace_package',
-    version='1.0',
-    py_modules=['pep518_with_namespace_package'],
+    name="pep518_with_namespace_package",
+    version="1.0",
+    py_modules=["pep518_with_namespace_package"],
 )
diff --git a/tests/data/src/prjwithdatafile/setup.py b/tests/data/src/prjwithdatafile/setup.py
index 94863b57b01..5ed643c96ce 100755
--- a/tests/data/src/prjwithdatafile/setup.py
+++ b/tests/data/src/prjwithdatafile/setup.py
@@ -2,11 +2,11 @@
 from setuptools import setup
 
 setup(
-    name='prjwithdatafile',
+    name="prjwithdatafile",
     version="1.0",
-    packages=['prjwithdatafile'],
+    packages=["prjwithdatafile"],
     data_files=[
-        (r'packages1', ['prjwithdatafile/README.txt']),
-        (r'packages2', ['prjwithdatafile/README.txt'])
-    ]
+        (r"packages1", ["prjwithdatafile/README.txt"]),
+        (r"packages2", ["prjwithdatafile/README.txt"]),
+    ],
 )
diff --git a/tests/data/src/requires_capitalized/setup.py b/tests/data/src/requires_capitalized/setup.py
index b3f37b919a6..287704f8628 100644
--- a/tests/data/src/requires_capitalized/setup.py
+++ b/tests/data/src/requires_capitalized/setup.py
@@ -1,6 +1,3 @@
 from setuptools import setup
 
-setup(name='Requires_Capitalized',
-      version='0.1',
-      install_requires=['simple==1.0']
-      )
+setup(name="Requires_Capitalized", version="0.1", install_requires=["simple==1.0"])
diff --git a/tests/data/src/requires_requires_capitalized/setup.py b/tests/data/src/requires_requires_capitalized/setup.py
index d124d072846..8d099fddd21 100644
--- a/tests/data/src/requires_requires_capitalized/setup.py
+++ b/tests/data/src/requires_requires_capitalized/setup.py
@@ -1,6 +1,7 @@
 from setuptools import setup
 
-setup(name='requires_requires_capitalized',
-      version='1.0',
-      install_requires=['requires_Capitalized==0.1']
-      )
+setup(
+    name="requires_requires_capitalized",
+    version="1.0",
+    install_requires=["requires_Capitalized==0.1"],
+)
diff --git a/tests/data/src/requires_simple/setup.py b/tests/data/src/requires_simple/setup.py
index 57122041aed..5eebde770d2 100644
--- a/tests/data/src/requires_simple/setup.py
+++ b/tests/data/src/requires_simple/setup.py
@@ -1,6 +1,3 @@
 from setuptools import find_packages, setup
 
-setup(name='requires_simple',
-      version='0.1',
-      install_requires=['simple==1.0']
-      )
+setup(name="requires_simple", version="0.1", install_requires=["simple==1.0"])
diff --git a/tests/data/src/requires_simple_extra/setup.py b/tests/data/src/requires_simple_extra/setup.py
index 3378c2ce7d1..5562ebc9541 100644
--- a/tests/data/src/requires_simple_extra/setup.py
+++ b/tests/data/src/requires_simple_extra/setup.py
@@ -1,9 +1,8 @@
 from setuptools import setup
 
-setup(name='requires_simple_extra',
-      version='0.1',
-      py_modules=['requires_simple_extra'],
-      extras_require={
-          'extra': ['simple==1.0']
-      }
+setup(
+    name="requires_simple_extra",
+    version="0.1",
+    py_modules=["requires_simple_extra"],
+    extras_require={"extra": ["simple==1.0"]},
 )
diff --git a/tests/data/src/simple_namespace/setup.py b/tests/data/src/simple_namespace/setup.py
index 9a49d52b757..c6b5978641c 100644
--- a/tests/data/src/simple_namespace/setup.py
+++ b/tests/data/src/simple_namespace/setup.py
@@ -1,8 +1,8 @@
 from setuptools import setup
 
 setup(
-    name='simple_namespace',
-    version='1.0',
-    namespace_packages=['simple_namespace'],
-    packages=['simple_namespace.module'],
+    name="simple_namespace",
+    version="1.0",
+    namespace_packages=["simple_namespace"],
+    packages=["simple_namespace.module"],
 )
diff --git a/tests/data/src/simplewheel-1.0/setup.py b/tests/data/src/simplewheel-1.0/setup.py
index 461536dce68..28ee850cd48 100644
--- a/tests/data/src/simplewheel-1.0/setup.py
+++ b/tests/data/src/simplewheel-1.0/setup.py
@@ -3,7 +3,8 @@
 
 import simplewheel
 
-setup(name='simplewheel',
-      version=simplewheel.__version__,
-      packages=['simplewheel'],
-      )
+setup(
+    name="simplewheel",
+    version=simplewheel.__version__,
+    packages=["simplewheel"],
+)
diff --git a/tests/data/src/simplewheel-1.0/simplewheel/__init__.py b/tests/data/src/simplewheel-1.0/simplewheel/__init__.py
index 7e49527e386..4802e90f8ed 100644
--- a/tests/data/src/simplewheel-1.0/simplewheel/__init__.py
+++ b/tests/data/src/simplewheel-1.0/simplewheel/__init__.py
@@ -1 +1 @@
-__version__ = '1.0'
+__version__ = "1.0"
diff --git a/tests/data/src/simplewheel-2.0/setup.py b/tests/data/src/simplewheel-2.0/setup.py
index 461536dce68..28ee850cd48 100644
--- a/tests/data/src/simplewheel-2.0/setup.py
+++ b/tests/data/src/simplewheel-2.0/setup.py
@@ -3,7 +3,8 @@
 
 import simplewheel
 
-setup(name='simplewheel',
-      version=simplewheel.__version__,
-      packages=['simplewheel'],
-      )
+setup(
+    name="simplewheel",
+    version=simplewheel.__version__,
+    packages=["simplewheel"],
+)
diff --git a/tests/data/src/simplewheel-2.0/simplewheel/__init__.py b/tests/data/src/simplewheel-2.0/simplewheel/__init__.py
index 3b3dacb9af5..f2dc0e40061 100644
--- a/tests/data/src/simplewheel-2.0/simplewheel/__init__.py
+++ b/tests/data/src/simplewheel-2.0/simplewheel/__init__.py
@@ -1 +1 @@
-__version__ = '2.0'
+__version__ = "2.0"
diff --git a/tests/data/src/singlemodule/setup.py b/tests/data/src/singlemodule/setup.py
index 622af1f8e99..e6358e2f7ca 100644
--- a/tests/data/src/singlemodule/setup.py
+++ b/tests/data/src/singlemodule/setup.py
@@ -2,7 +2,7 @@
 
 setup(
     name="singlemodule",
-    version='0.0.1',
+    version="0.0.1",
     description="A sample Python project with a single module",
-    py_modules=['singlemodule'],
+    py_modules=["singlemodule"],
 )
diff --git a/tests/data/src/withpyproject/setup.py b/tests/data/src/withpyproject/setup.py
index 1ea9e3e41c5..af10b3e3f37 100644
--- a/tests/data/src/withpyproject/setup.py
+++ b/tests/data/src/withpyproject/setup.py
@@ -1,3 +1,3 @@
 from setuptools import setup
 
-setup(name='withpyproject', version='0.0.1')
+setup(name="withpyproject", version="0.0.1")
diff --git a/tests/functional/test_broken_stdout.py b/tests/functional/test_broken_stdout.py
index cb98e31f017..c154566a005 100644
--- a/tests/functional/test_broken_stdout.py
+++ b/tests/functional/test_broken_stdout.py
@@ -12,14 +12,16 @@
 
 def setup_broken_stdout_test(args, deprecated_python):
     proc = subprocess.Popen(
-        args, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+        args,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
     )
     # Call close() on stdout to cause a broken pipe.
     proc.stdout.close()
     returncode = proc.wait()
-    stderr = proc.stderr.read().decode('utf-8')
+    stderr = proc.stderr.read().decode("utf-8")
 
-    expected_msg = 'ERROR: Pipe to stdout was broken'
+    expected_msg = "ERROR: Pipe to stdout was broken"
     if deprecated_python:
         assert expected_msg in stderr
     else:
@@ -33,12 +35,13 @@ def test_broken_stdout_pipe(deprecated_python):
     Test a broken pipe to stdout.
     """
     stderr, returncode = setup_broken_stdout_test(
-        ['pip', 'list'], deprecated_python=deprecated_python,
+        ["pip", "list"],
+        deprecated_python=deprecated_python,
     )
 
     # Check that no traceback occurs.
-    assert 'raise BrokenStdoutLoggingError()' not in stderr
-    assert stderr.count('Traceback') == 0
+    assert "raise BrokenStdoutLoggingError()" not in stderr
+    assert stderr.count("Traceback") == 0
 
     assert returncode == _BROKEN_STDOUT_RETURN_CODE
 
@@ -47,15 +50,15 @@ def test_broken_stdout_pipe__log_option(deprecated_python, tmpdir):
     """
     Test a broken pipe to stdout when --log is passed.
     """
-    log_path = os.path.join(str(tmpdir), 'log.txt')
+    log_path = os.path.join(str(tmpdir), "log.txt")
     stderr, returncode = setup_broken_stdout_test(
-        ['pip', '--log', log_path, 'list'],
+        ["pip", "--log", log_path, "list"],
         deprecated_python=deprecated_python,
     )
 
     # Check that no traceback occurs.
-    assert 'raise BrokenStdoutLoggingError()' not in stderr
-    assert stderr.count('Traceback') == 0
+    assert "raise BrokenStdoutLoggingError()" not in stderr
+    assert stderr.count("Traceback") == 0
 
     assert returncode == _BROKEN_STDOUT_RETURN_CODE
 
@@ -65,12 +68,13 @@ def test_broken_stdout_pipe__verbose(deprecated_python):
     Test a broken pipe to stdout with verbose logging enabled.
     """
     stderr, returncode = setup_broken_stdout_test(
-        ['pip', '-v', 'list'], deprecated_python=deprecated_python,
+        ["pip", "-v", "list"],
+        deprecated_python=deprecated_python,
     )
 
     # Check that a traceback occurs and that it occurs at most once.
     # We permit up to two because the exception can be chained.
-    assert 'raise BrokenStdoutLoggingError()' in stderr
-    assert 1 <= stderr.count('Traceback') <= 2
+    assert "raise BrokenStdoutLoggingError()" in stderr
+    assert 1 <= stderr.count("Traceback") <= 2
 
     assert returncode == _BROKEN_STDOUT_RETURN_CODE
diff --git a/tests/functional/test_cache.py b/tests/functional/test_cache.py
index 603e11b5b0e..3d158998708 100644
--- a/tests/functional/test_cache.py
+++ b/tests/functional/test_cache.py
@@ -8,26 +8,26 @@
 @pytest.fixture
 def cache_dir(script):
     result = script.run(
-        'python', '-c',
-        'from pip._internal.locations import USER_CACHE_DIR;'
-        'print(USER_CACHE_DIR)'
+        "python",
+        "-c",
+        "from pip._internal.locations import USER_CACHE_DIR;" "print(USER_CACHE_DIR)",
     )
     return result.stdout.strip()
 
 
 @pytest.fixture
 def wheel_cache_dir(cache_dir):
-    return os.path.normcase(os.path.join(cache_dir, 'wheels'))
+    return os.path.normcase(os.path.join(cache_dir, "wheels"))
 
 
 @pytest.fixture
 def wheel_cache_files(wheel_cache_dir):
-    destination = os.path.join(wheel_cache_dir, 'arbitrary', 'pathname')
+    destination = os.path.join(wheel_cache_dir, "arbitrary", "pathname")
 
     if not os.path.exists(destination):
         return []
 
-    filenames = glob(os.path.join(destination, '*.whl'))
+    filenames = glob(os.path.join(destination, "*.whl"))
     files = []
     for filename in filenames:
         files.append(os.path.join(destination, filename))
@@ -36,18 +36,18 @@ def wheel_cache_files(wheel_cache_dir):
 
 @pytest.fixture
 def populate_wheel_cache(wheel_cache_dir):
-    destination = os.path.join(wheel_cache_dir, 'arbitrary', 'pathname')
+    destination = os.path.join(wheel_cache_dir, "arbitrary", "pathname")
     os.makedirs(destination)
 
     files = [
-        ('yyy-1.2.3', os.path.join(destination, 'yyy-1.2.3-py3-none-any.whl')),
-        ('zzz-4.5.6', os.path.join(destination, 'zzz-4.5.6-py3-none-any.whl')),
-        ('zzz-4.5.7', os.path.join(destination, 'zzz-4.5.7-py3-none-any.whl')),
-        ('zzz-7.8.9', os.path.join(destination, 'zzz-7.8.9-py3-none-any.whl')),
+        ("yyy-1.2.3", os.path.join(destination, "yyy-1.2.3-py3-none-any.whl")),
+        ("zzz-4.5.6", os.path.join(destination, "zzz-4.5.6-py3-none-any.whl")),
+        ("zzz-4.5.7", os.path.join(destination, "zzz-4.5.7-py3-none-any.whl")),
+        ("zzz-7.8.9", os.path.join(destination, "zzz-7.8.9-py3-none-any.whl")),
     ]
 
     for _name, filename in files:
-        with open(filename, 'w'):
+        with open(filename, "w"):
             pass
 
     return files
@@ -66,7 +66,7 @@ def list_matches_wheel(wheel_name, result):
     E.g., If wheel_name is `foo-1.2.3` it searches for a line starting with
           `- foo-1.2.3-py3-none-any.whl `."""
     lines = result.stdout.splitlines()
-    expected = ' - {}-py3-none-any.whl '.format(wheel_name)
+    expected = " - {}-py3-none-any.whl ".format(wheel_name)
     return any(map(lambda l: l.startswith(expected), lines))
 
 
@@ -78,9 +78,13 @@ def list_matches_wheel_abspath(wheel_name, result):
     E.g., If wheel_name is `foo-1.2.3` it searches for a line starting with
           `foo-1.2.3-py3-none-any.whl`."""
     lines = result.stdout.splitlines()
-    expected = '{}-py3-none-any.whl'.format(wheel_name)
-    return any(map(lambda l: os.path.basename(l).startswith(expected)
-               and os.path.exists(l), lines))
+    expected = "{}-py3-none-any.whl".format(wheel_name)
+    return any(
+        map(
+            lambda l: os.path.basename(l).startswith(expected) and os.path.exists(l),
+            lines,
+        )
+    )
 
 
 @pytest.fixture
@@ -95,73 +99,76 @@ def remove_matches_wheel(wheel_cache_dir):
     def _remove_matches_wheel(wheel_name, result):
         lines = result.stdout.splitlines()
 
-        wheel_filename = '{}-py3-none-any.whl'.format(wheel_name)
+        wheel_filename = "{}-py3-none-any.whl".format(wheel_name)
 
         # The "/arbitrary/pathname/" bit is an implementation detail of how
         # the `populate_wheel_cache` fixture is implemented.
         path = os.path.join(
-            wheel_cache_dir, 'arbitrary', 'pathname', wheel_filename,
+            wheel_cache_dir,
+            "arbitrary",
+            "pathname",
+            wheel_filename,
         )
-        expected = 'Removed {}'.format(path)
+        expected = "Removed {}".format(path)
         return expected in lines
 
     return _remove_matches_wheel
 
 
 def test_cache_dir(script, cache_dir):
-    result = script.pip('cache', 'dir')
+    result = script.pip("cache", "dir")
 
     assert os.path.normcase(cache_dir) == result.stdout.strip()
 
 
 def test_cache_dir_too_many_args(script, cache_dir):
-    result = script.pip('cache', 'dir', 'aaa', expect_error=True)
+    result = script.pip("cache", "dir", "aaa", expect_error=True)
 
-    assert result.stdout == ''
+    assert result.stdout == ""
 
     # This would be `result.stderr == ...`, but pip prints deprecation
     # warnings on Python 2.7, so we check if the _line_ is in stderr.
-    assert 'ERROR: Too many arguments' in result.stderr.splitlines()
+    assert "ERROR: Too many arguments" in result.stderr.splitlines()
 
 
 @pytest.mark.usefixtures("populate_wheel_cache")
 def test_cache_info(script, wheel_cache_dir, wheel_cache_files):
-    result = script.pip('cache', 'info')
+    result = script.pip("cache", "info")
 
-    assert 'Location: {}'.format(wheel_cache_dir) in result.stdout
+    assert "Location: {}".format(wheel_cache_dir) in result.stdout
     num_wheels = len(wheel_cache_files)
-    assert 'Number of wheels: {}'.format(num_wheels) in result.stdout
+    assert "Number of wheels: {}".format(num_wheels) in result.stdout
 
 
 @pytest.mark.usefixtures("populate_wheel_cache")
 def test_cache_list(script):
     """Running `pip cache list` should return exactly what the
     populate_wheel_cache fixture adds."""
-    result = script.pip('cache', 'list')
+    result = script.pip("cache", "list")
 
-    assert list_matches_wheel('yyy-1.2.3', result)
-    assert list_matches_wheel('zzz-4.5.6', result)
-    assert list_matches_wheel('zzz-4.5.7', result)
-    assert list_matches_wheel('zzz-7.8.9', result)
+    assert list_matches_wheel("yyy-1.2.3", result)
+    assert list_matches_wheel("zzz-4.5.6", result)
+    assert list_matches_wheel("zzz-4.5.7", result)
+    assert list_matches_wheel("zzz-7.8.9", result)
 
 
 @pytest.mark.usefixtures("populate_wheel_cache")
 def test_cache_list_abspath(script):
     """Running `pip cache list --format=abspath` should return full
     paths of exactly what the populate_wheel_cache fixture adds."""
-    result = script.pip('cache', 'list', '--format=abspath')
+    result = script.pip("cache", "list", "--format=abspath")
 
-    assert list_matches_wheel_abspath('yyy-1.2.3', result)
-    assert list_matches_wheel_abspath('zzz-4.5.6', result)
-    assert list_matches_wheel_abspath('zzz-4.5.7', result)
-    assert list_matches_wheel_abspath('zzz-7.8.9', result)
+    assert list_matches_wheel_abspath("yyy-1.2.3", result)
+    assert list_matches_wheel_abspath("zzz-4.5.6", result)
+    assert list_matches_wheel_abspath("zzz-4.5.7", result)
+    assert list_matches_wheel_abspath("zzz-7.8.9", result)
 
 
 @pytest.mark.usefixtures("empty_wheel_cache")
 def test_cache_list_with_empty_cache(script):
     """Running `pip cache list` with an empty cache should print
     "Nothing cached." and exit."""
-    result = script.pip('cache', 'list')
+    result = script.pip("cache", "list")
     assert result.stdout == "Nothing cached.\n"
 
 
@@ -169,124 +176,119 @@ def test_cache_list_with_empty_cache(script):
 def test_cache_list_with_empty_cache_abspath(script):
     """Running `pip cache list --format=abspath` with an empty cache should not
     print anything and exit."""
-    result = script.pip('cache', 'list', '--format=abspath')
+    result = script.pip("cache", "list", "--format=abspath")
     assert result.stdout.strip() == ""
 
 
 def test_cache_list_too_many_args(script):
     """Passing `pip cache list` too many arguments should cause an error."""
-    script.pip('cache', 'list', 'aaa', 'bbb',
-               expect_error=True)
+    script.pip("cache", "list", "aaa", "bbb", expect_error=True)
 
 
 @pytest.mark.usefixtures("populate_wheel_cache")
 def test_cache_list_name_match(script):
     """Running `pip cache list zzz` should list zzz-4.5.6, zzz-4.5.7,
     zzz-7.8.9, but nothing else."""
-    result = script.pip('cache', 'list', 'zzz', '--verbose')
+    result = script.pip("cache", "list", "zzz", "--verbose")
 
-    assert not list_matches_wheel('yyy-1.2.3', result)
-    assert list_matches_wheel('zzz-4.5.6', result)
-    assert list_matches_wheel('zzz-4.5.7', result)
-    assert list_matches_wheel('zzz-7.8.9', result)
+    assert not list_matches_wheel("yyy-1.2.3", result)
+    assert list_matches_wheel("zzz-4.5.6", result)
+    assert list_matches_wheel("zzz-4.5.7", result)
+    assert list_matches_wheel("zzz-7.8.9", result)
 
 
 @pytest.mark.usefixtures("populate_wheel_cache")
 def test_cache_list_name_match_abspath(script):
     """Running `pip cache list zzz --format=abspath` should list paths of
     zzz-4.5.6, zzz-4.5.7, zzz-7.8.9, but nothing else."""
-    result = script.pip('cache', 'list', 'zzz', '--format=abspath',
-                        '--verbose')
+    result = script.pip("cache", "list", "zzz", "--format=abspath", "--verbose")
 
-    assert not list_matches_wheel_abspath('yyy-1.2.3', result)
-    assert list_matches_wheel_abspath('zzz-4.5.6', result)
-    assert list_matches_wheel_abspath('zzz-4.5.7', result)
-    assert list_matches_wheel_abspath('zzz-7.8.9', result)
+    assert not list_matches_wheel_abspath("yyy-1.2.3", result)
+    assert list_matches_wheel_abspath("zzz-4.5.6", result)
+    assert list_matches_wheel_abspath("zzz-4.5.7", result)
+    assert list_matches_wheel_abspath("zzz-7.8.9", result)
 
 
 @pytest.mark.usefixtures("populate_wheel_cache")
 def test_cache_list_name_and_version_match(script):
     """Running `pip cache list zzz-4.5.6` should list zzz-4.5.6, but
     nothing else."""
-    result = script.pip('cache', 'list', 'zzz-4.5.6', '--verbose')
+    result = script.pip("cache", "list", "zzz-4.5.6", "--verbose")
 
-    assert not list_matches_wheel('yyy-1.2.3', result)
-    assert list_matches_wheel('zzz-4.5.6', result)
-    assert not list_matches_wheel('zzz-4.5.7', result)
-    assert not list_matches_wheel('zzz-7.8.9', result)
+    assert not list_matches_wheel("yyy-1.2.3", result)
+    assert list_matches_wheel("zzz-4.5.6", result)
+    assert not list_matches_wheel("zzz-4.5.7", result)
+    assert not list_matches_wheel("zzz-7.8.9", result)
 
 
 @pytest.mark.usefixtures("populate_wheel_cache")
 def test_cache_list_name_and_version_match_abspath(script):
     """Running `pip cache list zzz-4.5.6 --format=abspath` should list path of
     zzz-4.5.6, but nothing else."""
-    result = script.pip('cache', 'list', 'zzz-4.5.6', '--format=abspath',
-                        '--verbose')
+    result = script.pip("cache", "list", "zzz-4.5.6", "--format=abspath", "--verbose")
 
-    assert not list_matches_wheel_abspath('yyy-1.2.3', result)
-    assert list_matches_wheel_abspath('zzz-4.5.6', result)
-    assert not list_matches_wheel_abspath('zzz-4.5.7', result)
-    assert not list_matches_wheel_abspath('zzz-7.8.9', result)
+    assert not list_matches_wheel_abspath("yyy-1.2.3", result)
+    assert list_matches_wheel_abspath("zzz-4.5.6", result)
+    assert not list_matches_wheel_abspath("zzz-4.5.7", result)
+    assert not list_matches_wheel_abspath("zzz-7.8.9", result)
 
 
 @pytest.mark.usefixtures("populate_wheel_cache")
 def test_cache_remove_no_arguments(script):
     """Running `pip cache remove` with no arguments should cause an error."""
-    script.pip('cache', 'remove', expect_error=True)
+    script.pip("cache", "remove", expect_error=True)
 
 
 def test_cache_remove_too_many_args(script):
     """Passing `pip cache remove` too many arguments should cause an error."""
-    script.pip('cache', 'remove', 'aaa', 'bbb',
-               expect_error=True)
+    script.pip("cache", "remove", "aaa", "bbb", expect_error=True)
 
 
 @pytest.mark.usefixtures("populate_wheel_cache")
 def test_cache_remove_name_match(script, remove_matches_wheel):
     """Running `pip cache remove zzz` should remove zzz-4.5.6 and zzz-7.8.9,
     but nothing else."""
-    result = script.pip('cache', 'remove', 'zzz', '--verbose')
+    result = script.pip("cache", "remove", "zzz", "--verbose")
 
-    assert not remove_matches_wheel('yyy-1.2.3', result)
-    assert remove_matches_wheel('zzz-4.5.6', result)
-    assert remove_matches_wheel('zzz-4.5.7', result)
-    assert remove_matches_wheel('zzz-7.8.9', result)
+    assert not remove_matches_wheel("yyy-1.2.3", result)
+    assert remove_matches_wheel("zzz-4.5.6", result)
+    assert remove_matches_wheel("zzz-4.5.7", result)
+    assert remove_matches_wheel("zzz-7.8.9", result)
 
 
 @pytest.mark.usefixtures("populate_wheel_cache")
 def test_cache_remove_name_and_version_match(script, remove_matches_wheel):
     """Running `pip cache remove zzz-4.5.6` should remove zzz-4.5.6, but
     nothing else."""
-    result = script.pip('cache', 'remove', 'zzz-4.5.6', '--verbose')
+    result = script.pip("cache", "remove", "zzz-4.5.6", "--verbose")
 
-    assert not remove_matches_wheel('yyy-1.2.3', result)
-    assert remove_matches_wheel('zzz-4.5.6', result)
-    assert not remove_matches_wheel('zzz-4.5.7', result)
-    assert not remove_matches_wheel('zzz-7.8.9', result)
+    assert not remove_matches_wheel("yyy-1.2.3", result)
+    assert remove_matches_wheel("zzz-4.5.6", result)
+    assert not remove_matches_wheel("zzz-4.5.7", result)
+    assert not remove_matches_wheel("zzz-7.8.9", result)
 
 
 @pytest.mark.usefixtures("populate_wheel_cache")
 def test_cache_purge(script, remove_matches_wheel):
     """Running `pip cache purge` should remove all cached wheels."""
-    result = script.pip('cache', 'purge', '--verbose')
+    result = script.pip("cache", "purge", "--verbose")
 
-    assert remove_matches_wheel('yyy-1.2.3', result)
-    assert remove_matches_wheel('zzz-4.5.6', result)
-    assert remove_matches_wheel('zzz-4.5.7', result)
-    assert remove_matches_wheel('zzz-7.8.9', result)
+    assert remove_matches_wheel("yyy-1.2.3", result)
+    assert remove_matches_wheel("zzz-4.5.6", result)
+    assert remove_matches_wheel("zzz-4.5.7", result)
+    assert remove_matches_wheel("zzz-7.8.9", result)
 
 
 @pytest.mark.usefixtures("populate_wheel_cache")
 def test_cache_purge_too_many_args(script, wheel_cache_files):
     """Running `pip cache purge aaa` should raise an error and remove no
     cached wheels."""
-    result = script.pip('cache', 'purge', 'aaa', '--verbose',
-                        expect_error=True)
-    assert result.stdout == ''
+    result = script.pip("cache", "purge", "aaa", "--verbose", expect_error=True)
+    assert result.stdout == ""
 
     # This would be `result.stderr == ...`, but pip prints deprecation
     # warnings on Python 2.7, so we check if the _line_ is in stderr.
-    assert 'ERROR: Too many arguments' in result.stderr.splitlines()
+    assert "ERROR: Too many arguments" in result.stderr.splitlines()
 
     # Make sure nothing was deleted.
     for filename in wheel_cache_files:
@@ -297,9 +299,10 @@ def test_cache_purge_too_many_args(script, wheel_cache_files):
 def test_cache_abort_when_no_cache_dir(script, command):
     """Running any pip cache command when cache is disabled should
     abort and log an informative error"""
-    result = script.pip('cache', command, '--no-cache-dir',
-                        expect_error=True)
-    assert result.stdout == ''
+    result = script.pip("cache", command, "--no-cache-dir", expect_error=True)
+    assert result.stdout == ""
 
-    assert ('ERROR: pip cache commands can not function'
-            ' since cache is disabled.' in result.stderr.splitlines())
+    assert (
+        "ERROR: pip cache commands can not function"
+        " since cache is disabled." in result.stderr.splitlines()
+    )
diff --git a/tests/functional/test_check.py b/tests/functional/test_check.py
index 5cb41a97e72..d039e52676a 100644
--- a/tests/functional/test_check.py
+++ b/tests/functional/test_check.py
@@ -5,20 +5,16 @@ def matches_expected_lines(string, expected_lines):
     # Ignore empty lines
     output_lines = list(filter(None, string.splitlines()))
     # We'll match the last n lines, given n lines to match.
-    last_few_output_lines = output_lines[-len(expected_lines):]
+    last_few_output_lines = output_lines[-len(expected_lines) :]
     # And order does not matter
     return set(last_few_output_lines) == set(expected_lines)
 
 
 def test_basic_check_clean(script):
-    """On a clean environment, check should print a helpful message.
+    """On a clean environment, check should print a helpful message."""
+    result = script.pip("check")
 
-    """
-    result = script.pip('check')
-
-    expected_lines = (
-        "No broken requirements found.",
-    )
+    expected_lines = ("No broken requirements found.",)
     assert matches_expected_lines(result.stdout, expected_lines)
     assert result.returncode == 0
 
@@ -27,17 +23,17 @@ def test_basic_check_missing_dependency(script):
     # Setup a small project
     pkga_path = create_test_package_with_setup(
         script,
-        name='pkga', version='1.0', install_requires=['missing==0.1'],
+        name="pkga",
+        version="1.0",
+        install_requires=["missing==0.1"],
     )
     # Let's install pkga without its dependency
-    res = script.pip('install', '--no-index', pkga_path, '--no-deps')
+    res = script.pip("install", "--no-index", pkga_path, "--no-deps")
     assert "Successfully installed pkga-1.0" in res.stdout, str(res)
 
-    result = script.pip('check', expect_error=True)
+    result = script.pip("check", expect_error=True)
 
-    expected_lines = (
-        "pkga 1.0 requires missing, which is not installed.",
-    )
+    expected_lines = ("pkga 1.0 requires missing, which is not installed.",)
     assert matches_expected_lines(result.stdout, expected_lines)
     assert result.returncode == 1
 
@@ -46,28 +42,32 @@ def test_basic_check_broken_dependency(script):
     # Setup pkga depending on pkgb>=1.0
     pkga_path = create_test_package_with_setup(
         script,
-        name='pkga', version='1.0', install_requires=['broken>=1.0'],
+        name="pkga",
+        version="1.0",
+        install_requires=["broken>=1.0"],
     )
     # Let's install pkga without its dependency
-    res = script.pip('install', '--no-index', pkga_path, '--no-deps')
+    res = script.pip("install", "--no-index", pkga_path, "--no-deps")
     assert "Successfully installed pkga-1.0" in res.stdout, str(res)
 
     # Setup broken==0.1
     broken_path = create_test_package_with_setup(
         script,
-        name='broken', version='0.1',
+        name="broken",
+        version="0.1",
     )
     # Let's install broken==0.1
     res = script.pip(
-        'install', '--no-index', broken_path, '--no-warn-conflicts',
+        "install",
+        "--no-index",
+        broken_path,
+        "--no-warn-conflicts",
     )
     assert "Successfully installed broken-0.1" in res.stdout, str(res)
 
-    result = script.pip('check', expect_error=True)
+    result = script.pip("check", expect_error=True)
 
-    expected_lines = (
-        "pkga 1.0 has requirement broken>=1.0, but you have broken 0.1.",
-    )
+    expected_lines = ("pkga 1.0 has requirement broken>=1.0, but you have broken 0.1.",)
     assert matches_expected_lines(result.stdout, expected_lines)
     assert result.returncode == 1
 
@@ -75,26 +75,30 @@ def test_basic_check_broken_dependency(script):
 def test_basic_check_broken_dependency_and_missing_dependency(script):
     pkga_path = create_test_package_with_setup(
         script,
-        name='pkga', version='1.0', install_requires=['broken>=1.0'],
+        name="pkga",
+        version="1.0",
+        install_requires=["broken>=1.0"],
     )
     # Let's install pkga without its dependency
-    res = script.pip('install', '--no-index', pkga_path, '--no-deps')
+    res = script.pip("install", "--no-index", pkga_path, "--no-deps")
     assert "Successfully installed pkga-1.0" in res.stdout, str(res)
 
     # Setup broken==0.1
     broken_path = create_test_package_with_setup(
         script,
-        name='broken', version='0.1', install_requires=['missing'],
+        name="broken",
+        version="0.1",
+        install_requires=["missing"],
     )
     # Let's install broken==0.1
-    res = script.pip('install', '--no-index', broken_path, '--no-deps')
+    res = script.pip("install", "--no-index", broken_path, "--no-deps")
     assert "Successfully installed broken-0.1" in res.stdout, str(res)
 
-    result = script.pip('check', expect_error=True)
+    result = script.pip("check", expect_error=True)
 
     expected_lines = (
         "broken 0.1 requires missing, which is not installed.",
-        "pkga 1.0 has requirement broken>=1.0, but you have broken 0.1."
+        "pkga 1.0 has requirement broken>=1.0, but you have broken 0.1.",
     )
 
     assert matches_expected_lines(result.stdout, expected_lines)
@@ -104,18 +108,17 @@ def test_basic_check_broken_dependency_and_missing_dependency(script):
 def test_check_complicated_name_missing(script):
     package_a_path = create_test_package_with_setup(
         script,
-        name='package_A', version='1.0',
-        install_requires=['Dependency-B>=1.0'],
+        name="package_A",
+        version="1.0",
+        install_requires=["Dependency-B>=1.0"],
     )
 
     # Without dependency
-    result = script.pip('install', '--no-index', package_a_path, '--no-deps')
+    result = script.pip("install", "--no-index", package_a_path, "--no-deps")
     assert "Successfully installed package-A-1.0" in result.stdout, str(result)
 
-    result = script.pip('check', expect_error=True)
-    expected_lines = (
-        "package-a 1.0 requires dependency-b, which is not installed.",
-    )
+    result = script.pip("check", expect_error=True)
+    expected_lines = ("package-a 1.0 requires dependency-b, which is not installed.",)
     assert matches_expected_lines(result.stdout, expected_lines)
     assert result.returncode == 1
 
@@ -123,24 +126,29 @@ def test_check_complicated_name_missing(script):
 def test_check_complicated_name_broken(script):
     package_a_path = create_test_package_with_setup(
         script,
-        name='package_A', version='1.0',
-        install_requires=['Dependency-B>=1.0'],
+        name="package_A",
+        version="1.0",
+        install_requires=["Dependency-B>=1.0"],
     )
     dependency_b_path_incompatible = create_test_package_with_setup(
         script,
-        name='dependency-b', version='0.1',
+        name="dependency-b",
+        version="0.1",
     )
 
     # With broken dependency
-    result = script.pip('install', '--no-index', package_a_path, '--no-deps')
+    result = script.pip("install", "--no-index", package_a_path, "--no-deps")
     assert "Successfully installed package-A-1.0" in result.stdout, str(result)
 
     result = script.pip(
-        'install', '--no-index', dependency_b_path_incompatible, '--no-deps',
+        "install",
+        "--no-index",
+        dependency_b_path_incompatible,
+        "--no-deps",
     )
     assert "Successfully installed dependency-b-0.1" in result.stdout
 
-    result = script.pip('check', expect_error=True)
+    result = script.pip("check", expect_error=True)
     expected_lines = (
         "package-a 1.0 has requirement Dependency-B>=1.0, but you have "
         "dependency-b 0.1.",
@@ -152,26 +160,29 @@ def test_check_complicated_name_broken(script):
 def test_check_complicated_name_clean(script):
     package_a_path = create_test_package_with_setup(
         script,
-        name='package_A', version='1.0',
-        install_requires=['Dependency-B>=1.0'],
+        name="package_A",
+        version="1.0",
+        install_requires=["Dependency-B>=1.0"],
     )
     dependency_b_path = create_test_package_with_setup(
         script,
-        name='dependency-b', version='1.0',
+        name="dependency-b",
+        version="1.0",
     )
 
-    result = script.pip('install', '--no-index', package_a_path, '--no-deps')
+    result = script.pip("install", "--no-index", package_a_path, "--no-deps")
     assert "Successfully installed package-A-1.0" in result.stdout, str(result)
 
     result = script.pip(
-        'install', '--no-index', dependency_b_path, '--no-deps',
+        "install",
+        "--no-index",
+        dependency_b_path,
+        "--no-deps",
     )
     assert "Successfully installed dependency-b-1.0" in result.stdout
 
-    result = script.pip('check')
-    expected_lines = (
-        "No broken requirements found.",
-    )
+    result = script.pip("check")
+    expected_lines = ("No broken requirements found.",)
     assert matches_expected_lines(result.stdout, expected_lines)
     assert result.returncode == 0
 
@@ -179,20 +190,19 @@ def test_check_complicated_name_clean(script):
 def test_check_considers_conditional_reqs(script):
     package_a_path = create_test_package_with_setup(
         script,
-        name='package_A', version='1.0',
+        name="package_A",
+        version="1.0",
         install_requires=[
             "Dependency-B>=1.0; python_version != '2.7'",
             "Dependency-B>=2.0; python_version == '2.7'",
         ],
     )
 
-    result = script.pip('install', '--no-index', package_a_path, '--no-deps')
+    result = script.pip("install", "--no-index", package_a_path, "--no-deps")
     assert "Successfully installed package-A-1.0" in result.stdout, str(result)
 
-    result = script.pip('check', expect_error=True)
-    expected_lines = (
-        "package-a 1.0 requires dependency-b, which is not installed.",
-    )
+    result = script.pip("check", expect_error=True)
+    expected_lines = ("package-a 1.0 requires dependency-b, which is not installed.",)
     assert matches_expected_lines(result.stdout, expected_lines)
     assert result.returncode == 1
 
@@ -201,45 +211,50 @@ def test_check_development_versions_are_also_considered(script):
     # Setup pkga depending on pkgb>=1.0
     pkga_path = create_test_package_with_setup(
         script,
-        name='pkga', version='1.0', install_requires=['depend>=1.0'],
+        name="pkga",
+        version="1.0",
+        install_requires=["depend>=1.0"],
     )
     # Let's install pkga without its dependency
-    res = script.pip('install', '--no-index', pkga_path, '--no-deps')
+    res = script.pip("install", "--no-index", pkga_path, "--no-deps")
     assert "Successfully installed pkga-1.0" in res.stdout, str(res)
 
     # Setup depend==1.1.0.dev0
     depend_path = create_test_package_with_setup(
         script,
-        name='depend', version='1.1.0.dev0',
+        name="depend",
+        version="1.1.0.dev0",
     )
     # Let's install depend==1.1.0.dev0
     res = script.pip(
-        'install', '--no-index', depend_path, '--no-warn-conflicts',
+        "install",
+        "--no-index",
+        depend_path,
+        "--no-warn-conflicts",
     )
     assert "Successfully installed depend-1.1.0.dev0" in res.stdout, str(res)
 
-    result = script.pip('check')
-    expected_lines = (
-        "No broken requirements found.",
-    )
+    result = script.pip("check")
+    expected_lines = ("No broken requirements found.",)
     assert matches_expected_lines(result.stdout, expected_lines)
     assert result.returncode == 0
 
 
 def test_basic_check_broken_metadata(script):
     # Create some corrupt metadata
-    dist_info_dir = script.site_packages_path / 'pkga-1.0.dist-info'
+    dist_info_dir = script.site_packages_path / "pkga-1.0.dist-info"
     dist_info_dir.mkdir()
-    with open(dist_info_dir / 'METADATA', 'w') as f:
-        f.write('Metadata-Version: 2.1\n'
-                'Name: pkga\n'
-                'Version: 1.0\n'
-                'Requires-Dist: pip; python_version == "3.4";extra == "test"\n'
-                )
+    with open(dist_info_dir / "METADATA", "w") as f:
+        f.write(
+            "Metadata-Version: 2.1\n"
+            "Name: pkga\n"
+            "Version: 1.0\n"
+            'Requires-Dist: pip; python_version == "3.4";extra == "test"\n'
+        )
 
-    result = script.pip('check', expect_error=True)
+    result = script.pip("check", expect_error=True)
 
-    assert 'Error parsing requirements' in result.stderr
+    assert "Error parsing requirements" in result.stderr
     assert result.returncode == 1
 
 
@@ -252,18 +267,15 @@ def test_check_skip_work_dir_pkg(script):
     # Create a test package with dependency missing
     # and create .egg-info dir
     pkg_path = create_test_package_with_setup(
-        script, name='simple', version='1.0',
-        install_requires=['missing==0.1'])
+        script, name="simple", version="1.0", install_requires=["missing==0.1"]
+    )
 
-    script.run('python', 'setup.py', 'egg_info',
-               expect_stderr=True, cwd=pkg_path)
+    script.run("python", "setup.py", "egg_info", expect_stderr=True, cwd=pkg_path)
 
     # Check should not complain about broken requirements
     # when run from package directory
-    result = script.pip('check', cwd=pkg_path)
-    expected_lines = (
-        "No broken requirements found.",
-    )
+    result = script.pip("check", cwd=pkg_path)
+    expected_lines = ("No broken requirements found.",)
     assert matches_expected_lines(result.stdout, expected_lines)
     assert result.returncode == 0
 
@@ -277,20 +289,17 @@ def test_check_include_work_dir_pkg(script):
     # Create a test package with dependency missing
     # and create .egg-info dir
     pkg_path = create_test_package_with_setup(
-        script, name='simple', version='1.0',
-        install_requires=['missing==0.1'])
+        script, name="simple", version="1.0", install_requires=["missing==0.1"]
+    )
 
-    script.run('python', 'setup.py', 'egg_info',
-               expect_stderr=True, cwd=pkg_path)
+    script.run("python", "setup.py", "egg_info", expect_stderr=True, cwd=pkg_path)
 
-    script.environ.update({'PYTHONPATH': pkg_path})
+    script.environ.update({"PYTHONPATH": pkg_path})
 
     # Check should mention about missing requirement simple
     # when run from package directory, when package directory
     # is in PYTHONPATH
-    result = script.pip('check', expect_error=True, cwd=pkg_path)
-    expected_lines = (
-        "simple 1.0 requires missing, which is not installed.",
-    )
+    result = script.pip("check", expect_error=True, cwd=pkg_path)
+    expected_lines = ("simple 1.0 requires missing, which is not installed.",)
     assert matches_expected_lines(result.stdout, expected_lines)
     assert result.returncode == 1
diff --git a/tests/functional/test_cli.py b/tests/functional/test_cli.py
index e416315125f..1df4836f9b8 100644
--- a/tests/functional/test_cli.py
+++ b/tests/functional/test_cli.py
@@ -5,15 +5,20 @@
 import pytest
 
 
-@pytest.mark.parametrize("entrypoint", [
-    ("fake_pip = pip._internal.main:main",),
-    ("fake_pip = pip._internal:main",),
-    ("fake_pip = pip:main",),
-])
+@pytest.mark.parametrize(
+    "entrypoint",
+    [
+        ("fake_pip = pip._internal.main:main",),
+        ("fake_pip = pip._internal:main",),
+        ("fake_pip = pip:main",),
+    ],
+)
 def test_entrypoints_work(entrypoint, script):
     fake_pkg = script.temp_path / "fake_pkg"
     fake_pkg.mkdir()
-    fake_pkg.joinpath("setup.py").write_text(dedent("""
+    fake_pkg.joinpath("setup.py").write_text(
+        dedent(
+            """
     from setuptools import setup
 
     setup(
@@ -25,7 +30,11 @@ def test_entrypoints_work(entrypoint, script):
             ]
         }}
     )
-    """.format(entrypoint)))
+    """.format(
+                entrypoint
+            )
+        )
+    )
 
     script.pip("install", "-vvv", str(fake_pkg))
     result = script.pip("-V")
diff --git a/tests/functional/test_completion.py b/tests/functional/test_completion.py
index a3986811b6f..906ab5c7d30 100644
--- a/tests/functional/test_completion.py
+++ b/tests/functional/test_completion.py
@@ -6,15 +6,20 @@
 from tests.lib.path import Path
 
 COMPLETION_FOR_SUPPORTED_SHELLS_TESTS = (
-    ('bash', """\
+    (
+        "bash",
+        """\
 _pip_completion()
 {
     COMPREPLY=( $( COMP_WORDS="${COMP_WORDS[*]}" \\
                    COMP_CWORD=$COMP_CWORD \\
                    PIP_AUTO_COMPLETE=1 $1 2>/dev/null ) )
 }
-complete -o default -F _pip_completion pip"""),
-    ('fish', """\
+complete -o default -F _pip_completion pip""",
+    ),
+    (
+        "fish",
+        """\
 function __fish_complete_pip
     set -lx COMP_WORDS (commandline -o) ""
     set -lx COMP_CWORD ( \\
@@ -23,8 +28,11 @@
     set -lx PIP_AUTO_COMPLETE 1
     string split \\  -- (eval $COMP_WORDS[1])
 end
-complete -fa "(__fish_complete_pip)" -c pip"""),
-    ('zsh', """\
+complete -fa "(__fish_complete_pip)" -c pip""",
+    ),
+    (
+        "zsh",
+        """\
 function _pip_completion {
   local words cword
   read -Ac words
@@ -33,35 +41,30 @@
              COMP_CWORD=$(( cword-1 )) \\
              PIP_AUTO_COMPLETE=1 $words[1] 2>/dev/null ))
 }
-compctl -K _pip_completion pip"""),
+compctl -K _pip_completion pip""",
+    ),
 )
 
 
 @pytest.fixture(scope="session")
-def script_with_launchers(
-    tmpdir_factory, script_factory, common_wheels, pip_src
-):
+def script_with_launchers(tmpdir_factory, script_factory, common_wheels, pip_src):
     tmpdir = Path(str(tmpdir_factory.mktemp("script_with_launchers")))
     script = script_factory(tmpdir.joinpath("workspace"))
     # Re-install pip so we get the launchers.
-    script.pip_install_local('-f', common_wheels, pip_src)
+    script.pip_install_local("-f", common_wheels, pip_src)
     return script
 
 
 @pytest.mark.parametrize(
-    'shell, completion',
+    "shell, completion",
     COMPLETION_FOR_SUPPORTED_SHELLS_TESTS,
     ids=[t[0] for t in COMPLETION_FOR_SUPPORTED_SHELLS_TESTS],
 )
-def test_completion_for_supported_shells(
-    script_with_launchers, shell, completion
-):
+def test_completion_for_supported_shells(script_with_launchers, shell, completion):
     """
     Test getting completion for bash shell
     """
-    result = script_with_launchers.pip(
-        'completion', '--' + shell, use_module=False
-    )
+    result = script_with_launchers.pip("completion", "--" + shell, use_module=False)
     assert completion in result.stdout, str(result.stdout)
 
 
@@ -73,16 +76,17 @@ def autocomplete_script(tmpdir_factory, script_factory):
 
 @pytest.fixture
 def autocomplete(autocomplete_script, monkeypatch):
-    monkeypatch.setattr(autocomplete_script, 'environ', os.environ.copy())
-    autocomplete_script.environ['PIP_AUTO_COMPLETE'] = '1'
+    monkeypatch.setattr(autocomplete_script, "environ", os.environ.copy())
+    autocomplete_script.environ["PIP_AUTO_COMPLETE"] = "1"
 
     def do_autocomplete(words, cword, cwd=None):
-        autocomplete_script.environ['COMP_WORDS'] = words
-        autocomplete_script.environ['COMP_CWORD'] = cword
+        autocomplete_script.environ["COMP_WORDS"] = words
+        autocomplete_script.environ["COMP_CWORD"] = cword
         result = autocomplete_script.run(
-            'python', '-c',
-            'from pip._internal.cli.autocompletion import autocomplete;'
-            'autocomplete()',
+            "python",
+            "-c",
+            "from pip._internal.cli.autocompletion import autocomplete;"
+            "autocomplete()",
             expect_error=True,
             cwd=cwd,
         )
@@ -96,20 +100,19 @@ def test_completion_for_unknown_shell(autocomplete_script):
     """
     Test getting completion for an unknown shell
     """
-    error_msg = 'no such option: --myfooshell'
-    result = autocomplete_script.pip(
-        'completion', '--myfooshell', expect_error=True
-    )
-    assert error_msg in result.stderr, 'tests for an unknown shell failed'
+    error_msg = "no such option: --myfooshell"
+    result = autocomplete_script.pip("completion", "--myfooshell", expect_error=True)
+    assert error_msg in result.stderr, "tests for an unknown shell failed"
 
 
 def test_completion_alone(autocomplete_script):
     """
     Test getting completion for none shell, just pip completion
     """
-    result = autocomplete_script.pip('completion', allow_stderr_error=True)
-    assert 'ERROR: You must pass --bash or --fish or --zsh' in result.stderr, \
-           'completion alone failed -- ' + result.stderr
+    result = autocomplete_script.pip("completion", allow_stderr_error=True)
+    assert "ERROR: You must pass --bash or --fish or --zsh" in result.stderr, (
+        "completion alone failed -- " + result.stderr
+    )
 
 
 def test_completion_for_un_snippet(autocomplete):
@@ -117,8 +120,8 @@ def test_completion_for_un_snippet(autocomplete):
     Test getting completion for ``un`` should return uninstall
     """
 
-    res, env = autocomplete('pip un', '1')
-    assert res.stdout.strip().split() == ['uninstall'], res.stdout
+    res, env = autocomplete("pip un", "1")
+    assert res.stdout.strip().split() == ["uninstall"], res.stdout
 
 
 def test_completion_for_default_parameters(autocomplete):
@@ -126,9 +129,8 @@ def test_completion_for_default_parameters(autocomplete):
     Test getting completion for ``--`` should contain --help
     """
 
-    res, env = autocomplete('pip --', '1')
-    assert '--help' in res.stdout,\
-           "autocomplete function could not complete ``--``"
+    res, env = autocomplete("pip --", "1")
+    assert "--help" in res.stdout, "autocomplete function could not complete ``--``"
 
 
 def test_completion_option_for_command(autocomplete):
@@ -136,9 +138,8 @@ def test_completion_option_for_command(autocomplete):
     Test getting completion for ``--`` in command (e.g. ``pip search --``)
     """
 
-    res, env = autocomplete('pip search --', '2')
-    assert '--help' in res.stdout,\
-           "autocomplete function could not complete ``--``"
+    res, env = autocomplete("pip search --", "2")
+    assert "--help" in res.stdout, "autocomplete function could not complete ``--``"
 
 
 def test_completion_short_option(autocomplete):
@@ -146,10 +147,11 @@ def test_completion_short_option(autocomplete):
     Test getting completion for short options after ``-`` (eg. pip -)
     """
 
-    res, env = autocomplete('pip -', '1')
+    res, env = autocomplete("pip -", "1")
 
-    assert '-h' in res.stdout.split(),\
-           "autocomplete function could not complete short options after ``-``"
+    assert (
+        "-h" in res.stdout.split()
+    ), "autocomplete function could not complete short options after ``-``"
 
 
 def test_completion_short_option_for_command(autocomplete):
@@ -158,10 +160,11 @@ def test_completion_short_option_for_command(autocomplete):
     (eg. pip search -)
     """
 
-    res, env = autocomplete('pip search -', '2')
+    res, env = autocomplete("pip search -", "2")
 
-    assert '-h' in res.stdout.split(),\
-           "autocomplete function could not complete short options after ``-``"
+    assert (
+        "-h" in res.stdout.split()
+    ), "autocomplete function could not complete short options after ``-``"
 
 
 def test_completion_files_after_option(autocomplete, data):
@@ -170,32 +173,29 @@ def test_completion_files_after_option(autocomplete, data):
     (e.g. ``pip install -r``)
     """
     res, env = autocomplete(
-        words=('pip install -r r'),
-        cword='3',
+        words=("pip install -r r"),
+        cword="3",
         cwd=data.completion_paths,
     )
-    assert 'requirements.txt' in res.stdout, (
-        "autocomplete function could not complete <file> "
-        "after options in command"
+    assert "requirements.txt" in res.stdout, (
+        "autocomplete function could not complete <file> " "after options in command"
     )
-    assert os.path.join('resources', '') in res.stdout, (
-        "autocomplete function could not complete <dir> "
-        "after options in command"
+    assert os.path.join("resources", "") in res.stdout, (
+        "autocomplete function could not complete <dir> " "after options in command"
     )
-    assert not any(out in res.stdout for out in
-                   (os.path.join('REPLAY', ''), 'README.txt')), (
+    assert not any(
+        out in res.stdout for out in (os.path.join("REPLAY", ""), "README.txt")
+    ), (
         "autocomplete function completed <file> or <dir> that "
         "should not be completed"
     )
-    if sys.platform != 'win32':
+    if sys.platform != "win32":
         return
-    assert 'readme.txt' in res.stdout, (
-        "autocomplete function could not complete <file> "
-        "after options in command"
+    assert "readme.txt" in res.stdout, (
+        "autocomplete function could not complete <file> " "after options in command"
     )
-    assert os.path.join('replay', '') in res.stdout, (
-        "autocomplete function could not complete <dir> "
-        "after options in command"
+    assert os.path.join("replay", "") in res.stdout, (
+        "autocomplete function could not complete <dir> " "after options in command"
     )
 
 
@@ -205,45 +205,35 @@ def test_completion_not_files_after_option(autocomplete, data):
     (e.g. ``pip install``)
     """
     res, env = autocomplete(
-        words=('pip install r'),
-        cword='2',
+        words=("pip install r"),
+        cword="2",
         cwd=data.completion_paths,
     )
-    assert not any(out in res.stdout for out in
-                   ('requirements.txt', 'readme.txt',)), (
-        "autocomplete function completed <file> when "
-        "it should not complete"
-    )
-    assert not any(os.path.join(out, '') in res.stdout
-                   for out in ('replay', 'resources')), (
-        "autocomplete function completed <dir> when "
-        "it should not complete"
+    assert not any(out in res.stdout for out in ("requirements.txt", "readme.txt",)), (
+        "autocomplete function completed <file> when " "it should not complete"
     )
+    assert not any(
+        os.path.join(out, "") in res.stdout for out in ("replay", "resources")
+    ), ("autocomplete function completed <dir> when " "it should not complete")
 
 
 @pytest.mark.parametrize("cl_opts", ["-U", "--user", "-h"])
-def test_completion_not_files_after_nonexpecting_option(
-    autocomplete, data, cl_opts
-):
+def test_completion_not_files_after_nonexpecting_option(autocomplete, data, cl_opts):
     """
     Test not getting completion files after options which not applicable
     (e.g. ``pip install``)
     """
     res, env = autocomplete(
-        words=('pip install {cl_opts} r'.format(**locals())),
-        cword='2',
+        words=("pip install {cl_opts} r".format(**locals())),
+        cword="2",
         cwd=data.completion_paths,
     )
-    assert not any(out in res.stdout for out in
-                   ('requirements.txt', 'readme.txt',)), (
-        "autocomplete function completed <file> when "
-        "it should not complete"
-    )
-    assert not any(os.path.join(out, '') in res.stdout
-                   for out in ('replay', 'resources')), (
-        "autocomplete function completed <dir> when "
-        "it should not complete"
+    assert not any(out in res.stdout for out in ("requirements.txt", "readme.txt",)), (
+        "autocomplete function completed <file> when " "it should not complete"
     )
+    assert not any(
+        os.path.join(out, "") in res.stdout for out in ("replay", "resources")
+    ), ("autocomplete function completed <dir> when " "it should not complete")
 
 
 def test_completion_directories_after_option(autocomplete, data):
@@ -252,22 +242,21 @@ def test_completion_directories_after_option(autocomplete, data):
     (e.g. ``pip --cache-dir``)
     """
     res, env = autocomplete(
-        words=('pip --cache-dir r'),
-        cword='2',
+        words=("pip --cache-dir r"),
+        cword="2",
         cwd=data.completion_paths,
     )
-    assert os.path.join('resources', '') in res.stdout, (
-        "autocomplete function could not complete <dir> after options"
-    )
-    assert not any(out in res.stdout for out in (
-        'requirements.txt', 'README.txt', os.path.join('REPLAY', ''))), (
-            "autocomplete function completed <dir> when "
-            "it should not complete"
-    )
-    if sys.platform == 'win32':
-        assert os.path.join('replay', '') in res.stdout, (
-            "autocomplete function could not complete <dir> after options"
-        )
+    assert (
+        os.path.join("resources", "") in res.stdout
+    ), "autocomplete function could not complete <dir> after options"
+    assert not any(
+        out in res.stdout
+        for out in ("requirements.txt", "README.txt", os.path.join("REPLAY", ""))
+    ), ("autocomplete function completed <dir> when " "it should not complete")
+    if sys.platform == "win32":
+        assert (
+            os.path.join("replay", "") in res.stdout
+        ), "autocomplete function could not complete <dir> after options"
 
 
 def test_completion_subdirectories_after_option(autocomplete, data):
@@ -276,12 +265,11 @@ def test_completion_subdirectories_after_option(autocomplete, data):
     given path of a directory
     """
     res, env = autocomplete(
-        words=('pip --cache-dir ' + os.path.join('resources', '')),
-        cword='2',
+        words=("pip --cache-dir " + os.path.join("resources", "")),
+        cword="2",
         cwd=data.completion_paths,
     )
-    assert os.path.join('resources',
-                        os.path.join('images', '')) in res.stdout, (
+    assert os.path.join("resources", os.path.join("images", "")) in res.stdout, (
         "autocomplete function could not complete <dir> "
         "given path of a directory after options"
     )
@@ -293,24 +281,28 @@ def test_completion_path_after_option(autocomplete, data):
     given absolute path
     """
     res, env = autocomplete(
-        words=('pip install -e ' + os.path.join(data.completion_paths, 'R')),
-        cword='3',
+        words=("pip install -e " + os.path.join(data.completion_paths, "R")),
+        cword="3",
     )
-    assert all(os.path.normcase(os.path.join(data.completion_paths, out))
-               in res.stdout for out in (
-               'README.txt', os.path.join('REPLAY', ''))), (
+    assert all(
+        os.path.normcase(os.path.join(data.completion_paths, out)) in res.stdout
+        for out in ("README.txt", os.path.join("REPLAY", ""))
+    ), (
         "autocomplete function could not complete <path> "
         "after options in command given absolute path"
     )
 
 
-@pytest.mark.parametrize('flag', ['--bash', '--zsh', '--fish'])
+@pytest.mark.parametrize("flag", ["--bash", "--zsh", "--fish"])
 def test_completion_uses_same_executable_name(
     autocomplete_script, flag, deprecated_python
 ):
-    executable_name = 'pip{}'.format(sys.version_info[0])
+    executable_name = "pip{}".format(sys.version_info[0])
     # Deprecated python versions produce an extra deprecation warning
     result = autocomplete_script.run(
-        executable_name, 'completion', flag, expect_stderr=deprecated_python,
+        executable_name,
+        "completion",
+        flag,
+        expect_stderr=deprecated_python,
     )
     assert executable_name in result.stdout
diff --git a/tests/functional/test_configuration.py b/tests/functional/test_configuration.py
index 63b243f788e..615f356f6c8 100644
--- a/tests/functional/test_configuration.py
+++ b/tests/functional/test_configuration.py
@@ -7,20 +7,16 @@
 import pytest
 
 from pip._internal.cli.status_codes import ERROR
-from pip._internal.configuration import (
-    CONFIG_BASENAME,
-    get_configuration_files,
-)
+from pip._internal.configuration import CONFIG_BASENAME, get_configuration_files
 from tests.lib.configuration_helpers import ConfigurationMixin, kinds
 
 
 def test_no_options_passed_should_error(script):
-    result = script.pip('config', expect_error=True)
+    result = script.pip("config", expect_error=True)
     assert result.returncode == ERROR
 
 
 class TestBasicLoading(ConfigurationMixin):
-
     @pytest.mark.skip("Can't modify underlying file for any mode")
     def test_reads_file_appropriately(self, script):
         contents = """
@@ -50,10 +46,9 @@ def test_listing_is_correct(self, script):
 
         result = script.pip("config", "list")
 
-        lines = list(filter(
-            lambda x: x.startswith("test.listing-"),
-            result.stdout.splitlines()
-        ))
+        lines = list(
+            filter(lambda x: x.startswith("test.listing-"), result.stdout.splitlines())
+        )
 
         expected = """
             test.listing-alpha='1'
@@ -64,8 +59,7 @@ def test_listing_is_correct(self, script):
         assert lines == textwrap.dedent(expected).strip().splitlines()
 
     def test_forget_section(self, script):
-        result = script.pip("config", "set", "isolated", "true",
-                            expect_error=True)
+        result = script.pip("config", "set", "isolated", "true", expect_error=True)
         assert "global.isolated" in result.stderr
 
     def test_env_var_values(self, script):
@@ -75,7 +69,7 @@ def test_env_var_values(self, script):
 
         env_vars = {
             "PIP_DEFAULT_TIMEOUT": "60",
-            "PIP_FIND_LINKS": "http://mirror.example.com"
+            "PIP_FIND_LINKS": "http://mirror.example.com",
         }
         script.environ.update(env_vars)
 
@@ -91,14 +85,18 @@ def test_env_values(self, script):
         """
 
         config_file = script.scratch_path / "test-pip.cfg"
-        script.environ['PIP_CONFIG_FILE'] = str(config_file)
-        config_file.write_text(textwrap.dedent("""\
+        script.environ["PIP_CONFIG_FILE"] = str(config_file)
+        config_file.write_text(
+            textwrap.dedent(
+                """\
             [global]
             timeout = 60
 
             [freeze]
             timeout = 10
-            """))
+            """
+            )
+        )
 
         result = script.pip("config", "debug")
         assert "{}, exists: True".format(config_file) in result.stdout
@@ -106,7 +104,10 @@ def test_env_values(self, script):
         assert "freeze.timeout: 10" in result.stdout
         assert re.search(r"env:\n(  .+\n)+", result.stdout)
 
-    def test_user_values(self, script,):
+    def test_user_values(
+        self,
+        script,
+    ):
         """Test that the user pip configuration set using --user
         is correctly displayed under "user".  This configuration takes place
         of custom path location using the environment variable PIP_CONFIG_FILE
diff --git a/tests/functional/test_debug.py b/tests/functional/test_debug.py
index f309604df58..d94554e409a 100644
--- a/tests/functional/test_debug.py
+++ b/tests/functional/test_debug.py
@@ -4,26 +4,28 @@
 from pip._internal.utils import compatibility_tags
 
 
-@pytest.mark.parametrize('expected_text', [
-    'sys.executable: ',
-    'sys.getdefaultencoding: ',
-    'sys.getfilesystemencoding: ',
-    'locale.getpreferredencoding: ',
-    'sys.platform: ',
-    'sys.implementation:',
-    '\'cert\' config value: ',
-    'REQUESTS_CA_BUNDLE: ',
-    'CURL_CA_BUNDLE: ',
-    'pip._vendor.certifi.where(): ',
-    'pip._vendor.DEBUNDLED: ',
-    'vendored library versions:',
-
-])
+@pytest.mark.parametrize(
+    "expected_text",
+    [
+        "sys.executable: ",
+        "sys.getdefaultencoding: ",
+        "sys.getfilesystemencoding: ",
+        "locale.getpreferredencoding: ",
+        "sys.platform: ",
+        "sys.implementation:",
+        "'cert' config value: ",
+        "REQUESTS_CA_BUNDLE: ",
+        "CURL_CA_BUNDLE: ",
+        "pip._vendor.certifi.where(): ",
+        "pip._vendor.DEBUNDLED: ",
+        "vendored library versions:",
+    ],
+)
 def test_debug(script, expected_text):
     """
     Check that certain strings are present in the output.
     """
-    args = ['debug']
+    args = ["debug"]
     result = script.pip(*args, allow_stderr_warning=True)
     stdout = result.stdout
 
@@ -34,53 +36,53 @@ def test_debug__library_versions(script):
     """
     Check the library versions normal output.
     """
-    args = ['debug']
+    args = ["debug"]
     result = script.pip(*args, allow_stderr_warning=True)
     print(result.stdout)
 
     vendored_versions = create_vendor_txt_map()
     for name, value in vendored_versions.items():
-        assert '{}=={}'.format(name, value) in result.stdout
+        assert "{}=={}".format(name, value) in result.stdout
 
 
 @pytest.mark.parametrize(
-    'args',
+    "args",
     [
         [],
-        ['--verbose'],
-    ]
+        ["--verbose"],
+    ],
 )
 def test_debug__tags(script, args):
     """
     Check the compatible tag output.
     """
-    args = ['debug'] + args
+    args = ["debug"] + args
     result = script.pip(*args, allow_stderr_warning=True)
     stdout = result.stdout
 
     tags = compatibility_tags.get_supported()
-    expected_tag_header = 'Compatible tags: {}'.format(len(tags))
+    expected_tag_header = "Compatible tags: {}".format(len(tags))
     assert expected_tag_header in stdout
 
-    show_verbose_note = '--verbose' not in args
+    show_verbose_note = "--verbose" not in args
     assert (
-        '...\n  [First 10 tags shown. Pass --verbose to show all.]' in stdout
+        "...\n  [First 10 tags shown. Pass --verbose to show all.]" in stdout
     ) == show_verbose_note
 
 
 @pytest.mark.parametrize(
-    'args, expected',
+    "args, expected",
     [
-        (['--python-version', '3.7'], "(target: version_info='3.7')"),
-    ]
+        (["--python-version", "3.7"], "(target: version_info='3.7')"),
+    ],
 )
 def test_debug__target_options(script, args, expected):
     """
     Check passing target-related options.
     """
-    args = ['debug'] + args
+    args = ["debug"] + args
     result = script.pip(*args, allow_stderr_warning=True)
     stdout = result.stdout
 
-    assert 'Compatible tags: ' in stdout
+    assert "Compatible tags: " in stdout
     assert expected in stdout
diff --git a/tests/functional/test_download.py b/tests/functional/test_download.py
index 3291d580d23..4245057f3f8 100644
--- a/tests/functional/test_download.py
+++ b/tests/functional/test_download.py
@@ -25,13 +25,9 @@ def test_download_if_requested(script):
     """
     It should download (in the scratch path) and not install if requested.
     """
-    result = script.pip(
-        'download', '-d', 'pip_downloads', 'INITools==0.1'
-    )
-    result.did_create(
-        Path('scratch') / 'pip_downloads' / 'INITools-0.1.tar.gz'
-    )
-    result.did_not_create(script.site_packages / 'initools')
+    result = script.pip("download", "-d", "pip_downloads", "INITools==0.1")
+    result.did_create(Path("scratch") / "pip_downloads" / "INITools-0.1.tar.gz")
+    result.did_not_create(script.site_packages / "initools")
 
 
 @pytest.mark.network
@@ -39,11 +35,9 @@ def test_basic_download_setuptools(script):
     """
     It should download (in the scratch path) and not install if requested.
     """
-    result = script.pip('download', 'setuptools')
-    setuptools_prefix = str(Path('scratch') / 'setuptools')
-    assert any(
-        path.startswith(setuptools_prefix) for path in result.files_created
-    )
+    result = script.pip("download", "setuptools")
+    setuptools_prefix = str(Path("scratch") / "setuptools")
+    assert any(path.startswith(setuptools_prefix) for path in result.files_created)
 
 
 def test_download_wheel(script, data):
@@ -51,13 +45,10 @@ def test_download_wheel(script, data):
     Test using "pip download" to download a *.whl archive.
     """
     result = script.pip(
-        'download',
-        '--no-index',
-        '-f', data.packages,
-        '-d', '.', 'meta'
+        "download", "--no-index", "-f", data.packages, "-d", ".", "meta"
     )
-    result.did_create(Path('scratch') / 'meta-1.0-py2.py3-none-any.whl')
-    result.did_not_create(script.site_packages / 'piptestpackage')
+    result.did_create(Path("scratch") / "meta-1.0-py2.py3-none-any.whl")
+    result.did_not_create(script.site_packages / "piptestpackage")
 
 
 @pytest.mark.network
@@ -66,14 +57,22 @@ def test_single_download_from_requirements_file(script):
     It should support download (in the scratch path) from PyPI from a
     requirements file
     """
-    script.scratch_path.joinpath("test-req.txt").write_text(textwrap.dedent("""
+    script.scratch_path.joinpath("test-req.txt").write_text(
+        textwrap.dedent(
+            """
         INITools==0.1
-        """))
+        """
+        )
+    )
     result = script.pip(
-        'download', '-r', script.scratch_path / 'test-req.txt', '-d', '.',
+        "download",
+        "-r",
+        script.scratch_path / "test-req.txt",
+        "-d",
+        ".",
     )
-    result.did_create(Path('scratch') / 'INITools-0.1.tar.gz')
-    result.did_not_create(script.site_packages / 'initools')
+    result.did_create(Path("scratch") / "INITools-0.1.tar.gz")
+    result.did_not_create(script.site_packages / "initools")
 
 
 @pytest.mark.network
@@ -81,43 +80,35 @@ def test_basic_download_should_download_dependencies(script):
     """
     It should download dependencies (in the scratch path)
     """
-    result = script.pip(
-        'download', 'Paste[openid]==1.7.5.1', '-d', '.'
-    )
-    result.did_create(Path('scratch') / 'Paste-1.7.5.1.tar.gz')
-    openid_tarball_prefix = str(Path('scratch') / 'python-openid-')
-    assert any(
-        path.startswith(openid_tarball_prefix) for path in result.files_created
-    )
-    result.did_not_create(script.site_packages / 'openid')
+    result = script.pip("download", "Paste[openid]==1.7.5.1", "-d", ".")
+    result.did_create(Path("scratch") / "Paste-1.7.5.1.tar.gz")
+    openid_tarball_prefix = str(Path("scratch") / "python-openid-")
+    assert any(path.startswith(openid_tarball_prefix) for path in result.files_created)
+    result.did_not_create(script.site_packages / "openid")
 
 
 def test_download_wheel_archive(script, data):
     """
     It should download a wheel archive path
     """
-    wheel_filename = 'colander-0.9.9-py2.py3-none-any.whl'
-    wheel_path = '/'.join((data.find_links, wheel_filename))
-    result = script.pip(
-        'download', wheel_path,
-        '-d', '.', '--no-deps'
-    )
-    result.did_create(Path('scratch') / wheel_filename)
+    wheel_filename = "colander-0.9.9-py2.py3-none-any.whl"
+    wheel_path = "/".join((data.find_links, wheel_filename))
+    result = script.pip("download", wheel_path, "-d", ".", "--no-deps")
+    result.did_create(Path("scratch") / wheel_filename)
 
 
 def test_download_should_download_wheel_deps(script, data):
     """
     It should download dependencies for wheels(in the scratch path)
     """
-    wheel_filename = 'colander-0.9.9-py2.py3-none-any.whl'
-    dep_filename = 'translationstring-1.1.tar.gz'
-    wheel_path = '/'.join((data.find_links, wheel_filename))
+    wheel_filename = "colander-0.9.9-py2.py3-none-any.whl"
+    dep_filename = "translationstring-1.1.tar.gz"
+    wheel_path = "/".join((data.find_links, wheel_filename))
     result = script.pip(
-        'download', wheel_path,
-        '-d', '.', '--find-links', data.find_links, '--no-index'
+        "download", wheel_path, "-d", ".", "--find-links", data.find_links, "--no-index"
     )
-    result.did_create(Path('scratch') / wheel_filename)
-    result.did_create(Path('scratch') / dep_filename)
+    result.did_create(Path("scratch") / wheel_filename)
+    result.did_create(Path("scratch") / dep_filename)
 
 
 @pytest.mark.network
@@ -125,33 +116,47 @@ def test_download_should_skip_existing_files(script):
     """
     It should not download files already existing in the scratch dir
     """
-    script.scratch_path.joinpath("test-req.txt").write_text(textwrap.dedent("""
+    script.scratch_path.joinpath("test-req.txt").write_text(
+        textwrap.dedent(
+            """
         INITools==0.1
-        """))
+        """
+        )
+    )
 
     result = script.pip(
-        'download', '-r', script.scratch_path / 'test-req.txt', '-d', '.',
+        "download",
+        "-r",
+        script.scratch_path / "test-req.txt",
+        "-d",
+        ".",
     )
-    result.did_create(Path('scratch') / 'INITools-0.1.tar.gz')
-    result.did_not_create(script.site_packages / 'initools')
+    result.did_create(Path("scratch") / "INITools-0.1.tar.gz")
+    result.did_not_create(script.site_packages / "initools")
 
     # adding second package to test-req.txt
-    script.scratch_path.joinpath("test-req.txt").write_text(textwrap.dedent("""
+    script.scratch_path.joinpath("test-req.txt").write_text(
+        textwrap.dedent(
+            """
         INITools==0.1
         python-openid==2.2.5
-        """))
+        """
+        )
+    )
 
     # only the second package should be downloaded
     result = script.pip(
-        'download', '-r', script.scratch_path / 'test-req.txt', '-d', '.',
+        "download",
+        "-r",
+        script.scratch_path / "test-req.txt",
+        "-d",
+        ".",
     )
-    openid_tarball_prefix = str(Path('scratch') / 'python-openid-')
-    assert any(
-        path.startswith(openid_tarball_prefix) for path in result.files_created
-    )
-    result.did_not_create(Path('scratch') / 'INITools-0.1.tar.gz')
-    result.did_not_create(script.site_packages / 'initools')
-    result.did_not_create(script.site_packages / 'openid')
+    openid_tarball_prefix = str(Path("scratch") / "python-openid-")
+    assert any(path.startswith(openid_tarball_prefix) for path in result.files_created)
+    result.did_not_create(Path("scratch") / "INITools-0.1.tar.gz")
+    result.did_not_create(script.site_packages / "initools")
+    result.did_not_create(script.site_packages / "openid")
 
 
 @pytest.mark.network
@@ -160,10 +165,10 @@ def test_download_vcs_link(script):
     It should allow -d flag for vcs links, regression test for issue #798.
     """
     result = script.pip(
-        'download', '-d', '.', 'git+git://github.com/pypa/pip-test-package.git'
+        "download", "-d", ".", "git+git://github.com/pypa/pip-test-package.git"
     )
-    result.did_create(Path('scratch') / 'pip-test-package-0.1.1.zip')
-    result.did_not_create(script.site_packages / 'piptestpackage')
+    result.did_create(Path("scratch") / "pip-test-package-0.1.1.zip")
+    result.did_not_create(script.site_packages / "piptestpackage")
 
 
 def test_only_binary_set_then_download_specific_platform(script, data):
@@ -171,16 +176,21 @@ def test_only_binary_set_then_download_specific_platform(script, data):
     Confirm that specifying an interpreter/platform constraint
     is allowed when ``--only-binary=:all:`` is set.
     """
-    fake_wheel(data, 'fake-1.0-py2.py3-none-any.whl')
+    fake_wheel(data, "fake-1.0-py2.py3-none-any.whl")
 
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--platform', 'linux_x86_64',
-        'fake'
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--platform",
+        "linux_x86_64",
+        "fake",
     )
-    result.did_create(Path('scratch') / 'fake-1.0-py2.py3-none-any.whl')
+    result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-any.whl")
 
 
 def test_no_deps_set_then_download_specific_platform(script, data):
@@ -188,16 +198,21 @@ def test_no_deps_set_then_download_specific_platform(script, data):
     Confirm that specifying an interpreter/platform constraint
     is allowed when ``--no-deps`` is set.
     """
-    fake_wheel(data, 'fake-1.0-py2.py3-none-any.whl')
+    fake_wheel(data, "fake-1.0-py2.py3-none-any.whl")
 
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--no-deps',
-        '--dest', '.',
-        '--platform', 'linux_x86_64',
-        'fake'
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--no-deps",
+        "--dest",
+        ".",
+        "--platform",
+        "linux_x86_64",
+        "fake",
     )
-    result.did_create(Path('scratch') / 'fake-1.0-py2.py3-none-any.whl')
+    result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-any.whl")
 
 
 def test_download_specific_platform_fails(script, data):
@@ -205,16 +220,21 @@ def test_download_specific_platform_fails(script, data):
     Confirm that specifying an interpreter/platform constraint
     enforces that ``--no-deps`` or ``--only-binary=:all:`` is set.
     """
-    fake_wheel(data, 'fake-1.0-py2.py3-none-any.whl')
+    fake_wheel(data, "fake-1.0-py2.py3-none-any.whl")
 
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--dest', '.',
-        '--platform', 'linux_x86_64',
-        'fake',
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--dest",
+        ".",
+        "--platform",
+        "linux_x86_64",
+        "fake",
         expect_error=True,
     )
-    assert '--only-binary=:all:' in result.stderr
+    assert "--only-binary=:all:" in result.stderr
 
 
 def test_no_binary_set_then_download_specific_platform_fails(script, data):
@@ -222,18 +242,23 @@ def test_no_binary_set_then_download_specific_platform_fails(script, data):
     Confirm that specifying an interpreter/platform constraint
     enforces that ``--only-binary=:all:`` is set without ``--no-binary``.
     """
-    fake_wheel(data, 'fake-1.0-py2.py3-none-any.whl')
+    fake_wheel(data, "fake-1.0-py2.py3-none-any.whl")
 
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--no-binary=fake',
-        '--dest', '.',
-        '--platform', 'linux_x86_64',
-        'fake',
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--no-binary=fake",
+        "--dest",
+        ".",
+        "--platform",
+        "linux_x86_64",
+        "fake",
         expect_error=True,
     )
-    assert '--only-binary=:all:' in result.stderr
+    assert "--only-binary=:all:" in result.stderr
 
 
 def test_download_specify_platform(script, data):
@@ -241,73 +266,98 @@ def test_download_specify_platform(script, data):
     Test using "pip download --platform" to download a .whl archive
     supported for a specific platform
     """
-    fake_wheel(data, 'fake-1.0-py2.py3-none-any.whl')
+    fake_wheel(data, "fake-1.0-py2.py3-none-any.whl")
 
     # Confirm that universal wheels are returned even for specific
     # platforms.
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--platform', 'linux_x86_64',
-        'fake'
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--platform",
+        "linux_x86_64",
+        "fake",
     )
-    result.did_create(Path('scratch') / 'fake-1.0-py2.py3-none-any.whl')
+    result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-any.whl")
 
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--platform', 'macosx_10_9_x86_64',
-        'fake'
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--platform",
+        "macosx_10_9_x86_64",
+        "fake",
     )
 
     data.reset()
-    fake_wheel(data, 'fake-1.0-py2.py3-none-macosx_10_9_x86_64.whl')
-    fake_wheel(data, 'fake-2.0-py2.py3-none-linux_x86_64.whl')
+    fake_wheel(data, "fake-1.0-py2.py3-none-macosx_10_9_x86_64.whl")
+    fake_wheel(data, "fake-2.0-py2.py3-none-linux_x86_64.whl")
 
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--platform', 'macosx_10_10_x86_64',
-        'fake'
-    )
-    result.did_create(
-        Path('scratch') /
-        'fake-1.0-py2.py3-none-macosx_10_9_x86_64.whl'
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--platform",
+        "macosx_10_10_x86_64",
+        "fake",
     )
+    result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-macosx_10_9_x86_64.whl")
 
     # OSX platform wheels are not backward-compatible.
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--platform', 'macosx_10_8_x86_64',
-        'fake',
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--platform",
+        "macosx_10_8_x86_64",
+        "fake",
         expect_error=True,
     )
 
     # No linux wheel provided for this version.
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--platform', 'linux_x86_64',
-        'fake==1',
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--platform",
+        "linux_x86_64",
+        "fake==1",
         expect_error=True,
     )
 
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--platform', 'linux_x86_64',
-        'fake==2'
-    )
-    result.did_create(
-        Path('scratch') / 'fake-2.0-py2.py3-none-linux_x86_64.whl'
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--platform",
+        "linux_x86_64",
+        "fake==2",
     )
+    result.did_create(Path("scratch") / "fake-2.0-py2.py3-none-linux_x86_64.whl")
 
 
 class TestDownloadPlatformManylinuxes(object):
@@ -316,50 +366,70 @@ class TestDownloadPlatformManylinuxes(object):
     manylinux platforms.
     """
 
-    @pytest.mark.parametrize("platform", [
-        "linux_x86_64",
-        "manylinux1_x86_64",
-        "manylinux2010_x86_64",
-        "manylinux2014_x86_64",
-    ])
+    @pytest.mark.parametrize(
+        "platform",
+        [
+            "linux_x86_64",
+            "manylinux1_x86_64",
+            "manylinux2010_x86_64",
+            "manylinux2014_x86_64",
+        ],
+    )
     def test_download_universal(self, platform, script, data):
         """
         Universal wheels are returned even for specific platforms.
         """
-        fake_wheel(data, 'fake-1.0-py2.py3-none-any.whl')
+        fake_wheel(data, "fake-1.0-py2.py3-none-any.whl")
         result = script.pip(
-            'download', '--no-index', '--find-links', data.find_links,
-            '--only-binary=:all:',
-            '--dest', '.',
-            '--platform', platform,
-            'fake',
+            "download",
+            "--no-index",
+            "--find-links",
+            data.find_links,
+            "--only-binary=:all:",
+            "--dest",
+            ".",
+            "--platform",
+            platform,
+            "fake",
         )
-        result.did_create(Path('scratch') / 'fake-1.0-py2.py3-none-any.whl')
-
-    @pytest.mark.parametrize("wheel_abi,platform", [
-        ("manylinux1_x86_64", "manylinux1_x86_64"),
-        ("manylinux1_x86_64", "manylinux2010_x86_64"),
-        ("manylinux2010_x86_64", "manylinux2010_x86_64"),
-        ("manylinux1_x86_64", "manylinux2014_x86_64"),
-        ("manylinux2010_x86_64", "manylinux2014_x86_64"),
-        ("manylinux2014_x86_64", "manylinux2014_x86_64"),
-    ])
+        result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-any.whl")
+
+    @pytest.mark.parametrize(
+        "wheel_abi,platform",
+        [
+            ("manylinux1_x86_64", "manylinux1_x86_64"),
+            ("manylinux1_x86_64", "manylinux2010_x86_64"),
+            ("manylinux2010_x86_64", "manylinux2010_x86_64"),
+            ("manylinux1_x86_64", "manylinux2014_x86_64"),
+            ("manylinux2010_x86_64", "manylinux2014_x86_64"),
+            ("manylinux2014_x86_64", "manylinux2014_x86_64"),
+        ],
+    )
     def test_download_compatible_manylinuxes(
-            self, wheel_abi, platform, script, data,
+        self,
+        wheel_abi,
+        platform,
+        script,
+        data,
     ):
         """
         Earlier manylinuxes are compatible with later manylinuxes.
         """
-        wheel = 'fake-1.0-py2.py3-none-{}.whl'.format(wheel_abi)
+        wheel = "fake-1.0-py2.py3-none-{}.whl".format(wheel_abi)
         fake_wheel(data, wheel)
         result = script.pip(
-            'download', '--no-index', '--find-links', data.find_links,
-            '--only-binary=:all:',
-            '--dest', '.',
-            '--platform', platform,
-            'fake',
+            "download",
+            "--no-index",
+            "--find-links",
+            data.find_links,
+            "--only-binary=:all:",
+            "--dest",
+            ".",
+            "--platform",
+            platform,
+            "fake",
         )
-        result.did_create(Path('scratch') / wheel)
+        result.did_create(Path("scratch") / wheel)
 
     def test_explicit_platform_only(self, data, script):
         """
@@ -367,13 +437,18 @@ def test_explicit_platform_only(self, data, script):
         explicit platform--it won't ever be added to the compatible
         tags.
         """
-        fake_wheel(data, 'fake-1.0-py2.py3-none-linux_x86_64.whl')
+        fake_wheel(data, "fake-1.0-py2.py3-none-linux_x86_64.whl")
         script.pip(
-            'download', '--no-index', '--find-links', data.find_links,
-            '--only-binary=:all:',
-            '--dest', '.',
-            '--platform', 'linux_x86_64',
-            'fake',
+            "download",
+            "--no-index",
+            "--find-links",
+            data.find_links,
+            "--only-binary=:all:",
+            "--dest",
+            ".",
+            "--platform",
+            "linux_x86_64",
+            "fake",
         )
 
 
@@ -382,79 +457,119 @@ def test_download__python_version(script, data):
     Test using "pip download --python-version" to download a .whl archive
     supported for a specific interpreter
     """
-    fake_wheel(data, 'fake-1.0-py2.py3-none-any.whl')
+    fake_wheel(data, "fake-1.0-py2.py3-none-any.whl")
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--python-version', '2',
-        'fake'
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--python-version",
+        "2",
+        "fake",
     )
-    result.did_create(Path('scratch') / 'fake-1.0-py2.py3-none-any.whl')
+    result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-any.whl")
 
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--python-version', '3',
-        'fake'
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--python-version",
+        "3",
+        "fake",
     )
 
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--python-version', '27',
-        'fake'
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--python-version",
+        "27",
+        "fake",
     )
 
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--python-version', '33',
-        'fake'
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--python-version",
+        "33",
+        "fake",
     )
 
     data.reset()
-    fake_wheel(data, 'fake-1.0-py2-none-any.whl')
-    fake_wheel(data, 'fake-2.0-py3-none-any.whl')
+    fake_wheel(data, "fake-1.0-py2-none-any.whl")
+    fake_wheel(data, "fake-2.0-py3-none-any.whl")
 
     # No py3 provided for version 1.
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--python-version', '3',
-        'fake==1.0',
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--python-version",
+        "3",
+        "fake==1.0",
         expect_error=True,
     )
 
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--python-version', '2',
-        'fake'
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--python-version",
+        "2",
+        "fake",
     )
-    result.did_create(Path('scratch') / 'fake-1.0-py2-none-any.whl')
+    result.did_create(Path("scratch") / "fake-1.0-py2-none-any.whl")
 
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--python-version', '26',
-        'fake'
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--python-version",
+        "26",
+        "fake",
     )
 
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--python-version', '3',
-        'fake'
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--python-version",
+        "3",
+        "fake",
     )
-    result.did_create(Path('scratch') / 'fake-2.0-py3-none-any.whl')
+    result.did_create(Path("scratch") / "fake-2.0-py3-none-any.whl")
 
 
 def make_wheel_with_python_requires(script, package_name, python_requires):
@@ -466,52 +581,67 @@ def make_wheel_with_python_requires(script, package_name, python_requires):
     package_dir = script.scratch_path / package_name
     package_dir.mkdir()
 
-    text = textwrap.dedent("""\
+    text = textwrap.dedent(
+        """\
     from setuptools import setup
     setup(name='{}',
           python_requires='{}',
           version='1.0')
-    """).format(package_name, python_requires)
-    package_dir.joinpath('setup.py').write_text(text)
+    """
+    ).format(package_name, python_requires)
+    package_dir.joinpath("setup.py").write_text(text)
     script.run(
-        'python', 'setup.py', 'bdist_wheel', '--universal', cwd=package_dir,
+        "python",
+        "setup.py",
+        "bdist_wheel",
+        "--universal",
+        cwd=package_dir,
         allow_stderr_warning=PY2,
     )
 
-    file_name = '{}-1.0-py2.py3-none-any.whl'.format(package_name)
-    return package_dir / 'dist' / file_name
+    file_name = "{}-1.0-py2.py3-none-any.whl".format(package_name)
+    return package_dir / "dist" / file_name
 
 
 def test_download__python_version_used_for_python_requires(
-    script, data, with_wheel,
+    script,
+    data,
+    with_wheel,
 ):
     """
     Test that --python-version is used for the Requires-Python check.
     """
     wheel_path = make_wheel_with_python_requires(
-        script, 'mypackage', python_requires='==3.2',
+        script,
+        "mypackage",
+        python_requires="==3.2",
     )
     wheel_dir = os.path.dirname(wheel_path)
 
     def make_args(python_version):
         return [
-            'download', '--no-index', '--find-links', wheel_dir,
-            '--only-binary=:all:',
-            '--dest', '.',
-            '--python-version', python_version,
-            'mypackage==1.0',
+            "download",
+            "--no-index",
+            "--find-links",
+            wheel_dir,
+            "--only-binary=:all:",
+            "--dest",
+            ".",
+            "--python-version",
+            python_version,
+            "mypackage==1.0",
         ]
 
-    args = make_args('33')
+    args = make_args("33")
     result = script.pip(*args, expect_error=True)
     expected_err = (
         "ERROR: Package 'mypackage' requires a different Python: "
         "3.3.0 not in '==3.2'"
     )
-    assert expected_err in result.stderr, 'stderr: {}'.format(result.stderr)
+    assert expected_err in result.stderr, "stderr: {}".format(result.stderr)
 
     # Now try with a --python-version that satisfies the Requires-Python.
-    args = make_args('32')
+    args = make_args("32")
     script.pip(*args)  # no exception
 
 
@@ -520,58 +650,88 @@ def test_download_specify_abi(script, data):
     Test using "pip download --abi" to download a .whl archive
     supported for a specific abi
     """
-    fake_wheel(data, 'fake-1.0-py2.py3-none-any.whl')
-    result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--implementation', 'fk',
-        '--abi', 'fake_abi',
-        'fake'
-    )
-    result.did_create(Path('scratch') / 'fake-1.0-py2.py3-none-any.whl')
-
-    result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--implementation', 'fk',
-        '--abi', 'none',
-        'fake'
-    )
-
-    result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--abi', 'cp27m',
-        'fake',
+    fake_wheel(data, "fake-1.0-py2.py3-none-any.whl")
+    result = script.pip(
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--implementation",
+        "fk",
+        "--abi",
+        "fake_abi",
+        "fake",
+    )
+    result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-any.whl")
+
+    result = script.pip(
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--implementation",
+        "fk",
+        "--abi",
+        "none",
+        "fake",
+    )
+
+    result = script.pip(
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--abi",
+        "cp27m",
+        "fake",
     )
 
     data.reset()
-    fake_wheel(data, 'fake-1.0-fk2-fakeabi-fake_platform.whl')
-    result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--python-version', '2',
-        '--implementation', 'fk',
-        '--platform', 'fake_platform',
-        '--abi', 'fakeabi',
-        'fake'
-    )
-    result.did_create(
-        Path('scratch') / 'fake-1.0-fk2-fakeabi-fake_platform.whl'
-    )
-
-    result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--implementation', 'fk',
-        '--platform', 'fake_platform',
-        '--abi', 'none',
-        'fake',
+    fake_wheel(data, "fake-1.0-fk2-fakeabi-fake_platform.whl")
+    result = script.pip(
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--python-version",
+        "2",
+        "--implementation",
+        "fk",
+        "--platform",
+        "fake_platform",
+        "--abi",
+        "fakeabi",
+        "fake",
+    )
+    result.did_create(Path("scratch") / "fake-1.0-fk2-fakeabi-fake_platform.whl")
+
+    result = script.pip(
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--implementation",
+        "fk",
+        "--platform",
+        "fake_platform",
+        "--abi",
+        "none",
+        "fake",
         expect_error=True,
     )
 
@@ -581,35 +741,52 @@ def test_download_specify_implementation(script, data):
     Test using "pip download --abi" to download a .whl archive
     supported for a specific abi
     """
-    fake_wheel(data, 'fake-1.0-py2.py3-none-any.whl')
+    fake_wheel(data, "fake-1.0-py2.py3-none-any.whl")
     result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--implementation', 'fk',
-        'fake'
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--implementation",
+        "fk",
+        "fake",
     )
-    result.did_create(Path('scratch') / 'fake-1.0-py2.py3-none-any.whl')
+    result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-any.whl")
 
     data.reset()
-    fake_wheel(data, 'fake-1.0-fk3-none-any.whl')
-    result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--implementation', 'fk',
-        '--python-version', '3',
-        'fake'
-    )
-    result.did_create(Path('scratch') / 'fake-1.0-fk3-none-any.whl')
-
-    result = script.pip(
-        'download', '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--dest', '.',
-        '--implementation', 'fk',
-        '--python-version', '2',
-        'fake',
+    fake_wheel(data, "fake-1.0-fk3-none-any.whl")
+    result = script.pip(
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--implementation",
+        "fk",
+        "--python-version",
+        "3",
+        "fake",
+    )
+    result.did_create(Path("scratch") / "fake-1.0-fk3-none-any.whl")
+
+    result = script.pip(
+        "download",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--dest",
+        ".",
+        "--implementation",
+        "fk",
+        "--python-version",
+        "2",
+        "fake",
         expect_error=True,
     )
 
@@ -618,10 +795,8 @@ def test_download_exit_status_code_when_no_requirements(script):
     """
     Test download exit status code when no requirements specified
     """
-    result = script.pip('download', expect_error=True)
-    assert (
-        "You must give at least one requirement to download" in result.stderr
-    )
+    result = script.pip("download", expect_error=True)
+    assert "You must give at least one requirement to download" in result.stderr
     assert result.returncode == ERROR
 
 
@@ -630,100 +805,134 @@ def test_download_exit_status_code_when_blank_requirements_file(script):
     Test download exit status code when blank requirements file specified
     """
     script.scratch_path.joinpath("blank.txt").write_text("\n")
-    script.pip('download', '-r', 'blank.txt')
+    script.pip("download", "-r", "blank.txt")
 
 
 def test_download_prefer_binary_when_tarball_higher_than_wheel(script, data):
-    fake_wheel(data, 'source-0.8-py2.py3-none-any.whl')
+    fake_wheel(data, "source-0.8-py2.py3-none-any.whl")
     result = script.pip(
-        'download',
-        '--prefer-binary',
-        '--no-index',
-        '-f', data.packages,
-        '-d', '.', 'source'
+        "download",
+        "--prefer-binary",
+        "--no-index",
+        "-f",
+        data.packages,
+        "-d",
+        ".",
+        "source",
     )
-    result.did_create(Path('scratch') / 'source-0.8-py2.py3-none-any.whl')
-    result.did_not_create(Path('scratch') / 'source-1.0.tar.gz')
+    result.did_create(Path("scratch") / "source-0.8-py2.py3-none-any.whl")
+    result.did_not_create(Path("scratch") / "source-1.0.tar.gz")
 
 
 def test_prefer_binary_tarball_higher_than_wheel_req_file(script, data):
-    fake_wheel(data, 'source-0.8-py2.py3-none-any.whl')
-    script.scratch_path.joinpath("test-req.txt").write_text(textwrap.dedent("""
+    fake_wheel(data, "source-0.8-py2.py3-none-any.whl")
+    script.scratch_path.joinpath("test-req.txt").write_text(
+        textwrap.dedent(
+            """
                 --prefer-binary
                  source
-                """))
+                """
+        )
+    )
     result = script.pip(
-        'download',
-        '-r', script.scratch_path / 'test-req.txt',
-        '--no-index',
-        '-f', data.packages,
-        '-d', '.'
+        "download",
+        "-r",
+        script.scratch_path / "test-req.txt",
+        "--no-index",
+        "-f",
+        data.packages,
+        "-d",
+        ".",
     )
 
-    result.did_create(Path('scratch') / 'source-0.8-py2.py3-none-any.whl')
-    result.did_not_create(Path('scratch') / 'source-1.0.tar.gz')
+    result.did_create(Path("scratch") / "source-0.8-py2.py3-none-any.whl")
+    result.did_not_create(Path("scratch") / "source-1.0.tar.gz")
 
 
 def test_download_prefer_binary_when_wheel_doesnt_satisfy_req(script, data):
-    fake_wheel(data, 'source-0.8-py2.py3-none-any.whl')
-    script.scratch_path.joinpath("test-req.txt").write_text(textwrap.dedent("""
+    fake_wheel(data, "source-0.8-py2.py3-none-any.whl")
+    script.scratch_path.joinpath("test-req.txt").write_text(
+        textwrap.dedent(
+            """
         source>0.9
-        """))
+        """
+        )
+    )
 
     result = script.pip(
-        'download',
-        '--prefer-binary',
-        '--no-index',
-        '-f', data.packages,
-        '-d', '.',
-        '-r', script.scratch_path / 'test-req.txt'
+        "download",
+        "--prefer-binary",
+        "--no-index",
+        "-f",
+        data.packages,
+        "-d",
+        ".",
+        "-r",
+        script.scratch_path / "test-req.txt",
     )
-    result.did_create(Path('scratch') / 'source-1.0.tar.gz')
-    result.did_not_create(Path('scratch') / 'source-0.8-py2.py3-none-any.whl')
+    result.did_create(Path("scratch") / "source-1.0.tar.gz")
+    result.did_not_create(Path("scratch") / "source-0.8-py2.py3-none-any.whl")
 
 
 def test_prefer_binary_when_wheel_doesnt_satisfy_req_req_file(script, data):
-    fake_wheel(data, 'source-0.8-py2.py3-none-any.whl')
-    script.scratch_path.joinpath("test-req.txt").write_text(textwrap.dedent("""
+    fake_wheel(data, "source-0.8-py2.py3-none-any.whl")
+    script.scratch_path.joinpath("test-req.txt").write_text(
+        textwrap.dedent(
+            """
         --prefer-binary
         source>0.9
-        """))
+        """
+        )
+    )
 
     result = script.pip(
-        'download',
-        '--no-index',
-        '-f', data.packages,
-        '-d', '.',
-        '-r', script.scratch_path / 'test-req.txt'
+        "download",
+        "--no-index",
+        "-f",
+        data.packages,
+        "-d",
+        ".",
+        "-r",
+        script.scratch_path / "test-req.txt",
     )
-    result.did_create(Path('scratch') / 'source-1.0.tar.gz')
-    result.did_not_create(Path('scratch') / 'source-0.8-py2.py3-none-any.whl')
+    result.did_create(Path("scratch") / "source-1.0.tar.gz")
+    result.did_not_create(Path("scratch") / "source-0.8-py2.py3-none-any.whl")
 
 
 def test_download_prefer_binary_when_only_tarball_exists(script, data):
     result = script.pip(
-        'download',
-        '--prefer-binary',
-        '--no-index',
-        '-f', data.packages,
-        '-d', '.', 'source'
+        "download",
+        "--prefer-binary",
+        "--no-index",
+        "-f",
+        data.packages,
+        "-d",
+        ".",
+        "source",
     )
-    result.did_create(Path('scratch') / 'source-1.0.tar.gz')
+    result.did_create(Path("scratch") / "source-1.0.tar.gz")
 
 
 def test_prefer_binary_when_only_tarball_exists_req_file(script, data):
-    script.scratch_path.joinpath("test-req.txt").write_text(textwrap.dedent("""
+    script.scratch_path.joinpath("test-req.txt").write_text(
+        textwrap.dedent(
+            """
             --prefer-binary
             source
-            """))
+            """
+        )
+    )
     result = script.pip(
-        'download',
-        '--no-index',
-        '-f', data.packages,
-        '-d', '.',
-        '-r', script.scratch_path / 'test-req.txt'
+        "download",
+        "--no-index",
+        "-f",
+        data.packages,
+        "-d",
+        ".",
+        "-r",
+        script.scratch_path / "test-req.txt",
     )
-    result.did_create(Path('scratch') / 'source-1.0.tar.gz')
+    result.did_create(Path("scratch") / "source-1.0.tar.gz")
 
 
 @pytest.fixture(scope="session")
@@ -734,17 +943,17 @@ def shared_script(tmpdir_factory, script_factory):
 
 
 def test_download_file_url(shared_script, shared_data, tmpdir):
-    download_dir = tmpdir / 'download'
+    download_dir = tmpdir / "download"
     download_dir.mkdir()
-    downloaded_path = download_dir / 'simple-1.0.tar.gz'
+    downloaded_path = download_dir / "simple-1.0.tar.gz"
 
-    simple_pkg = shared_data.packages / 'simple-1.0.tar.gz'
+    simple_pkg = shared_data.packages / "simple-1.0.tar.gz"
 
     shared_script.pip(
-        'download',
-        '-d',
+        "download",
+        "-d",
         str(download_dir),
-        '--no-index',
+        "--no-index",
         path_to_url(str(simple_pkg)),
     )
 
@@ -752,69 +961,61 @@ def test_download_file_url(shared_script, shared_data, tmpdir):
     assert simple_pkg.read_bytes() == downloaded_path.read_bytes()
 
 
-def test_download_file_url_existing_ok_download(
-    shared_script, shared_data, tmpdir
-):
-    download_dir = tmpdir / 'download'
+def test_download_file_url_existing_ok_download(shared_script, shared_data, tmpdir):
+    download_dir = tmpdir / "download"
     download_dir.mkdir()
-    downloaded_path = download_dir / 'simple-1.0.tar.gz'
-    fake_existing_package = shared_data.packages / 'simple-2.0.tar.gz'
+    downloaded_path = download_dir / "simple-1.0.tar.gz"
+    fake_existing_package = shared_data.packages / "simple-2.0.tar.gz"
     shutil.copy(str(fake_existing_package), str(downloaded_path))
     downloaded_path_bytes = downloaded_path.read_bytes()
     digest = sha256(downloaded_path_bytes).hexdigest()
 
-    simple_pkg = shared_data.packages / 'simple-1.0.tar.gz'
+    simple_pkg = shared_data.packages / "simple-1.0.tar.gz"
     url = "{}#sha256={}".format(path_to_url(simple_pkg), digest)
 
-    shared_script.pip('download', '-d', str(download_dir), url)
+    shared_script.pip("download", "-d", str(download_dir), url)
 
     assert downloaded_path_bytes == downloaded_path.read_bytes()
 
 
-def test_download_file_url_existing_bad_download(
-    shared_script, shared_data, tmpdir
-):
-    download_dir = tmpdir / 'download'
+def test_download_file_url_existing_bad_download(shared_script, shared_data, tmpdir):
+    download_dir = tmpdir / "download"
     download_dir.mkdir()
-    downloaded_path = download_dir / 'simple-1.0.tar.gz'
-    fake_existing_package = shared_data.packages / 'simple-2.0.tar.gz'
+    downloaded_path = download_dir / "simple-1.0.tar.gz"
+    fake_existing_package = shared_data.packages / "simple-2.0.tar.gz"
     shutil.copy(str(fake_existing_package), str(downloaded_path))
 
-    simple_pkg = shared_data.packages / 'simple-1.0.tar.gz'
+    simple_pkg = shared_data.packages / "simple-1.0.tar.gz"
     simple_pkg_bytes = simple_pkg.read_bytes()
     digest = sha256(simple_pkg_bytes).hexdigest()
     url = "{}#sha256={}".format(path_to_url(simple_pkg), digest)
 
-    shared_script.pip('download', '-d', str(download_dir), url)
+    shared_script.pip("download", "-d", str(download_dir), url)
 
     assert simple_pkg_bytes == downloaded_path.read_bytes()
 
 
-def test_download_http_url_bad_hash(
-    shared_script, shared_data, tmpdir, mock_server
-):
-    download_dir = tmpdir / 'download'
+def test_download_http_url_bad_hash(shared_script, shared_data, tmpdir, mock_server):
+    download_dir = tmpdir / "download"
     download_dir.mkdir()
-    downloaded_path = download_dir / 'simple-1.0.tar.gz'
-    fake_existing_package = shared_data.packages / 'simple-2.0.tar.gz'
+    downloaded_path = download_dir / "simple-1.0.tar.gz"
+    fake_existing_package = shared_data.packages / "simple-2.0.tar.gz"
     shutil.copy(str(fake_existing_package), str(downloaded_path))
 
-    simple_pkg = shared_data.packages / 'simple-1.0.tar.gz'
+    simple_pkg = shared_data.packages / "simple-1.0.tar.gz"
     simple_pkg_bytes = simple_pkg.read_bytes()
     digest = sha256(simple_pkg_bytes).hexdigest()
-    mock_server.set_responses([
-        file_response(simple_pkg)
-    ])
+    mock_server.set_responses([file_response(simple_pkg)])
     mock_server.start()
-    base_address = 'http://{}:{}'.format(mock_server.host, mock_server.port)
+    base_address = "http://{}:{}".format(mock_server.host, mock_server.port)
     url = "{}/simple-1.0.tar.gz#sha256={}".format(base_address, digest)
 
-    shared_script.pip('download', '-d', str(download_dir), url)
+    shared_script.pip("download", "-d", str(download_dir), url)
 
     assert simple_pkg_bytes == downloaded_path.read_bytes()
 
     mock_server.stop()
     requests = mock_server.get_requests()
     assert len(requests) == 1
-    assert requests[0]['PATH_INFO'] == '/simple-1.0.tar.gz'
-    assert requests[0]['HTTP_ACCEPT_ENCODING'] == 'identity'
+    assert requests[0]["PATH_INFO"] == "/simple-1.0.tar.gz"
+    assert requests[0]["HTTP_ACCEPT_ENCODING"] == "identity"
diff --git a/tests/functional/test_fast_deps.py b/tests/functional/test_fast_deps.py
index 655440b881b..bfdab4285f5 100644
--- a/tests/functional/test_fast_deps.py
+++ b/tests/functional/test_fast_deps.py
@@ -8,72 +8,87 @@
 
 def pip(script, command, requirement):
     return script.pip(
-        command, '--prefer-binary', '--no-cache-dir',
-        '--use-feature=fast-deps', requirement,
+        command,
+        "--prefer-binary",
+        "--no-cache-dir",
+        "--use-feature=fast-deps",
+        requirement,
         allow_stderr_warning=True,
     )
 
 
 def assert_installed(script, names):
-    list_output = json.loads(script.pip('list', '--format=json').stdout)
-    installed = {canonicalize_name(item['name']) for item in list_output}
+    list_output = json.loads(script.pip("list", "--format=json").stdout)
+    installed = {canonicalize_name(item["name"]) for item in list_output}
     assert installed.issuperset(map(canonicalize_name, names))
 
 
 @mark.network
-@mark.parametrize(('requirement', 'expected'), (
-    ('Paste==3.4.2', ('Paste', 'six')),
-    ('Paste[flup]==3.4.2', ('Paste', 'six', 'flup')),
-))
+@mark.parametrize(
+    ("requirement", "expected"),
+    (
+        ("Paste==3.4.2", ("Paste", "six")),
+        ("Paste[flup]==3.4.2", ("Paste", "six", "flup")),
+    ),
+)
 def test_install_from_pypi(requirement, expected, script):
-    pip(script, 'install', requirement)
+    pip(script, "install", requirement)
     assert_installed(script, expected)
 
 
 @mark.network
-@mark.parametrize(('requirement', 'expected'), (
-    ('Paste==3.4.2', ('Paste-3.4.2-*.whl', 'six-*.whl')),
-    ('Paste[flup]==3.4.2', ('Paste-3.4.2-*.whl', 'six-*.whl', 'flup-*')),
-))
+@mark.parametrize(
+    ("requirement", "expected"),
+    (
+        ("Paste==3.4.2", ("Paste-3.4.2-*.whl", "six-*.whl")),
+        ("Paste[flup]==3.4.2", ("Paste-3.4.2-*.whl", "six-*.whl", "flup-*")),
+    ),
+)
 def test_download_from_pypi(requirement, expected, script):
-    result = pip(script, 'download', requirement)
+    result = pip(script, "download", requirement)
     created = list(map(basename, result.files_created))
     assert all(fnmatch.filter(created, f) for f in expected)
 
 
 @mark.network
 def test_build_wheel_with_deps(data, script):
-    result = pip(script, 'wheel', data.packages/'requiresPaste')
+    result = pip(script, "wheel", data.packages / "requiresPaste")
     created = list(map(basename, result.files_created))
-    assert fnmatch.filter(created, 'requiresPaste-3.1.4-*.whl')
-    assert fnmatch.filter(created, 'Paste-3.4.2-*.whl')
-    assert fnmatch.filter(created, 'six-*.whl')
+    assert fnmatch.filter(created, "requiresPaste-3.1.4-*.whl")
+    assert fnmatch.filter(created, "Paste-3.4.2-*.whl")
+    assert fnmatch.filter(created, "six-*.whl")
 
 
 @mark.network
 def test_require_hash(script, tmp_path):
-    reqs = tmp_path / 'requirements.txt'
+    reqs = tmp_path / "requirements.txt"
     reqs.write_text(
-        u'idna==2.10'
-        ' --hash=sha256:'
-        'b97d804b1e9b523befed77c48dacec60e6dcb0b5391d57af6a65a312a90648c0'
-        ' --hash=sha256:'
-        'b307872f855b18632ce0c21c5e45be78c0ea7ae4c15c828c20788b26921eb3f6'
+        u"idna==2.10"
+        " --hash=sha256:"
+        "b97d804b1e9b523befed77c48dacec60e6dcb0b5391d57af6a65a312a90648c0"
+        " --hash=sha256:"
+        "b307872f855b18632ce0c21c5e45be78c0ea7ae4c15c828c20788b26921eb3f6"
     )
     result = script.pip(
-        'download', '--use-feature=fast-deps', '-r', str(reqs),
+        "download",
+        "--use-feature=fast-deps",
+        "-r",
+        str(reqs),
         allow_stderr_warning=True,
     )
     created = list(map(basename, result.files_created))
-    assert fnmatch.filter(created, 'idna-2.10*')
+    assert fnmatch.filter(created, "idna-2.10*")
 
 
 @mark.network
 def test_hash_mismatch(script, tmp_path):
-    reqs = tmp_path / 'requirements.txt'
-    reqs.write_text(u'idna==2.10 --hash=sha256:irna')
+    reqs = tmp_path / "requirements.txt"
+    reqs.write_text(u"idna==2.10 --hash=sha256:irna")
     result = script.pip(
-        'download', '--use-feature=fast-deps', '-r', str(reqs),
+        "download",
+        "--use-feature=fast-deps",
+        "-r",
+        str(reqs),
         expect_error=True,
     )
-    assert 'DO NOT MATCH THE HASHES' in result.stderr
+    assert "DO NOT MATCH THE HASHES" in result.stderr
diff --git a/tests/functional/test_freeze.py b/tests/functional/test_freeze.py
index ef22169869b..77f423a9484 100644
--- a/tests/functional/test_freeze.py
+++ b/tests/functional/test_freeze.py
@@ -18,7 +18,7 @@
     path_to_url,
 )
 
-distribute_re = re.compile('^distribute==[0-9.]+\n', re.MULTILINE)
+distribute_re = re.compile("^distribute==[0-9.]+\n", re.MULTILINE)
 
 
 def _check_output(result, expected):
@@ -33,19 +33,18 @@ def _check_output(result, expected):
     # but then you have to remember to upcase <BLANKLINE>.  The right
     # thing to do in the end is probably to find out how to report
     # the proper fully-cased package name in our error message.
-    if sys.platform == 'win32':
-        actual = actual.replace('initools', 'INITools')
+    if sys.platform == "win32":
+        actual = actual.replace("initools", "INITools")
 
     # This allows our existing tests to work when run in a context
     # with distribute installed.
-    actual = distribute_re.sub('', actual)
+    actual = distribute_re.sub("", actual)
 
     def banner(msg):
-        return '\n========== {msg} ==========\n'.format(**locals())
+        return "\n========== {msg} ==========\n".format(**locals())
 
     assert checker.check_output(expected, actual, ELLIPSIS), (
-        banner('EXPECTED') + expected + banner('ACTUAL') + actual +
-        banner(6 * '=')
+        banner("EXPECTED") + expected + banner("ACTUAL") + actual + banner(6 * "=")
     )
 
 
@@ -58,26 +57,33 @@ def test_basic_freeze(script):
     currently it is not).
 
     """
-    script.scratch_path.joinpath("initools-req.txt").write_text(textwrap.dedent("""\
+    script.scratch_path.joinpath("initools-req.txt").write_text(
+        textwrap.dedent(
+            """\
         simple==2.0
         # and something else to test out:
         simple2<=3.0
-        """))
+        """
+        )
+    )
     script.pip_install_local(
-        '-r', script.scratch_path / 'initools-req.txt',
+        "-r",
+        script.scratch_path / "initools-req.txt",
     )
-    result = script.pip('freeze', expect_stderr=True)
-    expected = textwrap.dedent("""\
+    result = script.pip("freeze", expect_stderr=True)
+    expected = textwrap.dedent(
+        """\
         ...simple==2.0
         simple2==3.0...
-        <BLANKLINE>""")
+        <BLANKLINE>"""
+    )
     _check_output(result.stdout, expected)
 
 
 def test_freeze_with_pip(script):
     """Test pip shows itself"""
-    result = script.pip('freeze', '--all')
-    assert 'pip==' in result.stdout
+    result = script.pip("freeze", "--all")
+    assert "pip==" in result.stdout
 
 
 def test_freeze_with_invalid_names(script):
@@ -87,39 +93,43 @@ def test_freeze_with_invalid_names(script):
 
     def fake_install(pkgname, dest):
         egg_info_path = os.path.join(
-            dest, '{}-1.0-py{}.{}.egg-info'.format(
-                pkgname.replace('-', '_'),
-                sys.version_info[0],
-                sys.version_info[1]
-            )
+            dest,
+            "{}-1.0-py{}.{}.egg-info".format(
+                pkgname.replace("-", "_"), sys.version_info[0], sys.version_info[1]
+            ),
         )
-        with open(egg_info_path, 'w') as egg_info_file:
-            egg_info_file.write(textwrap.dedent("""\
+        with open(egg_info_path, "w") as egg_info_file:
+            egg_info_file.write(
+                textwrap.dedent(
+                    """\
                 Metadata-Version: 1.0
                 Name: {}
                 Version: 1.0
-                """.format(pkgname)
-            ))
+                """.format(
+                        pkgname
+                    )
+                )
+            )
 
-    valid_pkgnames = ('middle-dash', 'middle_underscore', 'middle.dot')
+    valid_pkgnames = ("middle-dash", "middle_underscore", "middle.dot")
     invalid_pkgnames = (
-        '-leadingdash', '_leadingunderscore', '.leadingdot',
-        'trailingdash-', 'trailingunderscore_', 'trailingdot.'
+        "-leadingdash",
+        "_leadingunderscore",
+        ".leadingdot",
+        "trailingdash-",
+        "trailingunderscore_",
+        "trailingdot.",
     )
     for pkgname in valid_pkgnames + invalid_pkgnames:
         fake_install(pkgname, script.site_packages_path)
-    result = script.pip('freeze', expect_stderr=True)
+    result = script.pip("freeze", expect_stderr=True)
     for pkgname in valid_pkgnames:
-        _check_output(
-            result.stdout,
-            '...{}==1.0...'.format(pkgname.replace('_', '-'))
-        )
+        _check_output(result.stdout, "...{}==1.0...".format(pkgname.replace("_", "-")))
     for pkgname in invalid_pkgnames:
         # Check that the full distribution repr is present.
-        dist_repr = '{} 1.0 ('.format(pkgname.replace('_', '-'))
-        expected = (
-            '...Could not generate requirement for '
-            'distribution {}...'.format(dist_repr)
+        dist_repr = "{} 1.0 (".format(pkgname.replace("_", "-"))
+        expected = "...Could not generate requirement for " "distribution {}...".format(
+            dist_repr
         )
         _check_output(result.stderr, expected)
 
@@ -138,16 +148,20 @@ def test_freeze_editable_not_vcs(script, tmpdir):
     pkg_path = _create_test_package(script)
     # Rename the .git directory so the directory is no longer recognized
     # as a VCS directory.
-    os.rename(os.path.join(pkg_path, '.git'), os.path.join(pkg_path, '.bak'))
-    script.pip('install', '-e', pkg_path)
-    result = script.pip('freeze')
+    os.rename(os.path.join(pkg_path, ".git"), os.path.join(pkg_path, ".bak"))
+    script.pip("install", "-e", pkg_path)
+    result = script.pip("freeze")
 
     # We need to apply os.path.normcase() to the path since that is what
     # the freeze code does.
-    expected = textwrap.dedent("""\
+    expected = textwrap.dedent(
+        """\
     ...# Editable install with no version control (version-pkg==0.1)
     -e {}
-    ...""".format(os.path.normcase(pkg_path)))
+    ...""".format(
+            os.path.normcase(pkg_path)
+        )
+    )
     _check_output(result.stdout, expected)
 
 
@@ -157,18 +171,22 @@ def test_freeze_editable_git_with_no_remote(script, tmpdir, deprecated_python):
     Test an editable Git install with no remote url.
     """
     pkg_path = _create_test_package(script)
-    script.pip('install', '-e', pkg_path)
-    result = script.pip('freeze')
+    script.pip("install", "-e", pkg_path)
+    result = script.pip("freeze")
 
     if not deprecated_python:
-        assert result.stderr == ''
+        assert result.stderr == ""
 
     # We need to apply os.path.normcase() to the path since that is what
     # the freeze code does.
-    expected = textwrap.dedent("""\
+    expected = textwrap.dedent(
+        """\
     ...# Editable Git install with no remote (version-pkg==0.1)
     -e {}
-    ...""".format(os.path.normcase(pkg_path)))
+    ...""".format(
+            os.path.normcase(pkg_path)
+        )
+    )
     _check_output(result.stdout, expected)
 
 
@@ -176,17 +194,16 @@ def test_freeze_editable_git_with_no_remote(script, tmpdir, deprecated_python):
 def test_freeze_svn(script, tmpdir):
     """Test freezing a svn checkout"""
 
-    checkout_path = _create_test_package(script, vcs='svn')
+    checkout_path = _create_test_package(script, vcs="svn")
 
     # Install with develop
-    script.run(
-        'python', 'setup.py', 'develop',
-        cwd=checkout_path, expect_stderr=True
-    )
-    result = script.pip('freeze', expect_stderr=True)
-    expected = textwrap.dedent("""\
+    script.run("python", "setup.py", "develop", cwd=checkout_path, expect_stderr=True)
+    result = script.pip("freeze", expect_stderr=True)
+    expected = textwrap.dedent(
+        """\
         ...-e svn+...#egg=version_pkg
-        ...""")
+        ..."""
+    )
     _check_output(result.stdout, expected)
 
 
@@ -205,16 +222,21 @@ def test_freeze_exclude_editable(script, tmpdir):
     pkg_version = _create_test_package(script)
 
     result = script.run(
-        'git', 'clone', pkg_version, 'pip-test-package',
+        "git",
+        "clone",
+        pkg_version,
+        "pip-test-package",
         expect_stderr=True,
     )
-    repo_dir = script.scratch_path / 'pip-test-package'
+    repo_dir = script.scratch_path / "pip-test-package"
     result = script.run(
-        'python', 'setup.py', 'develop',
+        "python",
+        "setup.py",
+        "develop",
         cwd=repo_dir,
         expect_stderr=True,
     )
-    result = script.pip('freeze', '--exclude-editable', expect_stderr=True)
+    result = script.pip("freeze", "--exclude-editable", expect_stderr=True)
     expected = textwrap.dedent(
         """
             ...-e git+...#egg=version_pkg
@@ -233,16 +255,21 @@ def test_freeze_git_clone(script, tmpdir):
     pkg_version = _create_test_package(script)
 
     result = script.run(
-        'git', 'clone', pkg_version, 'pip-test-package',
+        "git",
+        "clone",
+        pkg_version,
+        "pip-test-package",
         expect_stderr=True,
     )
-    repo_dir = script.scratch_path / 'pip-test-package'
+    repo_dir = script.scratch_path / "pip-test-package"
     result = script.run(
-        'python', 'setup.py', 'develop',
+        "python",
+        "setup.py",
+        "develop",
         cwd=repo_dir,
         expect_stderr=True,
     )
-    result = script.pip('freeze', expect_stderr=True)
+    result = script.pip("freeze", expect_stderr=True)
     expected = textwrap.dedent(
         """
             ...-e git+...#egg=version_pkg
@@ -252,7 +279,9 @@ def test_freeze_git_clone(script, tmpdir):
     _check_output(result.stdout, expected)
 
     result = script.pip(
-        'freeze', '-f', '{repo_dir}#egg=pip_test_package'.format(**locals()),
+        "freeze",
+        "-f",
+        "{repo_dir}#egg=pip_test_package".format(**locals()),
         expect_stderr=True,
     )
     expected = textwrap.dedent(
@@ -260,24 +289,29 @@ def test_freeze_git_clone(script, tmpdir):
             -f {repo}#egg=pip_test_package...
             -e git+...#egg=version_pkg
             ...
-        """.format(repo=repo_dir),
+        """.format(
+            repo=repo_dir
+        ),
     ).strip()
     _check_output(result.stdout, expected)
 
     # Check that slashes in branch or tag names are translated.
     # See also issue #1083: https://github.com/pypa/pip/issues/1083
     script.run(
-        'git', 'checkout', '-b', 'branch/name/with/slash',
+        "git",
+        "checkout",
+        "-b",
+        "branch/name/with/slash",
         cwd=repo_dir,
         expect_stderr=True,
     )
     # Create a new commit to ensure that the commit has only one branch
     # or tag name associated to it (to avoid the non-determinism reported
     # in issue #1867).
-    (repo_dir / 'newfile').touch()
-    script.run('git', 'add', 'newfile', cwd=repo_dir)
-    _git_commit(script, repo_dir, message='...')
-    result = script.pip('freeze', expect_stderr=True)
+    (repo_dir / "newfile").touch()
+    script.run("git", "add", "newfile", cwd=repo_dir)
+    _git_commit(script, repo_dir, message="...")
+    result = script.pip("freeze", expect_stderr=True)
     expected = textwrap.dedent(
         """
             ...-e ...@...#egg=version_pkg
@@ -298,16 +332,21 @@ def test_freeze_git_clone_srcdir(script, tmpdir):
     pkg_version = _create_test_package_with_srcdir(script)
 
     result = script.run(
-        'git', 'clone', pkg_version, 'pip-test-package',
+        "git",
+        "clone",
+        pkg_version,
+        "pip-test-package",
         expect_stderr=True,
     )
-    repo_dir = script.scratch_path / 'pip-test-package'
+    repo_dir = script.scratch_path / "pip-test-package"
     result = script.run(
-        'python', 'setup.py', 'develop',
-        cwd=repo_dir / 'subdir',
+        "python",
+        "setup.py",
+        "develop",
+        cwd=repo_dir / "subdir",
         expect_stderr=True,
     )
-    result = script.pip('freeze', expect_stderr=True)
+    result = script.pip("freeze", expect_stderr=True)
     expected = textwrap.dedent(
         """
             ...-e git+...#egg=version_pkg&subdirectory=subdir
@@ -317,7 +356,9 @@ def test_freeze_git_clone_srcdir(script, tmpdir):
     _check_output(result.stdout, expected)
 
     result = script.pip(
-        'freeze', '-f', '{repo_dir}#egg=pip_test_package'.format(**locals()),
+        "freeze",
+        "-f",
+        "{repo_dir}#egg=pip_test_package".format(**locals()),
         expect_stderr=True,
     )
     expected = textwrap.dedent(
@@ -325,7 +366,9 @@ def test_freeze_git_clone_srcdir(script, tmpdir):
             -f {repo}#egg=pip_test_package...
             -e git+...#egg=version_pkg&subdirectory=subdir
             ...
-        """.format(repo=repo_dir),
+        """.format(
+            repo=repo_dir
+        ),
     ).strip()
     _check_output(result.stdout, expected)
 
@@ -338,17 +381,12 @@ def test_freeze_mercurial_clone_srcdir(script, tmpdir):
     relative to setup.py.
     """
     # Returns path to a generated package called "version_pkg"
-    pkg_version = _create_test_package_with_srcdir(script, vcs='hg')
+    pkg_version = _create_test_package_with_srcdir(script, vcs="hg")
 
-    result = script.run(
-        'hg', 'clone', pkg_version, 'pip-test-package'
-    )
-    repo_dir = script.scratch_path / 'pip-test-package'
-    result = script.run(
-        'python', 'setup.py', 'develop',
-        cwd=repo_dir / 'subdir'
-    )
-    result = script.pip('freeze')
+    result = script.run("hg", "clone", pkg_version, "pip-test-package")
+    repo_dir = script.scratch_path / "pip-test-package"
+    result = script.run("python", "setup.py", "develop", cwd=repo_dir / "subdir")
+    result = script.pip("freeze")
     expected = textwrap.dedent(
         """
             ...-e hg+...#egg=version_pkg&subdirectory=subdir
@@ -358,14 +396,16 @@ def test_freeze_mercurial_clone_srcdir(script, tmpdir):
     _check_output(result.stdout, expected)
 
     result = script.pip(
-        'freeze', '-f', '{repo_dir}#egg=pip_test_package'.format(**locals())
+        "freeze", "-f", "{repo_dir}#egg=pip_test_package".format(**locals())
     )
     expected = textwrap.dedent(
         """
             -f {repo}#egg=pip_test_package...
             -e hg+...#egg=version_pkg&subdirectory=subdir
             ...
-        """.format(repo=repo_dir),
+        """.format(
+            repo=repo_dir
+        ),
     ).strip()
     _check_output(result.stdout, expected)
 
@@ -379,47 +419,64 @@ def test_freeze_git_remote(script, tmpdir):
     pkg_version = _create_test_package(script)
 
     result = script.run(
-        'git', 'clone', pkg_version, 'pip-test-package',
+        "git",
+        "clone",
+        pkg_version,
+        "pip-test-package",
         expect_stderr=True,
     )
-    repo_dir = script.scratch_path / 'pip-test-package'
+    repo_dir = script.scratch_path / "pip-test-package"
     result = script.run(
-        'python', 'setup.py', 'develop',
+        "python",
+        "setup.py",
+        "develop",
         cwd=repo_dir,
         expect_stderr=True,
     )
     origin_remote = pkg_version
-    other_remote = pkg_version + '-other'
+    other_remote = pkg_version + "-other"
     # check frozen remote after clone
-    result = script.pip('freeze', expect_stderr=True)
-    expected = textwrap.dedent(
-        """
+    result = script.pip("freeze", expect_stderr=True)
+    expected = (
+        textwrap.dedent(
+            """
             ...-e git+{remote}@...#egg=version_pkg
             ...
         """
-    ).format(remote=origin_remote).strip()
+        )
+        .format(remote=origin_remote)
+        .strip()
+    )
     _check_output(result.stdout, expected)
     # check frozen remote when there is no remote named origin
-    script.run('git', 'remote', 'remove', 'origin', cwd=repo_dir)
-    script.run('git', 'remote', 'add', 'other', other_remote, cwd=repo_dir)
-    result = script.pip('freeze', expect_stderr=True)
-    expected = textwrap.dedent(
-        """
+    script.run("git", "remote", "remove", "origin", cwd=repo_dir)
+    script.run("git", "remote", "add", "other", other_remote, cwd=repo_dir)
+    result = script.pip("freeze", expect_stderr=True)
+    expected = (
+        textwrap.dedent(
+            """
             ...-e git+{remote}@...#egg=version_pkg
             ...
         """
-    ).format(remote=other_remote).strip()
+        )
+        .format(remote=other_remote)
+        .strip()
+    )
     _check_output(result.stdout, expected)
     # when there are more than one origin, priority is given to the
     # remote named origin
-    script.run('git', 'remote', 'add', 'origin', origin_remote, cwd=repo_dir)
-    result = script.pip('freeze', expect_stderr=True)
-    expected = textwrap.dedent(
-        """
+    script.run("git", "remote", "add", "origin", origin_remote, cwd=repo_dir)
+    result = script.pip("freeze", expect_stderr=True)
+    expected = (
+        textwrap.dedent(
+            """
             ...-e git+{remote}@...#egg=version_pkg
             ...
         """
-    ).format(remote=origin_remote).strip()
+        )
+        .format(remote=origin_remote)
+        .strip()
+    )
     _check_output(result.stdout, expected)
 
 
@@ -430,19 +487,24 @@ def test_freeze_mercurial_clone(script, tmpdir):
 
     """
     # Returns path to a generated package called "version_pkg"
-    pkg_version = _create_test_package(script, vcs='hg')
+    pkg_version = _create_test_package(script, vcs="hg")
 
     result = script.run(
-        'hg', 'clone', pkg_version, 'pip-test-package',
+        "hg",
+        "clone",
+        pkg_version,
+        "pip-test-package",
         expect_stderr=True,
     )
-    repo_dir = script.scratch_path / 'pip-test-package'
+    repo_dir = script.scratch_path / "pip-test-package"
     result = script.run(
-        'python', 'setup.py', 'develop',
+        "python",
+        "setup.py",
+        "develop",
         cwd=repo_dir,
         expect_stderr=True,
     )
-    result = script.pip('freeze', expect_stderr=True)
+    result = script.pip("freeze", expect_stderr=True)
     expected = textwrap.dedent(
         """
             ...-e hg+...#egg=version_pkg
@@ -452,7 +514,9 @@ def test_freeze_mercurial_clone(script, tmpdir):
     _check_output(result.stdout, expected)
 
     result = script.pip(
-        'freeze', '-f', '{repo_dir}#egg=pip_test_package'.format(**locals()),
+        "freeze",
+        "-f",
+        "{repo_dir}#egg=pip_test_package".format(**locals()),
         expect_stderr=True,
     )
     expected = textwrap.dedent(
@@ -460,7 +524,9 @@ def test_freeze_mercurial_clone(script, tmpdir):
             -f {repo}#egg=pip_test_package...
             ...-e hg+...#egg=version_pkg
             ...
-        """.format(repo=repo_dir),
+        """.format(
+            repo=repo_dir
+        ),
     ).strip()
     _check_output(result.stdout, expected)
 
@@ -472,33 +538,40 @@ def test_freeze_bazaar_clone(script, tmpdir):
 
     """
     try:
-        checkout_path = _create_test_package(script, vcs='bazaar')
+        checkout_path = _create_test_package(script, vcs="bazaar")
     except OSError as e:
-        pytest.fail('Invoking `bzr` failed: {e}'.format(e=e))
+        pytest.fail("Invoking `bzr` failed: {e}".format(e=e))
 
+    result = script.run("bzr", "checkout", checkout_path, "bzr-package")
     result = script.run(
-        'bzr', 'checkout', checkout_path, 'bzr-package'
-    )
-    result = script.run(
-        'python', 'setup.py', 'develop',
-        cwd=script.scratch_path / 'bzr-package',
+        "python",
+        "setup.py",
+        "develop",
+        cwd=script.scratch_path / "bzr-package",
         expect_stderr=True,
     )
-    result = script.pip('freeze', expect_stderr=True)
-    expected = textwrap.dedent("""\
+    result = script.pip("freeze", expect_stderr=True)
+    expected = textwrap.dedent(
+        """\
         ...-e bzr+file://...@1#egg=version_pkg
-        ...""")
+        ..."""
+    )
     _check_output(result.stdout, expected)
 
     result = script.pip(
-        'freeze', '-f',
-        '{checkout_path}/#egg=django-wikiapp'.format(**locals()),
+        "freeze",
+        "-f",
+        "{checkout_path}/#egg=django-wikiapp".format(**locals()),
         expect_stderr=True,
     )
-    expected = textwrap.dedent("""\
+    expected = textwrap.dedent(
+        """\
         -f {repo}/#egg=django-wikiapp
         ...-e bzr+file://...@...#egg=version_pkg
-        ...""".format(repo=checkout_path))
+        ...""".format(
+            repo=checkout_path
+        )
+    )
     _check_output(result.stdout, expected)
 
 
@@ -509,8 +582,7 @@ def test_freeze_bazaar_clone(script, tmpdir):
     [("hg", "git"), ("git", "hg")],
 )
 def test_freeze_nested_vcs(script, outer_vcs, inner_vcs):
-    """Test VCS can be correctly freezed when resides inside another VCS repo.
-    """
+    """Test VCS can be correctly freezed when resides inside another VCS repo."""
     # Create Python package.
     pkg_path = _create_test_package(script, vcs=inner_vcs)
 
@@ -536,7 +608,8 @@ def test_freeze_nested_vcs(script, outer_vcs, inner_vcs):
 
 
 # used by the test_freeze_with_requirement_* tests below
-_freeze_req_opts = textwrap.dedent("""\
+_freeze_req_opts = textwrap.dedent(
+    """\
     # Unchanged requirements below this line
     -r ignore.txt
     --requirement ignore.txt
@@ -549,25 +622,30 @@ def test_freeze_nested_vcs(script, outer_vcs, inner_vcs):
     --find-links http://ignore
     --index-url http://ignore
     --use-feature 2020-resolver
-""")
+"""
+)
 
 
 def test_freeze_with_requirement_option_file_url_egg_not_installed(
-        script, deprecated_python):
+    script, deprecated_python
+):
     """
     Test "freeze -r requirements.txt" with a local file URL whose egg name
     is not installed.
     """
 
-    url = path_to_url('my-package.tar.gz') + '#egg=Does.Not-Exist'
-    requirements_path = script.scratch_path.joinpath('requirements.txt')
-    requirements_path.write_text(url + '\n')
+    url = path_to_url("my-package.tar.gz") + "#egg=Does.Not-Exist"
+    requirements_path = script.scratch_path.joinpath("requirements.txt")
+    requirements_path.write_text(url + "\n")
 
     result = script.pip(
-        'freeze', '--requirement', 'requirements.txt', expect_stderr=True,
+        "freeze",
+        "--requirement",
+        "requirements.txt",
+        expect_stderr=True,
     )
     expected_err = (
-        'WARNING: Requirement file [requirements.txt] contains {}, '
+        "WARNING: Requirement file [requirements.txt] contains {}, "
         "but package 'Does.Not-Exist' is not installed\n"
     ).format(url)
     if deprecated_python:
@@ -582,26 +660,40 @@ def test_freeze_with_requirement_option(script):
 
     """
 
-    script.scratch_path.joinpath("hint1.txt").write_text(textwrap.dedent("""\
+    script.scratch_path.joinpath("hint1.txt").write_text(
+        textwrap.dedent(
+            """\
         INITools==0.1
         NoExist==4.2  # A comment that ensures end of line comments work.
         simple==3.0; python_version > '1.0'
-        """) + _freeze_req_opts)
-    script.scratch_path.joinpath("hint2.txt").write_text(textwrap.dedent("""\
+        """
+        )
+        + _freeze_req_opts
+    )
+    script.scratch_path.joinpath("hint2.txt").write_text(
+        textwrap.dedent(
+            """\
         iniTools==0.1
         Noexist==4.2  # A comment that ensures end of line comments work.
         Simple==3.0; python_version > '1.0'
-        """) + _freeze_req_opts)
-    result = script.pip_install_local('initools==0.2')
-    result = script.pip_install_local('simple')
+        """
+        )
+        + _freeze_req_opts
+    )
+    result = script.pip_install_local("initools==0.2")
+    result = script.pip_install_local("simple")
     result = script.pip(
-        'freeze', '--requirement', 'hint1.txt',
+        "freeze",
+        "--requirement",
+        "hint1.txt",
         expect_stderr=True,
     )
-    expected = textwrap.dedent("""\
+    expected = textwrap.dedent(
+        """\
         INITools==0.2
         simple==3.0
-    """)
+    """
+    )
     expected += _freeze_req_opts
     expected += "## The following requirements were added by pip freeze:..."
     _check_output(result.stdout, expected)
@@ -610,7 +702,9 @@ def test_freeze_with_requirement_option(script):
         "'NoExist' is not installed"
     ) in result.stderr
     result = script.pip(
-        'freeze', '--requirement', 'hint2.txt',
+        "freeze",
+        "--requirement",
+        "hint2.txt",
         expect_stderr=True,
     )
     _check_output(result.stdout, expected)
@@ -626,35 +720,55 @@ def test_freeze_with_requirement_option_multiple(script):
     --requirement hints
 
     """
-    script.scratch_path.joinpath('hint1.txt').write_text(textwrap.dedent("""\
+    script.scratch_path.joinpath("hint1.txt").write_text(
+        textwrap.dedent(
+            """\
         INITools==0.1
         NoExist==4.2
         simple==3.0; python_version > '1.0'
-    """) + _freeze_req_opts)
-    script.scratch_path.joinpath('hint2.txt').write_text(textwrap.dedent("""\
+    """
+        )
+        + _freeze_req_opts
+    )
+    script.scratch_path.joinpath("hint2.txt").write_text(
+        textwrap.dedent(
+            """\
         NoExist2==2.0
         simple2==1.0
-    """) + _freeze_req_opts)
-    result = script.pip_install_local('initools==0.2')
-    result = script.pip_install_local('simple')
-    result = script.pip_install_local('simple2==1.0')
-    result = script.pip_install_local('meta')
+    """
+        )
+        + _freeze_req_opts
+    )
+    result = script.pip_install_local("initools==0.2")
+    result = script.pip_install_local("simple")
+    result = script.pip_install_local("simple2==1.0")
+    result = script.pip_install_local("meta")
     result = script.pip(
-        'freeze', '--requirement', 'hint1.txt', '--requirement', 'hint2.txt',
+        "freeze",
+        "--requirement",
+        "hint1.txt",
+        "--requirement",
+        "hint2.txt",
         expect_stderr=True,
     )
-    expected = textwrap.dedent("""\
+    expected = textwrap.dedent(
+        """\
         INITools==0.2
         simple==1.0
-    """)
+    """
+    )
     expected += _freeze_req_opts
-    expected += textwrap.dedent("""\
+    expected += textwrap.dedent(
+        """\
         simple2==1.0
-    """)
+    """
+    )
     expected += "## The following requirements were added by pip freeze:"
-    expected += '\n' + textwrap.dedent("""\
+    expected += "\n" + textwrap.dedent(
+        """\
         ...meta==1.0...
-    """)
+    """
+    )
     _check_output(result.stdout, expected)
     assert (
         "Requirement file [hint1.txt] contains NoExist==4.2, but package "
@@ -674,71 +788,102 @@ def test_freeze_with_requirement_option_package_repeated_one_file(script):
     Test freezing with single requirements file that contains a package
     multiple times
     """
-    script.scratch_path.joinpath('hint1.txt').write_text(textwrap.dedent("""\
+    script.scratch_path.joinpath("hint1.txt").write_text(
+        textwrap.dedent(
+            """\
         simple2
         simple2
         NoExist
-    """) + _freeze_req_opts)
-    result = script.pip_install_local('simple2==1.0')
-    result = script.pip_install_local('meta')
+    """
+        )
+        + _freeze_req_opts
+    )
+    result = script.pip_install_local("simple2==1.0")
+    result = script.pip_install_local("meta")
     result = script.pip(
-        'freeze', '--requirement', 'hint1.txt',
+        "freeze",
+        "--requirement",
+        "hint1.txt",
         expect_stderr=True,
     )
-    expected_out = textwrap.dedent("""\
+    expected_out = textwrap.dedent(
+        """\
         simple2==1.0
-    """)
+    """
+    )
     expected_out += _freeze_req_opts
     expected_out += "## The following requirements were added by pip freeze:"
-    expected_out += '\n' + textwrap.dedent("""\
+    expected_out += "\n" + textwrap.dedent(
+        """\
         ...meta==1.0...
-    """)
+    """
+    )
     _check_output(result.stdout, expected_out)
-    err1 = ("Requirement file [hint1.txt] contains NoExist, "
-            "but package 'NoExist' is not installed\n")
+    err1 = (
+        "Requirement file [hint1.txt] contains NoExist, "
+        "but package 'NoExist' is not installed\n"
+    )
     err2 = "Requirement simple2 included multiple times [hint1.txt]\n"
     assert err1 in result.stderr
     assert err2 in result.stderr
     # there shouldn't be any other 'is not installed' warnings
-    assert result.stderr.count('is not installed') == 1
+    assert result.stderr.count("is not installed") == 1
 
 
 def test_freeze_with_requirement_option_package_repeated_multi_file(script):
     """
     Test freezing with multiple requirements file that contain a package
     """
-    script.scratch_path.joinpath('hint1.txt').write_text(textwrap.dedent("""\
+    script.scratch_path.joinpath("hint1.txt").write_text(
+        textwrap.dedent(
+            """\
         simple
-    """) + _freeze_req_opts)
-    script.scratch_path.joinpath('hint2.txt').write_text(textwrap.dedent("""\
+    """
+        )
+        + _freeze_req_opts
+    )
+    script.scratch_path.joinpath("hint2.txt").write_text(
+        textwrap.dedent(
+            """\
         simple
         NoExist
-    """) + _freeze_req_opts)
-    result = script.pip_install_local('simple==1.0')
-    result = script.pip_install_local('meta')
+    """
+        )
+        + _freeze_req_opts
+    )
+    result = script.pip_install_local("simple==1.0")
+    result = script.pip_install_local("meta")
     result = script.pip(
-        'freeze', '--requirement', 'hint1.txt',
-        '--requirement', 'hint2.txt',
+        "freeze",
+        "--requirement",
+        "hint1.txt",
+        "--requirement",
+        "hint2.txt",
         expect_stderr=True,
     )
-    expected_out = textwrap.dedent("""\
+    expected_out = textwrap.dedent(
+        """\
         simple==1.0
-    """)
+    """
+    )
     expected_out += _freeze_req_opts
     expected_out += "## The following requirements were added by pip freeze:"
-    expected_out += '\n' + textwrap.dedent("""\
+    expected_out += "\n" + textwrap.dedent(
+        """\
         ...meta==1.0...
-    """)
+    """
+    )
     _check_output(result.stdout, expected_out)
 
-    err1 = ("Requirement file [hint2.txt] contains NoExist, but package "
-            "'NoExist' is not installed\n")
-    err2 = ("Requirement simple included multiple times "
-            "[hint1.txt, hint2.txt]\n")
+    err1 = (
+        "Requirement file [hint2.txt] contains NoExist, but package "
+        "'NoExist' is not installed\n"
+    )
+    err2 = "Requirement simple included multiple times " "[hint1.txt, hint2.txt]\n"
     assert err1 in result.stderr
     assert err2 in result.stderr
     # there shouldn't be any other 'is not installed' warnings
-    assert result.stderr.count('is not installed') == 1
+    assert result.stderr.count("is not installed") == 1
 
 
 @pytest.mark.network
@@ -747,17 +892,17 @@ def test_freeze_user(script, virtualenv, data):
     """
     Testing freeze with --user, first we have to install some stuff.
     """
-    script.pip('download', 'setuptools', 'wheel', '-d', data.packages)
-    script.pip_install_local('--find-links', data.find_links,
-                             '--user', 'simple==2.0')
-    script.pip_install_local('--find-links', data.find_links,
-                             'simple2==3.0')
-    result = script.pip('freeze', '--user', expect_stderr=True)
-    expected = textwrap.dedent("""\
+    script.pip("download", "setuptools", "wheel", "-d", data.packages)
+    script.pip_install_local("--find-links", data.find_links, "--user", "simple==2.0")
+    script.pip_install_local("--find-links", data.find_links, "simple2==3.0")
+    result = script.pip("freeze", "--user", expect_stderr=True)
+    expected = textwrap.dedent(
+        """\
         simple==2.0
-        <BLANKLINE>""")
+        <BLANKLINE>"""
+    )
     _check_output(result.stdout, expected)
-    assert 'simple2' not in result.stdout
+    assert "simple2" not in result.stdout
 
 
 @pytest.mark.network
@@ -765,12 +910,15 @@ def test_freeze_path(tmpdir, script, data):
     """
     Test freeze with --path.
     """
-    script.pip('install', '--find-links', data.find_links,
-               '--target', tmpdir, 'simple==2.0')
-    result = script.pip('freeze', '--path', tmpdir)
-    expected = textwrap.dedent("""\
+    script.pip(
+        "install", "--find-links", data.find_links, "--target", tmpdir, "simple==2.0"
+    )
+    result = script.pip("freeze", "--path", tmpdir)
+    expected = textwrap.dedent(
+        """\
         simple==2.0
-        <BLANKLINE>""")
+        <BLANKLINE>"""
+    )
     _check_output(result.stdout, expected)
 
 
@@ -781,19 +929,23 @@ def test_freeze_path_exclude_user(tmpdir, script, data):
     Test freeze with --path and make sure packages from --user are not picked
     up.
     """
-    script.pip_install_local('--find-links', data.find_links,
-                             '--user', 'simple2')
-    script.pip('install', '--find-links', data.find_links,
-               '--target', tmpdir, 'simple==1.0')
-    result = script.pip('freeze', '--user')
-    expected = textwrap.dedent("""\
+    script.pip_install_local("--find-links", data.find_links, "--user", "simple2")
+    script.pip(
+        "install", "--find-links", data.find_links, "--target", tmpdir, "simple==1.0"
+    )
+    result = script.pip("freeze", "--user")
+    expected = textwrap.dedent(
+        """\
         simple2==3.0
-        <BLANKLINE>""")
+        <BLANKLINE>"""
+    )
     _check_output(result.stdout, expected)
-    result = script.pip('freeze', '--path', tmpdir)
-    expected = textwrap.dedent("""\
+    result = script.pip("freeze", "--path", tmpdir)
+    expected = textwrap.dedent(
+        """\
         simple==1.0
-        <BLANKLINE>""")
+        <BLANKLINE>"""
+    )
     _check_output(result.stdout, expected)
 
 
@@ -806,20 +958,26 @@ def test_freeze_path_multiple(tmpdir, script, data):
     os.mkdir(path1)
     path2 = tmpdir / "path2"
     os.mkdir(path2)
-    script.pip('install', '--find-links', data.find_links,
-               '--target', path1, 'simple==2.0')
-    script.pip('install', '--find-links', data.find_links,
-               '--target', path2, 'simple2==3.0')
-    result = script.pip('freeze', '--path', path1)
-    expected = textwrap.dedent("""\
+    script.pip(
+        "install", "--find-links", data.find_links, "--target", path1, "simple==2.0"
+    )
+    script.pip(
+        "install", "--find-links", data.find_links, "--target", path2, "simple2==3.0"
+    )
+    result = script.pip("freeze", "--path", path1)
+    expected = textwrap.dedent(
+        """\
         simple==2.0
-        <BLANKLINE>""")
+        <BLANKLINE>"""
+    )
     _check_output(result.stdout, expected)
-    result = script.pip('freeze', '--path', path1, '--path', path2)
-    expected = textwrap.dedent("""\
+    result = script.pip("freeze", "--path", path1, "--path", path2)
+    expected = textwrap.dedent(
+        """\
         simple==2.0
         simple2==3.0
-        <BLANKLINE>""")
+        <BLANKLINE>"""
+    )
     _check_output(result.stdout, expected)
 
 
@@ -838,14 +996,12 @@ def test_freeze_skip_work_dir_pkg(script):
     """
 
     # Create a test package and create .egg-info dir
-    pkg_path = create_test_package_with_setup(
-        script, name='simple', version='1.0')
-    script.run('python', 'setup.py', 'egg_info',
-               expect_stderr=True, cwd=pkg_path)
+    pkg_path = create_test_package_with_setup(script, name="simple", version="1.0")
+    script.run("python", "setup.py", "egg_info", expect_stderr=True, cwd=pkg_path)
 
     # Freeze should not include package simple when run from package directory
-    result = script.pip('freeze', cwd=pkg_path)
-    assert 'simple' not in result.stdout
+    result = script.pip("freeze", cwd=pkg_path)
+    assert "simple" not in result.stdout
 
 
 def test_freeze_include_work_dir_pkg(script):
@@ -855,14 +1011,12 @@ def test_freeze_include_work_dir_pkg(script):
     """
 
     # Create a test package and create .egg-info dir
-    pkg_path = create_test_package_with_setup(
-        script, name='simple', version='1.0')
-    script.run('python', 'setup.py', 'egg_info',
-               expect_stderr=True, cwd=pkg_path)
+    pkg_path = create_test_package_with_setup(script, name="simple", version="1.0")
+    script.run("python", "setup.py", "egg_info", expect_stderr=True, cwd=pkg_path)
 
-    script.environ.update({'PYTHONPATH': pkg_path})
+    script.environ.update({"PYTHONPATH": pkg_path})
 
     # Freeze should include package simple when run from package directory,
     # when package directory is in PYTHONPATH
-    result = script.pip('freeze', cwd=pkg_path)
-    assert 'simple==1.0' in result.stdout
+    result = script.pip("freeze", cwd=pkg_path)
+    assert "simple==1.0" in result.stdout
diff --git a/tests/functional/test_hash.py b/tests/functional/test_hash.py
index 5d7bd975e18..f6dd8b2a3d5 100644
--- a/tests/functional/test_hash.py
+++ b/tests/functional/test_hash.py
@@ -3,30 +3,35 @@
 
 def test_basic_hash(script, tmpdir):
     """Run 'pip hash' through its default behavior."""
-    expected = ('--hash=sha256:2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425'
-                'e73043362938b9824')
-    result = script.pip('hash', _hello_file(tmpdir))
+    expected = (
+        "--hash=sha256:2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425"
+        "e73043362938b9824"
+    )
+    result = script.pip("hash", _hello_file(tmpdir))
     assert expected in str(result)
 
 
 def test_good_algo_option(script, tmpdir):
     """Make sure the -a option works."""
-    expected = ('--hash=sha512:9b71d224bd62f3785d96d46ad3ea3d73319bfbc2890caad'
-                'ae2dff72519673ca72323c3d99ba5c11d7c7acc6e14b8c5da0c4663475c2e'
-                '5c3adef46f73bcdec043')
-    result = script.pip('hash', '-a', 'sha512', _hello_file(tmpdir))
+    expected = (
+        "--hash=sha512:9b71d224bd62f3785d96d46ad3ea3d73319bfbc2890caad"
+        "ae2dff72519673ca72323c3d99ba5c11d7c7acc6e14b8c5da0c4663475c2e"
+        "5c3adef46f73bcdec043"
+    )
+    result = script.pip("hash", "-a", "sha512", _hello_file(tmpdir))
     assert expected in str(result)
 
 
 def test_bad_algo_option(script, tmpdir):
     """Make sure the -a option raises an error when given a bad operand."""
-    result = script.pip('hash', '-a', 'invalidname', _hello_file(tmpdir),
-                        expect_error=True)
+    result = script.pip(
+        "hash", "-a", "invalidname", _hello_file(tmpdir), expect_error=True
+    )
     assert "invalid choice: 'invalidname'" in str(result)
 
 
 def _hello_file(tmpdir):
     """Return a temp file to hash containing "hello"."""
-    file = tmpdir / 'hashable'
-    file.write_text('hello')
+    file = tmpdir / "hashable"
+    file.write_text("hello")
     return file
diff --git a/tests/functional/test_help.py b/tests/functional/test_help.py
index 00a395006b7..bf6cbca9b56 100644
--- a/tests/functional/test_help.py
+++ b/tests/functional/test_help.py
@@ -11,8 +11,8 @@ def test_run_method_should_return_success_when_finds_command_name():
     Test HelpCommand.run for existing command
     """
     options_mock = Mock()
-    args = ('freeze',)
-    help_cmd = create_command('help')
+    args = ("freeze",)
+    help_cmd = create_command("help")
     status = help_cmd.run(options_mock, args)
     assert status == SUCCESS
 
@@ -23,7 +23,7 @@ def test_run_method_should_return_success_when_command_name_not_specified():
     """
     options_mock = Mock()
     args = ()
-    help_cmd = create_command('help')
+    help_cmd = create_command("help")
     status = help_cmd.run(options_mock, args)
     assert status == SUCCESS
 
@@ -33,8 +33,8 @@ def test_run_method_should_raise_command_error_when_command_does_not_exist():
     Test HelpCommand.run for non-existing command
     """
     options_mock = Mock()
-    args = ('mycommand',)
-    help_cmd = create_command('help')
+    args = ("mycommand",)
+    help_cmd = create_command("help")
 
     with pytest.raises(CommandError):
         help_cmd.run(options_mock, args)
@@ -44,7 +44,7 @@ def test_help_command_should_exit_status_ok_when_command_exists(script):
     """
     Test `help` command for existing command
     """
-    result = script.pip('help', 'freeze')
+    result = script.pip("help", "freeze")
     assert result.returncode == SUCCESS
 
 
@@ -52,7 +52,7 @@ def test_help_command_should_exit_status_ok_when_no_cmd_is_specified(script):
     """
     Test `help` command for no command
     """
-    result = script.pip('help')
+    result = script.pip("help")
     assert result.returncode == SUCCESS
 
 
@@ -60,7 +60,7 @@ def test_help_command_should_exit_status_error_when_cmd_does_not_exist(script):
     """
     Test `help` command for non-existing command
     """
-    result = script.pip('help', 'mycommand', expect_error=True)
+    result = script.pip("help", "mycommand", expect_error=True)
     assert result.returncode == ERROR
 
 
@@ -68,19 +68,20 @@ def test_help_commands_equally_functional(in_memory_pip):
     """
     Test if `pip help` and 'pip --help' behave the same way.
     """
-    results = list(map(in_memory_pip.pip, ('help', '--help')))
+    results = list(map(in_memory_pip.pip, ("help", "--help")))
     results.append(in_memory_pip.pip())
 
     out = map(lambda x: x.stdout, results)
     ret = map(lambda x: x.returncode, results)
 
     msg = '"pip --help" != "pip help" != "pip"'
-    assert len(set(out)) == 1, 'output of: ' + msg
-    assert sum(ret) == 0, 'exit codes of: ' + msg
+    assert len(set(out)) == 1, "output of: " + msg
+    assert sum(ret) == 0, "exit codes of: " + msg
     assert all(len(o) > 0 for o in out)
 
     for name in commands_dict:
         assert (
-            in_memory_pip.pip('help', name).stdout ==
-            in_memory_pip.pip(name, '--help').stdout != ""
+            in_memory_pip.pip("help", name).stdout
+            == in_memory_pip.pip(name, "--help").stdout
+            != ""
         )
diff --git a/tests/functional/test_install.py b/tests/functional/test_install.py
index 17a72bca82e..bdfdb488960 100644
--- a/tests/functional/test_install.py
+++ b/tests/functional/test_install.py
@@ -41,59 +41,76 @@
 )
 
 
-@pytest.mark.parametrize('command', ('install', 'wheel'))
-@pytest.mark.parametrize('variant', ('missing_setuptools', 'bad_setuptools'))
+@pytest.mark.parametrize("command", ("install", "wheel"))
+@pytest.mark.parametrize("variant", ("missing_setuptools", "bad_setuptools"))
 def test_pep518_uses_build_env(script, data, common_wheels, command, variant):
-    if variant == 'missing_setuptools':
+    if variant == "missing_setuptools":
         script.pip("uninstall", "-y", "setuptools")
-    elif variant == 'bad_setuptools':
+    elif variant == "bad_setuptools":
         setuptools_mod = script.site_packages_path.joinpath("setuptools.py")
-        with open(setuptools_mod, 'a') as f:
+        with open(setuptools_mod, "a") as f:
             f.write('\nraise ImportError("toto")')
     else:
         raise ValueError(variant)
     script.pip(
-        command, '--no-index', '-f', common_wheels, '-f', data.packages,
+        command,
+        "--no-index",
+        "-f",
+        common_wheels,
+        "-f",
+        data.packages,
         data.src.joinpath("pep518-3.0"),
     )
 
 
 def test_pep518_build_env_uses_same_pip(
-        script, data, pip_src, common_wheels, deprecated_python):
+    script, data, pip_src, common_wheels, deprecated_python
+):
     """Ensure the subprocess call to pip for installing the
     build dependencies is using the same version of pip.
     """
-    with open(script.scratch_path / 'pip.py', 'w') as fp:
-        fp.write('raise ImportError')
+    with open(script.scratch_path / "pip.py", "w") as fp:
+        fp.write("raise ImportError")
     script.run(
-        'python', pip_src / 'src/pip', 'install', '--no-index',
-        '-f', common_wheels, '-f', data.packages,
+        "python",
+        pip_src / "src/pip",
+        "install",
+        "--no-index",
+        "-f",
+        common_wheels,
+        "-f",
+        data.packages,
         data.src.joinpath("pep518-3.0"),
         expect_stderr=deprecated_python,
     )
 
 
 def test_pep518_refuses_conflicting_requires(script, data):
-    create_basic_wheel_for_package(script, 'setuptools', '1.0')
-    create_basic_wheel_for_package(script, 'wheel', '1.0')
+    create_basic_wheel_for_package(script, "setuptools", "1.0")
+    create_basic_wheel_for_package(script, "wheel", "1.0")
     project_dir = data.src.joinpath("pep518_conflicting_requires")
-    result = script.pip_install_local('-f', script.scratch_path,
-                                      project_dir, expect_error=True)
+    result = script.pip_install_local(
+        "-f", script.scratch_path, project_dir, expect_error=True
+    )
     assert (
-        result.returncode != 0 and (
-            'Some build dependencies for {url} conflict '
-            'with PEP 517/518 supported '
-            'requirements: setuptools==1.0 is incompatible with '
-            'setuptools>=40.8.0.'
-            .format(url=path_to_url(project_dir))) in result.stderr
+        result.returncode != 0
+        and (
+            "Some build dependencies for {url} conflict "
+            "with PEP 517/518 supported "
+            "requirements: setuptools==1.0 is incompatible with "
+            "setuptools>=40.8.0.".format(url=path_to_url(project_dir))
+        )
+        in result.stderr
     ), str(result)
 
 
 def test_pep518_refuses_invalid_requires(script, data, common_wheels):
     result = script.pip(
-        'install', '-f', common_wheels,
+        "install",
+        "-f",
+        common_wheels,
         data.src.joinpath("pep518_invalid_requires"),
-        expect_error=True
+        expect_error=True,
     )
     assert result.returncode == 1
     assert "does not comply with PEP 518" in result.stderr
@@ -101,9 +118,11 @@ def test_pep518_refuses_invalid_requires(script, data, common_wheels):
 
 def test_pep518_refuses_invalid_build_system(script, data, common_wheels):
     result = script.pip(
-        'install', '-f', common_wheels,
+        "install",
+        "-f",
+        common_wheels,
         data.src.joinpath("pep518_invalid_build_system"),
-        expect_error=True
+        expect_error=True,
     )
     assert result.returncode == 1
     assert "does not comply with PEP 518" in result.stderr
@@ -111,9 +130,11 @@ def test_pep518_refuses_invalid_build_system(script, data, common_wheels):
 
 def test_pep518_allows_missing_requires(script, data, common_wheels):
     result = script.pip(
-        'install', '-f', common_wheels,
+        "install",
+        "-f",
+        common_wheels,
         data.src.joinpath("pep518_missing_requires"),
-        expect_stderr=True
+        expect_stderr=True,
     )
     # Make sure we don't warn when this occurs.
     assert "does not comply with PEP 518" not in result.stderr
@@ -136,81 +157,97 @@ def test_pep518_with_user_pip(script, pip_src, data, common_wheels):
     non-isolated environment, and break pip in the system site-packages,
     so that isolated uses of pip will fail.
     """
-    script.pip("install", "--ignore-installed",
-               "-f", common_wheels, "--user", pip_src)
-    system_pip_dir = script.site_packages_path / 'pip'
+    script.pip("install", "--ignore-installed", "-f", common_wheels, "--user", pip_src)
+    system_pip_dir = script.site_packages_path / "pip"
     assert not system_pip_dir.exists()
     system_pip_dir.mkdir()
-    with open(system_pip_dir / '__init__.py', 'w') as fp:
-        fp.write('raise ImportError\n')
+    with open(system_pip_dir / "__init__.py", "w") as fp:
+        fp.write("raise ImportError\n")
     script.pip(
-        'wheel', '--no-index', '-f', common_wheels, '-f', data.packages,
+        "wheel",
+        "--no-index",
+        "-f",
+        common_wheels,
+        "-f",
+        data.packages,
         data.src.joinpath("pep518-3.0"),
     )
 
 
 def test_pep518_with_extra_and_markers(script, data, common_wheels):
     script.pip(
-        'wheel', '--no-index',
-        '-f', common_wheels,
-        '-f', data.find_links,
+        "wheel",
+        "--no-index",
+        "-f",
+        common_wheels,
+        "-f",
+        data.find_links,
         data.src.joinpath("pep518_with_extra_and_markers-1.0"),
     )
 
 
 def test_pep518_with_namespace_package(script, data, common_wheels):
     script.pip(
-        'wheel', '--no-index',
-        '-f', common_wheels,
-        '-f', data.find_links,
+        "wheel",
+        "--no-index",
+        "-f",
+        common_wheels,
+        "-f",
+        data.find_links,
         data.src.joinpath("pep518_with_namespace_package-1.0"),
         use_module=True,
     )
 
 
 @pytest.mark.timeout(60)
-@pytest.mark.parametrize('command', ('install', 'wheel'))
-@pytest.mark.parametrize('package', ('pep518_forkbomb',
-                                     'pep518_twin_forkbombs_first',
-                                     'pep518_twin_forkbombs_second'))
+@pytest.mark.parametrize("command", ("install", "wheel"))
+@pytest.mark.parametrize(
+    "package",
+    ("pep518_forkbomb", "pep518_twin_forkbombs_first", "pep518_twin_forkbombs_second"),
+)
 def test_pep518_forkbombs(script, data, common_wheels, command, package):
-    package_source = next(data.packages.glob(package + '-[0-9]*.tar.gz'))
+    package_source = next(data.packages.glob(package + "-[0-9]*.tar.gz"))
     result = script.pip(
-        command, '--no-index', '-v',
-        '-f', common_wheels,
-        '-f', data.find_links,
+        command,
+        "--no-index",
+        "-v",
+        "-f",
+        common_wheels,
+        "-f",
+        data.find_links,
         package,
         expect_error=True,
     )
-    assert '{1} is already being built: {0} from {1}'.format(
-        package, path_to_url(package_source),
-    ) in result.stderr, str(result)
+    assert (
+        "{1} is already being built: {0} from {1}".format(
+            package,
+            path_to_url(package_source),
+        )
+        in result.stderr
+    ), str(result)
 
 
 @pytest.mark.network
 def test_pip_second_command_line_interface_works(
-        script, pip_src, data, common_wheels, deprecated_python, with_wheel
+    script, pip_src, data, common_wheels, deprecated_python, with_wheel
 ):
     """
     Check if ``pip<PYVERSION>`` commands behaves equally
     """
     # Re-install pip so we get the launchers.
-    script.pip_install_local('-f', common_wheels, pip_src)
+    script.pip_install_local("-f", common_wheels, pip_src)
     # On old versions of Python, urllib3/requests will raise a warning about
     # the lack of an SSLContext.
-    kwargs = {'expect_stderr': deprecated_python}
+    kwargs = {"expect_stderr": deprecated_python}
     if pyversion_tuple < (2, 7, 9):
-        kwargs['expect_stderr'] = True
+        kwargs["expect_stderr"] = True
 
-    args = ['pip{pyversion}'.format(**globals())]
-    args.extend(['install', 'INITools==0.2'])
-    args.extend(['-f', data.packages])
+    args = ["pip{pyversion}".format(**globals())]
+    args.extend(["install", "INITools==0.2"])
+    args.extend(["-f", data.packages])
     result = script.run(*args, **kwargs)
-    dist_info_folder = (
-        script.site_packages /
-        'INITools-0.2.dist-info'
-    )
-    initools_folder = script.site_packages / 'initools'
+    dist_info_folder = script.site_packages / "INITools-0.2.dist-info"
+    initools_folder = script.site_packages / "initools"
     result.did_create(dist_info_folder)
     result.did_create(initools_folder)
 
@@ -219,7 +256,7 @@ def test_install_exit_status_code_when_no_requirements(script):
     """
     Test install exit status code when no requirements specified
     """
-    result = script.pip('install', expect_error=True)
+    result = script.pip("install", expect_error=True)
     assert "You must give at least one requirement to install" in result.stderr
     assert result.returncode == ERROR
 
@@ -229,7 +266,7 @@ def test_install_exit_status_code_when_blank_requirements_file(script):
     Test install exit status code when blank requirements file specified
     """
     script.scratch_path.joinpath("blank.txt").write_text("\n")
-    script.pip('install', '-r', 'blank.txt')
+    script.pip("install", "-r", "blank.txt")
 
 
 @pytest.mark.network
@@ -237,12 +274,9 @@ def test_basic_install_from_pypi(script, with_wheel):
     """
     Test installing a package from PyPI.
     """
-    result = script.pip('install', 'INITools==0.2')
-    dist_info_folder = (
-        script.site_packages /
-        'INITools-0.2.dist-info'
-    )
-    initools_folder = script.site_packages / 'initools'
+    result = script.pip("install", "INITools==0.2")
+    dist_info_folder = script.site_packages / "INITools-0.2.dist-info"
+    initools_folder = script.site_packages / "initools"
     result.did_create(dist_info_folder)
     result.did_create(initools_folder)
 
@@ -262,11 +296,8 @@ def test_basic_editable_install(script):
     """
     Test editable installation.
     """
-    result = script.pip('install', '-e', 'INITools==0.2', expect_error=True)
-    assert (
-        "INITools==0.2 is not a valid editable requirement"
-        in result.stderr
-    )
+    result = script.pip("install", "-e", "INITools==0.2", expect_error=True)
+    assert "INITools==0.2 is not a valid editable requirement" in result.stderr
     assert not result.files_created
 
 
@@ -277,30 +308,27 @@ def test_basic_install_editable_from_svn(script):
     """
     checkout_path = _create_test_package(script)
     repo_url = _create_svn_repo(script, checkout_path)
-    result = script.pip(
-        'install',
-        '-e', 'svn+' + repo_url + '#egg=version-pkg'
-    )
-    result.assert_installed('version-pkg', with_files=['.svn'])
+    result = script.pip("install", "-e", "svn+" + repo_url + "#egg=version-pkg")
+    result.assert_installed("version-pkg", with_files=[".svn"])
 
 
 def _test_install_editable_from_git(script, tmpdir):
     """Test cloning from Git."""
-    pkg_path = _create_test_package(script, name='testpackage', vcs='git')
+    pkg_path = _create_test_package(script, name="testpackage", vcs="git")
     args = [
-        'install', '-e',
-        'git+{url}#egg=testpackage'.format(url=path_to_url(pkg_path)),
+        "install",
+        "-e",
+        "git+{url}#egg=testpackage".format(url=path_to_url(pkg_path)),
     ]
     result = script.pip(*args)
-    result.assert_installed('testpackage', with_files=['.git'])
+    result.assert_installed("testpackage", with_files=[".git"])
 
 
 def test_basic_install_editable_from_git(script, tmpdir):
     _test_install_editable_from_git(script, tmpdir)
 
 
-def test_install_editable_from_git_autobuild_wheel(
-        script, tmpdir, with_wheel):
+def test_install_editable_from_git_autobuild_wheel(script, tmpdir, with_wheel):
     _test_install_editable_from_git(script, tmpdir)
 
 
@@ -314,20 +342,23 @@ def test_install_editable_uninstalls_existing(data, script, tmpdir):
     """
     to_install = data.packages.joinpath("pip-test-package-0.1.tar.gz")
     result = script.pip_install_local(to_install)
-    assert 'Successfully installed pip-test-package' in result.stdout
-    result.assert_installed('piptestpackage', editable=False)
+    assert "Successfully installed pip-test-package" in result.stdout
+    result.assert_installed("piptestpackage", editable=False)
 
     result = script.pip(
-        'install', '-e',
-        '{dir}#egg=pip-test-package'.format(
+        "install",
+        "-e",
+        "{dir}#egg=pip-test-package".format(
             dir=local_checkout(
-                'git+https://github.com/pypa/pip-test-package.git', tmpdir,
-            )),
+                "git+https://github.com/pypa/pip-test-package.git",
+                tmpdir,
+            )
+        ),
     )
-    result.assert_installed('pip-test-package', with_files=['.git'])
-    assert 'Found existing installation: pip-test-package 0.1' in result.stdout
-    assert 'Uninstalling pip-test-package-' in result.stdout
-    assert 'Successfully uninstalled pip-test-package' in result.stdout
+    result.assert_installed("pip-test-package", with_files=[".git"])
+    assert "Found existing installation: pip-test-package 0.1" in result.stdout
+    assert "Uninstalling pip-test-package-" in result.stdout
+    assert "Successfully uninstalled pip-test-package" in result.stdout
 
 
 def test_install_editable_uninstalls_existing_from_path(script, data):
@@ -335,34 +366,35 @@ def test_install_editable_uninstalls_existing_from_path(script, data):
     Test that installing an editable uninstalls a previously installed
     non-editable version from path
     """
-    to_install = data.src.joinpath('simplewheel-1.0')
+    to_install = data.src.joinpath("simplewheel-1.0")
     result = script.pip_install_local(to_install)
-    assert 'Successfully installed simplewheel' in result.stdout
-    simple_folder = script.site_packages / 'simplewheel'
-    result.assert_installed('simplewheel', editable=False)
+    assert "Successfully installed simplewheel" in result.stdout
+    simple_folder = script.site_packages / "simplewheel"
+    result.assert_installed("simplewheel", editable=False)
     result.did_create(simple_folder)
 
     result = script.pip(
-        'install', '-e',
+        "install",
+        "-e",
         to_install,
     )
-    install_path = script.site_packages / 'simplewheel.egg-link'
+    install_path = script.site_packages / "simplewheel.egg-link"
     result.did_create(install_path)
-    assert 'Found existing installation: simplewheel 1.0' in result.stdout
-    assert 'Uninstalling simplewheel-' in result.stdout
-    assert 'Successfully uninstalled simplewheel' in result.stdout
+    assert "Found existing installation: simplewheel 1.0" in result.stdout
+    assert "Uninstalling simplewheel-" in result.stdout
+    assert "Successfully uninstalled simplewheel" in result.stdout
     assert simple_folder in result.files_deleted, str(result.stdout)
 
 
 @need_mercurial
 def test_basic_install_editable_from_hg(script, tmpdir):
     """Test cloning and hg+file install from Mercurial."""
-    pkg_path = _create_test_package(script, name='testpackage', vcs='hg')
-    url = 'hg+{}#egg=testpackage'.format(path_to_url(pkg_path))
-    assert url.startswith('hg+file')
-    args = ['install', '-e', url]
+    pkg_path = _create_test_package(script, name="testpackage", vcs="hg")
+    url = "hg+{}#egg=testpackage".format(path_to_url(pkg_path))
+    assert url.startswith("hg+file")
+    args = ["install", "-e", url]
     result = script.pip(*args)
-    result.assert_installed('testpackage', with_files=['.hg'])
+    result.assert_installed("testpackage", with_files=[".hg"])
 
 
 @need_mercurial
@@ -370,23 +402,27 @@ def test_vcs_url_final_slash_normalization(script, tmpdir):
     """
     Test that presence or absence of final slash in VCS URL is normalized.
     """
-    pkg_path = _create_test_package(script, name='testpackage', vcs='hg')
+    pkg_path = _create_test_package(script, name="testpackage", vcs="hg")
     args = [
-        'install',
-        '-e', 'hg+{url}/#egg=testpackage'.format(url=path_to_url(pkg_path))]
+        "install",
+        "-e",
+        "hg+{url}/#egg=testpackage".format(url=path_to_url(pkg_path)),
+    ]
     result = script.pip(*args)
-    result.assert_installed('testpackage', with_files=['.hg'])
+    result.assert_installed("testpackage", with_files=[".hg"])
 
 
 @need_bzr
 def test_install_editable_from_bazaar(script, tmpdir):
     """Test checking out from Bazaar."""
-    pkg_path = _create_test_package(script, name='testpackage', vcs='bazaar')
+    pkg_path = _create_test_package(script, name="testpackage", vcs="bazaar")
     args = [
-        'install',
-        '-e', 'bzr+{url}/#egg=testpackage'.format(url=path_to_url(pkg_path))]
+        "install",
+        "-e",
+        "bzr+{url}/#egg=testpackage".format(url=path_to_url(pkg_path)),
+    ]
     result = script.pip(*args)
-    result.assert_installed('testpackage', with_files=['.bzr'])
+    result.assert_installed("testpackage", with_files=[".bzr"])
 
 
 @pytest.mark.network
@@ -396,21 +432,21 @@ def test_vcs_url_urlquote_normalization(script, tmpdir):
     Test that urlquoted characters are normalized for repo URL comparison.
     """
     script.pip(
-        'install', '-e',
-        '{url}/#egg=django-wikiapp'.format(
+        "install",
+        "-e",
+        "{url}/#egg=django-wikiapp".format(
             url=local_checkout(
-                'bzr+http://bazaar.launchpad.net/'
-                '%7Edjango-wikiapp/django-wikiapp'
-                '/release-0.1',
+                "bzr+http://bazaar.launchpad.net/"
+                "%7Edjango-wikiapp/django-wikiapp"
+                "/release-0.1",
                 tmpdir,
-            )),
+            )
+        ),
     )
 
 
 @pytest.mark.parametrize("resolver", ["", "--use-feature=2020-resolver"])
-def test_basic_install_from_local_directory(
-    script, data, resolver, with_wheel
-):
+def test_basic_install_from_local_directory(script, data, resolver, with_wheel):
     """
     Test installing from a local directory.
     """
@@ -420,45 +456,38 @@ def test_basic_install_from_local_directory(
     to_install = data.packages.joinpath("FSPkg")
     args.append(to_install)
     result = script.pip(*args)
-    fspkg_folder = script.site_packages / 'fspkg'
-    dist_info_folder = (
-        script.site_packages /
-        'FSPkg-0.1.dev0.dist-info'
-    )
+    fspkg_folder = script.site_packages / "fspkg"
+    dist_info_folder = script.site_packages / "FSPkg-0.1.dev0.dist-info"
     result.did_create(fspkg_folder)
     result.did_create(dist_info_folder)
 
 
-@pytest.mark.parametrize("test_type,editable", [
-    ("rel_path", False),
-    ("rel_path", True),
-    ("rel_url", False),
-    ("rel_url", True),
-    ("embedded_rel_path", False),
-    ("embedded_rel_path", True),
-])
+@pytest.mark.parametrize(
+    "test_type,editable",
+    [
+        ("rel_path", False),
+        ("rel_path", True),
+        ("rel_url", False),
+        ("rel_url", True),
+        ("embedded_rel_path", False),
+        ("embedded_rel_path", True),
+    ],
+)
 def test_basic_install_relative_directory(
     script, data, test_type, editable, with_wheel
 ):
     """
     Test installing a requirement using a relative path.
     """
-    dist_info_folder = (
-        script.site_packages /
-        'FSPkg-0.1.dev0.dist-info'
-    )
-    egg_link_file = (
-        script.site_packages / 'FSPkg.egg-link'
-    )
-    package_folder = script.site_packages / 'fspkg'
+    dist_info_folder = script.site_packages / "FSPkg-0.1.dev0.dist-info"
+    egg_link_file = script.site_packages / "FSPkg.egg-link"
+    package_folder = script.site_packages / "fspkg"
 
     # Compute relative install path to FSPkg from scratch path.
     full_rel_path = Path(
-        os.path.relpath(data.packages.joinpath('FSPkg'), script.scratch_path)
-    )
-    full_rel_url = (
-        'file:' + full_rel_path.replace(os.path.sep, '/') + '#egg=FSPkg'
+        os.path.relpath(data.packages.joinpath("FSPkg"), script.scratch_path)
     )
+    full_rel_url = "file:" + full_rel_path.replace(os.path.sep, "/") + "#egg=FSPkg"
     embedded_rel_path = script.scratch_path.joinpath(full_rel_path)
 
     req_path = {
@@ -469,14 +498,12 @@ def test_basic_install_relative_directory(
 
     # Install as either editable or not.
     if not editable:
-        result = script.pip('install', req_path,
-                            cwd=script.scratch_path)
+        result = script.pip("install", req_path, cwd=script.scratch_path)
         result.did_create(dist_info_folder)
         result.did_create(package_folder)
     else:
         # Editable install.
-        result = script.pip('install', '-e' + req_path,
-                            cwd=script.scratch_path)
+        result = script.pip("install", "-e" + req_path, cwd=script.scratch_path)
         result.did_create(egg_link_file)
 
 
@@ -489,7 +516,7 @@ def test_install_quiet(script, data):
     #   https://github.com/pypa/pip/issues/3418
     #   https://github.com/docker-library/python/issues/83
     to_install = data.packages.joinpath("FSPkg")
-    result = script.pip('install', '-qqq', to_install)
+    result = script.pip("install", "-qqq", to_install)
     assert result.stdout == ""
     assert result.stderr == ""
 
@@ -503,15 +530,15 @@ def test_hashed_install_success(script, data, tmpdir):
     scenes).
 
     """
-    file_url = path_to_url(
-        (data.packages / 'simple-1.0.tar.gz').resolve())
+    file_url = path_to_url((data.packages / "simple-1.0.tar.gz").resolve())
     with requirements_file(
-            'simple2==1.0 --hash=sha256:9336af72ca661e6336eb87bc7de3e8844d853e'
-            '3848c2b9bbd2e8bf01db88c2c7\n'
-            '{simple} --hash=sha256:393043e672415891885c9a2a0929b1af95fb866d6c'
-            'a016b42d2e6ce53619b653'.format(simple=file_url),
-            tmpdir) as reqs_file:
-        script.pip_install_local('-r', reqs_file.resolve())
+        "simple2==1.0 --hash=sha256:9336af72ca661e6336eb87bc7de3e8844d853e"
+        "3848c2b9bbd2e8bf01db88c2c7\n"
+        "{simple} --hash=sha256:393043e672415891885c9a2a0929b1af95fb866d6c"
+        "a016b42d2e6ce53619b653".format(simple=file_url),
+        tmpdir,
+    ) as reqs_file:
+        script.pip_install_local("-r", reqs_file.resolve())
 
 
 def test_hashed_install_failure(script, tmpdir):
@@ -522,19 +549,17 @@ def test_hashed_install_failure(script, tmpdir):
     kinds of hashes are in test_req.py.
 
     """
-    with requirements_file('simple2==1.0 --hash=sha256:9336af72ca661e6336eb87b'
-                           'c7de3e8844d853e3848c2b9bbd2e8bf01db88c2c\n',
-                           tmpdir) as reqs_file:
-        result = script.pip_install_local('-r',
-                                          reqs_file.resolve(),
-                                          expect_error=True)
+    with requirements_file(
+        "simple2==1.0 --hash=sha256:9336af72ca661e6336eb87b"
+        "c7de3e8844d853e3848c2b9bbd2e8bf01db88c2c\n",
+        tmpdir,
+    ) as reqs_file:
+        result = script.pip_install_local("-r", reqs_file.resolve(), expect_error=True)
     assert len(result.files_created) == 0
 
 
 def assert_re_match(pattern, text):
-    assert re.search(pattern, text), (
-        "Could not find {!r} in {!r}".format(pattern, text)
-    )
+    assert re.search(pattern, text), "Could not find {!r} in {!r}".format(pattern, text)
 
 
 @pytest.mark.network
@@ -549,37 +574,32 @@ def test_hashed_install_failure_later_flag(script, tmpdir):
         "packages/source/p/peep/peep-3.1.1.tar.gz\n",
         tmpdir,
     ) as reqs_file:
-        result = script.pip(
-            "install", "-r", reqs_file.resolve(), expect_error=True
-        )
+        result = script.pip("install", "-r", reqs_file.resolve(), expect_error=True)
 
     assert_re_match(
-        r'Hashes are required in --require-hashes mode, but they are '
-        r'missing .*\n'
-        r'    https://files\.pythonhosted\.org/packages/source/p/peep/peep'
-        r'-3\.1\.1\.tar\.gz --hash=sha256:[0-9a-f]+\n'
-        r'    blessings==1.0 --hash=sha256:[0-9a-f]+\n'
-        r'THESE PACKAGES DO NOT MATCH THE HASHES.*\n'
-        r'    tracefront==0.1 .*:\n'
-        r'        Expected sha256 somehash\n'
-        r'             Got        [0-9a-f]+',
+        r"Hashes are required in --require-hashes mode, but they are "
+        r"missing .*\n"
+        r"    https://files\.pythonhosted\.org/packages/source/p/peep/peep"
+        r"-3\.1\.1\.tar\.gz --hash=sha256:[0-9a-f]+\n"
+        r"    blessings==1.0 --hash=sha256:[0-9a-f]+\n"
+        r"THESE PACKAGES DO NOT MATCH THE HASHES.*\n"
+        r"    tracefront==0.1 .*:\n"
+        r"        Expected sha256 somehash\n"
+        r"             Got        [0-9a-f]+",
         result.stderr,
     )
 
 
 def test_install_from_local_directory_with_symlinks_to_directories(
-        script, data, with_wheel
+    script, data, with_wheel
 ):
     """
     Test installing from a local directory containing symlinks to directories.
     """
     to_install = data.packages.joinpath("symlinks")
-    result = script.pip('install', to_install)
-    pkg_folder = script.site_packages / 'symlinks'
-    dist_info_folder = (
-        script.site_packages /
-        'symlinks-0.1.dev0.dist-info'
-    )
+    result = script.pip("install", to_install)
+    pkg_folder = script.site_packages / "symlinks"
+    dist_info_folder = script.site_packages / "symlinks-0.1.dev0.dist-info"
     result.did_create(pkg_folder)
     result.did_create(dist_info_folder)
 
@@ -591,10 +611,7 @@ def test_install_from_local_directory_with_socket_file(
     """
     Test installing from a local directory containing a socket file.
     """
-    dist_info_folder = (
-        script.site_packages /
-        "FSPkg-0.1.dev0.dist-info"
-    )
+    dist_info_folder = script.site_packages / "FSPkg-0.1.dev0.dist-info"
     package_folder = script.site_packages / "fspkg"
     to_copy = data.packages.joinpath("FSPkg")
     to_install = tmpdir.joinpath("src")
@@ -614,18 +631,17 @@ def test_install_from_local_directory_with_no_setup_py(script, data):
     """
     Test installing from a local directory with no 'setup.py'.
     """
-    result = script.pip('install', data.root, expect_error=True)
+    result = script.pip("install", data.root, expect_error=True)
     assert not result.files_created
     assert "is not installable." in result.stderr
     assert "Neither 'setup.py' nor 'pyproject.toml' found." in result.stderr
 
 
-def test_editable_install__local_dir_no_setup_py(
-        script, data, deprecated_python):
+def test_editable_install__local_dir_no_setup_py(script, data, deprecated_python):
     """
     Test installing in editable mode from a local directory with no setup.py.
     """
-    result = script.pip('install', '-e', data.root, expect_error=True)
+    result = script.pip("install", "-e", data.root, expect_error=True)
     assert not result.files_created
 
     msg = result.stderr
@@ -633,21 +649,22 @@ def test_editable_install__local_dir_no_setup_py(
         assert 'File "setup.py" not found. ' in msg
     else:
         assert msg.startswith('ERROR: File "setup.py" not found. ')
-    assert 'pyproject.toml' not in msg
+    assert "pyproject.toml" not in msg
 
 
 def test_editable_install__local_dir_no_setup_py_with_pyproject(
-        script, deprecated_python):
+    script, deprecated_python
+):
     """
     Test installing in editable mode from a local directory with no setup.py
     but that does have pyproject.toml.
     """
-    local_dir = script.scratch_path.joinpath('temp')
+    local_dir = script.scratch_path.joinpath("temp")
     local_dir.mkdir()
-    pyproject_path = local_dir.joinpath('pyproject.toml')
-    pyproject_path.write_text('')
+    pyproject_path = local_dir.joinpath("pyproject.toml")
+    pyproject_path.write_text("")
 
-    result = script.pip('install', '-e', local_dir, expect_error=True)
+    result = script.pip("install", "-e", local_dir, expect_error=True)
     assert not result.files_created
 
     msg = result.stderr
@@ -668,7 +685,7 @@ def test_install_argparse_shadowed(script):
     # bad.
     # XXX: Note, this test hits the outside-environment check, not the
     # in-stdlib check, because our tests run in virtualenvs...
-    result = script.pip('install', 'argparse>=1.4')
+    result = script.pip("install", "argparse>=1.4")
     assert "Not uninstalling argparse" in result.stdout
 
 
@@ -677,8 +694,8 @@ def test_install_argparse_shadowed(script):
 def test_upgrade_argparse_shadowed(script):
     # If argparse is installed - even if shadowed for imported - we support
     # upgrading it and properly remove the older versions files.
-    script.pip('install', 'argparse==1.3')
-    result = script.pip('install', 'argparse>=1.4')
+    script.pip("install", "argparse==1.3")
+    result = script.pip("install", "argparse>=1.4")
     assert "Not uninstalling argparse" not in result.stdout
 
 
@@ -691,12 +708,9 @@ def test_install_curdir(script, data, with_wheel):
     egg_info = join(run_from, "FSPkg.egg-info")
     if os.path.isdir(egg_info):
         rmtree(egg_info)
-    result = script.pip('install', curdir, cwd=run_from)
-    fspkg_folder = script.site_packages / 'fspkg'
-    dist_info_folder = (
-        script.site_packages /
-        'FSPkg-0.1.dev0.dist-info'
-    )
+    result = script.pip("install", curdir, cwd=run_from)
+    fspkg_folder = script.site_packages / "fspkg"
+    dist_info_folder = script.site_packages / "FSPkg-0.1.dev0.dist-info"
     result.did_create(fspkg_folder)
     result.did_create(dist_info_folder)
 
@@ -706,12 +720,9 @@ def test_install_pardir(script, data, with_wheel):
     Test installing parent directory ('..').
     """
     run_from = data.packages.joinpath("FSPkg", "fspkg")
-    result = script.pip('install', pardir, cwd=run_from)
-    fspkg_folder = script.site_packages / 'fspkg'
-    dist_info_folder = (
-        script.site_packages /
-        'FSPkg-0.1.dev0.dist-info'
-    )
+    result = script.pip("install", pardir, cwd=run_from)
+    fspkg_folder = script.site_packages / "fspkg"
+    dist_info_folder = script.site_packages / "FSPkg-0.1.dev0.dist-info"
     result.did_create(fspkg_folder)
     result.did_create(dist_info_folder)
 
@@ -723,9 +734,9 @@ def test_install_global_option(script):
     (In particular those that disable the actual install action)
     """
     result = script.pip(
-        'install', '--global-option=--version', "INITools==0.1",
-        expect_stderr=True)
-    assert 'INITools==0.1\n' in result.stdout
+        "install", "--global-option=--version", "INITools==0.1", expect_stderr=True
+    )
+    assert "INITools==0.1\n" in result.stdout
     assert not result.files_created
 
 
@@ -734,8 +745,8 @@ def test_install_with_hacked_egg_info(script, data):
     test installing a package which defines its own egg_info class
     """
     run_from = data.packages.joinpath("HackedEggInfo")
-    result = script.pip('install', '.', cwd=run_from)
-    assert 'Successfully installed hackedegginfo-0.0.0\n' in result.stdout
+    result = script.pip("install", ".", cwd=run_from)
+    assert "Successfully installed hackedegginfo-0.0.0\n" in result.stdout
 
 
 @pytest.mark.network
@@ -743,17 +754,19 @@ def test_install_using_install_option_and_editable(script, tmpdir):
     """
     Test installing a tool using -e and --install-option
     """
-    folder = 'script_folder'
+    folder = "script_folder"
     script.scratch_path.joinpath(folder).mkdir()
-    url = 'git+git://github.com/pypa/pip-test-package'
+    url = "git+git://github.com/pypa/pip-test-package"
     result = script.pip(
-        'install', '-e', '{url}#egg=pip-test-package'
-        .format(url=local_checkout(url, tmpdir)),
-        '--install-option=--script-dir={folder}'.format(**locals()),
-        expect_stderr=True)
+        "install",
+        "-e",
+        "{url}#egg=pip-test-package".format(url=local_checkout(url, tmpdir)),
+        "--install-option=--script-dir={folder}".format(**locals()),
+        expect_stderr=True,
+    )
     script_file = (
-        script.venv / 'src' / 'pip-test-package' /
-        folder / 'pip-test-package' + script.exe
+        script.venv / "src" / "pip-test-package" / folder / "pip-test-package"
+        + script.exe
     )
     result.did_create(script_file)
 
@@ -766,12 +779,15 @@ def test_install_global_option_using_editable(script, tmpdir):
     """
     Test using global distutils options, but in an editable installation
     """
-    url = 'hg+http://bitbucket.org/runeh/anyjson'
+    url = "hg+http://bitbucket.org/runeh/anyjson"
     result = script.pip(
-        'install', '--global-option=--version', '-e',
-        '{url}@0.2.5#egg=anyjson'.format(url=local_checkout(url, tmpdir)),
-        expect_stderr=True)
-    assert 'Successfully installed anyjson' in result.stdout
+        "install",
+        "--global-option=--version",
+        "-e",
+        "{url}@0.2.5#egg=anyjson".format(url=local_checkout(url, tmpdir)),
+        expect_stderr=True,
+    )
+    assert "Successfully installed anyjson" in result.stdout
 
 
 @pytest.mark.network
@@ -780,18 +796,17 @@ def test_install_package_with_same_name_in_curdir(script, with_wheel):
     Test installing a package with the same name of a local folder
     """
     script.scratch_path.joinpath("mock==0.6").mkdir()
-    result = script.pip('install', 'mock==0.6')
-    dist_info_folder = (
-        script.site_packages /
-        'mock-0.6.0.dist-info'
-    )
+    result = script.pip("install", "mock==0.6")
+    dist_info_folder = script.site_packages / "mock-0.6.0.dist-info"
     result.did_create(dist_info_folder)
 
 
-mock100_setup_py = textwrap.dedent('''\
+mock100_setup_py = textwrap.dedent(
+    """\
                         from setuptools import setup
                         setup(name='mock',
-                              version='100.1')''')
+                              version='100.1')"""
+)
 
 
 def test_install_folder_using_dot_slash(script, with_wheel):
@@ -799,13 +814,10 @@ def test_install_folder_using_dot_slash(script, with_wheel):
     Test installing a folder using pip install ./foldername
     """
     script.scratch_path.joinpath("mock").mkdir()
-    pkg_path = script.scratch_path / 'mock'
+    pkg_path = script.scratch_path / "mock"
     pkg_path.joinpath("setup.py").write_text(mock100_setup_py)
-    result = script.pip('install', './mock')
-    dist_info_folder = (
-        script.site_packages /
-        'mock-100.1.dist-info'
-    )
+    result = script.pip("install", "./mock")
+    dist_info_folder = script.site_packages / "mock-100.1.dist-info"
     result.did_create(dist_info_folder)
 
 
@@ -814,13 +826,10 @@ def test_install_folder_using_slash_in_the_end(script, with_wheel):
     Test installing a folder using pip install foldername/ or foldername\
     """
     script.scratch_path.joinpath("mock").mkdir()
-    pkg_path = script.scratch_path / 'mock'
+    pkg_path = script.scratch_path / "mock"
     pkg_path.joinpath("setup.py").write_text(mock100_setup_py)
-    result = script.pip('install', 'mock' + os.path.sep)
-    dist_info_folder = (
-        script.site_packages /
-        'mock-100.1.dist-info'
-    )
+    result = script.pip("install", "mock" + os.path.sep)
+    dist_info_folder = script.site_packages / "mock-100.1.dist-info"
     result.did_create(dist_info_folder)
 
 
@@ -830,13 +839,10 @@ def test_install_folder_using_relative_path(script, with_wheel):
     """
     script.scratch_path.joinpath("initools").mkdir()
     script.scratch_path.joinpath("initools", "mock").mkdir()
-    pkg_path = script.scratch_path / 'initools' / 'mock'
+    pkg_path = script.scratch_path / "initools" / "mock"
     pkg_path.joinpath("setup.py").write_text(mock100_setup_py)
-    result = script.pip('install', Path('initools') / 'mock')
-    dist_info_folder = (
-        script.site_packages /
-        'mock-100.1.dist-info'.format(**globals())
-    )
+    result = script.pip("install", Path("initools") / "mock")
+    dist_info_folder = script.site_packages / "mock-100.1.dist-info".format(**globals())
     result.did_create(dist_info_folder)
 
 
@@ -845,12 +851,9 @@ def test_install_package_which_contains_dev_in_name(script, with_wheel):
     """
     Test installing package from PyPI which contains 'dev' in name
     """
-    result = script.pip('install', 'django-devserver==0.0.4')
-    devserver_folder = script.site_packages / 'devserver'
-    dist_info_folder = (
-        script.site_packages /
-        'django_devserver-0.0.4.dist-info'
-    )
+    result = script.pip("install", "django-devserver==0.0.4")
+    devserver_folder = script.site_packages / "devserver"
+    dist_info_folder = script.site_packages / "django_devserver-0.0.4.dist-info"
     result.did_create(devserver_folder)
     result.did_create(dist_info_folder)
 
@@ -859,116 +862,121 @@ def test_install_package_with_target(script, with_wheel):
     """
     Test installing a package using pip install --target
     """
-    target_dir = script.scratch_path / 'target'
-    result = script.pip_install_local('-t', target_dir, "simple==1.0")
-    result.did_create(Path('scratch') / 'target' / 'simple')
+    target_dir = script.scratch_path / "target"
+    result = script.pip_install_local("-t", target_dir, "simple==1.0")
+    result.did_create(Path("scratch") / "target" / "simple")
 
     # Test repeated call without --upgrade, no files should have changed
     result = script.pip_install_local(
-        '-t', target_dir, "simple==1.0", expect_stderr=True,
+        "-t",
+        target_dir,
+        "simple==1.0",
+        expect_stderr=True,
     )
-    result.did_not_update(Path('scratch') / 'target' / 'simple')
+    result.did_not_update(Path("scratch") / "target" / "simple")
 
     # Test upgrade call, check that new version is installed
-    result = script.pip_install_local('--upgrade', '-t',
-                                      target_dir, "simple==2.0")
-    result.did_update(Path('scratch') / 'target' / 'simple')
-    dist_info_folder = (
-        Path('scratch') / 'target' /
-        'simple-2.0.dist-info'
-    )
+    result = script.pip_install_local("--upgrade", "-t", target_dir, "simple==2.0")
+    result.did_update(Path("scratch") / "target" / "simple")
+    dist_info_folder = Path("scratch") / "target" / "simple-2.0.dist-info"
     result.did_create(dist_info_folder)
 
     # Test install and upgrade of single-module package
-    result = script.pip_install_local('-t', target_dir, 'singlemodule==0.0.0')
-    singlemodule_py = Path('scratch') / 'target' / 'singlemodule.py'
+    result = script.pip_install_local("-t", target_dir, "singlemodule==0.0.0")
+    singlemodule_py = Path("scratch") / "target" / "singlemodule.py"
     result.did_create(singlemodule_py)
 
-    result = script.pip_install_local('-t', target_dir, 'singlemodule==0.0.1',
-                                      '--upgrade')
+    result = script.pip_install_local(
+        "-t", target_dir, "singlemodule==0.0.1", "--upgrade"
+    )
     result.did_update(singlemodule_py)
 
 
-@pytest.mark.parametrize("target_option", ['--target', '-t'])
-def test_install_package_to_usersite_with_target_must_fail(script,
-                                                           target_option):
+@pytest.mark.parametrize("target_option", ["--target", "-t"])
+def test_install_package_to_usersite_with_target_must_fail(script, target_option):
     """
     Test that installing package to usersite with target
     must raise error
     """
-    target_dir = script.scratch_path / 'target'
+    target_dir = script.scratch_path / "target"
     result = script.pip_install_local(
-        '--user', target_option, target_dir, "simple==1.0", expect_error=True
-    )
-    assert "Can not combine '--user' and '--target'" in result.stderr, (
-        str(result)
+        "--user", target_option, target_dir, "simple==1.0", expect_error=True
     )
+    assert "Can not combine '--user' and '--target'" in result.stderr, str(result)
 
 
 def test_install_nonlocal_compatible_wheel(script, data):
-    target_dir = script.scratch_path / 'target'
+    target_dir = script.scratch_path / "target"
 
     # Test install with --target
     result = script.pip(
-        'install',
-        '-t', target_dir,
-        '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--python', '3',
-        '--platform', 'fakeplat',
-        '--abi', 'fakeabi',
-        'simplewheel',
+        "install",
+        "-t",
+        target_dir,
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--python",
+        "3",
+        "--platform",
+        "fakeplat",
+        "--abi",
+        "fakeabi",
+        "simplewheel",
     )
     assert result.returncode == SUCCESS
 
-    distinfo = Path('scratch') / 'target' / 'simplewheel-2.0-1.dist-info'
+    distinfo = Path("scratch") / "target" / "simplewheel-2.0-1.dist-info"
     result.did_create(distinfo)
 
     # Test install without --target
     result = script.pip(
-        'install',
-        '--no-index', '--find-links', data.find_links,
-        '--only-binary=:all:',
-        '--python', '3',
-        '--platform', 'fakeplat',
-        '--abi', 'fakeabi',
-        'simplewheel',
-        expect_error=True
+        "install",
+        "--no-index",
+        "--find-links",
+        data.find_links,
+        "--only-binary=:all:",
+        "--python",
+        "3",
+        "--platform",
+        "fakeplat",
+        "--abi",
+        "fakeabi",
+        "simplewheel",
+        expect_error=True,
     )
     assert result.returncode == ERROR
 
 
-def test_install_nonlocal_compatible_wheel_path(
-    script,
-    data,
-    use_new_resolver
-):
-    target_dir = script.scratch_path / 'target'
+def test_install_nonlocal_compatible_wheel_path(script, data, use_new_resolver):
+    target_dir = script.scratch_path / "target"
 
     # Test a full path requirement
     result = script.pip(
-        'install',
-        '-t', target_dir,
-        '--no-index',
-        '--only-binary=:all:',
-        Path(data.packages) / 'simplewheel-2.0-py3-fakeabi-fakeplat.whl',
-        expect_error=use_new_resolver
+        "install",
+        "-t",
+        target_dir,
+        "--no-index",
+        "--only-binary=:all:",
+        Path(data.packages) / "simplewheel-2.0-py3-fakeabi-fakeplat.whl",
+        expect_error=use_new_resolver,
     )
     if use_new_resolver:
         assert result.returncode == ERROR
     else:
         assert result.returncode == SUCCESS
 
-        distinfo = Path('scratch') / 'target' / 'simplewheel-2.0.dist-info'
+        distinfo = Path("scratch") / "target" / "simplewheel-2.0.dist-info"
         result.did_create(distinfo)
 
     # Test a full path requirement (without --target)
     result = script.pip(
-        'install',
-        '--no-index',
-        '--only-binary=:all:',
-        Path(data.packages) / 'simplewheel-2.0-py3-fakeabi-fakeplat.whl',
-        expect_error=True
+        "install",
+        "--no-index",
+        "--only-binary=:all:",
+        Path(data.packages) / "simplewheel-2.0-py3-fakeabi-fakeplat.whl",
+        expect_error=True,
     )
     assert result.returncode == ERROR
 
@@ -978,10 +986,12 @@ def test_install_with_target_and_scripts_no_warning(script, with_wheel):
     Test that installing with --target does not trigger the "script not
     in PATH" warning (issue #5201)
     """
-    target_dir = script.scratch_path / 'target'
-    pkga_path = script.scratch_path / 'pkga'
+    target_dir = script.scratch_path / "target"
+    pkga_path = script.scratch_path / "pkga"
     pkga_path.mkdir()
-    pkga_path.joinpath("setup.py").write_text(textwrap.dedent("""
+    pkga_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
         from setuptools import setup
         setup(name='pkga',
               version='0.1',
@@ -990,11 +1000,17 @@ def test_install_with_target_and_scripts_no_warning(script, with_wheel):
                   'console_scripts': ['pkga=pkga:main']
               }
         )
-    """))
-    pkga_path.joinpath("pkga.py").write_text(textwrap.dedent("""
+    """
+        )
+    )
+    pkga_path.joinpath("pkga.py").write_text(
+        textwrap.dedent(
+            """
         def main(): pass
-    """))
-    result = script.pip('install', '--target', target_dir, pkga_path)
+    """
+        )
+    )
+    result = script.pip("install", "--target", target_dir, pkga_path)
     # This assertion isn't actually needed, if we get the script warning
     # the script.pip() call will fail with "stderr not expected". But we
     # leave the assertion to make the intention of the code clearer.
@@ -1005,21 +1021,23 @@ def test_install_package_with_root(script, data, with_wheel):
     """
     Test installing a package using pip install --root
     """
-    root_dir = script.scratch_path / 'root'
+    root_dir = script.scratch_path / "root"
     result = script.pip(
-        'install', '--root', root_dir, '-f', data.find_links, '--no-index',
-        'simple==1.0',
+        "install",
+        "--root",
+        root_dir,
+        "-f",
+        data.find_links,
+        "--no-index",
+        "simple==1.0",
     )
     normal_install_path = (
-        script.base_path / script.site_packages /
-        'simple-1.0.dist-info'
+        script.base_path / script.site_packages / "simple-1.0.dist-info"
     )
     # use distutils to change the root exactly how the --root option does it
     from distutils.util import change_root
-    root_path = change_root(
-        os.path.join(script.scratch, 'root'),
-        normal_install_path
-    )
+
+    root_path = change_root(os.path.join(script.scratch, "root"), normal_install_path)
     result.did_create(root_path)
 
     # Should show find-links location in output
@@ -1031,36 +1049,49 @@ def test_install_package_with_prefix(script, data):
     """
     Test installing a package using pip install --prefix
     """
-    prefix_path = script.scratch_path / 'prefix'
+    prefix_path = script.scratch_path / "prefix"
     result = script.pip(
-        'install', '--prefix', prefix_path, '-f', data.find_links,
-        '--no-binary', 'simple', '--no-index', 'simple==1.0',
-    )
-
-    rel_prefix_path = script.scratch / 'prefix'
+        "install",
+        "--prefix",
+        prefix_path,
+        "-f",
+        data.find_links,
+        "--no-binary",
+        "simple",
+        "--no-index",
+        "simple==1.0",
+    )
+
+    rel_prefix_path = script.scratch / "prefix"
     install_path = (
-        distutils.sysconfig.get_python_lib(prefix=rel_prefix_path) /
+        distutils.sysconfig.get_python_lib(prefix=rel_prefix_path)
+        /
         # we still test for egg-info because no-binary implies setup.py install
-        'simple-1.0-py{}.egg-info'.format(pyversion)
+        "simple-1.0-py{}.egg-info".format(pyversion)
     )
     result.did_create(install_path)
 
 
 def test_install_editable_with_prefix(script):
     # make a dummy project
-    pkga_path = script.scratch_path / 'pkga'
+    pkga_path = script.scratch_path / "pkga"
     pkga_path.mkdir()
-    pkga_path.joinpath("setup.py").write_text(textwrap.dedent("""
+    pkga_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
         from setuptools import setup
         setup(name='pkga',
               version='0.1')
-    """))
+    """
+        )
+    )
 
     if hasattr(sys, "pypy_version_info"):
         site_packages = os.path.join(
-            'prefix', 'lib', 'python{}'.format(pyversion), 'site-packages')
+            "prefix", "lib", "python{}".format(pyversion), "site-packages"
+        )
     else:
-        site_packages = distutils.sysconfig.get_python_lib(prefix='prefix')
+        site_packages = distutils.sysconfig.get_python_lib(prefix="prefix")
 
     # make sure target path is in PYTHONPATH
     pythonpath = script.scratch_path / site_packages
@@ -1068,12 +1099,11 @@ def test_install_editable_with_prefix(script):
     script.environ["PYTHONPATH"] = pythonpath
 
     # install pkga package into the absolute prefix directory
-    prefix_path = script.scratch_path / 'prefix'
-    result = script.pip(
-        'install', '--editable', pkga_path, '--prefix', prefix_path)
+    prefix_path = script.scratch_path / "prefix"
+    result = script.pip("install", "--editable", pkga_path, "--prefix", prefix_path)
 
     # assert pkga is installed at correct location
-    install_path = script.scratch / site_packages / 'pkga.egg-link'
+    install_path = script.scratch / site_packages / "pkga.egg-link"
     result.did_create(install_path)
 
 
@@ -1081,15 +1111,20 @@ def test_install_package_conflict_prefix_and_user(script, data):
     """
     Test installing a package using pip install --prefix --user errors out
     """
-    prefix_path = script.scratch_path / 'prefix'
+    prefix_path = script.scratch_path / "prefix"
     result = script.pip(
-        'install', '-f', data.find_links, '--no-index', '--user',
-        '--prefix', prefix_path, 'simple==1.0',
-        expect_error=True, quiet=True,
-    )
-    assert (
-        "Can not combine '--user' and '--prefix'" in result.stderr
+        "install",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "--user",
+        "--prefix",
+        prefix_path,
+        "simple==1.0",
+        expect_error=True,
+        quiet=True,
     )
+    assert "Can not combine '--user' and '--prefix'" in result.stderr
 
 
 def test_install_package_that_emits_unicode(script, data):
@@ -1100,25 +1135,29 @@ def test_install_package_that_emits_unicode(script, data):
     """
     to_install = data.packages.joinpath("BrokenEmitsUTF8")
     result = script.pip(
-        'install', to_install, expect_error=True, expect_temp=True, quiet=True,
+        "install",
+        to_install,
+        expect_error=True,
+        expect_temp=True,
+        quiet=True,
     )
     assert (
-        'FakeError: this package designed to fail on install' in result.stderr
-    ), 'stderr: {}'.format(result.stderr)
-    assert 'UnicodeDecodeError' not in result.stderr
-    assert 'UnicodeDecodeError' not in result.stdout
+        "FakeError: this package designed to fail on install" in result.stderr
+    ), "stderr: {}".format(result.stderr)
+    assert "UnicodeDecodeError" not in result.stderr
+    assert "UnicodeDecodeError" not in result.stdout
 
 
 def test_install_package_with_utf8_setup(script, data):
     """Install a package with a setup.py that declares a utf-8 encoding."""
     to_install = data.packages.joinpath("SetupPyUTF8")
-    script.pip('install', to_install)
+    script.pip("install", to_install)
 
 
 def test_install_package_with_latin1_setup(script, data):
     """Install a package with a setup.py that declares a latin-1 encoding."""
     to_install = data.packages.joinpath("SetupPyLatin1")
-    script.pip('install', to_install)
+    script.pip("install", to_install)
 
 
 def test_url_req_case_mismatch_no_index(script, data, with_wheel):
@@ -1130,17 +1169,15 @@ def test_url_req_case_mismatch_no_index(script, data, with_wheel):
     tests/data/packages contains Upper-1.0.tar.gz and Upper-2.0.tar.gz
     'requiresupper' has install_requires = ['upper']
     """
-    Upper = '/'.join((data.find_links, 'Upper-1.0.tar.gz'))
+    Upper = "/".join((data.find_links, "Upper-1.0.tar.gz"))
     result = script.pip(
-        'install', '--no-index', '-f', data.find_links, Upper, 'requiresupper'
+        "install", "--no-index", "-f", data.find_links, Upper, "requiresupper"
     )
 
     # only Upper-1.0.tar.gz should get installed.
-    dist_info_folder = script.site_packages / \
-        'Upper-1.0.dist-info'
+    dist_info_folder = script.site_packages / "Upper-1.0.dist-info"
     result.did_create(dist_info_folder)
-    dist_info_folder = script.site_packages / \
-        'Upper-2.0.dist-info'
+    dist_info_folder = script.site_packages / "Upper-2.0.dist-info"
     result.did_not_create(dist_info_folder)
 
 
@@ -1159,17 +1196,15 @@ def test_url_req_case_mismatch_file_index(script, data, with_wheel):
     set of packages as it requires a prepared index.html file and
     subdirectory-per-package structure.
     """
-    Dinner = '/'.join((data.find_links3, 'dinner', 'Dinner-1.0.tar.gz'))
+    Dinner = "/".join((data.find_links3, "dinner", "Dinner-1.0.tar.gz"))
     result = script.pip(
-        'install', '--index-url', data.find_links3, Dinner, 'requiredinner'
+        "install", "--index-url", data.find_links3, Dinner, "requiredinner"
     )
 
     # only Upper-1.0.tar.gz should get installed.
-    dist_info_folder = script.site_packages / \
-        'Dinner-1.0.dist-info'
+    dist_info_folder = script.site_packages / "Dinner-1.0.dist-info"
     result.did_create(dist_info_folder)
-    dist_info_folder = script.site_packages / \
-        'Dinner-2.0.dist-info'
+    dist_info_folder = script.site_packages / "Dinner-2.0.dist-info"
     result.did_not_create(dist_info_folder)
 
 
@@ -1180,15 +1215,17 @@ def test_url_incorrect_case_no_index(script, data, with_wheel):
     rather than in a requirements file.
     """
     result = script.pip(
-        'install', '--no-index', '-f', data.find_links, "upper",
+        "install",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "upper",
     )
 
     # only Upper-2.0.tar.gz should get installed.
-    dist_info_folder = script.site_packages / \
-        'Upper-1.0.dist-info'
+    dist_info_folder = script.site_packages / "Upper-1.0.dist-info"
     result.did_not_create(dist_info_folder)
-    dist_info_folder = script.site_packages / \
-        'Upper-2.0.dist-info'
+    dist_info_folder = script.site_packages / "Upper-2.0.dist-info"
     result.did_create(dist_info_folder)
 
 
@@ -1199,16 +1236,17 @@ def test_url_incorrect_case_file_index(script, data, with_wheel):
     rather than in a requirements file.
     """
     result = script.pip(
-        'install', '--index-url', data.find_links3, "dinner",
+        "install",
+        "--index-url",
+        data.find_links3,
+        "dinner",
         expect_stderr=True,
     )
 
     # only Upper-2.0.tar.gz should get installed.
-    dist_info_folder = script.site_packages / \
-        'Dinner-1.0.dist-info'
+    dist_info_folder = script.site_packages / "Dinner-1.0.dist-info"
     result.did_not_create(dist_info_folder)
-    dist_info_folder = script.site_packages / \
-        'Dinner-2.0.dist-info'
+    dist_info_folder = script.site_packages / "Dinner-2.0.dist-info"
     result.did_create(dist_info_folder)
 
     # Should show index-url location in output
@@ -1260,31 +1298,39 @@ def test_no_compiles_pyc(script):
 
 def test_install_upgrade_editable_depending_on_other_editable(script):
     script.scratch_path.joinpath("pkga").mkdir()
-    pkga_path = script.scratch_path / 'pkga'
-    pkga_path.joinpath("setup.py").write_text(textwrap.dedent("""
+    pkga_path = script.scratch_path / "pkga"
+    pkga_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
         from setuptools import setup
         setup(name='pkga',
               version='0.1')
-    """))
-    script.pip('install', '--editable', pkga_path)
-    result = script.pip('list', '--format=freeze')
+    """
+        )
+    )
+    script.pip("install", "--editable", pkga_path)
+    result = script.pip("list", "--format=freeze")
     assert "pkga==0.1" in result.stdout
 
     script.scratch_path.joinpath("pkgb").mkdir()
-    pkgb_path = script.scratch_path / 'pkgb'
-    pkgb_path.joinpath("setup.py").write_text(textwrap.dedent("""
+    pkgb_path = script.scratch_path / "pkgb"
+    pkgb_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
         from setuptools import setup
         setup(name='pkgb',
               version='0.1',
               install_requires=['pkga'])
-    """))
-    script.pip('install', '--upgrade', '--editable', pkgb_path, '--no-index')
-    result = script.pip('list', '--format=freeze')
+    """
+        )
+    )
+    script.pip("install", "--upgrade", "--editable", pkgb_path, "--no-index")
+    result = script.pip("list", "--format=freeze")
     assert "pkgb==0.1" in result.stdout
 
 
 def test_install_subprocess_output_handling(script, data):
-    args = ['install', data.src.joinpath('chattymodule')]
+    args = ["install", data.src.joinpath("chattymodule")]
 
     # Regular install should not show output from the chatty setup.py
     result = script.pip(*args)
@@ -1300,47 +1346,50 @@ def test_install_subprocess_output_handling(script, data):
 
     # If the install fails, then we *should* show the output... but only once,
     # even if --verbose is given.
-    result = script.pip(*(args + ["--global-option=--fail"]),
-                        expect_error=True)
+    result = script.pip(*(args + ["--global-option=--fail"]), expect_error=True)
     assert 1 == result.stderr.count("I DIE, I DIE")
 
-    result = script.pip(*(args + ["--global-option=--fail", "--verbose"]),
-                        expect_error=True)
+    result = script.pip(
+        *(args + ["--global-option=--fail", "--verbose"]), expect_error=True
+    )
     assert 1 == result.stderr.count("I DIE, I DIE")
 
 
 def test_install_log(script, data, tmpdir):
     # test that verbose logs go to "--log" file
     f = tmpdir.joinpath("log.txt")
-    args = ['--log={f}'.format(**locals()),
-            'install', data.src.joinpath('chattymodule')]
+    args = [
+        "--log={f}".format(**locals()),
+        "install",
+        data.src.joinpath("chattymodule"),
+    ]
     result = script.pip(*args)
     assert 0 == result.stdout.count("HELLO FROM CHATTYMODULE")
-    with open(f, 'r') as fp:
+    with open(f, "r") as fp:
         # one from egg_info, one from install
         assert 2 == fp.read().count("HELLO FROM CHATTYMODULE")
 
 
 def test_install_topological_sort(script, data):
-    args = ['install', 'TopoRequires4', '--no-index', '-f', data.packages]
+    args = ["install", "TopoRequires4", "--no-index", "-f", data.packages]
     res = str(script.pip(*args))
-    order1 = 'TopoRequires, TopoRequires2, TopoRequires3, TopoRequires4'
-    order2 = 'TopoRequires, TopoRequires3, TopoRequires2, TopoRequires4'
+    order1 = "TopoRequires, TopoRequires2, TopoRequires3, TopoRequires4"
+    order2 = "TopoRequires, TopoRequires3, TopoRequires2, TopoRequires4"
     assert order1 in res or order2 in res, res
 
 
 def test_install_wheel_broken(script, with_wheel):
-    res = script.pip_install_local('wheelbroken', expect_stderr=True)
+    res = script.pip_install_local("wheelbroken", expect_stderr=True)
     assert "Successfully installed wheelbroken-0.1" in str(res), str(res)
 
 
 def test_cleanup_after_failed_wheel(script, with_wheel):
-    res = script.pip_install_local('wheelbrokenafter', expect_stderr=True)
+    res = script.pip_install_local("wheelbrokenafter", expect_stderr=True)
     # One of the effects of not cleaning up is broken scripts:
     script_py = script.bin_path / "script.py"
     assert script_py.exists(), script_py
-    shebang = open(script_py, 'r').readline().strip()
-    assert shebang != '#!python', shebang
+    shebang = open(script_py, "r").readline().strip()
+    assert shebang != "#!python", shebang
     # OK, assert that we *said* we were cleaning up:
     # /!\ if in need to change this, also change test_pep517_no_legacy_cleanup
     assert "Running setup.py clean for wheelbrokenafter" in str(res), str(res)
@@ -1348,20 +1397,26 @@ def test_cleanup_after_failed_wheel(script, with_wheel):
 
 def test_install_builds_wheels(script, data, with_wheel):
     # We need to use a subprocess to get the right value on Windows.
-    res = script.run('python', '-c', (
-        'from pip._internal.utils import appdirs; '
-        'print(appdirs.user_cache_dir("pip"))'
-    ))
-    wheels_cache = os.path.join(res.stdout.rstrip('\n'), 'wheels')
+    res = script.run(
+        "python",
+        "-c",
+        (
+            "from pip._internal.utils import appdirs; "
+            'print(appdirs.user_cache_dir("pip"))'
+        ),
+    )
+    wheels_cache = os.path.join(res.stdout.rstrip("\n"), "wheels")
     # NB This incidentally tests a local tree + tarball inputs
     # see test_install_editable_from_git_autobuild_wheel for editable
     # vcs coverage.
-    to_install = data.packages.joinpath('requires_wheelbroken_upper')
+    to_install = data.packages.joinpath("requires_wheelbroken_upper")
     res = script.pip(
-        'install', '--no-index', '-f', data.find_links,
-        to_install, expect_stderr=True)
-    expected = ("Successfully installed requires-wheelbroken-upper-0"
-                " upper-2.0 wheelbroken-0.1")
+        "install", "--no-index", "-f", data.find_links, to_install, expect_stderr=True
+    )
+    expected = (
+        "Successfully installed requires-wheelbroken-upper-0"
+        " upper-2.0 wheelbroken-0.1"
+    )
     # Must have installed it all
     assert expected in str(res), str(res)
     wheels = []
@@ -1388,12 +1443,20 @@ def test_install_builds_wheels(script, data, with_wheel):
 
 
 def test_install_no_binary_disables_building_wheels(script, data, with_wheel):
-    to_install = data.packages.joinpath('requires_wheelbroken_upper')
+    to_install = data.packages.joinpath("requires_wheelbroken_upper")
     res = script.pip(
-        'install', '--no-index', '--no-binary=upper', '-f', data.find_links,
-        to_install, expect_stderr=True)
-    expected = ("Successfully installed requires-wheelbroken-upper-0"
-                " upper-2.0 wheelbroken-0.1")
+        "install",
+        "--no-index",
+        "--no-binary=upper",
+        "-f",
+        data.find_links,
+        to_install,
+        expect_stderr=True,
+    )
+    expected = (
+        "Successfully installed requires-wheelbroken-upper-0"
+        " upper-2.0 wheelbroken-0.1"
+    )
     # Must have installed it all
     assert expected in str(res), str(res)
     # and built wheels for wheelbroken only
@@ -1412,11 +1475,9 @@ def test_install_no_binary_disables_building_wheels(script, data, with_wheel):
 @pytest.mark.network
 @windows_workaround_7667
 def test_install_no_binary_builds_pep_517_wheel(script, data, with_wheel):
-    to_install = data.packages.joinpath('pep517_setup_and_pyproject')
-    res = script.pip(
-        'install', '--no-binary=:all:', '-f', data.find_links, to_install
-    )
-    expected = ("Successfully installed pep517-setup-and-pyproject")
+    to_install = data.packages.joinpath("pep517_setup_and_pyproject")
+    res = script.pip("install", "--no-binary=:all:", "-f", data.find_links, to_install)
+    expected = "Successfully installed pep517-setup-and-pyproject"
     # Must have installed the package
     assert expected in str(res), str(res)
 
@@ -1426,13 +1487,10 @@ def test_install_no_binary_builds_pep_517_wheel(script, data, with_wheel):
 
 @pytest.mark.network
 @windows_workaround_7667
-def test_install_no_binary_uses_local_backend(
-        script, data, with_wheel, tmpdir):
-    to_install = data.packages.joinpath('pep517_wrapper_buildsys')
-    script.environ['PIP_TEST_MARKER_FILE'] = marker = str(tmpdir / 'marker')
-    res = script.pip(
-        'install', '--no-binary=:all:', '-f', data.find_links, to_install
-    )
+def test_install_no_binary_uses_local_backend(script, data, with_wheel, tmpdir):
+    to_install = data.packages.joinpath("pep517_wrapper_buildsys")
+    script.environ["PIP_TEST_MARKER_FILE"] = marker = str(tmpdir / "marker")
+    res = script.pip("install", "--no-binary=:all:", "-f", data.find_links, to_install)
     expected = "Successfully installed pep517-wrapper-buildsys"
     # Must have installed the package
     assert expected in str(res), str(res)
@@ -1442,13 +1500,17 @@ def test_install_no_binary_uses_local_backend(
 
 def test_install_no_binary_disables_cached_wheels(script, data, with_wheel):
     # Seed the cache
-    script.pip(
-        'install', '--no-index', '-f', data.find_links,
-        'upper')
-    script.pip('uninstall', 'upper', '-y')
+    script.pip("install", "--no-index", "-f", data.find_links, "upper")
+    script.pip("uninstall", "upper", "-y")
     res = script.pip(
-        'install', '--no-index', '--no-binary=:all:', '-f', data.find_links,
-        'upper', expect_stderr=True)
+        "install",
+        "--no-index",
+        "--no-binary=:all:",
+        "-f",
+        data.find_links,
+        "upper",
+        expect_stderr=True,
+    )
     assert "Successfully installed upper-2.0" in str(res), str(res)
     # No wheel building for upper, which was blacklisted
     assert "Building wheel for upper" not in str(res), str(res)
@@ -1458,20 +1520,27 @@ def test_install_no_binary_disables_cached_wheels(script, data, with_wheel):
 
 def test_install_editable_with_wrong_egg_name(script, use_new_resolver):
     script.scratch_path.joinpath("pkga").mkdir()
-    pkga_path = script.scratch_path / 'pkga'
-    pkga_path.joinpath("setup.py").write_text(textwrap.dedent("""
+    pkga_path = script.scratch_path / "pkga"
+    pkga_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
         from setuptools import setup
         setup(name='pkga',
               version='0.1')
-    """))
+    """
+        )
+    )
     result = script.pip(
-        'install', '--editable',
-        'file://{pkga_path}#egg=pkgb'.format(**locals()),
+        "install",
+        "--editable",
+        "file://{pkga_path}#egg=pkgb".format(**locals()),
         expect_error=use_new_resolver,
     )
-    assert ("Generating metadata for package pkgb produced metadata "
-            "for project name pkga. Fix your #egg=pkgb "
-            "fragments.") in result.stderr
+    assert (
+        "Generating metadata for package pkgb produced metadata "
+        "for project name pkga. Fix your #egg=pkgb "
+        "fragments."
+    ) in result.stderr
     if use_new_resolver:
         assert "has different name in metadata" in result.stderr, str(result)
     else:
@@ -1483,7 +1552,7 @@ def test_install_tar_xz(script, data):
         import lzma  # noqa
     except ImportError:
         pytest.skip("No lzma support")
-    res = script.pip('install', data.packages / 'singlemodule-0.0.1.tar.xz')
+    res = script.pip("install", data.packages / "singlemodule-0.0.1.tar.xz")
     assert "Successfully installed singlemodule-0.0.1" in res.stdout, res
 
 
@@ -1492,7 +1561,7 @@ def test_install_tar_lzma(script, data):
         import lzma  # noqa
     except ImportError:
         pytest.skip("No lzma support")
-    res = script.pip('install', data.packages / 'singlemodule-0.0.1.tar.lzma')
+    res = script.pip("install", data.packages / "singlemodule-0.0.1.tar.lzma")
     assert "Successfully installed singlemodule-0.0.1" in res.stdout, res
 
 
@@ -1500,7 +1569,7 @@ def test_double_install(script):
     """
     Test double install passing with two same version requirements
     """
-    result = script.pip('install', 'pip', 'pip')
+    result = script.pip("install", "pip", "pip")
     msg = "Double requirement given: pip (already in pip, name='pip')"
     assert msg not in result.stderr
 
@@ -1510,92 +1579,114 @@ def test_double_install_fail(script, use_new_resolver):
     Test double install failing with two different version requirements
     """
     result = script.pip(
-        'install',
-        'pip==7.*',
-        'pip==7.1.2',
+        "install",
+        "pip==7.*",
+        "pip==7.1.2",
         # The new resolver is perfectly capable of handling this
-        expect_error=(not use_new_resolver)
+        expect_error=(not use_new_resolver),
     )
     if not use_new_resolver:
-        msg = ("Double requirement given: pip==7.1.2 (already in pip==7.*, "
-               "name='pip')")
+        msg = (
+            "Double requirement given: pip==7.1.2 (already in pip==7.*, " "name='pip')"
+        )
         assert msg in result.stderr
 
 
 def _get_expected_error_text():
-    return (
-        "Package 'pkga' requires a different Python: {} not in '<1.0'"
-    ).format('.'.join(map(str, sys.version_info[:3])))
+    return ("Package 'pkga' requires a different Python: {} not in '<1.0'").format(
+        ".".join(map(str, sys.version_info[:3]))
+    )
 
 
 def test_install_incompatible_python_requires(script):
     script.scratch_path.joinpath("pkga").mkdir()
-    pkga_path = script.scratch_path / 'pkga'
-    pkga_path.joinpath("setup.py").write_text(textwrap.dedent("""
+    pkga_path = script.scratch_path / "pkga"
+    pkga_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
         from setuptools import setup
         setup(name='pkga',
               python_requires='<1.0',
               version='0.1')
-    """))
-    result = script.pip('install', pkga_path, expect_error=True)
+    """
+        )
+    )
+    result = script.pip("install", pkga_path, expect_error=True)
     assert _get_expected_error_text() in result.stderr, str(result)
 
 
 def test_install_incompatible_python_requires_editable(script):
     script.scratch_path.joinpath("pkga").mkdir()
-    pkga_path = script.scratch_path / 'pkga'
-    pkga_path.joinpath("setup.py").write_text(textwrap.dedent("""
+    pkga_path = script.scratch_path / "pkga"
+    pkga_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
         from setuptools import setup
         setup(name='pkga',
               python_requires='<1.0',
               version='0.1')
-    """))
+    """
+        )
+    )
     result = script.pip(
-        'install',
-        '--editable={pkga_path}'.format(**locals()),
-        expect_error=True)
+        "install", "--editable={pkga_path}".format(**locals()), expect_error=True
+    )
     assert _get_expected_error_text() in result.stderr, str(result)
 
 
 def test_install_incompatible_python_requires_wheel(script, with_wheel):
     script.scratch_path.joinpath("pkga").mkdir()
-    pkga_path = script.scratch_path / 'pkga'
-    pkga_path.joinpath("setup.py").write_text(textwrap.dedent("""
+    pkga_path = script.scratch_path / "pkga"
+    pkga_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
         from setuptools import setup
         setup(name='pkga',
               python_requires='<1.0',
               version='0.1')
-    """))
+    """
+        )
+    )
     script.run(
-        'python', 'setup.py', 'bdist_wheel', '--universal',
-        cwd=pkga_path, allow_stderr_warning=PY2,
+        "python",
+        "setup.py",
+        "bdist_wheel",
+        "--universal",
+        cwd=pkga_path,
+        allow_stderr_warning=PY2,
+    )
+    result = script.pip(
+        "install", "./pkga/dist/pkga-0.1-py2.py3-none-any.whl", expect_error=True
     )
-    result = script.pip('install', './pkga/dist/pkga-0.1-py2.py3-none-any.whl',
-                        expect_error=True)
     assert _get_expected_error_text() in result.stderr, str(result)
 
 
 def test_install_compatible_python_requires(script):
     script.scratch_path.joinpath("pkga").mkdir()
-    pkga_path = script.scratch_path / 'pkga'
-    pkga_path.joinpath("setup.py").write_text(textwrap.dedent("""
+    pkga_path = script.scratch_path / "pkga"
+    pkga_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
         from setuptools import setup
         setup(name='pkga',
               python_requires='>1.0',
               version='0.1')
-    """))
-    res = script.pip('install', pkga_path)
+    """
+        )
+    )
+    res = script.pip("install", pkga_path)
     assert "Successfully installed pkga-0.1" in res.stdout, res
 
 
 @pytest.mark.network
 def test_install_pep508_with_url(script):
     res = script.pip(
-        'install', '--no-index',
-        'packaging@https://files.pythonhosted.org/packages/2f/2b/'
-        'c681de3e1dbcd469537aefb15186b800209aa1f299d933d23b48d85c9d56/'
-        'packaging-15.3-py2.py3-none-any.whl#sha256='
-        'ce1a869fe039fbf7e217df36c4653d1dbe657778b2d41709593a0003584405f4'
+        "install",
+        "--no-index",
+        "packaging@https://files.pythonhosted.org/packages/2f/2b/"
+        "c681de3e1dbcd469537aefb15186b800209aa1f299d933d23b48d85c9d56/"
+        "packaging-15.3-py2.py3-none-any.whl#sha256="
+        "ce1a869fe039fbf7e217df36c4653d1dbe657778b2d41709593a0003584405f4",
     )
     assert "Successfully installed packaging-15.3" in str(res), str(res)
 
@@ -1603,26 +1694,28 @@ def test_install_pep508_with_url(script):
 @pytest.mark.network
 def test_install_pep508_with_url_in_install_requires(script):
     pkga_path = create_test_package_with_setup(
-        script, name='pkga', version='1.0',
+        script,
+        name="pkga",
+        version="1.0",
         install_requires=[
-            'packaging@https://files.pythonhosted.org/packages/2f/2b/'
-            'c681de3e1dbcd469537aefb15186b800209aa1f299d933d23b48d85c9d56/'
-            'packaging-15.3-py2.py3-none-any.whl#sha256='
-            'ce1a869fe039fbf7e217df36c4653d1dbe657778b2d41709593a0003584405f4'
+            "packaging@https://files.pythonhosted.org/packages/2f/2b/"
+            "c681de3e1dbcd469537aefb15186b800209aa1f299d933d23b48d85c9d56/"
+            "packaging-15.3-py2.py3-none-any.whl#sha256="
+            "ce1a869fe039fbf7e217df36c4653d1dbe657778b2d41709593a0003584405f4"
         ],
     )
-    res = script.pip('install', pkga_path)
+    res = script.pip("install", pkga_path)
     assert "Successfully installed packaging-15.3" in str(res), str(res)
 
 
 @pytest.mark.network
-@pytest.mark.parametrize('index', (PyPI.simple_url, TestPyPI.simple_url))
+@pytest.mark.parametrize("index", (PyPI.simple_url, TestPyPI.simple_url))
 def test_install_from_test_pypi_with_ext_url_dep_is_blocked(script, index):
     res = script.pip(
-        'install',
-        '--index-url',
+        "install",
+        "--index-url",
         index,
-        'pep-508-url-deps',
+        "pep-508-url-deps",
         expect_error=True,
     )
     error_message = (
@@ -1639,17 +1732,14 @@ def test_install_from_test_pypi_with_ext_url_dep_is_blocked(script, index):
 
 
 def test_installing_scripts_outside_path_prints_warning(script):
-    result = script.pip_install_local(
-        "--prefix", script.scratch_path, "script_wheel1"
-    )
+    result = script.pip_install_local("--prefix", script.scratch_path, "script_wheel1")
     assert "Successfully installed script-wheel1" in result.stdout, str(result)
     assert "--no-warn-script-location" in result.stderr
 
 
 def test_installing_scripts_outside_path_can_suppress_warning(script):
     result = script.pip_install_local(
-        "--prefix", script.scratch_path, "--no-warn-script-location",
-        "script_wheel1"
+        "--prefix", script.scratch_path, "--no-warn-script-location", "script_wheel1"
     )
     assert "Successfully installed script-wheel1" in result.stdout, str(result)
     assert "--no-warn-script-location" not in result.stderr
@@ -1667,18 +1757,16 @@ def test_installed_files_recorded_in_deterministic_order(script, data):
     order, to make installs reproducible.
     """
     to_install = data.packages.joinpath("FSPkg")
-    result = script.pip('install', to_install)
-    fspkg_folder = script.site_packages / 'fspkg'
-    egg_info = 'FSPkg-0.1.dev0-py{pyversion}.egg-info'.format(**globals())
-    installed_files_path = (
-        script.site_packages / egg_info / 'installed-files.txt'
-    )
+    result = script.pip("install", to_install)
+    fspkg_folder = script.site_packages / "fspkg"
+    egg_info = "FSPkg-0.1.dev0-py{pyversion}.egg-info".format(**globals())
+    installed_files_path = script.site_packages / egg_info / "installed-files.txt"
     result.did_create(fspkg_folder)
     result.did_create(installed_files_path)
 
     installed_files_path = result.files_created[installed_files_path].full
     installed_files_lines = [
-        p for p in Path(installed_files_path).read_text().split('\n') if p
+        p for p in Path(installed_files_path).read_text().split("\n") if p
     ]
     assert installed_files_lines == sorted(installed_files_lines)
 
@@ -1686,20 +1774,26 @@ def test_installed_files_recorded_in_deterministic_order(script, data):
 def test_install_conflict_results_in_warning(script, data):
     pkgA_path = create_test_package_with_setup(
         script,
-        name='pkgA', version='1.0', install_requires=['pkgb == 1.0'],
+        name="pkgA",
+        version="1.0",
+        install_requires=["pkgb == 1.0"],
     )
     pkgB_path = create_test_package_with_setup(
         script,
-        name='pkgB', version='2.0',
+        name="pkgB",
+        version="2.0",
     )
 
     # Install pkgA without its dependency
-    result1 = script.pip('install', '--no-index', pkgA_path, '--no-deps')
+    result1 = script.pip("install", "--no-index", pkgA_path, "--no-deps")
     assert "Successfully installed pkgA-1.0" in result1.stdout, str(result1)
 
     # Then install an incorrect version of the dependency
     result2 = script.pip(
-        'install', '--no-index', pkgB_path, allow_stderr_error=True,
+        "install",
+        "--no-index",
+        pkgB_path,
+        allow_stderr_error=True,
     )
     assert "pkga 1.0 requires pkgb==1.0" in result2.stderr, str(result2)
     assert "Successfully installed pkgB-2.0" in result2.stdout, str(result2)
@@ -1708,36 +1802,43 @@ def test_install_conflict_results_in_warning(script, data):
 def test_install_conflict_warning_can_be_suppressed(script, data):
     pkgA_path = create_test_package_with_setup(
         script,
-        name='pkgA', version='1.0', install_requires=['pkgb == 1.0'],
+        name="pkgA",
+        version="1.0",
+        install_requires=["pkgb == 1.0"],
     )
     pkgB_path = create_test_package_with_setup(
         script,
-        name='pkgB', version='2.0',
+        name="pkgB",
+        version="2.0",
     )
 
     # Install pkgA without its dependency
-    result1 = script.pip('install', '--no-index', pkgA_path, '--no-deps')
+    result1 = script.pip("install", "--no-index", pkgA_path, "--no-deps")
     assert "Successfully installed pkgA-1.0" in result1.stdout, str(result1)
 
     # Then install an incorrect version of the dependency; suppressing warning
-    result2 = script.pip(
-        'install', '--no-index', pkgB_path, '--no-warn-conflicts'
-    )
+    result2 = script.pip("install", "--no-index", pkgB_path, "--no-warn-conflicts")
     assert "Successfully installed pkgB-2.0" in result2.stdout, str(result2)
 
 
 def test_target_install_ignores_distutils_config_install_prefix(script):
-    prefix = script.scratch_path / 'prefix'
-    distutils_config = Path(os.path.expanduser('~'),
-                            'pydistutils.cfg' if sys.platform == 'win32'
-                            else '.pydistutils.cfg')
-    distutils_config.write_text(textwrap.dedent(
-        '''
+    prefix = script.scratch_path / "prefix"
+    distutils_config = Path(
+        os.path.expanduser("~"),
+        "pydistutils.cfg" if sys.platform == "win32" else ".pydistutils.cfg",
+    )
+    distutils_config.write_text(
+        textwrap.dedent(
+            """
         [install]
         prefix={prefix}
-        '''.format(**locals())))
-    target = script.scratch_path / 'target'
-    result = script.pip_install_local('simplewheel', '-t', target)
+        """.format(
+                **locals()
+            )
+        )
+    )
+    target = script.scratch_path / "target"
+    result = script.pip_install_local("simplewheel", "-t", target)
 
     assert "Successfully installed simplewheel" in result.stdout
 
@@ -1751,34 +1852,34 @@ def test_target_install_ignores_distutils_config_install_prefix(script):
 def test_user_config_accepted(script):
     # user set in the config file is parsed as 0/1 instead of True/False.
     # Check that this doesn't cause a problem.
-    config_file = script.scratch_path / 'pip.conf'
-    script.environ['PIP_CONFIG_FILE'] = str(config_file)
+    config_file = script.scratch_path / "pip.conf"
+    script.environ["PIP_CONFIG_FILE"] = str(config_file)
     config_file.write_text("[install]\nuser = true")
-    result = script.pip_install_local('simplewheel')
+    result = script.pip_install_local("simplewheel")
 
     assert "Successfully installed simplewheel" in result.stdout
 
     relative_user = os.path.relpath(script.user_site_path, script.base_path)
-    result.did_create(join(relative_user, 'simplewheel'))
+    result.did_create(join(relative_user, "simplewheel"))
 
 
 @pytest.mark.parametrize(
-    'install_args, expected_message', [
-        ([], 'Requirement already satisfied: pip'),
-        (['--upgrade'], 'Requirement already {}: pip in'),
-    ]
+    "install_args, expected_message",
+    [
+        ([], "Requirement already satisfied: pip"),
+        (["--upgrade"], "Requirement already {}: pip in"),
+    ],
 )
 @pytest.mark.parametrize("use_module", [True, False])
 def test_install_pip_does_not_modify_pip_when_satisfied(
-        script, install_args, expected_message, use_module, use_new_resolver):
+    script, install_args, expected_message, use_module, use_new_resolver
+):
     """
     Test it doesn't upgrade the pip if it already satisfies the requirement.
     """
     variation = "satisfied" if use_new_resolver else "up-to-date"
     expected_message = expected_message.format(variation)
-    result = script.pip_install_local(
-        'pip', *install_args, use_module=use_module
-    )
+    result = script.pip_install_local("pip", *install_args, use_module=use_module)
     assert expected_message in result.stdout, str(result)
 
 
@@ -1787,11 +1888,13 @@ def test_ignore_yanked_file(script, data):
     Test ignore a "yanked" file.
     """
     result = script.pip(
-        'install', 'simple',
-        '--index-url', data.index_url('yanked'),
+        "install",
+        "simple",
+        "--index-url",
+        data.index_url("yanked"),
     )
     # Make sure a "yanked" release is ignored
-    assert 'Successfully installed simple-2.0\n' in result.stdout, str(result)
+    assert "Successfully installed simple-2.0\n" in result.stdout, str(result)
 
 
 def test_invalid_index_url_argument(script, shared_data):
@@ -1799,12 +1902,19 @@ def test_invalid_index_url_argument(script, shared_data):
     Test the behaviour of an invalid --index-url argument
     """
 
-    result = script.pip('install', '--index-url', '--user',
-                        shared_data.find_links3, "Dinner",
-                        expect_error=True)
+    result = script.pip(
+        "install",
+        "--index-url",
+        "--user",
+        shared_data.find_links3,
+        "Dinner",
+        expect_error=True,
+    )
 
-    assert 'WARNING: The index url "--user" seems invalid, ' \
-           'please provide a scheme.' in result.stderr, str(result)
+    assert (
+        'WARNING: The index url "--user" seems invalid, '
+        "please provide a scheme." in result.stderr
+    ), str(result)
 
 
 def test_valid_index_url_argument(script, shared_data):
@@ -1812,11 +1922,9 @@ def test_valid_index_url_argument(script, shared_data):
     Test the behaviour of an valid --index-url argument
     """
 
-    result = script.pip('install', '--index-url',
-                        shared_data.find_links3,
-                        "Dinner")
+    result = script.pip("install", "--index-url", shared_data.find_links3, "Dinner")
 
-    assert 'Successfully installed Dinner' in result.stdout, str(result)
+    assert "Successfully installed Dinner" in result.stdout, str(result)
 
 
 def test_install_yanked_file_and_print_warning(script, data):
@@ -1827,20 +1935,25 @@ def test_install_yanked_file_and_print_warning(script, data):
     matches a version specifier that "pins" to an exact version (PEP 592).
     """
     result = script.pip(
-        'install', 'simple==3.0',
-        '--index-url', data.index_url('yanked'),
+        "install",
+        "simple==3.0",
+        "--index-url",
+        data.index_url("yanked"),
         expect_stderr=True,
     )
-    expected_warning = 'Reason for being yanked: test reason message'
+    expected_warning = "Reason for being yanked: test reason message"
     assert expected_warning in result.stderr, str(result)
     # Make sure a "yanked" release is installed
-    assert 'Successfully installed simple-3.0\n' in result.stdout, str(result)
+    assert "Successfully installed simple-3.0\n" in result.stdout, str(result)
 
 
-@pytest.mark.parametrize("install_args", [
-    (),
-    ("--trusted-host", "localhost"),
-])
+@pytest.mark.parametrize(
+    "install_args",
+    [
+        (),
+        ("--trusted-host", "localhost"),
+    ],
+)
 def test_install_sends_client_cert(install_args, script, cert_factory, data):
     cert_path = cert_factory()
     ctx = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
@@ -1850,9 +1963,11 @@ def test_install_sends_client_cert(install_args, script, cert_factory, data):
 
     server = make_mock_server(ssl_context=ctx)
     server.mock.side_effect = [
-        package_page({
-            "simple-3.0.tar.gz": "/files/simple-3.0.tar.gz",
-        }),
+        package_page(
+            {
+                "simple-3.0.tar.gz": "/files/simple-3.0.tar.gz",
+            }
+        ),
         file_response(str(data.packages / "simple-3.0.tar.gz")),
     ]
 
@@ -1881,25 +1996,29 @@ def test_install_skip_work_dir_pkg(script, data):
     """
 
     # Create a test package, install it and then uninstall it
-    pkg_path = create_test_package_with_setup(
-        script, name='simple', version='1.0')
-    script.pip('install', '-e', '.',
-               expect_stderr=True, cwd=pkg_path)
+    pkg_path = create_test_package_with_setup(script, name="simple", version="1.0")
+    script.pip("install", "-e", ".", expect_stderr=True, cwd=pkg_path)
 
-    script.pip('uninstall', 'simple', '-y')
+    script.pip("uninstall", "simple", "-y")
 
     # Running the install command again from the working directory
     # will install the package as it was uninstalled earlier
-    result = script.pip('install', '--find-links',
-                        data.find_links, 'simple',
-                        expect_stderr=True, cwd=pkg_path)
+    result = script.pip(
+        "install",
+        "--find-links",
+        data.find_links,
+        "simple",
+        expect_stderr=True,
+        cwd=pkg_path,
+    )
 
-    assert 'Requirement already satisfied: simple' not in result.stdout
-    assert 'Successfully installed simple' in result.stdout
+    assert "Requirement already satisfied: simple" not in result.stdout
+    assert "Successfully installed simple" in result.stdout
 
 
-@pytest.mark.parametrize('package_name', ('simple-package', 'simple_package',
-                                          'simple.package'))
+@pytest.mark.parametrize(
+    "package_name", ("simple-package", "simple_package", "simple.package")
+)
 def test_install_verify_package_name_normalization(script, package_name):
 
     """
@@ -1908,18 +2027,17 @@ def test_install_verify_package_name_normalization(script, package_name):
     since the package is already installed
     """
     pkg_path = create_test_package_with_setup(
-        script, name='simple-package', version='1.0')
-    result = script.pip('install', '-e', '.',
-                        expect_stderr=True, cwd=pkg_path)
-    assert 'Successfully installed simple-package' in result.stdout
+        script, name="simple-package", version="1.0"
+    )
+    result = script.pip("install", "-e", ".", expect_stderr=True, cwd=pkg_path)
+    assert "Successfully installed simple-package" in result.stdout
 
-    result = script.pip('install', package_name)
-    assert 'Requirement already satisfied: {}'.format(
-        package_name) in result.stdout
+    result = script.pip("install", package_name)
+    assert "Requirement already satisfied: {}".format(package_name) in result.stdout
 
 
 def test_install_logs_pip_version_in_debug(script, shared_data):
-    fake_package = shared_data.packages / 'simple-2.0.tar.gz'
-    result = script.pip('install', '-v', fake_package)
+    fake_package = shared_data.packages / "simple-2.0.tar.gz"
+    result = script.pip("install", "-v", fake_package)
     pattern = "Using pip .* from .*"
     assert_re_match(pattern, result.stdout)
diff --git a/tests/functional/test_install_check.py b/tests/functional/test_install_check.py
index a173cb5504f..0b61bdae496 100644
--- a/tests/functional/test_install_check.py
+++ b/tests/functional/test_install_check.py
@@ -3,36 +3,38 @@
 
 def assert_contains_expected_lines(string, expected_lines):
     for expected_line in expected_lines:
-        assert (expected_line + '\n') in string
+        assert (expected_line + "\n") in string
 
 
 def test_check_install_canonicalization(script):
     pkga_path = create_test_package_with_setup(
         script,
-        name='pkgA',
-        version='1.0',
-        install_requires=['normal-missing', 'SPECIAL.missing'],
+        name="pkgA",
+        version="1.0",
+        install_requires=["normal-missing", "SPECIAL.missing"],
     )
     normal_path = create_test_package_with_setup(
         script,
-        name='normal-missing', version='0.1',
+        name="normal-missing",
+        version="0.1",
     )
     special_path = create_test_package_with_setup(
         script,
-        name='SPECIAL.missing', version='0.1',
+        name="SPECIAL.missing",
+        version="0.1",
     )
 
     # Let's install pkgA without its dependency
-    result = script.pip('install', '--no-index', pkga_path, '--no-deps')
+    result = script.pip("install", "--no-index", pkga_path, "--no-deps")
     assert "Successfully installed pkgA-1.0" in result.stdout, str(result)
 
     # Install the first missing dependency. Only an error for the
     # second dependency should remain.
     result = script.pip(
-        'install',
-        '--no-index',
+        "install",
+        "--no-index",
         normal_path,
-        '--quiet',
+        "--quiet",
         allow_stderr_error=True,
     )
     expected_lines = [
@@ -46,13 +48,16 @@ def test_check_install_canonicalization(script):
     # during the installation. This is special as the package name requires
     # name normalization (as in https://github.com/pypa/pip/issues/5134)
     result = script.pip(
-        'install', '--no-index', special_path, '--quiet',
+        "install",
+        "--no-index",
+        special_path,
+        "--quiet",
     )
     assert "requires" not in result.stderr
     assert result.returncode == 0
 
     # Double check that all errors are resolved in the end
-    result = script.pip('check')
+    result = script.pip("check")
     expected_lines = [
         "No broken requirements found.",
     ]
@@ -63,43 +68,52 @@ def test_check_install_canonicalization(script):
 def test_check_install_does_not_warn_for_out_of_graph_issues(script):
     pkg_broken_path = create_test_package_with_setup(
         script,
-        name='broken',
-        version='1.0',
-        install_requires=['missing', 'conflict < 1.0'],
+        name="broken",
+        version="1.0",
+        install_requires=["missing", "conflict < 1.0"],
     )
     pkg_unrelated_path = create_test_package_with_setup(
         script,
-        name='unrelated',
-        version='1.0',
+        name="unrelated",
+        version="1.0",
     )
     pkg_conflict_path = create_test_package_with_setup(
         script,
-        name='conflict',
-        version='1.0',
+        name="conflict",
+        version="1.0",
     )
 
     # Install a package without it's dependencies
-    result = script.pip('install', '--no-index', pkg_broken_path, '--no-deps')
+    result = script.pip("install", "--no-index", pkg_broken_path, "--no-deps")
     assert "requires" not in result.stderr
 
     # Install conflict package
     result = script.pip(
-        'install', '--no-index', pkg_conflict_path, allow_stderr_error=True,
+        "install",
+        "--no-index",
+        pkg_conflict_path,
+        allow_stderr_error=True,
+    )
+    assert_contains_expected_lines(
+        result.stderr,
+        [
+            "broken 1.0 requires missing, which is not installed.",
+            "broken 1.0 requires conflict<1.0, "
+            "but you'll have conflict 1.0 which is incompatible.",
+        ],
     )
-    assert_contains_expected_lines(result.stderr, [
-        "broken 1.0 requires missing, which is not installed.",
-        "broken 1.0 requires conflict<1.0, "
-        "but you'll have conflict 1.0 which is incompatible."
-    ])
 
     # Install unrelated package
     result = script.pip(
-        'install', '--no-index', pkg_unrelated_path, '--quiet',
+        "install",
+        "--no-index",
+        pkg_unrelated_path,
+        "--quiet",
     )
     # should not warn about broken's deps when installing unrelated package
     assert "requires" not in result.stderr
 
-    result = script.pip('check', expect_error=True)
+    result = script.pip("check", expect_error=True)
     expected_lines = [
         "broken 1.0 requires missing, which is not installed.",
         "broken 1.0 has requirement conflict<1.0, but you have conflict 1.0.",
diff --git a/tests/functional/test_install_cleanup.py b/tests/functional/test_install_cleanup.py
index c01c47c3e3e..44fd1420cf4 100644
--- a/tests/functional/test_install_cleanup.py
+++ b/tests/functional/test_install_cleanup.py
@@ -11,10 +11,15 @@ def test_no_clean_option_blocks_cleaning_after_install(script, data):
     """
     Test --no-clean option blocks cleaning after install
     """
-    build = script.base_path / 'pip-build'
+    build = script.base_path / "pip-build"
     script.pip(
-        'install', '--no-clean', '--no-index', '--build', build,
-        '--find-links={}'.format(data.find_links), 'simple',
+        "install",
+        "--no-clean",
+        "--no-index",
+        "--build",
+        build,
+        "--find-links={}".format(data.find_links),
+        "simple",
         expect_temp=True,
         # TODO: allow_stderr_warning is used for the --build deprecation,
         #       remove it when removing support for --build
@@ -32,21 +37,25 @@ def test_cleanup_prevented_upon_build_dir_exception(
     """
     Test no cleanup occurs after a PreviousBuildDirError
     """
-    build = script.venv_path / 'build'
-    build_simple = build / 'simple'
+    build = script.venv_path / "build"
+    build_simple = build / "simple"
     os.makedirs(build_simple)
     build_simple.joinpath("setup.py").write_text("#")
     result = script.pip(
-        'install', '-f', data.find_links, '--no-index', 'simple',
-        '--build', build,
+        "install",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "simple",
+        "--build",
+        build,
         expect_error=(not use_new_resolver),
         expect_temp=(not use_new_resolver),
         expect_stderr=True,
     )
 
     assert (
-        "The -b/--build/--build-dir/--build-directory "
-        "option is deprecated."
+        "The -b/--build/--build-dir/--build-directory " "option is deprecated."
     ) in result.stderr
 
     if not use_new_resolver:
@@ -58,12 +67,9 @@ def test_cleanup_prevented_upon_build_dir_exception(
 @pytest.mark.network
 def test_pep517_no_legacy_cleanup(script, data, with_wheel):
     """Test a PEP 517 failed build does not attempt a legacy cleanup"""
-    to_install = data.packages.joinpath('pep517_wrapper_buildsys')
+    to_install = data.packages.joinpath("pep517_wrapper_buildsys")
     script.environ["PIP_TEST_FAIL_BUILD_WHEEL"] = "1"
-    res = script.pip(
-        'install', '-f', data.find_links, to_install,
-        expect_error=True
-    )
+    res = script.pip("install", "-f", data.find_links, to_install, expect_error=True)
     # Must not have built the package
     expected = "Failed building wheel for pep517-wrapper-buildsys"
     assert expected in str(res)
diff --git a/tests/functional/test_install_compat.py b/tests/functional/test_install_compat.py
index a5a0df65218..2b964093f64 100644
--- a/tests/functional/test_install_compat.py
+++ b/tests/functional/test_install_compat.py
@@ -22,26 +22,22 @@ def test_debian_egg_name_workaround(script):
     https://bitbucket.org/ianb/pip/issue/104/pip-uninstall-on-ubuntu-linux
 
     """
-    result = script.pip('install', 'INITools==0.2')
+    result = script.pip("install", "INITools==0.2")
 
     egg_info = os.path.join(
-        script.site_packages,
-        "INITools-0.2-py{pyversion}.egg-info".format(**globals()))
+        script.site_packages, "INITools-0.2-py{pyversion}.egg-info".format(**globals())
+    )
 
     # Debian only removes pyversion for global installs, not inside a venv
     # so even if this test runs on a Debian/Ubuntu system with broken
     # setuptools, since our test runs inside a venv we'll still have the normal
     # .egg-info
-    result.did_create(
-        egg_info,
-        message="Couldn't find {egg_info}".format(**locals())
-    )
+    result.did_create(egg_info, message="Couldn't find {egg_info}".format(**locals()))
 
     # The Debian no-pyversion version of the .egg-info
     mangled = os.path.join(script.site_packages, "INITools-0.2.egg-info")
     result.did_not_create(
-        mangled,
-        message="Found unexpected {mangled}".format(**locals())
+        mangled, message="Found unexpected {mangled}".format(**locals())
     )
 
     # Simulate a Debian install by copying the .egg-info to their name for it
@@ -53,7 +49,7 @@ def test_debian_egg_name_workaround(script):
 
     # Try the uninstall and verify that everything is removed.
     result2 = script.pip("uninstall", "INITools", "-y")
-    assert_all_changes(result, result2, [script.venv / 'build', 'cache'])
+    assert_all_changes(result, result2, [script.venv / "build", "cache"])
 
 
 def test_setup_py_with_dos_line_endings(script, data):
@@ -63,4 +59,4 @@ def test_setup_py_with_dos_line_endings(script, data):
     Refs https://github.com/pypa/pip/issues/237
     """
     to_install = data.packages.joinpath("LineEndings")
-    script.pip('install', to_install)
+    script.pip("install", to_install)
diff --git a/tests/functional/test_install_config.py b/tests/functional/test_install_config.py
index dcc9c66d5a4..0c24e1ae149 100644
--- a/tests/functional/test_install_config.py
+++ b/tests/functional/test_install_config.py
@@ -19,8 +19,8 @@ def test_options_from_env_vars(script):
     Test if ConfigOptionParser reads env vars (e.g. not using PyPI here)
 
     """
-    script.environ['PIP_NO_INDEX'] = '1'
-    result = script.pip('install', '-vvv', 'INITools', expect_error=True)
+    script.environ["PIP_NO_INDEX"] = "1"
+    result = script.pip("install", "-vvv", "INITools", expect_error=True)
     assert "Ignoring indexes:" in result.stdout, str(result)
     msg = "DistributionNotFound: No matching distribution found for INITools"
     # Case insensitive as the new resolver canonicalises the project name
@@ -32,16 +32,16 @@ def test_command_line_options_override_env_vars(script, virtualenv):
     Test that command line options override environmental variables.
 
     """
-    script.environ['PIP_INDEX_URL'] = 'https://example.com/simple/'
-    result = script.pip('install', '-vvv', 'INITools', expect_error=True)
-    assert (
-        "Getting page https://example.com/simple/initools"
-        in result.stdout
-    )
+    script.environ["PIP_INDEX_URL"] = "https://example.com/simple/"
+    result = script.pip("install", "-vvv", "INITools", expect_error=True)
+    assert "Getting page https://example.com/simple/initools" in result.stdout
     virtualenv.clear()
     result = script.pip(
-        'install', '-vvv', '--index-url', 'https://download.zope.org/ppix',
-        'INITools',
+        "install",
+        "-vvv",
+        "--index-url",
+        "https://download.zope.org/ppix",
+        "INITools",
         expect_error=True,
     )
     assert "example.com" not in result.stdout
@@ -55,22 +55,26 @@ def test_env_vars_override_config_file(script, virtualenv):
     """
     config_file = script.scratch_path / "test-pip.cfg"
     # set this to make pip load it
-    script.environ['PIP_CONFIG_FILE'] = str(config_file)
+    script.environ["PIP_CONFIG_FILE"] = str(config_file)
     # It's important that we test this particular config value ('no-index')
     # because there is/was a bug which only shows up in cases in which
     # 'config-item' and 'config_item' hash to the same value modulo the size
     # of the config dictionary.
-    config_file.write_text(textwrap.dedent("""\
+    config_file.write_text(
+        textwrap.dedent(
+            """\
         [global]
         no-index = 1
-        """))
-    result = script.pip('install', '-vvv', 'INITools', expect_error=True)
+        """
+        )
+    )
+    result = script.pip("install", "-vvv", "INITools", expect_error=True)
     msg = "DistributionNotFound: No matching distribution found for INITools"
     # Case insensitive as the new resolver canonicalises the project name
     assert msg.lower() in result.stdout.lower(), str(result)
-    script.environ['PIP_NO_INDEX'] = '0'
+    script.environ["PIP_NO_INDEX"] = "0"
     virtualenv.clear()
-    result = script.pip('install', '-vvv', 'INITools')
+    result = script.pip("install", "-vvv", "INITools")
     assert "Successfully installed INITools" in result.stdout
 
 
@@ -81,10 +85,13 @@ def test_command_line_append_flags(script, virtualenv, data):
     variables.
 
     """
-    script.environ['PIP_FIND_LINKS'] = 'https://test.pypi.org'
+    script.environ["PIP_FIND_LINKS"] = "https://test.pypi.org"
     result = script.pip(
-        'install', '-vvv', 'INITools', '--trusted-host',
-        'test.pypi.org',
+        "install",
+        "-vvv",
+        "INITools",
+        "--trusted-host",
+        "test.pypi.org",
     )
     assert (
         "Fetching project page and analyzing links: https://test.pypi.org"
@@ -92,17 +99,21 @@ def test_command_line_append_flags(script, virtualenv, data):
     ), str(result)
     virtualenv.clear()
     result = script.pip(
-        'install', '-vvv', '--find-links', data.find_links, 'INITools',
-        '--trusted-host', 'test.pypi.org',
+        "install",
+        "-vvv",
+        "--find-links",
+        data.find_links,
+        "INITools",
+        "--trusted-host",
+        "test.pypi.org",
     )
     assert (
         "Fetching project page and analyzing links: https://test.pypi.org"
         in result.stdout
     )
     assert (
-        'Skipping link: not a file: {}'.format(data.find_links) in
-        result.stdout
-    ), 'stdout: {}'.format(result.stdout)
+        "Skipping link: not a file: {}".format(data.find_links) in result.stdout
+    ), "stdout: {}".format(result.stdout)
 
 
 @pytest.mark.network
@@ -111,12 +122,15 @@ def test_command_line_appends_correctly(script, data):
     Test multiple appending options set by environmental variables.
 
     """
-    script.environ['PIP_FIND_LINKS'] = (
-        'https://test.pypi.org {data.find_links}'.format(**locals())
+    script.environ["PIP_FIND_LINKS"] = "https://test.pypi.org {data.find_links}".format(
+        **locals()
     )
     result = script.pip(
-        'install', '-vvv', 'INITools', '--trusted-host',
-        'test.pypi.org',
+        "install",
+        "-vvv",
+        "INITools",
+        "--trusted-host",
+        "test.pypi.org",
     )
 
     assert (
@@ -124,50 +138,63 @@ def test_command_line_appends_correctly(script, data):
         in result.stdout
     ), result.stdout
     assert (
-        'Skipping link: not a file: {}'.format(data.find_links) in
-        result.stdout
-    ), 'stdout: {}'.format(result.stdout)
+        "Skipping link: not a file: {}".format(data.find_links) in result.stdout
+    ), "stdout: {}".format(result.stdout)
 
 
-def test_config_file_override_stack(
-    script, virtualenv, mock_server, shared_data
-):
+def test_config_file_override_stack(script, virtualenv, mock_server, shared_data):
     """
     Test config files (global, overriding a global config with a
     local, overriding all with a command line flag).
     """
-    mock_server.set_responses([
-        package_page({}),
-        package_page({}),
-        package_page({"INITools-0.2.tar.gz": "/files/INITools-0.2.tar.gz"}),
-        file_response(shared_data.packages.joinpath("INITools-0.2.tar.gz")),
-    ])
+    mock_server.set_responses(
+        [
+            package_page({}),
+            package_page({}),
+            package_page({"INITools-0.2.tar.gz": "/files/INITools-0.2.tar.gz"}),
+            file_response(shared_data.packages.joinpath("INITools-0.2.tar.gz")),
+        ]
+    )
     mock_server.start()
     base_address = "http://{}:{}".format(mock_server.host, mock_server.port)
 
     config_file = script.scratch_path / "test-pip.cfg"
 
     # set this to make pip load it
-    script.environ['PIP_CONFIG_FILE'] = str(config_file)
+    script.environ["PIP_CONFIG_FILE"] = str(config_file)
 
-    config_file.write_text(textwrap.dedent("""\
+    config_file.write_text(
+        textwrap.dedent(
+            """\
         [global]
         index-url = {}/simple1
-        """.format(base_address)))
-    script.pip('install', '-vvv', 'INITools', expect_error=True)
+        """.format(
+                base_address
+            )
+        )
+    )
+    script.pip("install", "-vvv", "INITools", expect_error=True)
     virtualenv.clear()
 
-    config_file.write_text(textwrap.dedent("""\
+    config_file.write_text(
+        textwrap.dedent(
+            """\
         [global]
         index-url = {address}/simple1
         [install]
         index-url = {address}/simple2
-        """.format(address=base_address))
+        """.format(
+                address=base_address
+            )
+        )
     )
-    script.pip('install', '-vvv', 'INITools', expect_error=True)
+    script.pip("install", "-vvv", "INITools", expect_error=True)
     script.pip(
-        'install', '-vvv', '--index-url', "{}/simple3".format(base_address),
-        'INITools',
+        "install",
+        "-vvv",
+        "--index-url",
+        "{}/simple3".format(base_address),
+        "INITools",
     )
 
     mock_server.stop()
@@ -185,30 +212,34 @@ def test_options_from_venv_config(script, virtualenv):
 
     """
     from pip._internal.configuration import CONFIG_BASENAME
+
     conf = "[global]\nno-index = true"
     ini = virtualenv.location / CONFIG_BASENAME
-    with open(ini, 'w') as f:
+    with open(ini, "w") as f:
         f.write(conf)
-    result = script.pip('install', '-vvv', 'INITools', expect_error=True)
+    result = script.pip("install", "-vvv", "INITools", expect_error=True)
     assert "Ignoring indexes:" in result.stdout, str(result)
     msg = "DistributionNotFound: No matching distribution found for INITools"
     # Case insensitive as the new resolver canonicalises the project name
     assert msg.lower() in result.stdout.lower(), str(result)
 
 
-def test_install_no_binary_via_config_disables_cached_wheels(
-        script, data, with_wheel):
-    config_file = tempfile.NamedTemporaryFile(mode='wt', delete=False)
+def test_install_no_binary_via_config_disables_cached_wheels(script, data, with_wheel):
+    config_file = tempfile.NamedTemporaryFile(mode="wt", delete=False)
     try:
-        script.environ['PIP_CONFIG_FILE'] = config_file.name
-        config_file.write(textwrap.dedent("""\
+        script.environ["PIP_CONFIG_FILE"] = config_file.name
+        config_file.write(
+            textwrap.dedent(
+                """\
             [global]
             no-binary = :all:
-            """))
+            """
+            )
+        )
         config_file.close()
         res = script.pip(
-            'install', '--no-index', '-f', data.find_links,
-            'upper', expect_stderr=True)
+            "install", "--no-index", "-f", data.find_links, "upper", expect_stderr=True
+        )
     finally:
         os.unlink(config_file.name)
     assert "Successfully installed upper-2.0" in str(res), str(res)
@@ -230,21 +261,32 @@ def test_prompt_for_authentication(script, data, cert_factory):
 
     server = make_mock_server(ssl_context=ctx)
     server.mock.side_effect = [
-        package_page({
-            "simple-3.0.tar.gz": "/files/simple-3.0.tar.gz",
-        }),
+        package_page(
+            {
+                "simple-3.0.tar.gz": "/files/simple-3.0.tar.gz",
+            }
+        ),
         authorization_response(str(data.packages / "simple-3.0.tar.gz")),
     ]
 
     url = "https://{}:{}/simple".format(server.host, server.port)
 
     with server_running(server):
-        result = script.pip('install', "--index-url", url,
-                            "--cert", cert_path, "--client-cert", cert_path,
-                            'simple', expect_error=True)
-
-    assert 'User for {}:{}'.format(server.host, server.port) in \
-           result.stdout, str(result)
+        result = script.pip(
+            "install",
+            "--index-url",
+            url,
+            "--cert",
+            cert_path,
+            "--client-cert",
+            cert_path,
+            "simple",
+            expect_error=True,
+        )
+
+    assert "User for {}:{}".format(server.host, server.port) in result.stdout, str(
+        result
+    )
 
 
 def test_do_not_prompt_for_authentication(script, data, cert_factory):
@@ -260,17 +302,28 @@ def test_do_not_prompt_for_authentication(script, data, cert_factory):
     server = make_mock_server(ssl_context=ctx)
 
     server.mock.side_effect = [
-        package_page({
-            "simple-3.0.tar.gz": "/files/simple-3.0.tar.gz",
-        }),
+        package_page(
+            {
+                "simple-3.0.tar.gz": "/files/simple-3.0.tar.gz",
+            }
+        ),
         authorization_response(str(data.packages / "simple-3.0.tar.gz")),
     ]
 
     url = "https://{}:{}/simple".format(server.host, server.port)
 
     with server_running(server):
-        result = script.pip('install', "--index-url", url,
-                            "--cert", cert_path, "--client-cert", cert_path,
-                            '--no-input', 'simple', expect_error=True)
+        result = script.pip(
+            "install",
+            "--index-url",
+            url,
+            "--cert",
+            cert_path,
+            "--client-cert",
+            cert_path,
+            "--no-input",
+            "simple",
+            expect_error=True,
+        )
 
     assert "ERROR: HTTP error 401" in result.stderr
diff --git a/tests/functional/test_install_extras.py b/tests/functional/test_install_extras.py
index d70067b6bca..ab75c3ab7dc 100644
--- a/tests/functional/test_install_extras.py
+++ b/tests/functional/test_install_extras.py
@@ -11,9 +11,11 @@ def test_simple_extras_install_from_pypi(script):
     Test installing a package from PyPI using extras dependency Paste[openid].
     """
     result = script.pip(
-        'install', 'Paste[openid]==1.7.5.1', expect_stderr=True,
+        "install",
+        "Paste[openid]==1.7.5.1",
+        expect_stderr=True,
     )
-    initools_folder = script.site_packages / 'openid'
+    initools_folder = script.site_packages / "openid"
     result.did_create(initools_folder)
 
 
@@ -21,17 +23,25 @@ def test_extras_after_wheel(script, data):
     """
     Test installing a package with extras after installing from a wheel.
     """
-    simple = script.site_packages / 'simple'
+    simple = script.site_packages / "simple"
 
     no_extra = script.pip(
-        'install', '--no-index', '-f', data.find_links,
-        'requires_simple_extra', expect_stderr=True,
+        "install",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "requires_simple_extra",
+        expect_stderr=True,
     )
     no_extra.did_not_create(simple)
 
     extra = script.pip(
-        'install', '--no-index', '-f', data.find_links,
-        'requires_simple_extra[extra]', expect_stderr=True,
+        "install",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "requires_simple_extra[extra]",
+        expect_stderr=True,
     )
     extra.did_create(simple)
 
@@ -42,13 +52,15 @@ def test_no_extras_uninstall(script):
     No extras dependency gets uninstalled when the root package is uninstalled
     """
     result = script.pip(
-        'install', 'Paste[openid]==1.7.5.1', expect_stderr=True,
+        "install",
+        "Paste[openid]==1.7.5.1",
+        expect_stderr=True,
     )
-    result.did_create(join(script.site_packages, 'paste'))
-    result.did_create(join(script.site_packages, 'openid'))
-    result2 = script.pip('uninstall', 'Paste', '-y')
+    result.did_create(join(script.site_packages, "paste"))
+    result.did_create(join(script.site_packages, "openid"))
+    result2 = script.pip("uninstall", "Paste", "-y")
     # openid should not be uninstalled
-    initools_folder = script.site_packages / 'openid'
+    initools_folder = script.site_packages / "openid"
     assert initools_folder not in result2.files_deleted, result.files_deleted
 
 
@@ -60,14 +72,16 @@ def test_nonexistent_extra_warns_user_no_wheel(script, data):
     This exercises source installs.
     """
     result = script.pip(
-        'install', '--no-binary=:all:', '--no-index',
-        '--find-links=' + data.find_links,
-        'simple[nonexistent]', expect_stderr=True,
+        "install",
+        "--no-binary=:all:",
+        "--no-index",
+        "--find-links=" + data.find_links,
+        "simple[nonexistent]",
+        expect_stderr=True,
+    )
+    assert "simple 3.0 does not provide the extra 'nonexistent'" in result.stderr, str(
+        result
     )
-    assert (
-        "simple 3.0 does not provide the extra 'nonexistent'"
-        in result.stderr
-    ), str(result)
 
 
 def test_nonexistent_extra_warns_user_with_wheel(script, data):
@@ -78,14 +92,13 @@ def test_nonexistent_extra_warns_user_with_wheel(script, data):
     This exercises wheel installs.
     """
     result = script.pip(
-        'install', '--no-index',
-        '--find-links=' + data.find_links,
-        'simplewheel[nonexistent]', expect_stderr=True,
-    )
-    assert (
-        "simplewheel 2.0 does not provide the extra 'nonexistent'"
-        in result.stderr
+        "install",
+        "--no-index",
+        "--find-links=" + data.find_links,
+        "simplewheel[nonexistent]",
+        expect_stderr=True,
     )
+    assert "simplewheel 2.0 does not provide the extra 'nonexistent'" in result.stderr
 
 
 def test_nonexistent_options_listed_in_order(script, data):
@@ -93,15 +106,16 @@ def test_nonexistent_options_listed_in_order(script, data):
     Warn the user for each extra that doesn't exist.
     """
     result = script.pip(
-        'install', '--no-index',
-        '--find-links=' + data.find_links,
-        'simplewheel[nonexistent, nope]', expect_stderr=True,
+        "install",
+        "--no-index",
+        "--find-links=" + data.find_links,
+        "simplewheel[nonexistent, nope]",
+        expect_stderr=True,
     )
     matches = re.findall(
-        "WARNING: simplewheel 2.0 does not provide the extra '([a-z]*)'",
-        result.stderr
+        "WARNING: simplewheel 2.0 does not provide the extra '([a-z]*)'", result.stderr
     )
-    assert matches == ['nonexistent', 'nope']
+    assert matches == ["nonexistent", "nope"]
 
 
 def test_install_deprecated_extra(script, data):
@@ -114,50 +128,65 @@ def test_install_deprecated_extra(script, data):
     script.scratch_path.joinpath("requirements.txt").write_text(
         "requires_simple_extra>=0.1[extra]"
     )
-    simple = script.site_packages / 'simple'
+    simple = script.site_packages / "simple"
 
     result = script.pip(
-        'install', '--no-index', '--find-links=' + data.find_links,
-        '-r', script.scratch_path / 'requirements.txt', expect_stderr=True,
+        "install",
+        "--no-index",
+        "--find-links=" + data.find_links,
+        "-r",
+        script.scratch_path / "requirements.txt",
+        expect_stderr=True,
     )
 
     result.did_create(simple)
-    assert ("DEPRECATION: Extras after version" in result.stderr)
+    assert "DEPRECATION: Extras after version" in result.stderr
 
 
 def test_install_special_extra(script):
     # Check that uppercase letters and '-' are dealt with
     # make a dummy project
-    pkga_path = script.scratch_path / 'pkga'
+    pkga_path = script.scratch_path / "pkga"
     pkga_path.mkdir()
-    pkga_path.joinpath("setup.py").write_text(textwrap.dedent("""
+    pkga_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
         from setuptools import setup
         setup(name='pkga',
               version='0.1',
               extras_require={'Hop_hOp-hoP': ['missing_pkg']},
         )
-    """))
+    """
+        )
+    )
 
     result = script.pip(
-        'install', '--no-index', '{pkga_path}[Hop_hOp-hoP]'.format(**locals()),
-        expect_error=True)
+        "install",
+        "--no-index",
+        "{pkga_path}[Hop_hOp-hoP]".format(**locals()),
+        expect_error=True,
+    )
     assert (
         "Could not find a version that satisfies the requirement missing_pkg"
     ) in result.stderr, str(result)
 
 
 @pytest.mark.parametrize(
-    "extra_to_install, simple_version", [
-        ['', '3.0'],
-        pytest.param('[extra1]', '2.0', marks=pytest.mark.xfail),
-        pytest.param('[extra2]', '1.0', marks=pytest.mark.xfail),
-        pytest.param('[extra1,extra2]', '1.0', marks=pytest.mark.xfail),
-    ])
+    "extra_to_install, simple_version",
+    [
+        ["", "3.0"],
+        pytest.param("[extra1]", "2.0", marks=pytest.mark.xfail),
+        pytest.param("[extra2]", "1.0", marks=pytest.mark.xfail),
+        pytest.param("[extra1,extra2]", "1.0", marks=pytest.mark.xfail),
+    ],
+)
 def test_install_extra_merging(script, data, extra_to_install, simple_version):
     # Check that extra specifications in the extras section are honoured.
-    pkga_path = script.scratch_path / 'pkga'
+    pkga_path = script.scratch_path / "pkga"
     pkga_path.mkdir()
-    pkga_path.joinpath("setup.py").write_text(textwrap.dedent("""
+    pkga_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
         from setuptools import setup
         setup(name='pkga',
               version='0.1',
@@ -165,11 +194,14 @@ def test_install_extra_merging(script, data, extra_to_install, simple_version):
               extras_require={'extra1': ['simple<3'],
                               'extra2': ['simple==1.*']},
         )
-    """))
+    """
+        )
+    )
 
     result = script.pip_install_local(
-        '{pkga_path}{extra_to_install}'.format(**locals()),
+        "{pkga_path}{extra_to_install}".format(**locals()),
     )
 
-    assert ('Successfully installed pkga-0.1 simple-{}'.format(simple_version)
-            ) in result.stdout
+    assert (
+        "Successfully installed pkga-0.1 simple-{}".format(simple_version)
+    ) in result.stdout
diff --git a/tests/functional/test_install_force_reinstall.py b/tests/functional/test_install_force_reinstall.py
index 0fbdeb276c4..88ffda62172 100644
--- a/tests/functional/test_install_force_reinstall.py
+++ b/tests/functional/test_install_force_reinstall.py
@@ -4,14 +4,14 @@
 
 
 def check_installed_version(script, package, expected):
-    result = script.pip('show', package)
+    result = script.pip("show", package)
     lines = result.stdout.splitlines()
     version = None
     for line in lines:
-        if line.startswith('Version: '):
+        if line.startswith("Version: "):
             version = line.split()[-1]
             break
-    assert version == expected, 'version {} != {}'.format(version, expected)
+    assert version == expected, "version {} != {}".format(version, expected)
 
 
 def check_force_reinstall(script, specifier, expected):
@@ -20,23 +20,23 @@ def check_force_reinstall(script, specifier, expected):
       specifier: the requirement specifier to force-reinstall.
       expected: the expected version after force-reinstalling.
     """
-    result = script.pip_install_local('simplewheel==1.0')
-    check_installed_version(script, 'simplewheel', '1.0')
+    result = script.pip_install_local("simplewheel==1.0")
+    check_installed_version(script, "simplewheel", "1.0")
 
     # Remove an installed file to test whether --force-reinstall fixes it.
     to_fix = script.site_packages_path.joinpath("simplewheel", "__init__.py")
     to_fix.unlink()
 
-    result2 = script.pip_install_local('--force-reinstall', specifier)
-    check_installed_version(script, 'simplewheel', expected)
+    result2 = script.pip_install_local("--force-reinstall", specifier)
+    check_installed_version(script, "simplewheel", expected)
 
     # site_packages_path is absolute, but files_created mapping uses
     # relative paths as key.
     fixed_key = os.path.relpath(to_fix, script.base_path)
-    result2.did_create(fixed_key, message='force-reinstall failed')
+    result2.did_create(fixed_key, message="force-reinstall failed")
 
-    result3 = script.pip('uninstall', 'simplewheel', '-y')
-    assert_all_changes(result, result3, [script.venv / 'build', 'cache'])
+    result3 = script.pip("uninstall", "simplewheel", "-y")
+    assert_all_changes(result, result3, [script.venv / "build", "cache"])
 
 
 def test_force_reinstall_with_no_version_specifier(script):
@@ -44,7 +44,7 @@ def test_force_reinstall_with_no_version_specifier(script):
     Check --force-reinstall when there is no version specifier and the
     installed version is not the newest version.
     """
-    check_force_reinstall(script, 'simplewheel', '2.0')
+    check_force_reinstall(script, "simplewheel", "2.0")
 
 
 def test_force_reinstall_with_same_version_specifier(script):
@@ -52,4 +52,4 @@ def test_force_reinstall_with_same_version_specifier(script):
     Check --force-reinstall when the version specifier equals the installed
     version and the installed version is not the newest version.
     """
-    check_force_reinstall(script, 'simplewheel==1.0', '1.0')
+    check_force_reinstall(script, "simplewheel==1.0", "1.0")
diff --git a/tests/functional/test_install_index.py b/tests/functional/test_install_index.py
index e887595b937..cf87eaab9b3 100644
--- a/tests/functional/test_install_index.py
+++ b/tests/functional/test_install_index.py
@@ -7,38 +7,40 @@
 def test_find_links_relative_path(script, data, with_wheel):
     """Test find-links as a relative path."""
     result = script.pip(
-        'install',
-        'parent==0.1',
-        '--no-index',
-        '--find-links',
-        'packages/',
+        "install",
+        "parent==0.1",
+        "--no-index",
+        "--find-links",
+        "packages/",
         cwd=data.root,
     )
-    dist_info_folder = (
-        script.site_packages / 'parent-0.1.dist-info'
-    )
-    initools_folder = script.site_packages / 'parent'
+    dist_info_folder = script.site_packages / "parent-0.1.dist-info"
+    initools_folder = script.site_packages / "parent"
     result.did_create(dist_info_folder)
     result.did_create(initools_folder)
 
 
 def test_find_links_requirements_file_relative_path(script, data, with_wheel):
     """Test find-links as a relative path to a reqs file."""
-    script.scratch_path.joinpath("test-req.txt").write_text(textwrap.dedent("""
+    script.scratch_path.joinpath("test-req.txt").write_text(
+        textwrap.dedent(
+            """
         --no-index
         --find-links={}
         parent==0.1
-        """ .format(data.packages.replace(os.path.sep, '/'))))
+        """.format(
+                data.packages.replace(os.path.sep, "/")
+            )
+        )
+    )
     result = script.pip(
-        'install',
-        '-r',
+        "install",
+        "-r",
         script.scratch_path / "test-req.txt",
         cwd=data.root,
     )
-    dist_info_folder = (
-        script.site_packages / 'parent-0.1.dist-info'
-    )
-    initools_folder = script.site_packages / 'parent'
+    dist_info_folder = script.site_packages / "parent-0.1.dist-info"
+    initools_folder = script.site_packages / "parent"
     result.did_create(dist_info_folder)
     result.did_create(initools_folder)
 
@@ -48,10 +50,8 @@ def test_install_from_file_index_hash_link(script, data, with_wheel):
     Test that a pkg can be installed from a file:// index using a link with a
     hash
     """
-    result = script.pip('install', '-i', data.index_url(), 'simple==1.0')
-    dist_info_folder = (
-        script.site_packages / 'simple-1.0.dist-info'
-    )
+    result = script.pip("install", "-i", data.index_url(), "simple==1.0")
+    dist_info_folder = script.site_packages / "simple-1.0.dist-info"
     result.did_create(dist_info_folder)
 
 
@@ -60,10 +60,6 @@ def test_file_index_url_quoting(script, data, with_wheel):
     Test url quoting of file index url with a space
     """
     index_url = data.index_url(urllib_parse.quote("in dex"))
-    result = script.pip(
-        'install', '-vvv', '--index-url', index_url, 'simple'
-    )
-    result.did_create(script.site_packages / 'simple')
-    result.did_create(
-        script.site_packages / 'simple-1.0.dist-info'
-    )
+    result = script.pip("install", "-vvv", "--index-url", index_url, "simple")
+    result.did_create(script.site_packages / "simple")
+    result.did_create(script.site_packages / "simple-1.0.dist-info")
diff --git a/tests/functional/test_install_reqs.py b/tests/functional/test_install_reqs.py
index c879b6903dd..da404ab4365 100644
--- a/tests/functional/test_install_reqs.py
+++ b/tests/functional/test_install_reqs.py
@@ -43,18 +43,14 @@ def arg_recording_sdist_maker(script):
         setup(name={name!r}, version="0.1.0")
         """
     )
-    output_dir = script.scratch_path.joinpath(
-        "args_recording_sdist_maker_output"
-    )
+    output_dir = script.scratch_path.joinpath("args_recording_sdist_maker_output")
     output_dir.mkdir(parents=True)
     script.environ["OUTPUT_DIR"] = str(output_dir)
 
     def _arg_recording_sdist_maker(name):
         # type: (str) -> ArgRecordingSdist
         extra_files = {"setup.py": arg_writing_setup_py.format(name=name)}
-        sdist_path = create_basic_sdist_for_package(
-            script, name, "0.1.0", extra_files
-        )
+        sdist_path = create_basic_sdist_for_package(script, name, "0.1.0", extra_files)
         args_path = output_dir / "{}.json".format(name)
         return ArgRecordingSdist(sdist_path, args_path)
 
@@ -67,22 +63,23 @@ def test_requirements_file(script, with_wheel):
     Test installing from a requirements file.
 
     """
-    other_lib_name, other_lib_version = 'anyjson', '0.3'
-    script.scratch_path.joinpath("initools-req.txt").write_text(textwrap.dedent("""\
+    other_lib_name, other_lib_version = "anyjson", "0.3"
+    script.scratch_path.joinpath("initools-req.txt").write_text(
+        textwrap.dedent(
+            """\
         INITools==0.2
         # and something else to test out:
         {other_lib_name}<={other_lib_version}
-        """.format(**locals())))
-    result = script.pip(
-        'install', '-r', script.scratch_path / 'initools-req.txt'
-    )
-    result.did_create(
-        script.site_packages / 'INITools-0.2.dist-info'
+        """.format(
+                **locals()
+            )
+        )
     )
-    result.did_create(script.site_packages / 'initools')
+    result = script.pip("install", "-r", script.scratch_path / "initools-req.txt")
+    result.did_create(script.site_packages / "INITools-0.2.dist-info")
+    result.did_create(script.site_packages / "initools")
     assert result.files_created[script.site_packages / other_lib_name].dir
-    fn = '{}-{}.dist-info'.format(
-        other_lib_name, other_lib_version)
+    fn = "{}-{}.dist-info".format(other_lib_name, other_lib_version)
     assert result.files_created[script.site_packages / fn].dir
 
 
@@ -99,41 +96,35 @@ def test_schema_check_in_requirements_file(script):
     )
 
     with pytest.raises(AssertionError):
-        script.pip(
-            "install", "-vvv", "-r", script.scratch_path / "file-egg-req.txt"
-        )
-
-
-@pytest.mark.parametrize("test_type,editable", [
-    ("rel_path", False),
-    ("rel_path", True),
-    ("rel_url", False),
-    ("rel_url", True),
-    ("embedded_rel_path", False),
-    ("embedded_rel_path", True),
-])
-def test_relative_requirements_file(
-    script, data, test_type, editable, with_wheel
-):
+        script.pip("install", "-vvv", "-r", script.scratch_path / "file-egg-req.txt")
+
+
+@pytest.mark.parametrize(
+    "test_type,editable",
+    [
+        ("rel_path", False),
+        ("rel_path", True),
+        ("rel_url", False),
+        ("rel_url", True),
+        ("embedded_rel_path", False),
+        ("embedded_rel_path", True),
+    ],
+)
+def test_relative_requirements_file(script, data, test_type, editable, with_wheel):
     """
     Test installing from a requirements file with a relative path. For path
     URLs, use an egg= definition.
 
     """
-    dist_info_folder = (
-        script.site_packages /
-        'FSPkg-0.1.dev0.dist-info'
-    )
-    egg_link_file = (
-        script.site_packages / 'FSPkg.egg-link'
-    )
-    package_folder = script.site_packages / 'fspkg'
+    dist_info_folder = script.site_packages / "FSPkg-0.1.dev0.dist-info"
+    egg_link_file = script.site_packages / "FSPkg.egg-link"
+    package_folder = script.site_packages / "fspkg"
 
     # Compute relative install path to FSPkg from scratch path.
     full_rel_path = Path(
-        os.path.relpath(data.packages.joinpath('FSPkg'), script.scratch_path)
+        os.path.relpath(data.packages.joinpath("FSPkg"), script.scratch_path)
     )
-    full_rel_url = 'file:' + full_rel_path + '#egg=FSPkg'
+    full_rel_url = "file:" + full_rel_path + "#egg=FSPkg"
     embedded_rel_path = script.scratch_path.joinpath(full_rel_path)
 
     req_path = {
@@ -142,20 +133,22 @@ def test_relative_requirements_file(
         "embedded_rel_path": embedded_rel_path,
     }[test_type]
 
-    req_path = req_path.replace(os.path.sep, '/')
+    req_path = req_path.replace(os.path.sep, "/")
     # Install as either editable or not.
     if not editable:
-        with requirements_file(req_path + '\n',
-                               script.scratch_path) as reqs_file:
-            result = script.pip('install', '-vvv', '-r', reqs_file.name,
-                                cwd=script.scratch_path)
+        with requirements_file(req_path + "\n", script.scratch_path) as reqs_file:
+            result = script.pip(
+                "install", "-vvv", "-r", reqs_file.name, cwd=script.scratch_path
+            )
             result.did_create(dist_info_folder)
             result.did_create(package_folder)
     else:
-        with requirements_file('-e ' + req_path + '\n',
-                               script.scratch_path) as reqs_file:
-            result = script.pip('install', '-vvv', '-r', reqs_file.name,
-                                cwd=script.scratch_path)
+        with requirements_file(
+            "-e " + req_path + "\n", script.scratch_path
+        ) as reqs_file:
+            result = script.pip(
+                "install", "-vvv", "-r", reqs_file.name, cwd=script.scratch_path
+            )
             result.did_create(egg_link_file)
 
 
@@ -167,144 +160,162 @@ def test_multiple_requirements_files(script, tmpdir, with_wheel):
     Test installing from multiple nested requirements files.
 
     """
-    other_lib_name, other_lib_version = 'anyjson', '0.3'
+    other_lib_name, other_lib_version = "anyjson", "0.3"
     script.scratch_path.joinpath("initools-req.txt").write_text(
-        textwrap.dedent("""
+        textwrap.dedent(
+            """
             -e {}@10#egg=INITools
             -r {}-req.txt
-        """).format
-        (
-            local_checkout('svn+http://svn.colorstudy.com/INITools', tmpdir),
-            other_lib_name
+        """
+        ).format(
+            local_checkout("svn+http://svn.colorstudy.com/INITools", tmpdir),
+            other_lib_name,
         ),
     )
     script.scratch_path.joinpath(
-        "{other_lib_name}-req.txt".format(**locals())).write_text(
-            "{other_lib_name}<={other_lib_version}".format(**locals())
-    )
-    result = script.pip(
-        'install', '-r', script.scratch_path / 'initools-req.txt'
-    )
+        "{other_lib_name}-req.txt".format(**locals())
+    ).write_text("{other_lib_name}<={other_lib_version}".format(**locals()))
+    result = script.pip("install", "-r", script.scratch_path / "initools-req.txt")
     assert result.files_created[script.site_packages / other_lib_name].dir
-    fn = '{other_lib_name}-{other_lib_version}.dist-info'.format(**locals())
+    fn = "{other_lib_name}-{other_lib_version}.dist-info".format(**locals())
     assert result.files_created[script.site_packages / fn].dir
-    result.did_create(script.venv / 'src' / 'initools')
+    result.did_create(script.venv / "src" / "initools")
 
 
 def test_package_in_constraints_and_dependencies(script, data):
     script.scratch_path.joinpath("constraints.txt").write_text(
         "TopoRequires2==0.0.1\nTopoRequires==0.0.1"
     )
-    result = script.pip('install', '--no-index', '-f',
-                        data.find_links, '-c', script.scratch_path /
-                        'constraints.txt', 'TopoRequires2')
-    assert 'installed TopoRequires-0.0.1' in result.stdout
+    result = script.pip(
+        "install",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "-c",
+        script.scratch_path / "constraints.txt",
+        "TopoRequires2",
+    )
+    assert "installed TopoRequires-0.0.1" in result.stdout
 
 
 def test_multiple_constraints_files(script, data):
     script.scratch_path.joinpath("outer.txt").write_text("-c inner.txt")
-    script.scratch_path.joinpath("inner.txt").write_text(
-        "Upper==1.0")
+    script.scratch_path.joinpath("inner.txt").write_text("Upper==1.0")
     result = script.pip(
-        'install', '--no-index', '-f', data.find_links, '-c',
-        script.scratch_path / 'outer.txt', 'Upper')
-    assert 'installed Upper-1.0' in result.stdout
+        "install",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "-c",
+        script.scratch_path / "outer.txt",
+        "Upper",
+    )
+    assert "installed Upper-1.0" in result.stdout
 
 
 def test_respect_order_in_requirements_file(script, data):
-    script.scratch_path.joinpath("frameworks-req.txt").write_text(textwrap.dedent("""\
+    script.scratch_path.joinpath("frameworks-req.txt").write_text(
+        textwrap.dedent(
+            """\
         parent
         child
         simple
-        """))
+        """
+        )
+    )
 
     result = script.pip(
-        'install', '--no-index', '-f', data.find_links, '-r',
-        script.scratch_path / 'frameworks-req.txt'
+        "install",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "-r",
+        script.scratch_path / "frameworks-req.txt",
     )
 
-    downloaded = [line for line in result.stdout.split('\n')
-                  if 'Processing' in line]
+    downloaded = [line for line in result.stdout.split("\n") if "Processing" in line]
 
-    assert 'parent' in downloaded[0], (
-        'First download should be "parent" but was "{}"'.format(downloaded[0])
-    )
-    assert 'child' in downloaded[1], (
-        'Second download should be "child" but was "{}"'.format(downloaded[1])
-    )
-    assert 'simple' in downloaded[2], (
-        'Third download should be "simple" but was "{}"'.format(downloaded[2])
-    )
+    assert (
+        "parent" in downloaded[0]
+    ), 'First download should be "parent" but was "{}"'.format(downloaded[0])
+    assert (
+        "child" in downloaded[1]
+    ), 'Second download should be "child" but was "{}"'.format(downloaded[1])
+    assert (
+        "simple" in downloaded[2]
+    ), 'Third download should be "simple" but was "{}"'.format(downloaded[2])
 
 
 def test_install_local_editable_with_extras(script, data):
     to_install = data.packages.joinpath("LocalExtras")
     res = script.pip_install_local(
-        '-e', to_install + '[bar]', allow_stderr_warning=True
+        "-e", to_install + "[bar]", allow_stderr_warning=True
     )
-    res.did_update(script.site_packages / 'easy-install.pth')
-    res.did_create(script.site_packages / 'LocalExtras.egg-link')
-    res.did_create(script.site_packages / 'simple')
+    res.did_update(script.site_packages / "easy-install.pth")
+    res.did_create(script.site_packages / "LocalExtras.egg-link")
+    res.did_create(script.site_packages / "simple")
 
 
 def test_install_collected_dependencies_first(script):
     result = script.pip_install_local(
-        'toporequires2',
+        "toporequires2",
     )
-    text = [line for line in result.stdout.split('\n')
-            if 'Installing' in line][0]
-    assert text.endswith('toporequires2')
+    text = [line for line in result.stdout.split("\n") if "Installing" in line][0]
+    assert text.endswith("toporequires2")
 
 
 @pytest.mark.network
 def test_install_local_editable_with_subdirectory(script):
-    version_pkg_path = _create_test_package_with_subdirectory(script,
-                                                              'version_subdir')
+    version_pkg_path = _create_test_package_with_subdirectory(script, "version_subdir")
     result = script.pip(
-        'install', '-e',
-        '{uri}#egg=version_subpkg&subdirectory=version_subdir'.format(
-            uri='git+' + path_to_url(version_pkg_path),
+        "install",
+        "-e",
+        "{uri}#egg=version_subpkg&subdirectory=version_subdir".format(
+            uri="git+" + path_to_url(version_pkg_path),
         ),
     )
 
-    result.assert_installed('version-subpkg', sub_dir='version_subdir')
+    result.assert_installed("version-subpkg", sub_dir="version_subdir")
 
 
 @pytest.mark.network
 def test_install_local_with_subdirectory(script):
-    version_pkg_path = _create_test_package_with_subdirectory(script,
-                                                              'version_subdir')
+    version_pkg_path = _create_test_package_with_subdirectory(script, "version_subdir")
     result = script.pip(
-        'install',
-        '{uri}#egg=version_subpkg&subdirectory=version_subdir'.format(
-            uri='git+' + path_to_url(version_pkg_path),
+        "install",
+        "{uri}#egg=version_subpkg&subdirectory=version_subdir".format(
+            uri="git+" + path_to_url(version_pkg_path),
         ),
     )
 
-    result.assert_installed('version_subpkg.py', editable=False)
+    result.assert_installed("version_subpkg.py", editable=False)
 
 
 @pytest.mark.incompatible_with_test_venv
-def test_wheel_user_with_prefix_in_pydistutils_cfg(
-        script, data, with_wheel):
-    if os.name == 'posix':
+def test_wheel_user_with_prefix_in_pydistutils_cfg(script, data, with_wheel):
+    if os.name == "posix":
         user_filename = ".pydistutils.cfg"
     else:
         user_filename = "pydistutils.cfg"
-    user_cfg = os.path.join(os.path.expanduser('~'), user_filename)
+    user_cfg = os.path.join(os.path.expanduser("~"), user_filename)
     script.scratch_path.joinpath("bin").mkdir()
     with open(user_cfg, "w") as cfg:
-        cfg.write(textwrap.dedent("""
+        cfg.write(
+            textwrap.dedent(
+                """
             [install]
-            prefix={script.scratch_path}""".format(**locals())))
+            prefix={script.scratch_path}""".format(
+                    **locals()
+                )
+            )
+        )
 
     result = script.pip(
-        'install', '--user', '--no-index',
-        '-f', data.find_links,
-        'requiresupper')
+        "install", "--user", "--no-index", "-f", data.find_links, "requiresupper"
+    )
     # Check that we are really installing a wheel
-    assert 'Running setup.py install for requiresupper' not in result.stdout
-    assert 'installed requiresupper' in result.stdout
+    assert "Running setup.py install for requiresupper" not in result.stdout
+    assert "installed requiresupper" in result.stdout
 
 
 def test_install_option_in_requirements_file_overrides_cli(
@@ -316,82 +327,108 @@ def test_install_option_in_requirements_file_overrides_cli(
     reqs_file.write_text("simple --install-option='-O0'")
 
     script.pip(
-        'install', '--no-index', '-f', str(simple_sdist.sdist_path.parent),
-        '-r', str(reqs_file), '--install-option=-O1',
+        "install",
+        "--no-index",
+        "-f",
+        str(simple_sdist.sdist_path.parent),
+        "-r",
+        str(reqs_file),
+        "--install-option=-O1",
     )
     simple_args = simple_sdist.args()
-    assert 'install' in simple_args
-    assert simple_args.index('-O1') < simple_args.index('-O0')
+    assert "install" in simple_args
+    assert simple_args.index("-O1") < simple_args.index("-O0")
 
 
 def test_constraints_not_installed_by_default(script, data):
     script.scratch_path.joinpath("c.txt").write_text("requiresupper")
     result = script.pip(
-        'install', '--no-index', '-f', data.find_links, '-c',
-        script.scratch_path / 'c.txt', 'Upper')
-    assert 'requiresupper' not in result.stdout
+        "install",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "-c",
+        script.scratch_path / "c.txt",
+        "Upper",
+    )
+    assert "requiresupper" not in result.stdout
 
 
 def test_constraints_only_causes_error(script, data):
     script.scratch_path.joinpath("c.txt").write_text("requiresupper")
     result = script.pip(
-        'install', '--no-index', '-f', data.find_links, '-c',
-        script.scratch_path / 'c.txt', expect_error=True)
-    assert 'installed requiresupper' not in result.stdout
+        "install",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "-c",
+        script.scratch_path / "c.txt",
+        expect_error=True,
+    )
+    assert "installed requiresupper" not in result.stdout
 
 
 def test_constraints_local_editable_install_causes_error(script, data):
-    script.scratch_path.joinpath("constraints.txt").write_text(
-        "singlemodule==0.0.0"
-    )
+    script.scratch_path.joinpath("constraints.txt").write_text("singlemodule==0.0.0")
     to_install = data.src.joinpath("singlemodule")
     result = script.pip(
-        'install', '--no-index', '-f', data.find_links, '-c',
-        script.scratch_path / 'constraints.txt', '-e',
-        to_install, expect_error=True)
-    assert 'Could not satisfy constraints for' in result.stderr
+        "install",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "-c",
+        script.scratch_path / "constraints.txt",
+        "-e",
+        to_install,
+        expect_error=True,
+    )
+    assert "Could not satisfy constraints for" in result.stderr
 
 
 @pytest.mark.network
 def test_constraints_local_editable_install_pep518(script, data):
     to_install = data.src.joinpath("pep518-3.0")
 
-    script.pip('download', 'setuptools', 'wheel', '-d', data.packages)
-    script.pip(
-        'install', '--no-index', '-f', data.find_links, '-e', to_install)
+    script.pip("download", "setuptools", "wheel", "-d", data.packages)
+    script.pip("install", "--no-index", "-f", data.find_links, "-e", to_install)
 
 
 def test_constraints_local_install_causes_error(script, data):
-    script.scratch_path.joinpath("constraints.txt").write_text(
-        "singlemodule==0.0.0"
-    )
+    script.scratch_path.joinpath("constraints.txt").write_text("singlemodule==0.0.0")
     to_install = data.src.joinpath("singlemodule")
     result = script.pip(
-        'install', '--no-index', '-f', data.find_links, '-c',
-        script.scratch_path / 'constraints.txt',
-        to_install, expect_error=True)
-    assert 'Could not satisfy constraints for' in result.stderr
+        "install",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "-c",
+        script.scratch_path / "constraints.txt",
+        to_install,
+        expect_error=True,
+    )
+    assert "Could not satisfy constraints for" in result.stderr
 
 
-def test_constraints_constrain_to_local_editable(
-    script,
-    data,
-    use_new_resolver
-):
+def test_constraints_constrain_to_local_editable(script, data, use_new_resolver):
     to_install = data.src.joinpath("singlemodule")
     script.scratch_path.joinpath("constraints.txt").write_text(
         "-e {url}#egg=singlemodule".format(url=path_to_url(to_install))
     )
     result = script.pip(
-        'install', '--no-index', '-f', data.find_links, '-c',
-        script.scratch_path / 'constraints.txt', 'singlemodule',
+        "install",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "-c",
+        script.scratch_path / "constraints.txt",
+        "singlemodule",
         allow_stderr_warning=True,
-        expect_error=use_new_resolver
+        expect_error=use_new_resolver,
     )
     if use_new_resolver:
-        assert 'Links are not allowed as constraints' in result.stderr
+        assert "Links are not allowed as constraints" in result.stderr
     else:
-        assert 'Running setup.py develop for singlemodule' in result.stdout
+        assert "Running setup.py develop for singlemodule" in result.stdout
 
 
 def test_constraints_constrain_to_local(script, data, use_new_resolver):
@@ -400,15 +437,20 @@ def test_constraints_constrain_to_local(script, data, use_new_resolver):
         "{url}#egg=singlemodule".format(url=path_to_url(to_install))
     )
     result = script.pip(
-        'install', '--no-index', '-f', data.find_links, '-c',
-        script.scratch_path / 'constraints.txt', 'singlemodule',
+        "install",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "-c",
+        script.scratch_path / "constraints.txt",
+        "singlemodule",
         allow_stderr_warning=True,
-        expect_error=use_new_resolver
+        expect_error=use_new_resolver,
     )
     if use_new_resolver:
-        assert 'Links are not allowed as constraints' in result.stderr
+        assert "Links are not allowed as constraints" in result.stderr
     else:
-        assert 'Running setup.py install for singlemodule' in result.stdout
+        assert "Running setup.py install for singlemodule" in result.stdout
 
 
 def test_constrained_to_url_install_same_url(script, data, use_new_resolver):
@@ -416,20 +458,23 @@ def test_constrained_to_url_install_same_url(script, data, use_new_resolver):
     constraints = path_to_url(to_install) + "#egg=singlemodule"
     script.scratch_path.joinpath("constraints.txt").write_text(constraints)
     result = script.pip(
-        'install', '--no-index', '-f', data.find_links, '-c',
-        script.scratch_path / 'constraints.txt', to_install,
+        "install",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "-c",
+        script.scratch_path / "constraints.txt",
+        to_install,
         allow_stderr_warning=True,
-        expect_error=use_new_resolver
+        expect_error=use_new_resolver,
     )
     if use_new_resolver:
-        assert 'Links are not allowed as constraints' in result.stderr
+        assert "Links are not allowed as constraints" in result.stderr
     else:
-        assert ('Running setup.py install for singlemodule'
-                in result.stdout), str(result)
+        assert "Running setup.py install for singlemodule" in result.stdout, str(result)
 
 
-def test_double_install_spurious_hash_mismatch(
-        script, tmpdir, data, with_wheel):
+def test_double_install_spurious_hash_mismatch(script, tmpdir, data, with_wheel):
     """Make sure installing the same hashed sdist twice doesn't throw hash
     mismatch errors.
 
@@ -440,26 +485,32 @@ def test_double_install_spurious_hash_mismatch(
 
     """
     # Install wheel package, otherwise, it won't try to build wheels.
-    with requirements_file('simple==1.0 --hash=sha256:393043e672415891885c9a2a'
-                           '0929b1af95fb866d6ca016b42d2e6ce53619b653',
-                           tmpdir) as reqs_file:
+    with requirements_file(
+        "simple==1.0 --hash=sha256:393043e672415891885c9a2a"
+        "0929b1af95fb866d6ca016b42d2e6ce53619b653",
+        tmpdir,
+    ) as reqs_file:
         # Install a package (and build its wheel):
         result = script.pip_install_local(
-            '--find-links', data.find_links,
-            '-r', reqs_file.resolve(),
+            "--find-links",
+            data.find_links,
+            "-r",
+            reqs_file.resolve(),
         )
-        assert 'Successfully installed simple-1.0' in str(result)
+        assert "Successfully installed simple-1.0" in str(result)
 
         # Uninstall it:
-        script.pip('uninstall', '-y', 'simple')
+        script.pip("uninstall", "-y", "simple")
 
         # Then install it again. We should not hit a hash mismatch, and the
         # package should install happily.
         result = script.pip_install_local(
-            '--find-links', data.find_links,
-            '-r', reqs_file.resolve(),
+            "--find-links",
+            data.find_links,
+            "-r",
+            reqs_file.resolve(),
         )
-        assert 'Successfully installed simple-1.0' in str(result)
+        assert "Successfully installed simple-1.0" in str(result)
 
 
 def test_install_with_extras_from_constraints(script, data, use_new_resolver):
@@ -468,14 +519,16 @@ def test_install_with_extras_from_constraints(script, data, use_new_resolver):
         "{url}#egg=LocalExtras[bar]".format(url=path_to_url(to_install))
     )
     result = script.pip_install_local(
-        '-c', script.scratch_path / 'constraints.txt', 'LocalExtras',
+        "-c",
+        script.scratch_path / "constraints.txt",
+        "LocalExtras",
         allow_stderr_warning=True,
-        expect_error=use_new_resolver
+        expect_error=use_new_resolver,
     )
     if use_new_resolver:
-        assert 'Links are not allowed as constraints' in result.stderr
+        assert "Links are not allowed as constraints" in result.stderr
     else:
-        result.did_create(script.site_packages / 'simple')
+        result.did_create(script.site_packages / "simple")
 
 
 def test_install_with_extras_from_install(script):
@@ -487,11 +540,13 @@ def test_install_with_extras_from_install(script):
     )
     script.scratch_path.joinpath("constraints.txt").write_text("LocalExtras")
     result = script.pip_install_local(
-        '--find-links', script.scratch_path,
-        '-c', script.scratch_path / 'constraints.txt',
-        'LocalExtras[baz]',
+        "--find-links",
+        script.scratch_path,
+        "-c",
+        script.scratch_path / "constraints.txt",
+        "LocalExtras[baz]",
     )
-    result.did_create(script.site_packages / 'singlemodule.py')
+    result.did_create(script.site_packages / "singlemodule.py")
 
 
 def test_install_with_extras_joined(script, data, use_new_resolver):
@@ -500,15 +555,17 @@ def test_install_with_extras_joined(script, data, use_new_resolver):
         "{url}#egg=LocalExtras[bar]".format(url=path_to_url(to_install))
     )
     result = script.pip_install_local(
-        '-c', script.scratch_path / 'constraints.txt', 'LocalExtras[baz]',
+        "-c",
+        script.scratch_path / "constraints.txt",
+        "LocalExtras[baz]",
         allow_stderr_warning=True,
-        expect_error=use_new_resolver
+        expect_error=use_new_resolver,
     )
     if use_new_resolver:
-        assert 'Links are not allowed as constraints' in result.stderr
+        assert "Links are not allowed as constraints" in result.stderr
     else:
-        result.did_create(script.site_packages / 'simple')
-        result.did_create(script.site_packages / 'singlemodule.py')
+        result.did_create(script.site_packages / "simple")
+        result.did_create(script.site_packages / "singlemodule.py")
 
 
 def test_install_with_extras_editable_joined(script, data, use_new_resolver):
@@ -517,24 +574,27 @@ def test_install_with_extras_editable_joined(script, data, use_new_resolver):
         "-e {url}#egg=LocalExtras[bar]".format(url=path_to_url(to_install))
     )
     result = script.pip_install_local(
-        '-c', script.scratch_path / 'constraints.txt', 'LocalExtras[baz]',
+        "-c",
+        script.scratch_path / "constraints.txt",
+        "LocalExtras[baz]",
         allow_stderr_warning=True,
-        expect_error=use_new_resolver
+        expect_error=use_new_resolver,
     )
     if use_new_resolver:
-        assert 'Links are not allowed as constraints' in result.stderr
+        assert "Links are not allowed as constraints" in result.stderr
     else:
-        result.did_create(script.site_packages / 'simple')
-        result.did_create(script.site_packages / 'singlemodule.py')
+        result.did_create(script.site_packages / "simple")
+        result.did_create(script.site_packages / "singlemodule.py")
 
 
 def test_install_distribution_full_union(script, data):
     to_install = data.packages.joinpath("LocalExtras")
     result = script.pip_install_local(
-        to_install, to_install + "[bar]", to_install + "[baz]")
-    assert 'Running setup.py install for LocalExtras' in result.stdout
-    result.did_create(script.site_packages / 'simple')
-    result.did_create(script.site_packages / 'singlemodule.py')
+        to_install, to_install + "[bar]", to_install + "[baz]"
+    )
+    assert "Running setup.py install for LocalExtras" in result.stdout
+    result.did_create(script.site_packages / "simple")
+    result.did_create(script.site_packages / "singlemodule.py")
 
 
 def test_install_distribution_duplicate_extras(script, data):
@@ -542,30 +602,28 @@ def test_install_distribution_duplicate_extras(script, data):
     package_name = to_install + "[bar]"
     with pytest.raises(AssertionError):
         result = script.pip_install_local(package_name, package_name)
-        expected = (
-            'Double requirement given: {package_name}'.format(**locals()))
+        expected = "Double requirement given: {package_name}".format(**locals())
         assert expected in result.stderr
 
 
-def test_install_distribution_union_with_constraints(
-    script,
-    data,
-    use_new_resolver
-):
+def test_install_distribution_union_with_constraints(script, data, use_new_resolver):
     to_install = data.packages.joinpath("LocalExtras")
     script.scratch_path.joinpath("constraints.txt").write_text(
-        "{to_install}[bar]".format(**locals()))
+        "{to_install}[bar]".format(**locals())
+    )
     result = script.pip_install_local(
-        '-c', script.scratch_path / 'constraints.txt', to_install + '[baz]',
+        "-c",
+        script.scratch_path / "constraints.txt",
+        to_install + "[baz]",
         allow_stderr_warning=True,
-        expect_error=use_new_resolver
+        expect_error=use_new_resolver,
     )
     if use_new_resolver:
-        msg = 'Unnamed requirements are not allowed as constraints'
+        msg = "Unnamed requirements are not allowed as constraints"
         assert msg in result.stderr
     else:
-        assert 'Running setup.py install for LocalExtras' in result.stdout
-        result.did_create(script.site_packages / 'singlemodule.py')
+        assert "Running setup.py install for LocalExtras" in result.stdout
+        result.did_create(script.site_packages / "singlemodule.py")
 
 
 def test_install_distribution_union_with_versions(
@@ -585,16 +643,11 @@ def test_install_distribution_union_with_versions(
             "Cannot install localextras[bar] 0.0.1 and localextras[baz] 0.0.2 "
             "because these package versions have conflicting dependencies."
         ) in result.stderr
-        assert (
-            "localextras[bar] 0.0.1 depends on localextras 0.0.1"
-        ) in result.stdout
-        assert (
-            "localextras[baz] 0.0.2 depends on localextras 0.0.2"
-        ) in result.stdout
+        assert ("localextras[bar] 0.0.1 depends on localextras 0.0.1") in result.stdout
+        assert ("localextras[baz] 0.0.2 depends on localextras 0.0.2") in result.stdout
     else:
         assert (
-            "Successfully installed LocalExtras-0.0.1 simple-3.0 "
-            "singlemodule-0.0.1"
+            "Successfully installed LocalExtras-0.0.1 simple-3.0 " "singlemodule-0.0.1"
         ) in result.stdout
 
 
@@ -605,27 +658,30 @@ def test_install_distribution_union_conflicting_extras(script, data):
     # and simple==2.0. Once a resolver is added, this conflict should be
     # detected.
     to_install = data.packages.joinpath("LocalExtras-0.0.2")
-    result = script.pip_install_local(to_install, to_install + "[bar]",
-                                      expect_error=True)
-    assert 'installed' not in result.stdout
+    result = script.pip_install_local(
+        to_install, to_install + "[bar]", expect_error=True
+    )
+    assert "installed" not in result.stdout
     assert "Conflict" in result.stderr
 
 
 def test_install_unsupported_wheel_link_with_marker(script):
     script.scratch_path.joinpath("with-marker.txt").write_text(
-        textwrap.dedent("""\
+        textwrap.dedent(
+            """\
             {url}; {req}
-        """).format(
-            url='https://github.com/a/b/c/asdf-1.5.2-cp27-none-xyz.whl',
+        """
+        ).format(
+            url="https://github.com/a/b/c/asdf-1.5.2-cp27-none-xyz.whl",
             req='sys_platform == "xyz"',
         )
     )
-    result = script.pip(
-        'install', '-r', script.scratch_path / 'with-marker.txt'
-    )
+    result = script.pip("install", "-r", script.scratch_path / "with-marker.txt")
 
-    assert ("Ignoring asdf: markers 'sys_platform == \"xyz\"' don't match "
-            "your environment") in result.stdout
+    assert (
+        "Ignoring asdf: markers 'sys_platform == \"xyz\"' don't match "
+        "your environment"
+    ) in result.stdout
     assert len(result.files_created) == 0
 
 
@@ -633,16 +689,27 @@ def test_install_unsupported_wheel_file(script, data):
     # Trying to install a local wheel with an incompatible version/type
     # should fail.
     path = data.packages.joinpath("simple.dist-0.1-py1-none-invalid.whl")
-    script.scratch_path.joinpath("wheel-file.txt").write_text(textwrap.dedent("""\
+    script.scratch_path.joinpath("wheel-file.txt").write_text(
+        textwrap.dedent(
+            """\
         {path}
-        """.format(**locals())))
+        """.format(
+                **locals()
+            )
+        )
+    )
     result = script.pip(
-        'install', '-r', script.scratch_path / 'wheel-file.txt',
+        "install",
+        "-r",
+        script.scratch_path / "wheel-file.txt",
         expect_error=True,
         expect_stderr=True,
     )
-    assert ("simple.dist-0.1-py1-none-invalid.whl is not a supported " +
-            "wheel on this platform" in result.stderr)
+    assert (
+        "simple.dist-0.1-py1-none-invalid.whl is not a supported "
+        + "wheel on this platform"
+        in result.stderr
+    )
     assert len(result.files_created) == 0
 
 
@@ -668,17 +735,20 @@ def test_install_options_local_to_package(script, arg_recording_sdist_maker):
         )
     )
     script.pip(
-        'install',
-        '--no-index', '-f', str(simple1_sdist.sdist_path.parent),
-        '-r', reqs_file,
+        "install",
+        "--no-index",
+        "-f",
+        str(simple1_sdist.sdist_path.parent),
+        "-r",
+        reqs_file,
     )
 
     simple1_args = simple1_sdist.args()
-    assert 'install' in simple1_args
-    assert '-O0' in simple1_args
+    assert "install" in simple1_args
+    assert "-O0" in simple1_args
     simple2_args = simple2_sdist.args()
-    assert 'install' in simple2_args
-    assert '-O0' not in simple2_args
+    assert "install" in simple2_args
+    assert "-O0" not in simple2_args
 
 
 def test_location_related_install_option_fails(script):
@@ -686,9 +756,12 @@ def test_location_related_install_option_fails(script):
     reqs_file = script.scratch_path.joinpath("reqs.txt")
     reqs_file.write_text("simple --install-option='--home=/tmp'")
     result = script.pip(
-        'install',
-        '--no-index', '-f', str(simple_sdist.parent),
-        '-r', reqs_file,
-        expect_error=True
+        "install",
+        "--no-index",
+        "-f",
+        str(simple_sdist.parent),
+        "-r",
+        reqs_file,
+        expect_error=True,
     )
     assert "['--home'] from simple" in result.stderr
diff --git a/tests/functional/test_install_requested.py b/tests/functional/test_install_requested.py
index 6caec988eb5..1f3977078ed 100644
--- a/tests/functional/test_install_requested.py
+++ b/tests/functional/test_install_requested.py
@@ -22,9 +22,7 @@ def test_install_requested_basic(script, data, with_wheel):
 
 
 def test_install_requested_requirements(script, data, with_wheel):
-    script.scratch_path.joinpath("requirements.txt").write_text(
-        "require_simple\n"
-    )
+    script.scratch_path.joinpath("requirements.txt").write_text("require_simple\n")
     result = script.pip(
         "install",
         "--no-index",
@@ -55,9 +53,7 @@ def test_install_requested_dep_in_requirements(script, data, with_wheel):
 
 
 def test_install_requested_reqs_and_constraints(script, data, with_wheel):
-    script.scratch_path.joinpath("requirements.txt").write_text(
-        "require_simple\n"
-    )
+    script.scratch_path.joinpath("requirements.txt").write_text("require_simple\n")
     script.scratch_path.joinpath("constraints.txt").write_text("simple<3\n")
     result = script.pip(
         "install",
diff --git a/tests/functional/test_install_upgrade.py b/tests/functional/test_install_upgrade.py
index 02e221101c5..15b55df44ae 100644
--- a/tests/functional/test_install_upgrade.py
+++ b/tests/functional/test_install_upgrade.py
@@ -17,11 +17,11 @@ def test_no_upgrade_unless_requested(script):
     No upgrade if not specifically requested.
 
     """
-    script.pip('install', 'INITools==0.1')
-    result = script.pip('install', 'INITools')
-    assert not result.files_created, (
-        'pip install INITools upgraded when it should not have'
-    )
+    script.pip("install", "INITools==0.1")
+    result = script.pip("install", "INITools")
+    assert (
+        not result.files_created
+    ), "pip install INITools upgraded when it should not have"
 
 
 def test_invalid_upgrade_strategy_causes_error(script):
@@ -30,8 +30,7 @@ def test_invalid_upgrade_strategy_causes_error(script):
 
     """
     result = script.pip_install_local(
-        '--upgrade', '--upgrade-strategy=bazinga', 'simple',
-        expect_error=True
+        "--upgrade", "--upgrade-strategy=bazinga", "simple", expect_error=True
     )
 
     assert result.returncode
@@ -39,27 +38,23 @@ def test_invalid_upgrade_strategy_causes_error(script):
 
 
 def test_only_if_needed_does_not_upgrade_deps_when_satisfied(
-    script,
-    use_new_resolver,
-    with_wheel
+    script, use_new_resolver, with_wheel
 ):
     """
     It doesn't upgrade a dependency if it already satisfies the requirements.
 
     """
-    script.pip_install_local('simple==2.0')
+    script.pip_install_local("simple==2.0")
     result = script.pip_install_local(
-        '--upgrade', '--upgrade-strategy=only-if-needed', 'require_simple'
+        "--upgrade", "--upgrade-strategy=only-if-needed", "require_simple"
     )
 
     assert (
-        (script.site_packages / 'require_simple-1.0.dist-info')
-        not in result.files_deleted
-    ), "should have installed require_simple==1.0"
+        script.site_packages / "require_simple-1.0.dist-info"
+    ) not in result.files_deleted, "should have installed require_simple==1.0"
     assert (
-        (script.site_packages / 'simple-2.0.dist-info')
-        not in result.files_deleted
-    ), "should not have uninstalled simple==2.0"
+        script.site_packages / "simple-2.0.dist-info"
+    ) not in result.files_deleted, "should not have uninstalled simple==2.0"
 
     msg = "Requirement already satisfied"
     if not use_new_resolver:
@@ -69,83 +64,62 @@ def test_only_if_needed_does_not_upgrade_deps_when_satisfied(
     ), "did not print correct message for not-upgraded requirement"
 
 
-def test_only_if_needed_does_upgrade_deps_when_no_longer_satisfied(
-    script, with_wheel
-):
+def test_only_if_needed_does_upgrade_deps_when_no_longer_satisfied(script, with_wheel):
     """
     It does upgrade a dependency if it no longer satisfies the requirements.
 
     """
-    script.pip_install_local('simple==1.0')
+    script.pip_install_local("simple==1.0")
     result = script.pip_install_local(
-        '--upgrade', '--upgrade-strategy=only-if-needed', 'require_simple'
+        "--upgrade", "--upgrade-strategy=only-if-needed", "require_simple"
     )
 
     assert (
-        (script.site_packages / 'require_simple-1.0.dist-info')
-        not in result.files_deleted
-    ), "should have installed require_simple==1.0"
-    expected = (
-        script.site_packages /
-        'simple-3.0.dist-info'
-    )
+        script.site_packages / "require_simple-1.0.dist-info"
+    ) not in result.files_deleted, "should have installed require_simple==1.0"
+    expected = script.site_packages / "simple-3.0.dist-info"
     result.did_create(expected, message="should have installed simple==3.0")
-    expected = (
-        script.site_packages /
-        'simple-1.0.dist-info'
-    )
-    assert (
-        expected in result.files_deleted
-    ), "should have uninstalled simple==1.0"
+    expected = script.site_packages / "simple-1.0.dist-info"
+    assert expected in result.files_deleted, "should have uninstalled simple==1.0"
 
 
-def test_eager_does_upgrade_dependecies_when_currently_satisfied(
-    script, with_wheel
-):
+def test_eager_does_upgrade_dependecies_when_currently_satisfied(script, with_wheel):
     """
     It does upgrade a dependency even if it already satisfies the requirements.
 
     """
-    script.pip_install_local('simple==2.0')
+    script.pip_install_local("simple==2.0")
     result = script.pip_install_local(
-        '--upgrade', '--upgrade-strategy=eager', 'require_simple'
+        "--upgrade", "--upgrade-strategy=eager", "require_simple"
     )
 
     assert (
-        (script.site_packages /
-            'require_simple-1.0.dist-info')
-        not in result.files_deleted
-    ), "should have installed require_simple==1.0"
+        script.site_packages / "require_simple-1.0.dist-info"
+    ) not in result.files_deleted, "should have installed require_simple==1.0"
     assert (
-        (script.site_packages /
-            'simple-2.0.dist-info')
-        in result.files_deleted
-    ), "should have uninstalled simple==2.0"
+        script.site_packages / "simple-2.0.dist-info"
+    ) in result.files_deleted, "should have uninstalled simple==2.0"
 
 
-def test_eager_does_upgrade_dependecies_when_no_longer_satisfied(
-    script, with_wheel
-):
+def test_eager_does_upgrade_dependecies_when_no_longer_satisfied(script, with_wheel):
     """
     It does upgrade a dependency if it no longer satisfies the requirements.
 
     """
-    script.pip_install_local('simple==1.0')
+    script.pip_install_local("simple==1.0")
     result = script.pip_install_local(
-        '--upgrade', '--upgrade-strategy=eager', 'require_simple'
+        "--upgrade", "--upgrade-strategy=eager", "require_simple"
     )
 
     assert (
-        (script.site_packages / 'require_simple-1.0.dist-info')
-        not in result.files_deleted
-    ), "should have installed require_simple==1.0"
+        script.site_packages / "require_simple-1.0.dist-info"
+    ) not in result.files_deleted, "should have installed require_simple==1.0"
     result.did_create(
-        script.site_packages / 'simple-3.0.dist-info',
-        message="should have installed simple==3.0"
+        script.site_packages / "simple-3.0.dist-info",
+        message="should have installed simple==3.0",
     )
     assert (
-        script.site_packages / 'simple-1.0.dist-info'
-        in result.files_deleted
+        script.site_packages / "simple-1.0.dist-info" in result.files_deleted
     ), "should have uninstalled simple==1.0"
 
 
@@ -155,18 +129,11 @@ def test_upgrade_to_specific_version(script, with_wheel):
     It does upgrade to specific version requested.
 
     """
-    script.pip('install', 'INITools==0.1')
-    result = script.pip('install', 'INITools==0.2')
-    assert result.files_created, (
-        'pip install with specific version did not upgrade'
-    )
-    assert (
-        script.site_packages / 'INITools-0.1.dist-info'
-        in result.files_deleted
-    )
-    result.did_create(
-        script.site_packages / 'INITools-0.2.dist-info'
-    )
+    script.pip("install", "INITools==0.1")
+    result = script.pip("install", "INITools==0.2")
+    assert result.files_created, "pip install with specific version did not upgrade"
+    assert script.site_packages / "INITools-0.1.dist-info" in result.files_deleted
+    result.did_create(script.site_packages / "INITools-0.2.dist-info")
 
 
 @pytest.mark.network
@@ -175,13 +142,10 @@ def test_upgrade_if_requested(script, with_wheel):
     And it does upgrade if requested.
 
     """
-    script.pip('install', 'INITools==0.1')
-    result = script.pip('install', '--upgrade', 'INITools')
-    assert result.files_created, 'pip install --upgrade did not upgrade'
-    result.did_not_create(
-        script.site_packages /
-        'INITools-0.1.dist-info'
-    )
+    script.pip("install", "INITools==0.1")
+    result = script.pip("install", "--upgrade", "INITools")
+    assert result.files_created, "pip install --upgrade did not upgrade"
+    result.did_not_create(script.site_packages / "INITools-0.1.dist-info")
 
 
 def test_upgrade_with_newest_already_installed(script, data, use_new_resolver):
@@ -189,11 +153,11 @@ def test_upgrade_with_newest_already_installed(script, data, use_new_resolver):
     If the newest version of a package is already installed, the package should
     not be reinstalled and the user should be informed.
     """
-    script.pip('install', '-f', data.find_links, '--no-index', 'simple')
+    script.pip("install", "-f", data.find_links, "--no-index", "simple")
     result = script.pip(
-        'install', '--upgrade', '-f', data.find_links, '--no-index', 'simple'
+        "install", "--upgrade", "-f", data.find_links, "--no-index", "simple"
     )
-    assert not result.files_created, 'simple upgraded when it should not have'
+    assert not result.files_created, "simple upgraded when it should not have"
     if use_new_resolver:
         msg = "Requirement already satisfied"
     else:
@@ -207,14 +171,12 @@ def test_upgrade_force_reinstall_newest(script):
     Force reinstallation of a package even if it is already at its newest
     version if --force-reinstall is supplied.
     """
-    result = script.pip('install', 'INITools')
-    result.did_create(script.site_packages / 'initools')
-    result2 = script.pip(
-        'install', '--upgrade', '--force-reinstall', 'INITools'
-    )
-    assert result2.files_updated, 'upgrade to INITools 0.3 failed'
-    result3 = script.pip('uninstall', 'initools', '-y')
-    assert_all_changes(result, result3, [script.venv / 'build', 'cache'])
+    result = script.pip("install", "INITools")
+    result.did_create(script.site_packages / "initools")
+    result2 = script.pip("install", "--upgrade", "--force-reinstall", "INITools")
+    assert result2.files_updated, "upgrade to INITools 0.3 failed"
+    result3 = script.pip("uninstall", "initools", "-y")
+    assert_all_changes(result, result3, [script.venv / "build", "cache"])
 
 
 @pytest.mark.network
@@ -223,12 +185,12 @@ def test_uninstall_before_upgrade(script):
     Automatic uninstall-before-upgrade.
 
     """
-    result = script.pip('install', 'INITools==0.2')
-    result.did_create(script.site_packages / 'initools')
-    result2 = script.pip('install', 'INITools==0.3')
-    assert result2.files_created, 'upgrade to INITools 0.3 failed'
-    result3 = script.pip('uninstall', 'initools', '-y')
-    assert_all_changes(result, result3, [script.venv / 'build', 'cache'])
+    result = script.pip("install", "INITools==0.2")
+    result.did_create(script.site_packages / "initools")
+    result2 = script.pip("install", "INITools==0.3")
+    assert result2.files_created, "upgrade to INITools 0.3 failed"
+    result3 = script.pip("uninstall", "initools", "-y")
+    assert_all_changes(result, result3, [script.venv / "build", "cache"])
 
 
 @pytest.mark.network
@@ -237,16 +199,16 @@ def test_uninstall_before_upgrade_from_url(script):
     Automatic uninstall-before-upgrade from URL.
 
     """
-    result = script.pip('install', 'INITools==0.2')
-    result.did_create(script.site_packages / 'initools')
+    result = script.pip("install", "INITools==0.2")
+    result.did_create(script.site_packages / "initools")
     result2 = script.pip(
-        'install',
-        'https://files.pythonhosted.org/packages/source/I/INITools/INITools-'
-        '0.3.tar.gz',
+        "install",
+        "https://files.pythonhosted.org/packages/source/I/INITools/INITools-"
+        "0.3.tar.gz",
     )
-    assert result2.files_created, 'upgrade to INITools 0.3 failed'
-    result3 = script.pip('uninstall', 'initools', '-y')
-    assert_all_changes(result, result3, [script.venv / 'build', 'cache'])
+    assert result2.files_created, "upgrade to INITools 0.3 failed"
+    result3 = script.pip("uninstall", "initools", "-y")
+    assert_all_changes(result, result3, [script.venv / "build", "cache"])
 
 
 @pytest.mark.network
@@ -256,18 +218,18 @@ def test_upgrade_to_same_version_from_url(script):
     need to uninstall and reinstall if --upgrade is not specified.
 
     """
-    result = script.pip('install', 'INITools==0.3')
-    result.did_create(script.site_packages / 'initools')
+    result = script.pip("install", "INITools==0.3")
+    result.did_create(script.site_packages / "initools")
     result2 = script.pip(
-        'install',
-        'https://files.pythonhosted.org/packages/source/I/INITools/INITools-'
-        '0.3.tar.gz',
+        "install",
+        "https://files.pythonhosted.org/packages/source/I/INITools/INITools-"
+        "0.3.tar.gz",
     )
-    assert script.site_packages / 'initools' not in result2.files_updated, (
-        'INITools 0.3 reinstalled same version'
-    )
-    result3 = script.pip('uninstall', 'initools', '-y')
-    assert_all_changes(result, result3, [script.venv / 'build', 'cache'])
+    assert (
+        script.site_packages / "initools" not in result2.files_updated
+    ), "INITools 0.3 reinstalled same version"
+    result3 = script.pip("uninstall", "initools", "-y")
+    assert_all_changes(result, result3, [script.venv / "build", "cache"])
 
 
 @pytest.mark.network
@@ -276,29 +238,33 @@ def test_upgrade_from_reqs_file(script):
     Upgrade from a requirements file.
 
     """
-    script.scratch_path.joinpath("test-req.txt").write_text(textwrap.dedent("""\
+    script.scratch_path.joinpath("test-req.txt").write_text(
+        textwrap.dedent(
+            """\
         PyLogo<0.4
         # and something else to test out:
         INITools==0.3
-        """))
-    install_result = script.pip(
-        'install', '-r', script.scratch_path / 'test-req.txt'
+        """
+        )
     )
-    script.scratch_path.joinpath("test-req.txt").write_text(textwrap.dedent("""\
+    install_result = script.pip("install", "-r", script.scratch_path / "test-req.txt")
+    script.scratch_path.joinpath("test-req.txt").write_text(
+        textwrap.dedent(
+            """\
         PyLogo
         # and something else to test out:
         INITools
-        """))
-    script.pip(
-        'install', '--upgrade', '-r', script.scratch_path / 'test-req.txt'
+        """
+        )
     )
+    script.pip("install", "--upgrade", "-r", script.scratch_path / "test-req.txt")
     uninstall_result = script.pip(
-        'uninstall', '-r', script.scratch_path / 'test-req.txt', '-y'
+        "uninstall", "-r", script.scratch_path / "test-req.txt", "-y"
     )
     assert_all_changes(
         install_result,
         uninstall_result,
-        [script.venv / 'build', 'cache', script.scratch / 'test-req.txt'],
+        [script.venv / "build", "cache", script.scratch / "test-req.txt"],
     )
 
 
@@ -308,22 +274,25 @@ def test_uninstall_rollback(script, data):
     crafted to fail on install).
 
     """
-    result = script.pip(
-        'install', '-f', data.find_links, '--no-index', 'broken==0.1'
-    )
-    result.did_create(script.site_packages / 'broken.py')
+    result = script.pip("install", "-f", data.find_links, "--no-index", "broken==0.1")
+    result.did_create(script.site_packages / "broken.py")
     result2 = script.pip(
-        'install', '-f', data.find_links, '--no-index', 'broken===0.2broken',
+        "install",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "broken===0.2broken",
         expect_error=True,
     )
     assert result2.returncode == 1, str(result2)
-    assert script.run(
-        'python', '-c', "import broken; print(broken.VERSION)"
-    ).stdout == '0.1\n'
+    assert (
+        script.run("python", "-c", "import broken; print(broken.VERSION)").stdout
+        == "0.1\n"
+    )
     assert_all_changes(
         result.files_after,
         result2,
-        [script.venv / 'build'],
+        [script.venv / "build"],
     )
 
 
@@ -333,17 +302,11 @@ def test_should_not_install_always_from_cache(script, with_wheel):
     If there is an old cached package, pip should download the newer version
     Related to issue #175
     """
-    script.pip('install', 'INITools==0.2')
-    script.pip('uninstall', '-y', 'INITools')
-    result = script.pip('install', 'INITools==0.1')
-    result.did_not_create(
-        script.site_packages /
-        'INITools-0.2.dist-info'
-    )
-    result.did_create(
-        script.site_packages /
-        'INITools-0.1.dist-info'
-    )
+    script.pip("install", "INITools==0.2")
+    script.pip("uninstall", "-y", "INITools")
+    result = script.pip("install", "INITools==0.1")
+    result.did_not_create(script.site_packages / "INITools-0.2.dist-info")
+    result.did_create(script.site_packages / "INITools-0.1.dist-info")
 
 
 @pytest.mark.network
@@ -351,18 +314,12 @@ def test_install_with_ignoreinstalled_requested(script, with_wheel):
     """
     Test old conflicting package is completely ignored
     """
-    script.pip('install', 'INITools==0.1')
-    result = script.pip('install', '-I', 'INITools==0.3')
-    assert result.files_created, 'pip install -I did not install'
+    script.pip("install", "INITools==0.1")
+    result = script.pip("install", "-I", "INITools==0.3")
+    assert result.files_created, "pip install -I did not install"
     # both the old and new metadata should be present.
-    assert os.path.exists(
-        script.site_packages_path /
-        'INITools-0.1.dist-info'
-    )
-    assert os.path.exists(
-        script.site_packages_path /
-        'INITools-0.3.dist-info'
-    )
+    assert os.path.exists(script.site_packages_path / "INITools-0.1.dist-info")
+    assert os.path.exists(script.site_packages_path / "INITools-0.3.dist-info")
 
 
 @pytest.mark.network
@@ -370,7 +327,8 @@ def test_upgrade_vcs_req_with_no_dists_found(script, tmpdir):
     """It can upgrade a VCS requirement that has no distributions otherwise."""
     req = "{checkout}#egg=pip-test-package".format(
         checkout=local_checkout(
-            "git+https://github.com/pypa/pip-test-package.git", tmpdir,
+            "git+https://github.com/pypa/pip-test-package.git",
+            tmpdir,
         )
     )
     script.pip("install", req)
@@ -383,13 +341,11 @@ def test_upgrade_vcs_req_with_dist_found(script):
     """It can upgrade a VCS requirement that has distributions on the index."""
     # TODO(pnasrat) Using local_checkout fails on windows - oddness with the
     # test path urls/git.
-    req = (
-        "{url}#egg=pretend".format(
-            url=(
-                "git+git://github.com/alex/pretend@e7f26ad7dbcb4a02a4995aade4"
-                "743aad47656b27"
-            ),
-        )
+    req = "{url}#egg=pretend".format(
+        url=(
+            "git+git://github.com/alex/pretend@e7f26ad7dbcb4a02a4995aade4"
+            "743aad47656b27"
+        ),
     )
     script.pip("install", req, expect_stderr=True)
     result = script.pip("install", "-U", req, expect_stderr=True)
@@ -421,31 +377,38 @@ class TestUpgradeDistributeToSetuptools(object):
 
     def prep_ve(self, script, version, pip_src, distribute=False):
         self.script = script
-        self.script.pip_install_local(
-            'virtualenv=={version}'.format(**locals()))
-        args = ['virtualenv', self.script.scratch_path / 'VE']
+        self.script.pip_install_local("virtualenv=={version}".format(**locals()))
+        args = ["virtualenv", self.script.scratch_path / "VE"]
         if distribute:
-            args.insert(1, '--distribute')
+            args.insert(1, "--distribute")
         if version == "1.9.1" and not distribute:
             # setuptools 0.6 didn't support PYTHONDONTWRITEBYTECODE
             del self.script.environ["PYTHONDONTWRITEBYTECODE"]
         self.script.run(*args)
-        if sys.platform == 'win32':
+        if sys.platform == "win32":
             bindir = "Scripts"
         else:
             bindir = "bin"
-        self.ve_bin = self.script.scratch_path / 'VE' / bindir
-        self.script.run(self.ve_bin / 'pip', 'uninstall', '-y', 'pip')
+        self.ve_bin = self.script.scratch_path / "VE" / bindir
+        self.script.run(self.ve_bin / "pip", "uninstall", "-y", "pip")
         self.script.run(
-            self.ve_bin / 'python', 'setup.py', 'install',
+            self.ve_bin / "python",
+            "setup.py",
+            "install",
             cwd=pip_src,
             expect_stderr=True,
         )
 
 
-@pytest.mark.parametrize("req1, req2", list(itertools.product(
-    ["foo.bar", "foo_bar", "foo-bar"], ["foo.bar", "foo_bar", "foo-bar"],
-)))
+@pytest.mark.parametrize(
+    "req1, req2",
+    list(
+        itertools.product(
+            ["foo.bar", "foo_bar", "foo-bar"],
+            ["foo.bar", "foo_bar", "foo-bar"],
+        )
+    ),
+)
 def test_install_find_existing_package_canonicalize(script, req1, req2):
     """Ensure an already-installed dist is found no matter how the dist name
     was normalized on installation. (pypa/pip#8645)
@@ -468,7 +431,11 @@ def test_install_find_existing_package_canonicalize(script, req1, req2):
     # Ensure the previously installed package can be correctly used to match
     # the dependency.
     result = script.pip(
-        "install", "--no-index", "--find-links", pkg_container, "pkg",
+        "install",
+        "--no-index",
+        "--find-links",
+        pkg_container,
+        "pkg",
     )
     satisfied_message = "Requirement already satisfied: {}".format(req2)
     assert satisfied_message in result.stdout, str(result)
diff --git a/tests/functional/test_install_user.py b/tests/functional/test_install_user.py
index c5d7acced80..3cc10eed435 100644
--- a/tests/functional/test_install_user.py
+++ b/tests/functional/test_install_user.py
@@ -17,7 +17,8 @@ def _patch_dist_in_site_packages(virtualenv):
     # error: Monkey patch `pip._internal.req.req_install.dist_in_site_packages`
     # and `pip._internal.resolution.resolvelib.factory.dist_in_site_packages`
     # so it's possible to install a conflicting distribution in the user site.
-    virtualenv.sitecustomize = textwrap.dedent("""
+    virtualenv.sitecustomize = textwrap.dedent(
+        """
         def dist_in_site_packages(dist):
             return False
 
@@ -25,67 +26,71 @@ def dist_in_site_packages(dist):
         from pip._internal.resolution.resolvelib import factory
         req_install.dist_in_site_packages = dist_in_site_packages
         factory.dist_in_site_packages = dist_in_site_packages
-    """)
+    """
+    )
 
 
 class Tests_UserSite:
-
     @pytest.mark.network
     @pytest.mark.incompatible_with_test_venv
     def test_reset_env_system_site_packages_usersite(self, script):
         """
         Check user site works as expected.
         """
-        script.pip('install', '--user', 'INITools==0.2')
+        script.pip("install", "--user", "INITools==0.2")
         result = script.run(
-            'python', '-c',
+            "python",
+            "-c",
             "import pkg_resources; print(pkg_resources.get_distribution"
             "('initools').project_name)",
         )
         project_name = result.stdout.strip()
-        assert 'INITools' == project_name, project_name
+        assert "INITools" == project_name, project_name
 
     @pytest.mark.xfail
     @pytest.mark.network
     @need_svn
     @pytest.mark.incompatible_with_test_venv
-    def test_install_subversion_usersite_editable_with_distribute(
-            self, script, tmpdir):
+    def test_install_subversion_usersite_editable_with_distribute(self, script, tmpdir):
         """
         Test installing current directory ('.') into usersite after installing
         distribute
         """
         result = script.pip(
-            'install', '--user', '-e',
-            '{checkout}#egg=initools'.format(
+            "install",
+            "--user",
+            "-e",
+            "{checkout}#egg=initools".format(
                 checkout=local_checkout(
-                    'svn+http://svn.colorstudy.com/INITools', tmpdir)
-            )
+                    "svn+http://svn.colorstudy.com/INITools", tmpdir
+                )
+            ),
         )
-        result.assert_installed('INITools', use_user_site=True)
+        result.assert_installed("INITools", use_user_site=True)
 
     @pytest.mark.incompatible_with_test_venv
     def test_install_from_current_directory_into_usersite(
-            self, script, data, with_wheel):
+        self, script, data, with_wheel
+    ):
         """
         Test installing current directory ('.') into usersite
         """
         run_from = data.packages.joinpath("FSPkg")
         result = script.pip(
-            'install', '-vvv', '--user', curdir,
+            "install",
+            "-vvv",
+            "--user",
+            curdir,
             cwd=run_from,
         )
 
-        fspkg_folder = script.user_site / 'fspkg'
+        fspkg_folder = script.user_site / "fspkg"
         result.did_create(fspkg_folder)
 
-        dist_info_folder = (
-            script.user_site / 'FSPkg-0.1.dev0.dist-info'
-        )
+        dist_info_folder = script.user_site / "FSPkg-0.1.dev0.dist-info"
         result.did_create(dist_info_folder)
 
-    def test_install_user_venv_nositepkgs_fails(self, virtualenv,
-                                                script, data):
+    def test_install_user_venv_nositepkgs_fails(self, virtualenv, script, data):
         """
         user install in virtualenv (with no system packages) fails with message
         """
@@ -94,7 +99,9 @@ def test_install_user_venv_nositepkgs_fails(self, virtualenv,
         virtualenv.user_site_packages = False
         run_from = data.packages.joinpath("FSPkg")
         result = script.pip(
-            'install', '--user', curdir,
+            "install",
+            "--user",
+            curdir,
             cwd=run_from,
             expect_error=True,
         )
@@ -110,21 +117,21 @@ def test_install_user_conflict_in_usersite(self, script):
         Test user install with conflict in usersite updates usersite.
         """
 
-        script.pip('install', '--user', 'INITools==0.3', '--no-binary=:all:')
+        script.pip("install", "--user", "INITools==0.3", "--no-binary=:all:")
 
-        result2 = script.pip(
-            'install', '--user', 'INITools==0.1', '--no-binary=:all:')
+        result2 = script.pip("install", "--user", "INITools==0.1", "--no-binary=:all:")
 
         # usersite has 0.1
         # we still test for egg-info because no-binary implies setup.py install
         egg_info_folder = (
-            script.user_site /
-            'INITools-0.1-py{pyversion}.egg-info'.format(**globals())
+            script.user_site / "INITools-0.1-py{pyversion}.egg-info".format(**globals())
         )
         initools_v3_file = (
             # file only in 0.3
-            script.base_path / script.user_site / 'initools' /
-            'configparser.py'
+            script.base_path
+            / script.user_site
+            / "initools"
+            / "configparser.py"
         )
         result2.did_create(egg_info_folder)
         assert not isfile(initools_v3_file), initools_v3_file
@@ -138,27 +145,26 @@ def test_install_user_conflict_in_globalsite(self, virtualenv, script):
         """
         _patch_dist_in_site_packages(virtualenv)
 
-        script.pip('install', 'INITools==0.2', '--no-binary=:all:')
+        script.pip("install", "INITools==0.2", "--no-binary=:all:")
 
-        result2 = script.pip(
-            'install', '--user', 'INITools==0.1', '--no-binary=:all:')
+        result2 = script.pip("install", "--user", "INITools==0.1", "--no-binary=:all:")
 
         # usersite has 0.1
         # we still test for egg-info because no-binary implies setup.py install
         egg_info_folder = (
-            script.user_site /
-            'INITools-0.1-py{pyversion}.egg-info'.format(**globals())
+            script.user_site / "INITools-0.1-py{pyversion}.egg-info".format(**globals())
         )
-        initools_folder = script.user_site / 'initools'
+        initools_folder = script.user_site / "initools"
         result2.did_create(egg_info_folder)
         result2.did_create(initools_folder)
 
         # site still has 0.2 (can't look in result1; have to check)
         egg_info_folder = (
-            script.base_path / script.site_packages /
-            'INITools-0.2-py{pyversion}.egg-info'.format(**globals())
+            script.base_path
+            / script.site_packages
+            / "INITools-0.2-py{pyversion}.egg-info".format(**globals())
         )
-        initools_folder = script.base_path / script.site_packages / 'initools'
+        initools_folder = script.base_path / script.site_packages / "initools"
         assert isdir(egg_info_folder)
         assert isdir(initools_folder)
 
@@ -171,85 +177,89 @@ def test_upgrade_user_conflict_in_globalsite(self, virtualenv, script):
         """
         _patch_dist_in_site_packages(virtualenv)
 
-        script.pip('install', 'INITools==0.2', '--no-binary=:all:')
+        script.pip("install", "INITools==0.2", "--no-binary=:all:")
         result2 = script.pip(
-            'install', '--user', '--upgrade', 'INITools', '--no-binary=:all:')
+            "install", "--user", "--upgrade", "INITools", "--no-binary=:all:"
+        )
 
         # usersite has 0.3.1
         # we still test for egg-info because no-binary implies setup.py install
         egg_info_folder = (
-            script.user_site /
-            'INITools-0.3.1-py{pyversion}.egg-info'.format(**globals())
+            script.user_site
+            / "INITools-0.3.1-py{pyversion}.egg-info".format(**globals())
         )
-        initools_folder = script.user_site / 'initools'
+        initools_folder = script.user_site / "initools"
         result2.did_create(egg_info_folder)
         result2.did_create(initools_folder)
 
         # site still has 0.2 (can't look in result1; have to check)
         egg_info_folder = (
-            script.base_path / script.site_packages /
-            'INITools-0.2-py{pyversion}.egg-info'.format(**globals())
+            script.base_path
+            / script.site_packages
+            / "INITools-0.2-py{pyversion}.egg-info".format(**globals())
         )
-        initools_folder = script.base_path / script.site_packages / 'initools'
+        initools_folder = script.base_path / script.site_packages / "initools"
         assert isdir(egg_info_folder), result2.stdout
         assert isdir(initools_folder)
 
     @pytest.mark.network
     @pytest.mark.incompatible_with_test_venv
-    def test_install_user_conflict_in_globalsite_and_usersite(
-            self, virtualenv, script):
+    def test_install_user_conflict_in_globalsite_and_usersite(self, virtualenv, script):
         """
         Test user install with conflict in globalsite and usersite ignores
         global site and updates usersite.
         """
         _patch_dist_in_site_packages(virtualenv)
 
-        script.pip('install', 'INITools==0.2', '--no-binary=:all:')
-        script.pip('install', '--user', 'INITools==0.3', '--no-binary=:all:')
+        script.pip("install", "INITools==0.2", "--no-binary=:all:")
+        script.pip("install", "--user", "INITools==0.3", "--no-binary=:all:")
 
-        result3 = script.pip(
-            'install', '--user', 'INITools==0.1', '--no-binary=:all:')
+        result3 = script.pip("install", "--user", "INITools==0.1", "--no-binary=:all:")
 
         # usersite has 0.1
         # we still test for egg-info because no-binary implies setup.py install
         egg_info_folder = (
-            script.user_site /
-            'INITools-0.1-py{pyversion}.egg-info'.format(**globals())
+            script.user_site / "INITools-0.1-py{pyversion}.egg-info".format(**globals())
         )
         initools_v3_file = (
             # file only in 0.3
-            script.base_path / script.user_site / 'initools' /
-            'configparser.py'
+            script.base_path
+            / script.user_site
+            / "initools"
+            / "configparser.py"
         )
         result3.did_create(egg_info_folder)
         assert not isfile(initools_v3_file), initools_v3_file
 
         # site still has 0.2 (can't just look in result1; have to check)
         egg_info_folder = (
-            script.base_path / script.site_packages /
-            'INITools-0.2-py{pyversion}.egg-info'.format(**globals())
+            script.base_path
+            / script.site_packages
+            / "INITools-0.2-py{pyversion}.egg-info".format(**globals())
         )
-        initools_folder = script.base_path / script.site_packages / 'initools'
+        initools_folder = script.base_path / script.site_packages / "initools"
         assert isdir(egg_info_folder)
         assert isdir(initools_folder)
 
     @pytest.mark.network
     @pytest.mark.incompatible_with_test_venv
-    def test_install_user_in_global_virtualenv_with_conflict_fails(
-            self, script):
+    def test_install_user_in_global_virtualenv_with_conflict_fails(self, script):
         """
         Test user install in --system-site-packages virtualenv with conflict in
         site fails.
         """
 
-        script.pip('install', 'INITools==0.2')
+        script.pip("install", "INITools==0.2")
 
         result2 = script.pip(
-            'install', '--user', 'INITools==0.1',
+            "install",
+            "--user",
+            "INITools==0.1",
             expect_error=True,
         )
         resultp = script.run(
-            'python', '-c',
+            "python",
+            "-c",
             "import pkg_resources; print(pkg_resources.get_distribution"
             "('initools').location)",
         )
@@ -257,7 +267,7 @@ def test_install_user_in_global_virtualenv_with_conflict_fails(
         assert (
             "Will not install to the user site because it will lack sys.path "
             "precedence to {name} in {location}".format(
-                name='INITools',
+                name="INITools",
                 location=dist_location,
             )
             in result2.stderr
diff --git a/tests/functional/test_install_vcs_git.py b/tests/functional/test_install_vcs_git.py
index 59393d34747..c630551ffa3 100644
--- a/tests/functional/test_install_vcs_git.py
+++ b/tests/functional/test_install_vcs_git.py
@@ -18,7 +18,7 @@ def _get_editable_repo_dir(script, package_name):
     """
     Return the repository directory for an editable install.
     """
-    return script.venv_path / 'src' / package_name
+    return script.venv_path / "src" / package_name
 
 
 def _get_editable_branch(script, package_name):
@@ -26,19 +26,15 @@ def _get_editable_branch(script, package_name):
     Return the current branch of an editable install.
     """
     repo_dir = _get_editable_repo_dir(script, package_name)
-    result = script.run(
-        'git', 'rev-parse', '--abbrev-ref', 'HEAD', cwd=repo_dir
-    )
+    result = script.run("git", "rev-parse", "--abbrev-ref", "HEAD", cwd=repo_dir)
     return result.stdout.strip()
 
 
 def _get_branch_remote(script, package_name, branch):
-    """
-
-    """
+    """"""
     repo_dir = _get_editable_repo_dir(script, package_name)
     result = script.run(
-        'git', 'config', 'branch.{}.remote'.format(branch), cwd=repo_dir
+        "git", "config", "branch.{}.remote".format(branch), cwd=repo_dir
     )
     return result.stdout.strip()
 
@@ -56,13 +52,13 @@ def _github_checkout(url_path, temp_dir, rev=None, egg=None, scheme=None):
       scheme: the scheme without the "git+" prefix. Defaults to "https".
     """
     if scheme is None:
-        scheme = 'https'
-    url = 'git+{}://github.com/{}'.format(scheme, url_path)
+        scheme = "https"
+    url = "git+{}://github.com/{}".format(scheme, url_path)
     local_url = local_checkout(url, temp_dir)
     if rev is not None:
-        local_url += '@{}'.format(rev)
+        local_url += "@{}".format(rev)
     if egg is not None:
-        local_url += '#egg={}'.format(egg)
+        local_url += "#egg={}".format(egg)
 
     return local_url
 
@@ -77,8 +73,8 @@ def _make_version_pkg_url(path, rev=None, name="version_pkg"):
       rev: an optional revision to install like a branch name, tag, or SHA.
     """
     file_url = _test_path_to_file_url(path)
-    url_rev = '' if rev is None else '@{}'.format(rev)
-    url = 'git+{}{}#egg={}'.format(file_url, url_rev, name)
+    url_rev = "" if rev is None else "@{}".format(rev)
+    url = "git+{}{}#egg={}".format(file_url, url_rev, name)
 
     return url
 
@@ -94,7 +90,7 @@ def _install_version_pkg_only(script, path, rev=None, expect_stderr=False):
       rev: an optional revision to install like a branch name or tag.
     """
     version_pkg_url = _make_version_pkg_url(path, rev=rev)
-    script.pip('install', '-e', version_pkg_url, expect_stderr=expect_stderr)
+    script.pip("install", "-e", version_pkg_url, expect_stderr=expect_stderr)
 
 
 def _install_version_pkg(script, path, rev=None, expect_stderr=False):
@@ -108,9 +104,12 @@ def _install_version_pkg(script, path, rev=None, expect_stderr=False):
       rev: an optional revision to install like a branch name or tag.
     """
     _install_version_pkg_only(
-        script, path, rev=rev, expect_stderr=expect_stderr,
+        script,
+        path,
+        rev=rev,
+        expect_stderr=expect_stderr,
     )
-    result = script.run('version_pkg')
+    result = script.run("version_pkg")
     version = result.stdout.strip()
 
     return version
@@ -127,11 +126,11 @@ def test_git_install_again_after_changes(script):
     """
     version_pkg_path = _create_test_package(script)
     version = _install_version_pkg(script, version_pkg_path)
-    assert version == '0.1'
+    assert version == "0.1"
 
     _change_test_package_version(script, version_pkg_path)
     version = _install_version_pkg(script, version_pkg_path)
-    assert version == 'some different version'
+    assert version == "some different version"
 
 
 def test_git_install_branch_again_after_branch_changes(script):
@@ -140,12 +139,12 @@ def test_git_install_branch_again_after_branch_changes(script):
     repository.
     """
     version_pkg_path = _create_test_package(script)
-    version = _install_version_pkg(script, version_pkg_path, rev='master')
-    assert version == '0.1'
+    version = _install_version_pkg(script, version_pkg_path, rev="master")
+    assert version == "0.1"
 
     _change_test_package_version(script, version_pkg_path)
-    version = _install_version_pkg(script, version_pkg_path, rev='master')
-    assert version == 'some different version'
+    version = _install_version_pkg(script, version_pkg_path, rev="master")
+    assert version == "some different version"
 
 
 @pytest.mark.network
@@ -153,10 +152,10 @@ def test_install_editable_from_git_with_https(script, tmpdir):
     """
     Test cloning from Git with https.
     """
-    url_path = 'pypa/pip-test-package.git'
-    local_url = _github_checkout(url_path, tmpdir, egg='pip-test-package')
-    result = script.pip('install', '-e', local_url)
-    result.assert_installed('pip-test-package', with_files=['.git'])
+    url_path = "pypa/pip-test-package.git"
+    local_url = _github_checkout(url_path, tmpdir, egg="pip-test-package")
+    result = script.pip("install", "-e", local_url)
+    result.assert_installed("pip-test-package", with_files=[".git"])
 
 
 @pytest.mark.network
@@ -165,17 +164,12 @@ def test_install_noneditable_git(script, tmpdir, with_wheel):
     Test installing from a non-editable git URL with a given tag.
     """
     result = script.pip(
-        'install',
-        'git+https://github.com/pypa/pip-test-package.git'
-        '@0.1.1#egg=pip-test-package'
+        "install",
+        "git+https://github.com/pypa/pip-test-package.git"
+        "@0.1.1#egg=pip-test-package",
     )
-    dist_info_folder = (
-        script.site_packages /
-        'pip_test_package-0.1.1.dist-info'
-    )
-    result.assert_installed('piptestpackage',
-                            without_egg_link=True,
-                            editable=False)
+    dist_info_folder = script.site_packages / "pip_test_package-0.1.1.dist-info"
+    result.assert_installed("piptestpackage", without_egg_link=True, editable=False)
     result.did_create(dist_info_folder)
 
 
@@ -186,11 +180,13 @@ def test_git_with_sha1_revisions(script):
     version_pkg_path = _create_test_package(script)
     _change_test_package_version(script, version_pkg_path)
     sha1 = script.run(
-        'git', 'rev-parse', 'HEAD~1',
+        "git",
+        "rev-parse",
+        "HEAD~1",
         cwd=version_pkg_path,
     ).stdout.strip()
     version = _install_version_pkg(script, version_pkg_path, rev=sha1)
-    assert '0.1' == version
+    assert "0.1" == version
 
 
 def test_git_with_short_sha1_revisions(script):
@@ -200,11 +196,13 @@ def test_git_with_short_sha1_revisions(script):
     version_pkg_path = _create_test_package(script)
     _change_test_package_version(script, version_pkg_path)
     sha1 = script.run(
-        'git', 'rev-parse', 'HEAD~1',
+        "git",
+        "rev-parse",
+        "HEAD~1",
         cwd=version_pkg_path,
     ).stdout.strip()[:7]
     version = _install_version_pkg(script, version_pkg_path, rev=sha1)
-    assert '0.1' == version
+    assert "0.1" == version
 
 
 def test_git_with_branch_name_as_revision(script):
@@ -212,11 +210,11 @@ def test_git_with_branch_name_as_revision(script):
     Git backend should be able to install from branch names
     """
     version_pkg_path = _create_test_package(script)
-    branch = 'test_branch'
-    script.run('git', 'checkout', '-b', branch, cwd=version_pkg_path)
+    branch = "test_branch"
+    script.run("git", "checkout", "-b", branch, cwd=version_pkg_path)
     _change_test_package_version(script, version_pkg_path)
     version = _install_version_pkg(script, version_pkg_path, rev=branch)
-    assert 'some different version' == version
+    assert "some different version" == version
 
 
 def test_git_with_tag_name_as_revision(script):
@@ -224,17 +222,17 @@ def test_git_with_tag_name_as_revision(script):
     Git backend should be able to install from tag names
     """
     version_pkg_path = _create_test_package(script)
-    script.run('git', 'tag', 'test_tag', cwd=version_pkg_path)
+    script.run("git", "tag", "test_tag", cwd=version_pkg_path)
     _change_test_package_version(script, version_pkg_path)
-    version = _install_version_pkg(script, version_pkg_path, rev='test_tag')
-    assert '0.1' == version
+    version = _install_version_pkg(script, version_pkg_path, rev="test_tag")
+    assert "0.1" == version
 
 
 def _add_ref(script, path, ref):
     """
     Add a new ref to a repository at the given path.
     """
-    script.run('git', 'update-ref', ref, 'HEAD', cwd=path)
+    script.run("git", "update-ref", ref, "HEAD", cwd=path)
 
 
 def test_git_install_ref(script):
@@ -242,13 +240,15 @@ def test_git_install_ref(script):
     The Git backend should be able to install a ref with the first install.
     """
     version_pkg_path = _create_test_package(script)
-    _add_ref(script, version_pkg_path, 'refs/foo/bar')
+    _add_ref(script, version_pkg_path, "refs/foo/bar")
     _change_test_package_version(script, version_pkg_path)
 
     version = _install_version_pkg(
-        script, version_pkg_path, rev='refs/foo/bar',
+        script,
+        version_pkg_path,
+        rev="refs/foo/bar",
     )
-    assert '0.1' == version
+    assert "0.1" == version
 
 
 def test_git_install_then_install_ref(script):
@@ -257,17 +257,19 @@ def test_git_install_then_install_ref(script):
     already been installed.
     """
     version_pkg_path = _create_test_package(script)
-    _add_ref(script, version_pkg_path, 'refs/foo/bar')
+    _add_ref(script, version_pkg_path, "refs/foo/bar")
     _change_test_package_version(script, version_pkg_path)
 
     version = _install_version_pkg(script, version_pkg_path)
-    assert 'some different version' == version
+    assert "some different version" == version
 
     # Now install the ref.
     version = _install_version_pkg(
-        script, version_pkg_path, rev='refs/foo/bar',
+        script,
+        version_pkg_path,
+        rev="refs/foo/bar",
     )
-    assert '0.1' == version
+    assert "0.1" == version
 
 
 @pytest.mark.network
@@ -275,18 +277,21 @@ def test_git_with_tag_name_and_update(script, tmpdir):
     """
     Test cloning a git repository and updating to a different version.
     """
-    url_path = 'pypa/pip-test-package.git'
+    url_path = "pypa/pip-test-package.git"
     base_local_url = _github_checkout(url_path, tmpdir)
 
-    local_url = '{}#egg=pip-test-package'.format(base_local_url)
-    result = script.pip('install', '-e', local_url)
-    result.assert_installed('pip-test-package', with_files=['.git'])
+    local_url = "{}#egg=pip-test-package".format(base_local_url)
+    result = script.pip("install", "-e", local_url)
+    result.assert_installed("pip-test-package", with_files=[".git"])
 
-    new_local_url = '{}@0.1.2#egg=pip-test-package'.format(base_local_url)
+    new_local_url = "{}@0.1.2#egg=pip-test-package".format(base_local_url)
     result = script.pip(
-        'install', '--global-option=--version', '-e', new_local_url,
+        "install",
+        "--global-option=--version",
+        "-e",
+        new_local_url,
     )
-    assert '0.1.2' in result.stdout
+    assert "0.1.2" in result.stdout
 
 
 @pytest.mark.network
@@ -295,11 +300,11 @@ def test_git_branch_should_not_be_changed(script, tmpdir):
     Editable installations should not change branch
     related to issue #32 and #161
     """
-    url_path = 'pypa/pip-test-package.git'
-    local_url = _github_checkout(url_path, tmpdir, egg='pip-test-package')
-    script.pip('install', '-e', local_url)
-    branch = _get_editable_branch(script, 'pip-test-package')
-    assert 'master' == branch
+    url_path = "pypa/pip-test-package.git"
+    local_url = _github_checkout(url_path, tmpdir, egg="pip-test-package")
+    script.pip("install", "-e", local_url)
+    branch = _get_editable_branch(script, "pip-test-package")
+    assert "master" == branch
 
 
 @pytest.mark.network
@@ -307,12 +312,15 @@ def test_git_with_non_editable_unpacking(script, tmpdir):
     """
     Test cloning a git repository from a non-editable URL with a given tag.
     """
-    url_path = 'pypa/pip-test-package.git'
+    url_path = "pypa/pip-test-package.git"
     local_url = _github_checkout(
-        url_path, tmpdir, rev='0.1.2', egg='pip-test-package',
+        url_path,
+        tmpdir,
+        rev="0.1.2",
+        egg="pip-test-package",
     )
-    result = script.pip('install', '--global-option=--version', local_url)
-    assert '0.1.2' in result.stdout
+    result = script.pip("install", "--global-option=--version", local_url)
+    assert "0.1.2" in result.stdout
 
 
 @pytest.mark.network
@@ -321,12 +329,15 @@ def test_git_with_editable_where_egg_contains_dev_string(script, tmpdir):
     Test cloning a git repository from an editable url which contains "dev"
     string
     """
-    url_path = 'dcramer/django-devserver.git'
+    url_path = "dcramer/django-devserver.git"
     local_url = _github_checkout(
-        url_path, tmpdir, egg='django-devserver', scheme='git',
+        url_path,
+        tmpdir,
+        egg="django-devserver",
+        scheme="git",
     )
-    result = script.pip('install', '-e', local_url)
-    result.assert_installed('django-devserver', with_files=['.git'])
+    result = script.pip("install", "-e", local_url)
+    result.assert_installed("django-devserver", with_files=[".git"])
 
 
 @pytest.mark.network
@@ -335,12 +346,15 @@ def test_git_with_non_editable_where_egg_contains_dev_string(script, tmpdir):
     Test cloning a git repository from a non-editable url which contains "dev"
     string
     """
-    url_path = 'dcramer/django-devserver.git'
+    url_path = "dcramer/django-devserver.git"
     local_url = _github_checkout(
-        url_path, tmpdir, egg='django-devserver', scheme='git',
+        url_path,
+        tmpdir,
+        egg="django-devserver",
+        scheme="git",
     )
-    result = script.pip('install', local_url)
-    devserver_folder = script.site_packages / 'devserver'
+    result = script.pip("install", local_url)
+    devserver_folder = script.site_packages / "devserver"
     result.did_create(devserver_folder)
 
 
@@ -349,13 +363,13 @@ def test_git_with_ambiguous_revs(script):
     Test git with two "names" (tag/branch) pointing to the same commit
     """
     version_pkg_path = _create_test_package(script)
-    version_pkg_url = _make_version_pkg_url(version_pkg_path, rev='0.1')
-    script.run('git', 'tag', '0.1', cwd=version_pkg_path)
-    result = script.pip('install', '-e', version_pkg_url)
-    assert 'Could not find a tag or branch' not in result.stdout
+    version_pkg_url = _make_version_pkg_url(version_pkg_path, rev="0.1")
+    script.run("git", "tag", "0.1", cwd=version_pkg_path)
+    result = script.pip("install", "-e", version_pkg_url)
+    assert "Could not find a tag or branch" not in result.stdout
     # it is 'version-pkg' instead of 'version_pkg' because
     # egg-link name is version-pkg.egg-link because it is a single .py module
-    result.assert_installed('version-pkg', with_files=['.git'])
+    result.assert_installed("version-pkg", with_files=[".git"])
 
 
 def test_editable__no_revision(script):
@@ -365,11 +379,11 @@ def test_editable__no_revision(script):
     version_pkg_path = _create_test_package(script)
     _install_version_pkg_only(script, version_pkg_path)
 
-    branch = _get_editable_branch(script, 'version-pkg')
-    assert branch == 'master'
+    branch = _get_editable_branch(script, "version-pkg")
+    assert branch == "master"
 
-    remote = _get_branch_remote(script, 'version-pkg', 'master')
-    assert remote == 'origin'
+    remote = _get_branch_remote(script, "version-pkg", "master")
+    assert remote == "origin"
 
 
 def test_editable__branch_with_sha_same_as_default(script):
@@ -379,14 +393,14 @@ def test_editable__branch_with_sha_same_as_default(script):
     """
     version_pkg_path = _create_test_package(script)
     # Create a second branch with the same SHA.
-    script.run('git', 'branch', 'develop', cwd=version_pkg_path)
-    _install_version_pkg_only(script, version_pkg_path, rev='develop')
+    script.run("git", "branch", "develop", cwd=version_pkg_path)
+    _install_version_pkg_only(script, version_pkg_path, rev="develop")
 
-    branch = _get_editable_branch(script, 'version-pkg')
-    assert branch == 'develop'
+    branch = _get_editable_branch(script, "version-pkg")
+    assert branch == "develop"
 
-    remote = _get_branch_remote(script, 'version-pkg', 'develop')
-    assert remote == 'origin'
+    remote = _get_branch_remote(script, "version-pkg", "develop")
+    assert remote == "origin"
 
 
 def test_editable__branch_with_sha_different_from_default(script):
@@ -396,18 +410,18 @@ def test_editable__branch_with_sha_different_from_default(script):
     """
     version_pkg_path = _create_test_package(script)
     # Create a second branch.
-    script.run('git', 'branch', 'develop', cwd=version_pkg_path)
+    script.run("git", "branch", "develop", cwd=version_pkg_path)
     # Add another commit to the master branch to give it a different sha.
     _change_test_package_version(script, version_pkg_path)
 
-    version = _install_version_pkg(script, version_pkg_path, rev='develop')
-    assert version == '0.1'
+    version = _install_version_pkg(script, version_pkg_path, rev="develop")
+    assert version == "0.1"
 
-    branch = _get_editable_branch(script, 'version-pkg')
-    assert branch == 'develop'
+    branch = _get_editable_branch(script, "version-pkg")
+    assert branch == "develop"
 
-    remote = _get_branch_remote(script, 'version-pkg', 'develop')
-    assert remote == 'origin'
+    remote = _get_branch_remote(script, "version-pkg", "develop")
+    assert remote == "origin"
 
 
 def test_editable__non_master_default_branch(script):
@@ -418,11 +432,11 @@ def test_editable__non_master_default_branch(script):
     version_pkg_path = _create_test_package(script)
     # Change the default branch of the remote repo to a name that is
     # alphabetically after "master".
-    script.run('git', 'checkout', '-b', 'release', cwd=version_pkg_path)
+    script.run("git", "checkout", "-b", "release", cwd=version_pkg_path)
     _install_version_pkg_only(script, version_pkg_path)
 
-    branch = _get_editable_branch(script, 'version-pkg')
-    assert branch == 'release'
+    branch = _get_editable_branch(script, "version-pkg")
+    assert branch == "release"
 
 
 def test_reinstalling_works_with_editable_non_master_branch(script):
@@ -433,14 +447,14 @@ def test_reinstalling_works_with_editable_non_master_branch(script):
     version_pkg_path = _create_test_package(script)
 
     # Switch the default branch to something other than 'master'
-    script.run('git', 'branch', '-m', 'foobar', cwd=version_pkg_path)
+    script.run("git", "branch", "-m", "foobar", cwd=version_pkg_path)
 
     version = _install_version_pkg(script, version_pkg_path)
-    assert '0.1' == version
+    assert "0.1" == version
 
     _change_test_package_version(script, version_pkg_path)
     version = _install_version_pkg(script, version_pkg_path)
-    assert 'some different version' == version
+    assert "some different version" == version
 
 
 # TODO(pnasrat) fix all helpers to do right things with paths on windows.
@@ -449,31 +463,31 @@ def test_check_submodule_addition(script):
     """
     Submodules are pulled in on install and updated on upgrade.
     """
-    module_path, submodule_path = (
-        _create_test_package_with_submodule(script, rel_path='testpkg/static')
+    module_path, submodule_path = _create_test_package_with_submodule(
+        script, rel_path="testpkg/static"
     )
 
     install_result = script.pip(
-        'install', '-e', 'git+' + module_path + '#egg=version_pkg'
-    )
-    install_result.did_create(
-        script.venv / 'src/version-pkg/testpkg/static/testfile'
+        "install", "-e", "git+" + module_path + "#egg=version_pkg"
     )
+    install_result.did_create(script.venv / "src/version-pkg/testpkg/static/testfile")
 
     _change_test_package_submodule(script, submodule_path)
     _pull_in_submodule_changes_to_module(
-        script, module_path, rel_path='testpkg/static',
+        script,
+        module_path,
+        rel_path="testpkg/static",
     )
 
     # expect error because git may write to stderr
     update_result = script.pip(
-        'install', '-e', 'git+' + module_path + '#egg=version_pkg',
-        '--upgrade',
+        "install",
+        "-e",
+        "git+" + module_path + "#egg=version_pkg",
+        "--upgrade",
     )
 
-    update_result.did_create(
-        script.venv / 'src/version-pkg/testpkg/static/testfile2'
-    )
+    update_result.did_create(script.venv / "src/version-pkg/testpkg/static/testfile2")
 
 
 def test_install_git_branch_not_cached(script, with_wheel):
@@ -488,9 +502,7 @@ def test_install_git_branch_not_cached(script, with_wheel):
     script.pip("uninstall", "-y", PKG)
     # build occurs on the second install too because it is not cached
     result = script.pip("install", url)
-    assert (
-        "Successfully built {}".format(PKG) in result.stdout
-    ), result.stdout
+    assert "Successfully built {}".format(PKG) in result.stdout, result.stdout
 
 
 def test_install_git_sha_cached(script, with_wheel):
@@ -499,15 +511,11 @@ def test_install_git_sha_cached(script, with_wheel):
     """
     PKG = "gitshacached"
     repo_dir = _create_test_package(script, name=PKG)
-    commit = script.run(
-        'git', 'rev-parse', 'HEAD', cwd=repo_dir
-    ).stdout.strip()
+    commit = script.run("git", "rev-parse", "HEAD", cwd=repo_dir).stdout.strip()
     url = _make_version_pkg_url(repo_dir, rev=commit, name=PKG)
     result = script.pip("install", url)
     assert "Successfully built {}".format(PKG) in result.stdout, result.stdout
     script.pip("uninstall", "-y", PKG)
     # build does not occur on the second install because it is cached
     result = script.pip("install", url)
-    assert (
-        "Successfully built {}".format(PKG) not in result.stdout
-    ), result.stdout
+    assert "Successfully built {}".format(PKG) not in result.stdout, result.stdout
diff --git a/tests/functional/test_install_wheel.py b/tests/functional/test_install_wheel.py
index ad4e749676f..90422527746 100644
--- a/tests/functional/test_install_wheel.py
+++ b/tests/functional/test_install_wheel.py
@@ -27,27 +27,24 @@ def test_install_from_future_wheel_version(script, tmpdir):
     - a minor version ahead of what we expect (ok)
     """
     from tests.lib import TestFailure
+
     package = make_wheel_with_file(
         name="futurewheel",
         version="3.0",
         wheel_metadata_updates={"Wheel-Version": "3.0"},
     ).save_to_dir(tmpdir)
 
-    result = script.pip('install', package, '--no-index', expect_error=True)
+    result = script.pip("install", package, "--no-index", expect_error=True)
     with pytest.raises(TestFailure):
-        result.assert_installed('futurewheel', without_egg_link=True,
-                                editable=False)
+        result.assert_installed("futurewheel", without_egg_link=True, editable=False)
 
     package = make_wheel_with_file(
         name="futurewheel",
         version="1.9",
         wheel_metadata_updates={"Wheel-Version": "1.9"},
     ).save_to_dir(tmpdir)
-    result = script.pip(
-        'install', package, '--no-index', expect_stderr=True
-    )
-    result.assert_installed('futurewheel', without_egg_link=True,
-                            editable=False)
+    result = script.pip("install", package, "--no-index", expect_stderr=True)
+    result.assert_installed("futurewheel", without_egg_link=True, editable=False)
 
 
 def test_install_from_broken_wheel(script, data):
@@ -55,27 +52,28 @@ def test_install_from_broken_wheel(script, data):
     Test that installing a broken wheel fails properly
     """
     from tests.lib import TestFailure
+
     package = data.packages.joinpath("brokenwheel-1.0-py2.py3-none-any.whl")
-    result = script.pip('install', package, '--no-index', expect_error=True)
+    result = script.pip("install", package, "--no-index", expect_error=True)
     with pytest.raises(TestFailure):
-        result.assert_installed('futurewheel', without_egg_link=True,
-                                editable=False)
+        result.assert_installed("futurewheel", without_egg_link=True, editable=False)
 
 
 def test_basic_install_from_wheel(script, shared_data, tmpdir):
     """
     Test installing from a wheel (that has a script)
     """
-    shutil.copy(
-        shared_data.packages / "has.script-1.0-py2.py3-none-any.whl", tmpdir
-    )
+    shutil.copy(shared_data.packages / "has.script-1.0-py2.py3-none-any.whl", tmpdir)
     result = script.pip(
-        'install', 'has.script==1.0', '--no-index',
-        '--find-links', tmpdir,
+        "install",
+        "has.script==1.0",
+        "--no-index",
+        "--find-links",
+        tmpdir,
     )
-    dist_info_folder = script.site_packages / 'has.script-1.0.dist-info'
+    dist_info_folder = script.site_packages / "has.script-1.0.dist-info"
     result.did_create(dist_info_folder)
-    script_file = script.bin / 'script.py'
+    script_file = script.bin / "script.py"
     result.did_create(script_file)
 
 
@@ -83,19 +81,18 @@ def test_basic_install_from_wheel_with_extras(script, shared_data, tmpdir):
     """
     Test installing from a wheel with extras.
     """
-    shutil.copy(
-        shared_data.packages / "complex_dist-0.1-py2.py3-none-any.whl", tmpdir
-    )
-    shutil.copy(
-        shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir
-    )
+    shutil.copy(shared_data.packages / "complex_dist-0.1-py2.py3-none-any.whl", tmpdir)
+    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir)
     result = script.pip(
-        'install', 'complex-dist[simple]', '--no-index',
-        '--find-links', tmpdir,
+        "install",
+        "complex-dist[simple]",
+        "--no-index",
+        "--find-links",
+        tmpdir,
     )
-    dist_info_folder = script.site_packages / 'complex_dist-0.1.dist-info'
+    dist_info_folder = script.site_packages / "complex_dist-0.1.dist-info"
     result.did_create(dist_info_folder)
-    dist_info_folder = script.site_packages / 'simple.dist-0.1.dist-info'
+    dist_info_folder = script.site_packages / "simple.dist-0.1.dist-info"
     result.did_create(dist_info_folder)
 
 
@@ -104,15 +101,15 @@ def test_basic_install_from_wheel_file(script, data):
     Test installing directly from a wheel file.
     """
     package = data.packages.joinpath("simple.dist-0.1-py2.py3-none-any.whl")
-    result = script.pip('install', package, '--no-index')
-    dist_info_folder = script.site_packages / 'simple.dist-0.1.dist-info'
+    result = script.pip("install", package, "--no-index")
+    dist_info_folder = script.site_packages / "simple.dist-0.1.dist-info"
     result.did_create(dist_info_folder)
-    installer = dist_info_folder / 'INSTALLER'
+    installer = dist_info_folder / "INSTALLER"
     result.did_create(installer)
-    with open(script.base_path / installer, 'rb') as installer_file:
+    with open(script.base_path / installer, "rb") as installer_file:
         installer_details = installer_file.read()
-        assert installer_details == b'pip\n'
-    installer_temp = dist_info_folder / 'INSTALLER.pip'
+        assert installer_details == b"pip\n"
+    installer_temp = dist_info_folder / "INSTALLER.pip"
     result.did_not_create(installer_temp)
 
 
@@ -124,25 +121,28 @@ def test_basic_install_from_unicode_wheel(script, data):
     Test installing from a wheel (that has a script)
     """
     make_wheel(
-        'unicode_package',
-        '1.0',
+        "unicode_package",
+        "1.0",
         extra_files={
-            'வணக�கம�/__init__.py': b'',
-            'வணக�கம�/નમસ�તે.py': b'',
+            "வணக�கம�/__init__.py": b"",
+            "வணக�கம�/નમસ�તે.py": b"",
         },
     ).save_to_dir(script.scratch_path)
 
     result = script.pip(
-        'install', 'unicode_package==1.0', '--no-index',
-        '--find-links', script.scratch_path,
+        "install",
+        "unicode_package==1.0",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
     )
-    dist_info_folder = script.site_packages / 'unicode_package-1.0.dist-info'
+    dist_info_folder = script.site_packages / "unicode_package-1.0.dist-info"
     result.did_create(dist_info_folder)
 
-    file1 = script.site_packages.joinpath('வணக�கம�', '__init__.py')
+    file1 = script.site_packages.joinpath("வணக�கம�", "__init__.py")
     result.did_create(file1)
 
-    file2 = script.site_packages.joinpath('வணக�கம�', 'નમસ�તે.py')
+    file2 = script.site_packages.joinpath("வணக�கம�", "નમસ�તે.py")
     result.did_create(file2)
 
 
@@ -152,7 +152,7 @@ def get_header_scheme_path_for_script(script, dist_name):
         "scheme = get_scheme({!r});"
         "print(scheme.headers);"
     ).format(dist_name)
-    result = script.run('python', '-c', command).stdout
+    result = script.run("python", "-c", command).stdout
     return Path(result.strip())
 
 
@@ -160,22 +160,18 @@ def test_install_from_wheel_with_headers(script):
     """
     Test installing from a wheel file with headers
     """
-    header_text = '/* hello world */\n'
+    header_text = "/* hello world */\n"
     package = make_wheel(
-        'headers.dist',
-        '0.1',
-        extra_data_files={
-            'headers/header.h': header_text
-        },
+        "headers.dist",
+        "0.1",
+        extra_data_files={"headers/header.h": header_text},
     ).save_to_dir(script.scratch_path)
-    result = script.pip('install', package, '--no-index')
-    dist_info_folder = script.site_packages / 'headers.dist-0.1.dist-info'
+    result = script.pip("install", package, "--no-index")
+    dist_info_folder = script.site_packages / "headers.dist-0.1.dist-info"
     result.did_create(dist_info_folder)
 
-    header_scheme_path = get_header_scheme_path_for_script(
-        script, 'headers.dist'
-    )
-    header_path = header_scheme_path / 'header.h'
+    header_scheme_path = get_header_scheme_path_for_script(script, "headers.dist")
+    header_path = header_scheme_path / "header.h"
     assert header_path.read_text() == header_text
 
 
@@ -183,15 +179,18 @@ def test_install_wheel_with_target(script, shared_data, with_wheel, tmpdir):
     """
     Test installing a wheel using pip install --target
     """
-    shutil.copy(
-        shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir
-    )
-    target_dir = script.scratch_path / 'target'
+    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir)
+    target_dir = script.scratch_path / "target"
     result = script.pip(
-        'install', 'simple.dist==0.1', '-t', target_dir,
-        '--no-index', '--find-links', tmpdir,
+        "install",
+        "simple.dist==0.1",
+        "-t",
+        target_dir,
+        "--no-index",
+        "--find-links",
+        tmpdir,
     )
-    result.did_create(Path('scratch') / 'target' / 'simpledist')
+    result.did_create(Path("scratch") / "target" / "simpledist")
 
 
 def test_install_wheel_with_target_and_data_files(script, data, with_wheel):
@@ -213,47 +212,49 @@ def test_install_wheel_with_target_and_data_files(script, data, with_wheel):
             ]
         )
     """
-    target_dir = script.scratch_path / 'prjwithdatafile'
-    package = data.packages.joinpath(
-        "prjwithdatafile-1.0-py2.py3-none-any.whl"
-    )
-    result = script.pip('install', package,
-                        '-t', target_dir,
-                        '--no-index')
-    project_path = Path('scratch') / 'prjwithdatafile'
-    result.did_create(project_path / 'packages1' / 'README.txt')
-    result.did_create(project_path / 'packages2' / 'README.txt')
-    result.did_not_create(project_path / 'lib' / 'python')
+    target_dir = script.scratch_path / "prjwithdatafile"
+    package = data.packages.joinpath("prjwithdatafile-1.0-py2.py3-none-any.whl")
+    result = script.pip("install", package, "-t", target_dir, "--no-index")
+    project_path = Path("scratch") / "prjwithdatafile"
+    result.did_create(project_path / "packages1" / "README.txt")
+    result.did_create(project_path / "packages2" / "README.txt")
+    result.did_not_create(project_path / "lib" / "python")
 
 
 def test_install_wheel_with_root(script, shared_data, tmpdir):
     """
     Test installing a wheel using pip install --root
     """
-    root_dir = script.scratch_path / 'root'
-    shutil.copy(
-        shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir
-    )
+    root_dir = script.scratch_path / "root"
+    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir)
     result = script.pip(
-        'install', 'simple.dist==0.1', '--root', root_dir,
-        '--no-index', '--find-links', tmpdir,
+        "install",
+        "simple.dist==0.1",
+        "--root",
+        root_dir,
+        "--no-index",
+        "--find-links",
+        tmpdir,
     )
-    result.did_create(Path('scratch') / 'root')
+    result.did_create(Path("scratch") / "root")
 
 
 def test_install_wheel_with_prefix(script, shared_data, tmpdir):
     """
     Test installing a wheel using pip install --prefix
     """
-    prefix_dir = script.scratch_path / 'prefix'
-    shutil.copy(
-        shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir
-    )
+    prefix_dir = script.scratch_path / "prefix"
+    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir)
     result = script.pip(
-        'install', 'simple.dist==0.1', '--prefix', prefix_dir,
-        '--no-index', '--find-links', tmpdir,
+        "install",
+        "simple.dist==0.1",
+        "--prefix",
+        prefix_dir,
+        "--no-index",
+        "--find-links",
+        tmpdir,
     )
-    lib = distutils.sysconfig.get_python_lib(prefix=Path('scratch') / 'prefix')
+    lib = distutils.sysconfig.get_python_lib(prefix=Path("scratch") / "prefix")
     result.did_create(lib)
 
 
@@ -262,14 +263,16 @@ def test_install_from_wheel_installs_deps(script, data, tmpdir):
     Test can install dependencies of wheels
     """
     # 'requires_source' depends on the 'source' project
-    package = data.packages.joinpath(
-        "requires_source-1.0-py2.py3-none-any.whl"
-    )
+    package = data.packages.joinpath("requires_source-1.0-py2.py3-none-any.whl")
     shutil.copy(data.packages / "source-1.0.tar.gz", tmpdir)
     result = script.pip(
-        'install', '--no-index', '--find-links', tmpdir, package,
+        "install",
+        "--no-index",
+        "--find-links",
+        tmpdir,
+        package,
     )
-    result.assert_installed('source', editable=False)
+    result.assert_installed("source", editable=False)
 
 
 def test_install_from_wheel_no_deps(script, data, tmpdir):
@@ -277,32 +280,32 @@ def test_install_from_wheel_no_deps(script, data, tmpdir):
     Test --no-deps works with wheel installs
     """
     # 'requires_source' depends on the 'source' project
-    package = data.packages.joinpath(
-        "requires_source-1.0-py2.py3-none-any.whl"
-    )
+    package = data.packages.joinpath("requires_source-1.0-py2.py3-none-any.whl")
     shutil.copy(data.packages / "source-1.0.tar.gz", tmpdir)
     result = script.pip(
-        'install', '--no-index', '--find-links', tmpdir, '--no-deps',
+        "install",
+        "--no-index",
+        "--find-links",
+        tmpdir,
+        "--no-deps",
         package,
     )
-    pkg_folder = script.site_packages / 'source'
+    pkg_folder = script.site_packages / "source"
     result.did_not_create(pkg_folder)
 
 
 def test_wheel_record_lines_in_deterministic_order(script, data):
     to_install = data.packages.joinpath("simplewheel-1.0-py2.py3-none-any.whl")
-    result = script.pip('install', to_install)
+    result = script.pip("install", to_install)
 
-    dist_info_folder = script.site_packages / 'simplewheel-1.0.dist-info'
-    record_path = dist_info_folder / 'RECORD'
+    dist_info_folder = script.site_packages / "simplewheel-1.0.dist-info"
+    record_path = dist_info_folder / "RECORD"
 
     result.did_create(dist_info_folder)
     result.did_create(record_path)
 
     record_path = result.files_created[record_path].full
-    record_lines = [
-        p for p in Path(record_path).read_text().split('\n') if p
-    ]
+    record_lines = [p for p in Path(record_path).read_text().split("\n") if p]
     assert record_lines == sorted(record_lines)
 
 
@@ -315,16 +318,13 @@ def test_wheel_record_lines_have_hash_for_data_files(script):
         },
     ).save_to_dir(script.scratch_path)
     script.pip("install", package)
-    record_file = (
-        script.site_packages_path / "simple-0.1.0.dist-info" / "RECORD"
-    )
+    record_file = script.site_packages_path / "simple-0.1.0.dist-info" / "RECORD"
     record_text = record_file.read_text()
     record_rows = list(csv.reader(record_text.splitlines()))
-    records = {
-        r[0]: r[1:] for r in record_rows
-    }
+    records = {r[0]: r[1:] for r in record_rows}
     assert records["info.txt"] == [
-        "sha256=Ln0sA6lQeuJl7PW1NWiFpTOTogKdJBOUmXJloaJa78Y", "1"
+        "sha256=Ln0sA6lQeuJl7PW1NWiFpTOTogKdJBOUmXJloaJa78Y",
+        "1",
     ]
 
 
@@ -333,16 +333,18 @@ def test_install_user_wheel(script, shared_data, with_wheel, tmpdir):
     """
     Test user install from wheel (that has a script)
     """
-    shutil.copy(
-        shared_data.packages / "has.script-1.0-py2.py3-none-any.whl", tmpdir
-    )
+    shutil.copy(shared_data.packages / "has.script-1.0-py2.py3-none-any.whl", tmpdir)
     result = script.pip(
-        'install', 'has.script==1.0', '--user', '--no-index',
-        '--find-links', tmpdir,
+        "install",
+        "has.script==1.0",
+        "--user",
+        "--no-index",
+        "--find-links",
+        tmpdir,
     )
-    dist_info_folder = script.user_site / 'has.script-1.0.dist-info'
+    dist_info_folder = script.user_site / "has.script-1.0.dist-info"
     result.did_create(dist_info_folder)
-    script_file = script.user_bin / 'script.py'
+    script_file = script.user_bin / "script.py"
     result.did_create(script_file)
 
 
@@ -355,39 +357,42 @@ def test_install_from_wheel_gen_entrypoint(script, shared_data, tmpdir):
         tmpdir,
     )
     result = script.pip(
-        'install', 'script.wheel1a==0.1', '--no-index',
-        '--find-links', tmpdir,
+        "install",
+        "script.wheel1a==0.1",
+        "--no-index",
+        "--find-links",
+        tmpdir,
     )
-    if os.name == 'nt':
-        wrapper_file = script.bin / 't1.exe'
+    if os.name == "nt":
+        wrapper_file = script.bin / "t1.exe"
     else:
-        wrapper_file = script.bin / 't1'
+        wrapper_file = script.bin / "t1"
     result.did_create(wrapper_file)
 
     if os.name != "nt":
         assert bool(os.access(script.base_path / wrapper_file, os.X_OK))
 
 
-def test_install_from_wheel_gen_uppercase_entrypoint(
-    script, shared_data, tmpdir
-):
+def test_install_from_wheel_gen_uppercase_entrypoint(script, shared_data, tmpdir):
     """
     Test installing scripts with uppercase letters in entry point names
     """
     shutil.copy(
-        shared_data.packages /
-        "console_scripts_uppercase-1.0-py2.py3-none-any.whl",
+        shared_data.packages / "console_scripts_uppercase-1.0-py2.py3-none-any.whl",
         tmpdir,
     )
     result = script.pip(
-        'install', 'console-scripts-uppercase==1.0', '--no-index',
-        '--find-links', tmpdir,
+        "install",
+        "console-scripts-uppercase==1.0",
+        "--no-index",
+        "--find-links",
+        tmpdir,
     )
-    if os.name == 'nt':
+    if os.name == "nt":
         # Case probably doesn't make any difference on NT
-        wrapper_file = script.bin / 'cmdName.exe'
+        wrapper_file = script.bin / "cmdName.exe"
     else:
-        wrapper_file = script.bin / 'cmdName'
+        wrapper_file = script.bin / "cmdName"
     result.did_create(wrapper_file)
 
     if os.name != "nt":
@@ -425,36 +430,38 @@ def test_install_from_wheel_with_legacy(script, shared_data, tmpdir):
         tmpdir,
     )
     result = script.pip(
-        'install', 'script.wheel2a==0.1', '--no-index',
-        '--find-links', tmpdir,
+        "install",
+        "script.wheel2a==0.1",
+        "--no-index",
+        "--find-links",
+        tmpdir,
     )
 
-    legacy_file1 = script.bin / 'testscript1.bat'
-    legacy_file2 = script.bin / 'testscript2'
+    legacy_file1 = script.bin / "testscript1.bat"
+    legacy_file2 = script.bin / "testscript2"
 
     result.did_create(legacy_file1)
     result.did_create(legacy_file2)
 
 
-def test_install_from_wheel_no_setuptools_entrypoint(
-    script, shared_data, tmpdir
-):
+def test_install_from_wheel_no_setuptools_entrypoint(script, shared_data, tmpdir):
     """
     Test that when we generate scripts, any existing setuptools wrappers in
     the wheel are skipped.
     """
-    shutil.copy(
-        shared_data.packages / "script.wheel1-0.1-py2.py3-none-any.whl", tmpdir
-    )
+    shutil.copy(shared_data.packages / "script.wheel1-0.1-py2.py3-none-any.whl", tmpdir)
     result = script.pip(
-        'install', 'script.wheel1==0.1', '--no-index',
-        '--find-links', tmpdir,
+        "install",
+        "script.wheel1==0.1",
+        "--no-index",
+        "--find-links",
+        tmpdir,
     )
-    if os.name == 'nt':
-        wrapper_file = script.bin / 't1.exe'
+    if os.name == "nt":
+        wrapper_file = script.bin / "t1.exe"
     else:
-        wrapper_file = script.bin / 't1'
-    wrapper_helper = script.bin / 't1-script.py'
+        wrapper_file = script.bin / "t1"
+    wrapper_helper = script.bin / "t1-script.py"
 
     # The wheel has t1.exe and t1-script.py. We will be generating t1 or
     # t1.exe depending on the platform. So we check that the correct wrapper
@@ -470,17 +477,18 @@ def test_skipping_setuptools_doesnt_skip_legacy(script, shared_data, tmpdir):
     Test installing scripts (legacy scripts are preserved even when we skip
     setuptools wrappers)
     """
-    shutil.copy(
-        shared_data.packages / "script.wheel2-0.1-py2.py3-none-any.whl", tmpdir
-    )
+    shutil.copy(shared_data.packages / "script.wheel2-0.1-py2.py3-none-any.whl", tmpdir)
     result = script.pip(
-        'install', 'script.wheel2==0.1', '--no-index',
-        '--find-links', tmpdir,
+        "install",
+        "script.wheel2==0.1",
+        "--no-index",
+        "--find-links",
+        tmpdir,
     )
 
-    legacy_file1 = script.bin / 'testscript1.bat'
-    legacy_file2 = script.bin / 'testscript2'
-    wrapper_helper = script.bin / 't1-script.py'
+    legacy_file1 = script.bin / "testscript1.bat"
+    legacy_file2 = script.bin / "testscript2"
+    wrapper_helper = script.bin / "t1-script.py"
 
     result.did_create(legacy_file1)
     result.did_create(legacy_file2)
@@ -491,17 +499,18 @@ def test_install_from_wheel_gui_entrypoint(script, shared_data, tmpdir):
     """
     Test installing scripts (gui entry points are generated)
     """
-    shutil.copy(
-        shared_data.packages / "script.wheel3-0.1-py2.py3-none-any.whl", tmpdir
-    )
+    shutil.copy(shared_data.packages / "script.wheel3-0.1-py2.py3-none-any.whl", tmpdir)
     result = script.pip(
-        'install', 'script.wheel3==0.1', '--no-index',
-        '--find-links', tmpdir,
+        "install",
+        "script.wheel3==0.1",
+        "--no-index",
+        "--find-links",
+        tmpdir,
     )
-    if os.name == 'nt':
-        wrapper_file = script.bin / 't1.exe'
+    if os.name == "nt":
+        wrapper_file = script.bin / "t1.exe"
     else:
-        wrapper_file = script.bin / 't1'
+        wrapper_file = script.bin / "t1"
     result.did_create(wrapper_file)
 
 
@@ -509,12 +518,14 @@ def test_wheel_compiles_pyc(script, shared_data, tmpdir):
     """
     Test installing from wheel with --compile on
     """
-    shutil.copy(
-        shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir
-    )
+    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir)
     script.pip(
-        "install", "--compile", "simple.dist==0.1", "--no-index",
-        "--find-links", tmpdir,
+        "install",
+        "--compile",
+        "simple.dist==0.1",
+        "--no-index",
+        "--find-links",
+        tmpdir,
     )
     # There are many locations for the __init__.pyc file so attempt to find
     #   any of them
@@ -533,12 +544,14 @@ def test_wheel_no_compiles_pyc(script, shared_data, tmpdir):
     """
     Test installing from wheel with --compile on
     """
-    shutil.copy(
-        shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir
-    )
+    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir)
     script.pip(
-        "install", "--no-compile", "simple.dist==0.1", "--no-index",
-        "--find-links", tmpdir,
+        "install",
+        "--no-compile",
+        "simple.dist==0.1",
+        "--no-index",
+        "--find-links",
+        tmpdir,
     )
     # There are many locations for the __init__.pyc file so attempt to find
     #   any of them
@@ -556,28 +569,27 @@ def test_wheel_no_compiles_pyc(script, shared_data, tmpdir):
 def test_install_from_wheel_uninstalls_old_version(script, data):
     # regression test for https://github.com/pypa/pip/issues/1825
     package = data.packages.joinpath("simplewheel-1.0-py2.py3-none-any.whl")
-    result = script.pip('install', package, '--no-index')
+    result = script.pip("install", package, "--no-index")
     package = data.packages.joinpath("simplewheel-2.0-py2.py3-none-any.whl")
-    result = script.pip('install', package, '--no-index')
-    dist_info_folder = script.site_packages / 'simplewheel-2.0.dist-info'
+    result = script.pip("install", package, "--no-index")
+    dist_info_folder = script.site_packages / "simplewheel-2.0.dist-info"
     result.did_create(dist_info_folder)
-    dist_info_folder = script.site_packages / 'simplewheel-1.0.dist-info'
+    dist_info_folder = script.site_packages / "simplewheel-1.0.dist-info"
     result.did_not_create(dist_info_folder)
 
 
 def test_wheel_compile_syntax_error(script, data):
     package = data.packages.joinpath("compilewheel-1.0-py2.py3-none-any.whl")
-    result = script.pip('install', '--compile', package, '--no-index')
-    assert 'yield from' not in result.stdout
-    assert 'SyntaxError: ' not in result.stdout
+    result = script.pip("install", "--compile", package, "--no-index")
+    assert "yield from" not in result.stdout
+    assert "SyntaxError: " not in result.stdout
 
 
 def test_wheel_install_with_no_cache_dir(script, tmpdir, data):
-    """Check wheel installations work, even with no cache.
-    """
+    """Check wheel installations work, even with no cache."""
     package = data.packages.joinpath("simple.dist-0.1-py2.py3-none-any.whl")
-    result = script.pip('install', '--no-cache-dir', '--no-index', package)
-    result.assert_installed('simpledist', editable=False)
+    result = script.pip("install", "--no-cache-dir", "--no-index", package)
+    result.assert_installed("simpledist", editable=False)
 
 
 def test_wheel_install_fails_with_extra_dist_info(script):
@@ -587,9 +599,7 @@ def test_wheel_install_fails_with_extra_dist_info(script):
         "0.1.0",
         extra_files={
             "unrelated-2.0.0.dist-info/WHEEL": "Wheel-Version: 1.0",
-            "unrelated-2.0.0.dist-info/METADATA": (
-                "Name: unrelated\nVersion: 2.0.0\n"
-            ),
+            "unrelated-2.0.0.dist-info/METADATA": ("Name: unrelated\nVersion: 2.0.0\n"),
         },
     )
     result = script.pip(
@@ -612,10 +622,7 @@ def test_wheel_install_fails_with_unrelated_dist_info(script):
         expect_error=True,
     )
 
-    assert (
-        "'simple-0.1.0.dist-info' does not start with 'unrelated'"
-        in result.stderr
-    )
+    assert "'simple-0.1.0.dist-info' does not start with 'unrelated'" in result.stderr
 
 
 def test_wheel_installs_ok_with_nested_dist_info(script):
@@ -630,25 +637,17 @@ def test_wheel_installs_ok_with_nested_dist_info(script):
             ),
         },
     )
-    script.pip(
-        "install", "--no-cache-dir", "--no-index", package
-    )
+    script.pip("install", "--no-cache-dir", "--no-index", package)
 
 
-def test_wheel_installs_ok_with_badly_encoded_irrelevant_dist_info_file(
-    script
-):
+def test_wheel_installs_ok_with_badly_encoded_irrelevant_dist_info_file(script):
     package = create_basic_wheel_for_package(
         script,
         "simple",
         "0.1.0",
-        extra_files={
-            "simple-0.1.0.dist-info/AUTHORS.txt": b"\xff"
-        },
-    )
-    script.pip(
-        "install", "--no-cache-dir", "--no-index", package
+        extra_files={"simple-0.1.0.dist-info/AUTHORS.txt": b"\xff"},
     )
+    script.pip("install", "--no-cache-dir", "--no-index", package)
 
 
 # Metadata is not decoded on Python 2.
@@ -658,9 +657,7 @@ def test_wheel_install_fails_with_badly_encoded_metadata(script):
         script,
         "simple",
         "0.1.0",
-        extra_files={
-            "simple-0.1.0.dist-info/METADATA": b"\xff"
-        },
+        extra_files={"simple-0.1.0.dist-info/METADATA": b"\xff"},
     )
     result = script.pip(
         "install", "--no-cache-dir", "--no-index", package, expect_error=True
@@ -671,22 +668,20 @@ def test_wheel_install_fails_with_badly_encoded_metadata(script):
 
 
 @pytest.mark.parametrize(
-    'package_name',
-    ['simple-package', 'simple_package'],
+    "package_name",
+    ["simple-package", "simple_package"],
 )
 def test_correct_package_name_while_creating_wheel_bug(script, package_name):
     """Check that the package name is correctly named while creating
     a .whl file with a given format
     """
-    package = create_basic_wheel_for_package(script, package_name, '1.0')
+    package = create_basic_wheel_for_package(script, package_name, "1.0")
     wheel_name = os.path.basename(package)
-    assert wheel_name == 'simple_package-1.0-py2.py3-none-any.whl'
+    assert wheel_name == "simple_package-1.0-py2.py3-none-any.whl"
 
 
 @pytest.mark.parametrize("name", ["purelib", "abc"])
-def test_wheel_with_file_in_data_dir_has_reasonable_error(
-    script, tmpdir, name
-):
+def test_wheel_with_file_in_data_dir_has_reasonable_error(script, tmpdir, name):
     """Normally we expect entities in the .data directory to be in a
     subdirectory, but if they are not then we should show a reasonable error
     message that includes the path.
@@ -695,22 +690,14 @@ def test_wheel_with_file_in_data_dir_has_reasonable_error(
         "simple", "0.1.0", extra_data_files={name: "hello world"}
     ).save_to_dir(tmpdir)
 
-    result = script.pip(
-        "install", "--no-index", str(wheel_path), expect_error=True
-    )
+    result = script.pip("install", "--no-index", str(wheel_path), expect_error=True)
     assert "simple-0.1.0.data/{}".format(name) in result.stderr
 
 
-def test_wheel_with_unknown_subdir_in_data_dir_has_reasonable_error(
-    script, tmpdir
-):
+def test_wheel_with_unknown_subdir_in_data_dir_has_reasonable_error(script, tmpdir):
     wheel_path = make_wheel(
-        "simple",
-        "0.1.0",
-        extra_data_files={"unknown/hello.txt": "hello world"}
+        "simple", "0.1.0", extra_data_files={"unknown/hello.txt": "hello world"}
     ).save_to_dir(tmpdir)
 
-    result = script.pip(
-        "install", "--no-index", str(wheel_path), expect_error=True
-    )
+    result = script.pip("install", "--no-index", str(wheel_path), expect_error=True)
     assert "simple-0.1.0.data/unknown/hello.txt" in result.stderr
diff --git a/tests/functional/test_list.py b/tests/functional/test_list.py
index 37787246bd0..870b5dce378 100644
--- a/tests/functional/test_list.py
+++ b/tests/functional/test_list.py
@@ -12,8 +12,12 @@ def simple_script(tmpdir_factory, script_factory, shared_data):
     tmpdir = Path(str(tmpdir_factory.mktemp("pip_test_package")))
     script = script_factory(tmpdir.joinpath("workspace"))
     script.pip(
-        'install', '-f', shared_data.find_links, '--no-index', 'simple==1.0',
-        'simple2==3.0',
+        "install",
+        "-f",
+        shared_data.find_links,
+        "--no-index",
+        "simple==1.0",
+        "simple2==3.0",
     )
     return script
 
@@ -23,54 +27,55 @@ def test_basic_list(simple_script):
     Test default behavior of list command without format specifier.
 
     """
-    result = simple_script.pip('list')
-    assert 'simple     1.0' in result.stdout, str(result)
-    assert 'simple2    3.0' in result.stdout, str(result)
+    result = simple_script.pip("list")
+    assert "simple     1.0" in result.stdout, str(result)
+    assert "simple2    3.0" in result.stdout, str(result)
 
 
 def test_verbose_flag(simple_script):
     """
     Test the list command with the '-v' option
     """
-    result = simple_script.pip('list', '-v', '--format=columns')
-    assert 'Package' in result.stdout, str(result)
-    assert 'Version' in result.stdout, str(result)
-    assert 'Location' in result.stdout, str(result)
-    assert 'Installer' in result.stdout, str(result)
-    assert 'simple     1.0' in result.stdout, str(result)
-    assert 'simple2    3.0' in result.stdout, str(result)
+    result = simple_script.pip("list", "-v", "--format=columns")
+    assert "Package" in result.stdout, str(result)
+    assert "Version" in result.stdout, str(result)
+    assert "Location" in result.stdout, str(result)
+    assert "Installer" in result.stdout, str(result)
+    assert "simple     1.0" in result.stdout, str(result)
+    assert "simple2    3.0" in result.stdout, str(result)
 
 
 def test_columns_flag(simple_script):
     """
     Test the list command with the '--format=columns' option
     """
-    result = simple_script.pip('list', '--format=columns')
-    assert 'Package' in result.stdout, str(result)
-    assert 'Version' in result.stdout, str(result)
-    assert 'simple (1.0)' not in result.stdout, str(result)
-    assert 'simple     1.0' in result.stdout, str(result)
-    assert 'simple2    3.0' in result.stdout, str(result)
+    result = simple_script.pip("list", "--format=columns")
+    assert "Package" in result.stdout, str(result)
+    assert "Version" in result.stdout, str(result)
+    assert "simple (1.0)" not in result.stdout, str(result)
+    assert "simple     1.0" in result.stdout, str(result)
+    assert "simple2    3.0" in result.stdout, str(result)
 
 
 def test_format_priority(simple_script):
     """
     Test that latest format has priority over previous ones.
     """
-    result = simple_script.pip('list', '--format=columns', '--format=freeze',
-                               expect_stderr=True)
-    assert 'simple==1.0' in result.stdout, str(result)
-    assert 'simple2==3.0' in result.stdout, str(result)
-    assert 'simple     1.0' not in result.stdout, str(result)
-    assert 'simple2    3.0' not in result.stdout, str(result)
+    result = simple_script.pip(
+        "list", "--format=columns", "--format=freeze", expect_stderr=True
+    )
+    assert "simple==1.0" in result.stdout, str(result)
+    assert "simple2==3.0" in result.stdout, str(result)
+    assert "simple     1.0" not in result.stdout, str(result)
+    assert "simple2    3.0" not in result.stdout, str(result)
 
-    result = simple_script.pip('list', '--format=freeze', '--format=columns')
-    assert 'Package' in result.stdout, str(result)
-    assert 'Version' in result.stdout, str(result)
-    assert 'simple==1.0' not in result.stdout, str(result)
-    assert 'simple2==3.0' not in result.stdout, str(result)
-    assert 'simple     1.0' in result.stdout, str(result)
-    assert 'simple2    3.0' in result.stdout, str(result)
+    result = simple_script.pip("list", "--format=freeze", "--format=columns")
+    assert "Package" in result.stdout, str(result)
+    assert "Version" in result.stdout, str(result)
+    assert "simple==1.0" not in result.stdout, str(result)
+    assert "simple2==3.0" not in result.stdout, str(result)
+    assert "simple     1.0" in result.stdout, str(result)
+    assert "simple2    3.0" in result.stdout, str(result)
 
 
 def test_local_flag(simple_script):
@@ -78,7 +83,7 @@ def test_local_flag(simple_script):
     Test the behavior of --local flag in the list command
 
     """
-    result = simple_script.pip('list', '--local', '--format=json')
+    result = simple_script.pip("list", "--local", "--format=json")
     assert {"name": "simple", "version": "1.0"} in json.loads(result.stdout)
 
 
@@ -87,11 +92,11 @@ def test_local_columns_flag(simple_script):
     Test the behavior of --local --format=columns flags in the list command
 
     """
-    result = simple_script.pip('list', '--local', '--format=columns')
-    assert 'Package' in result.stdout
-    assert 'Version' in result.stdout
-    assert 'simple (1.0)' not in result.stdout
-    assert 'simple     1.0' in result.stdout, str(result)
+    result = simple_script.pip("list", "--local", "--format=columns")
+    assert "Package" in result.stdout
+    assert "Version" in result.stdout
+    assert "simple (1.0)" not in result.stdout
+    assert "simple     1.0" in result.stdout, str(result)
 
 
 @pytest.mark.network
@@ -101,13 +106,11 @@ def test_user_flag(script, data):
     Test the behavior of --user flag in the list command
 
     """
-    script.pip('download', 'setuptools', 'wheel', '-d', data.packages)
-    script.pip('install', '-f', data.find_links, '--no-index', 'simple==1.0')
-    script.pip('install', '-f', data.find_links, '--no-index',
-               '--user', 'simple2==2.0')
-    result = script.pip('list', '--user', '--format=json')
-    assert {"name": "simple", "version": "1.0"} \
-        not in json.loads(result.stdout)
+    script.pip("download", "setuptools", "wheel", "-d", data.packages)
+    script.pip("install", "-f", data.find_links, "--no-index", "simple==1.0")
+    script.pip("install", "-f", data.find_links, "--no-index", "--user", "simple2==2.0")
+    result = script.pip("list", "--user", "--format=json")
+    assert {"name": "simple", "version": "1.0"} not in json.loads(result.stdout)
     assert {"name": "simple2", "version": "2.0"} in json.loads(result.stdout)
 
 
@@ -118,15 +121,14 @@ def test_user_columns_flag(script, data):
     Test the behavior of --user --format=columns flags in the list command
 
     """
-    script.pip('download', 'setuptools', 'wheel', '-d', data.packages)
-    script.pip('install', '-f', data.find_links, '--no-index', 'simple==1.0')
-    script.pip('install', '-f', data.find_links, '--no-index',
-               '--user', 'simple2==2.0')
-    result = script.pip('list', '--user', '--format=columns')
-    assert 'Package' in result.stdout
-    assert 'Version' in result.stdout
-    assert 'simple2 (2.0)' not in result.stdout
-    assert 'simple2 2.0' in result.stdout, str(result)
+    script.pip("download", "setuptools", "wheel", "-d", data.packages)
+    script.pip("install", "-f", data.find_links, "--no-index", "simple==1.0")
+    script.pip("install", "-f", data.find_links, "--no-index", "--user", "simple2==2.0")
+    result = script.pip("list", "--user", "--format=columns")
+    assert "Package" in result.stdout
+    assert "Version" in result.stdout
+    assert "simple2 (2.0)" not in result.stdout
+    assert "simple2 2.0" in result.stdout, str(result)
 
 
 @pytest.mark.network
@@ -136,21 +138,32 @@ def test_uptodate_flag(script, data):
 
     """
     script.pip(
-        'install', '-f', data.find_links, '--no-index', 'simple==1.0',
-        'simple2==3.0',
+        "install",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "simple==1.0",
+        "simple2==3.0",
     )
     script.pip(
-        'install', '-e',
-        'git+https://github.com/pypa/pip-test-package.git#egg=pip-test-package'
+        "install",
+        "-e",
+        "git+https://github.com/pypa/pip-test-package.git#egg=pip-test-package",
     )
     result = script.pip(
-        'list', '-f', data.find_links, '--no-index', '--uptodate',
-        '--format=json',
-    )
-    assert {"name": "simple", "version": "1.0"} \
-        not in json.loads(result.stdout)  # 3.0 is latest
-    assert {"name": "pip-test-package", "version": "0.1.1"} \
-        in json.loads(result.stdout)  # editables included
+        "list",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "--uptodate",
+        "--format=json",
+    )
+    assert {"name": "simple", "version": "1.0"} not in json.loads(
+        result.stdout
+    )  # 3.0 is latest
+    assert {"name": "pip-test-package", "version": "0.1.1"} in json.loads(
+        result.stdout
+    )  # editables included
     assert {"name": "simple2", "version": "3.0"} in json.loads(result.stdout)
 
 
@@ -161,23 +174,32 @@ def test_uptodate_columns_flag(script, data):
 
     """
     script.pip(
-        'install', '-f', data.find_links, '--no-index', 'simple==1.0',
-        'simple2==3.0',
+        "install",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "simple==1.0",
+        "simple2==3.0",
     )
     script.pip(
-        'install', '-e',
-        'git+https://github.com/pypa/pip-test-package.git#egg=pip-test-package'
+        "install",
+        "-e",
+        "git+https://github.com/pypa/pip-test-package.git#egg=pip-test-package",
     )
     result = script.pip(
-        'list', '-f', data.find_links, '--no-index', '--uptodate',
-        '--format=columns',
+        "list",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "--uptodate",
+        "--format=columns",
     )
-    assert 'Package' in result.stdout
-    assert 'Version' in result.stdout
-    assert 'Location' in result.stdout      # editables included
-    assert 'pip-test-package (0.1.1,' not in result.stdout
-    assert 'pip-test-package 0.1.1' in result.stdout, str(result)
-    assert 'simple2          3.0' in result.stdout, str(result)
+    assert "Package" in result.stdout
+    assert "Version" in result.stdout
+    assert "Location" in result.stdout  # editables included
+    assert "pip-test-package (0.1.1," not in result.stdout
+    assert "pip-test-package 0.1.1" in result.stdout, str(result)
+    assert "simple2          3.0" in result.stdout, str(result)
 
 
 @pytest.mark.network
@@ -187,27 +209,45 @@ def test_outdated_flag(script, data):
 
     """
     script.pip(
-        'install', '-f', data.find_links, '--no-index', 'simple==1.0',
-        'simple2==3.0', 'simplewheel==1.0',
+        "install",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "simple==1.0",
+        "simple2==3.0",
+        "simplewheel==1.0",
     )
     script.pip(
-        'install', '-e',
-        'git+https://github.com/pypa/pip-test-package.git'
-        '@0.1#egg=pip-test-package'
+        "install",
+        "-e",
+        "git+https://github.com/pypa/pip-test-package.git" "@0.1#egg=pip-test-package",
     )
     result = script.pip(
-        'list', '-f', data.find_links, '--no-index', '--outdated',
-        '--format=json',
-    )
-    assert {"name": "simple", "version": "1.0",
-            "latest_version": "3.0", "latest_filetype": "sdist"} \
-        in json.loads(result.stdout)
-    assert dict(name="simplewheel", version="1.0",
-                latest_version="2.0", latest_filetype="wheel") \
-        in json.loads(result.stdout)
-    assert dict(name="pip-test-package", version="0.1",
-                latest_version="0.1.1", latest_filetype="sdist") \
+        "list",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "--outdated",
+        "--format=json",
+    )
+    assert {
+        "name": "simple",
+        "version": "1.0",
+        "latest_version": "3.0",
+        "latest_filetype": "sdist",
+    } in json.loads(result.stdout)
+    assert dict(
+        name="simplewheel", version="1.0", latest_version="2.0", latest_filetype="wheel"
+    ) in json.loads(result.stdout)
+    assert (
+        dict(
+            name="pip-test-package",
+            version="0.1",
+            latest_version="0.1.1",
+            latest_filetype="sdist",
+        )
         in json.loads(result.stdout)
+    )
     assert "simple2" not in {p["name"] for p in json.loads(result.stdout)}
 
 
@@ -218,43 +258,47 @@ def test_outdated_columns_flag(script, data):
 
     """
     script.pip(
-        'install', '-f', data.find_links, '--no-index', 'simple==1.0',
-        'simple2==3.0', 'simplewheel==1.0',
+        "install",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "simple==1.0",
+        "simple2==3.0",
+        "simplewheel==1.0",
     )
     script.pip(
-        'install', '-e',
-        'git+https://github.com/pypa/pip-test-package.git'
-        '@0.1#egg=pip-test-package'
+        "install",
+        "-e",
+        "git+https://github.com/pypa/pip-test-package.git" "@0.1#egg=pip-test-package",
     )
     result = script.pip(
-        'list', '-f', data.find_links, '--no-index', '--outdated',
-        '--format=columns',
-    )
-    assert 'Package' in result.stdout
-    assert 'Version' in result.stdout
-    assert 'Latest' in result.stdout
-    assert 'Type' in result.stdout
-    assert 'simple (1.0) - Latest: 3.0 [sdist]' not in result.stdout
-    assert 'simplewheel (1.0) - Latest: 2.0 [wheel]' not in result.stdout
-    assert 'simple           1.0     3.0    sdist' in result.stdout, (
-        str(result)
-    )
-    assert 'simplewheel      1.0     2.0    wheel' in result.stdout, (
-        str(result)
-    )
-    assert 'simple2' not in result.stdout, str(result)  # 3.0 is latest
+        "list",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "--outdated",
+        "--format=columns",
+    )
+    assert "Package" in result.stdout
+    assert "Version" in result.stdout
+    assert "Latest" in result.stdout
+    assert "Type" in result.stdout
+    assert "simple (1.0) - Latest: 3.0 [sdist]" not in result.stdout
+    assert "simplewheel (1.0) - Latest: 2.0 [wheel]" not in result.stdout
+    assert "simple           1.0     3.0    sdist" in result.stdout, str(result)
+    assert "simplewheel      1.0     2.0    wheel" in result.stdout, str(result)
+    assert "simple2" not in result.stdout, str(result)  # 3.0 is latest
 
 
 @pytest.fixture(scope="session")
 def pip_test_package_script(tmpdir_factory, script_factory, shared_data):
     tmpdir = Path(str(tmpdir_factory.mktemp("pip_test_package")))
     script = script_factory(tmpdir.joinpath("workspace"))
+    script.pip("install", "-f", shared_data.find_links, "--no-index", "simple==1.0")
     script.pip(
-        'install', '-f', shared_data.find_links, '--no-index', 'simple==1.0'
-    )
-    script.pip(
-        'install', '-e',
-        'git+https://github.com/pypa/pip-test-package.git#egg=pip-test-package'
+        "install",
+        "-e",
+        "git+https://github.com/pypa/pip-test-package.git#egg=pip-test-package",
     )
     return script
 
@@ -264,11 +308,10 @@ def test_editables_flag(pip_test_package_script):
     """
     Test the behavior of --editables flag in the list command
     """
-    result = pip_test_package_script.pip('list', '--editable', '--format=json')
-    result2 = pip_test_package_script.pip('list', '--editable')
-    assert {"name": "simple", "version": "1.0"} \
-        not in json.loads(result.stdout)
-    assert os.path.join('src', 'pip-test-package') in result2.stdout
+    result = pip_test_package_script.pip("list", "--editable", "--format=json")
+    result2 = pip_test_package_script.pip("list", "--editable")
+    assert {"name": "simple", "version": "1.0"} not in json.loads(result.stdout)
+    assert os.path.join("src", "pip-test-package") in result2.stdout
 
 
 @pytest.mark.network
@@ -276,12 +319,9 @@ def test_exclude_editable_flag(pip_test_package_script):
     """
     Test the behavior of --editables flag in the list command
     """
-    result = pip_test_package_script.pip(
-        'list', '--exclude-editable', '--format=json'
-    )
+    result = pip_test_package_script.pip("list", "--exclude-editable", "--format=json")
     assert {"name": "simple", "version": "1.0"} in json.loads(result.stdout)
-    assert "pip-test-package" \
-        not in {p["name"] for p in json.loads(result.stdout)}
+    assert "pip-test-package" not in {p["name"] for p in json.loads(result.stdout)}
 
 
 @pytest.mark.network
@@ -289,15 +329,11 @@ def test_editables_columns_flag(pip_test_package_script):
     """
     Test the behavior of --editables flag in the list command
     """
-    result = pip_test_package_script.pip(
-        'list', '--editable', '--format=columns'
-    )
-    assert 'Package' in result.stdout
-    assert 'Version' in result.stdout
-    assert 'Location' in result.stdout
-    assert os.path.join('src', 'pip-test-package') in result.stdout, (
-        str(result)
-    )
+    result = pip_test_package_script.pip("list", "--editable", "--format=columns")
+    assert "Package" in result.stdout
+    assert "Version" in result.stdout
+    assert "Location" in result.stdout
+    assert os.path.join("src", "pip-test-package") in result.stdout, str(result)
 
 
 @pytest.mark.network
@@ -306,13 +342,15 @@ def test_uptodate_editables_flag(pip_test_package_script, data):
     test the behavior of --editable --uptodate flag in the list command
     """
     result = pip_test_package_script.pip(
-        'list', '-f', data.find_links, '--no-index',
-        '--editable', '--uptodate',
-    )
-    assert 'simple' not in result.stdout
-    assert os.path.join('src', 'pip-test-package') in result.stdout, (
-        str(result)
+        "list",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "--editable",
+        "--uptodate",
     )
+    assert "simple" not in result.stdout
+    assert os.path.join("src", "pip-test-package") in result.stdout, str(result)
 
 
 @pytest.mark.network
@@ -322,15 +360,18 @@ def test_uptodate_editables_columns_flag(pip_test_package_script, data):
     list command
     """
     result = pip_test_package_script.pip(
-        'list', '-f', data.find_links, '--no-index',
-        '--editable', '--uptodate', '--format=columns',
-    )
-    assert 'Package' in result.stdout
-    assert 'Version' in result.stdout
-    assert 'Location' in result.stdout
-    assert os.path.join('src', 'pip-test-package') in result.stdout, (
-        str(result)
+        "list",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "--editable",
+        "--uptodate",
+        "--format=columns",
     )
+    assert "Package" in result.stdout
+    assert "Version" in result.stdout
+    assert "Location" in result.stdout
+    assert os.path.join("src", "pip-test-package") in result.stdout, str(result)
 
 
 @pytest.mark.network
@@ -338,18 +379,22 @@ def test_outdated_editables_flag(script, data):
     """
     test the behavior of --editable --outdated flag in the list command
     """
-    script.pip('install', '-f', data.find_links, '--no-index', 'simple==1.0')
+    script.pip("install", "-f", data.find_links, "--no-index", "simple==1.0")
     result = script.pip(
-        'install', '-e',
-        'git+https://github.com/pypa/pip-test-package.git'
-        '@0.1#egg=pip-test-package'
+        "install",
+        "-e",
+        "git+https://github.com/pypa/pip-test-package.git" "@0.1#egg=pip-test-package",
     )
     result = script.pip(
-        'list', '-f', data.find_links, '--no-index',
-        '--editable', '--outdated',
+        "list",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "--editable",
+        "--outdated",
     )
-    assert 'simple' not in result.stdout
-    assert os.path.join('src', 'pip-test-package') in result.stdout
+    assert "simple" not in result.stdout
+    assert os.path.join("src", "pip-test-package") in result.stdout
 
 
 @pytest.mark.network
@@ -357,22 +402,25 @@ def test_outdated_editables_columns_flag(script, data):
     """
     test the behavior of --editable --outdated flag in the list command
     """
-    script.pip('install', '-f', data.find_links, '--no-index', 'simple==1.0')
+    script.pip("install", "-f", data.find_links, "--no-index", "simple==1.0")
     result = script.pip(
-        'install', '-e',
-        'git+https://github.com/pypa/pip-test-package.git'
-        '@0.1#egg=pip-test-package'
+        "install",
+        "-e",
+        "git+https://github.com/pypa/pip-test-package.git" "@0.1#egg=pip-test-package",
     )
     result = script.pip(
-        'list', '-f', data.find_links, '--no-index',
-        '--editable', '--outdated', '--format=columns',
-    )
-    assert 'Package' in result.stdout
-    assert 'Version' in result.stdout
-    assert 'Location' in result.stdout
-    assert os.path.join('src', 'pip-test-package') in result.stdout, (
-        str(result)
+        "list",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "--editable",
+        "--outdated",
+        "--format=columns",
     )
+    assert "Package" in result.stdout
+    assert "Version" in result.stdout
+    assert "Location" in result.stdout
+    assert os.path.join("src", "pip-test-package") in result.stdout, str(result)
 
 
 def test_outdated_not_required_flag(script, data):
@@ -380,94 +428,139 @@ def test_outdated_not_required_flag(script, data):
     test the behavior of --outdated --not-required flag in the list command
     """
     script.pip(
-        'install', '-f', data.find_links, '--no-index',
-        'simple==2.0', 'require_simple==1.0'
+        "install",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "simple==2.0",
+        "require_simple==1.0",
     )
     result = script.pip(
-        'list', '-f', data.find_links, '--no-index', '--outdated',
-        '--not-required', '--format=json',
+        "list",
+        "-f",
+        data.find_links,
+        "--no-index",
+        "--outdated",
+        "--not-required",
+        "--format=json",
     )
     assert [] == json.loads(result.stdout)
 
 
 def test_outdated_pre(script, data):
-    script.pip('install', '-f', data.find_links, '--no-index', 'simple==1.0')
+    script.pip("install", "-f", data.find_links, "--no-index", "simple==1.0")
 
     # Let's build a fake wheelhouse
     script.scratch_path.joinpath("wheelhouse").mkdir()
-    wheelhouse_path = script.scratch_path / 'wheelhouse'
-    wheelhouse_path.joinpath('simple-1.1-py2.py3-none-any.whl').write_text('')
-    wheelhouse_path.joinpath(
-        'simple-2.0.dev0-py2.py3-none-any.whl'
-    ).write_text('')
+    wheelhouse_path = script.scratch_path / "wheelhouse"
+    wheelhouse_path.joinpath("simple-1.1-py2.py3-none-any.whl").write_text("")
+    wheelhouse_path.joinpath("simple-2.0.dev0-py2.py3-none-any.whl").write_text("")
     result = script.pip(
-        'list', '--no-index', '--find-links', wheelhouse_path,
-        '--format=json',
+        "list",
+        "--no-index",
+        "--find-links",
+        wheelhouse_path,
+        "--format=json",
     )
     assert {"name": "simple", "version": "1.0"} in json.loads(result.stdout)
     result = script.pip(
-        'list', '--no-index', '--find-links', wheelhouse_path, '--outdated',
-        '--format=json',
-    )
-    assert {"name": "simple", "version": "1.0",
-            "latest_version": "1.1", "latest_filetype": "wheel"} \
-        in json.loads(result.stdout)
-    result_pre = script.pip('list', '--no-index',
-                            '--find-links', wheelhouse_path,
-                            '--outdated', '--pre', '--format=json')
-    assert {"name": "simple", "version": "1.0",
-            "latest_version": "2.0.dev0", "latest_filetype": "wheel"} \
-        in json.loads(result_pre.stdout)
+        "list",
+        "--no-index",
+        "--find-links",
+        wheelhouse_path,
+        "--outdated",
+        "--format=json",
+    )
+    assert {
+        "name": "simple",
+        "version": "1.0",
+        "latest_version": "1.1",
+        "latest_filetype": "wheel",
+    } in json.loads(result.stdout)
+    result_pre = script.pip(
+        "list",
+        "--no-index",
+        "--find-links",
+        wheelhouse_path,
+        "--outdated",
+        "--pre",
+        "--format=json",
+    )
+    assert {
+        "name": "simple",
+        "version": "1.0",
+        "latest_version": "2.0.dev0",
+        "latest_filetype": "wheel",
+    } in json.loads(result_pre.stdout)
 
 
 def test_outdated_formats(script, data):
     """ Test of different outdated formats """
-    script.pip('install', '-f', data.find_links, '--no-index', 'simple==1.0')
+    script.pip("install", "-f", data.find_links, "--no-index", "simple==1.0")
 
     # Let's build a fake wheelhouse
     script.scratch_path.joinpath("wheelhouse").mkdir()
-    wheelhouse_path = script.scratch_path / 'wheelhouse'
-    wheelhouse_path.joinpath('simple-1.1-py2.py3-none-any.whl').write_text('')
+    wheelhouse_path = script.scratch_path / "wheelhouse"
+    wheelhouse_path.joinpath("simple-1.1-py2.py3-none-any.whl").write_text("")
     result = script.pip(
-        'list', '--no-index', '--find-links', wheelhouse_path,
-        '--format=freeze',
+        "list",
+        "--no-index",
+        "--find-links",
+        wheelhouse_path,
+        "--format=freeze",
     )
-    assert 'simple==1.0' in result.stdout
+    assert "simple==1.0" in result.stdout
 
     # Check columns
     result = script.pip(
-        'list', '--no-index', '--find-links', wheelhouse_path,
-        '--outdated', '--format=columns',
+        "list",
+        "--no-index",
+        "--find-links",
+        wheelhouse_path,
+        "--outdated",
+        "--format=columns",
     )
-    assert 'Package Version Latest Type' in result.stdout
-    assert 'simple  1.0     1.1    wheel' in result.stdout
+    assert "Package Version Latest Type" in result.stdout
+    assert "simple  1.0     1.1    wheel" in result.stdout
 
     # Check freeze
     result = script.pip(
-        'list', '--no-index', '--find-links', wheelhouse_path,
-        '--outdated', '--format=freeze',
+        "list",
+        "--no-index",
+        "--find-links",
+        wheelhouse_path,
+        "--outdated",
+        "--format=freeze",
     )
-    assert 'simple==1.0' in result.stdout
+    assert "simple==1.0" in result.stdout
 
     # Check json
     result = script.pip(
-        'list', '--no-index', '--find-links', wheelhouse_path,
-        '--outdated', '--format=json',
+        "list",
+        "--no-index",
+        "--find-links",
+        wheelhouse_path,
+        "--outdated",
+        "--format=json",
     )
     data = json.loads(result.stdout)
-    assert data == [{'name': 'simple', 'version': '1.0',
-                     'latest_version': '1.1', 'latest_filetype': 'wheel'}]
+    assert data == [
+        {
+            "name": "simple",
+            "version": "1.0",
+            "latest_version": "1.1",
+            "latest_filetype": "wheel",
+        }
+    ]
 
 
 def test_not_required_flag(script, data):
-    script.pip(
-        'install', '-f', data.find_links, '--no-index', 'TopoRequires4'
-    )
-    result = script.pip('list', '--not-required', expect_stderr=True)
-    assert 'TopoRequires4 ' in result.stdout, str(result)
-    assert 'TopoRequires ' not in result.stdout
-    assert 'TopoRequires2 ' not in result.stdout
-    assert 'TopoRequires3 ' not in result.stdout
+    script.pip("install", "-f", data.find_links, "--no-index", "TopoRequires4")
+    result = script.pip("list", "--not-required", expect_stderr=True)
+    assert "TopoRequires4 " in result.stdout, str(result)
+    assert "TopoRequires " not in result.stdout
+    assert "TopoRequires2 " not in result.stdout
+    assert "TopoRequires3 " not in result.stdout
 
 
 def test_list_freeze(simple_script):
@@ -475,9 +568,9 @@ def test_list_freeze(simple_script):
     Test freeze formatting of list command
 
     """
-    result = simple_script.pip('list', '--format=freeze')
-    assert 'simple==1.0' in result.stdout, str(result)
-    assert 'simple2==3.0' in result.stdout, str(result)
+    result = simple_script.pip("list", "--format=freeze")
+    assert "simple==1.0" in result.stdout, str(result)
+    assert "simple2==3.0" in result.stdout, str(result)
 
 
 def test_list_json(simple_script):
@@ -485,24 +578,24 @@ def test_list_json(simple_script):
     Test json formatting of list command
 
     """
-    result = simple_script.pip('list', '--format=json')
+    result = simple_script.pip("list", "--format=json")
     data = json.loads(result.stdout)
-    assert {'name': 'simple', 'version': '1.0'} in data
-    assert {'name': 'simple2', 'version': '3.0'} in data
+    assert {"name": "simple", "version": "1.0"} in data
+    assert {"name": "simple2", "version": "3.0"} in data
 
 
 def test_list_path(tmpdir, script, data):
     """
     Test list with --path.
     """
-    result = script.pip('list', '--path', tmpdir, '--format=json')
+    result = script.pip("list", "--path", tmpdir, "--format=json")
     json_result = json.loads(result.stdout)
-    assert {'name': 'simple', 'version': '2.0'} not in json_result
+    assert {"name": "simple", "version": "2.0"} not in json_result
 
-    script.pip_install_local('--target', tmpdir, 'simple==2.0')
-    result = script.pip('list', '--path', tmpdir, '--format=json')
+    script.pip_install_local("--target", tmpdir, "simple==2.0")
+    result = script.pip("list", "--path", tmpdir, "--format=json")
     json_result = json.loads(result.stdout)
-    assert {'name': 'simple', 'version': '2.0'} in json_result
+    assert {"name": "simple", "version": "2.0"} in json_result
 
 
 @pytest.mark.incompatible_with_test_venv
@@ -511,16 +604,16 @@ def test_list_path_exclude_user(tmpdir, script, data):
     Test list with --path and make sure packages from --user are not picked
     up.
     """
-    script.pip_install_local('--user', 'simple2')
-    script.pip_install_local('--target', tmpdir, 'simple==1.0')
+    script.pip_install_local("--user", "simple2")
+    script.pip_install_local("--target", tmpdir, "simple==1.0")
 
-    result = script.pip('list', '--user', '--format=json')
+    result = script.pip("list", "--user", "--format=json")
     json_result = json.loads(result.stdout)
-    assert {'name': 'simple2', 'version': '3.0'} in json_result
+    assert {"name": "simple2", "version": "3.0"} in json_result
 
-    result = script.pip('list', '--path', tmpdir, '--format=json')
+    result = script.pip("list", "--path", tmpdir, "--format=json")
     json_result = json.loads(result.stdout)
-    assert {'name': 'simple', 'version': '1.0'} in json_result
+    assert {"name": "simple", "version": "1.0"} in json_result
 
 
 def test_list_path_multiple(tmpdir, script, data):
@@ -532,18 +625,17 @@ def test_list_path_multiple(tmpdir, script, data):
     path2 = tmpdir / "path2"
     os.mkdir(path2)
 
-    script.pip_install_local('--target', path1, 'simple==2.0')
-    script.pip_install_local('--target', path2, 'simple2==3.0')
+    script.pip_install_local("--target", path1, "simple==2.0")
+    script.pip_install_local("--target", path2, "simple2==3.0")
 
-    result = script.pip('list', '--path', path1, '--format=json')
+    result = script.pip("list", "--path", path1, "--format=json")
     json_result = json.loads(result.stdout)
-    assert {'name': 'simple', 'version': '2.0'} in json_result
+    assert {"name": "simple", "version": "2.0"} in json_result
 
-    result = script.pip('list', '--path', path1, '--path', path2,
-                        '--format=json')
+    result = script.pip("list", "--path", path1, "--path", path2, "--format=json")
     json_result = json.loads(result.stdout)
-    assert {'name': 'simple', 'version': '2.0'} in json_result
-    assert {'name': 'simple2', 'version': '3.0'} in json_result
+    assert {"name": "simple", "version": "2.0"} in json_result
+    assert {"name": "simple2", "version": "3.0"} in json_result
 
 
 def test_list_skip_work_dir_pkg(script):
@@ -552,15 +644,13 @@ def test_list_skip_work_dir_pkg(script):
     """
 
     # Create a test package and create .egg-info dir
-    pkg_path = create_test_package_with_setup(
-        script, name='simple', version='1.0')
-    script.run('python', 'setup.py', 'egg_info',
-               expect_stderr=True, cwd=pkg_path)
+    pkg_path = create_test_package_with_setup(script, name="simple", version="1.0")
+    script.run("python", "setup.py", "egg_info", expect_stderr=True, cwd=pkg_path)
 
     # List should not include package simple when run from package directory
-    result = script.pip('list', '--format=json', cwd=pkg_path)
+    result = script.pip("list", "--format=json", cwd=pkg_path)
     json_result = json.loads(result.stdout)
-    assert {'name': 'simple', 'version': '1.0'} not in json_result
+    assert {"name": "simple", "version": "1.0"} not in json_result
 
 
 def test_list_include_work_dir_pkg(script):
@@ -570,15 +660,13 @@ def test_list_include_work_dir_pkg(script):
     """
 
     # Create a test package and create .egg-info dir
-    pkg_path = create_test_package_with_setup(
-        script, name='simple', version='1.0')
-    script.run('python', 'setup.py', 'egg_info',
-               expect_stderr=True, cwd=pkg_path)
+    pkg_path = create_test_package_with_setup(script, name="simple", version="1.0")
+    script.run("python", "setup.py", "egg_info", expect_stderr=True, cwd=pkg_path)
 
-    script.environ.update({'PYTHONPATH': pkg_path})
+    script.environ.update({"PYTHONPATH": pkg_path})
 
     # List should include package simple when run from package directory
     # when the package directory is in PYTHONPATH
-    result = script.pip('list', '--format=json', cwd=pkg_path)
+    result = script.pip("list", "--format=json", cwd=pkg_path)
     json_result = json.loads(result.stdout)
-    assert {'name': 'simple', 'version': '1.0'} in json_result
+    assert {"name": "simple", "version": "1.0"} in json_result
diff --git a/tests/functional/test_new_resolver.py b/tests/functional/test_new_resolver.py
index 1dab8d47091..d4049b0a733 100644
--- a/tests/functional/test_new_resolver.py
+++ b/tests/functional/test_new_resolver.py
@@ -14,27 +14,24 @@
 
 
 def assert_installed(script, **kwargs):
-    ret = script.pip('list', '--format=json')
+    ret = script.pip("list", "--format=json")
     installed = set(
-        (canonicalize_name(val['name']), val['version'])
+        (canonicalize_name(val["name"]), val["version"])
         for val in json.loads(ret.stdout)
     )
     expected = set((canonicalize_name(k), v) for k, v in kwargs.items())
-    assert expected <= installed, \
-        "{!r} not all in {!r}".format(expected, installed)
+    assert expected <= installed, "{!r} not all in {!r}".format(expected, installed)
 
 
 def assert_not_installed(script, *args):
     ret = script.pip("list", "--format=json")
-    installed = set(
-        canonicalize_name(val["name"])
-        for val in json.loads(ret.stdout)
-    )
+    installed = set(canonicalize_name(val["name"]) for val in json.loads(ret.stdout))
     # None of the given names should be listed as installed, i.e. their
     # intersection should be empty.
     expected = set(canonicalize_name(k) for k in args)
-    assert not (expected & installed), \
-        "{!r} contained in {!r}".format(expected, installed)
+    assert not (expected & installed), "{!r} contained in {!r}".format(
+        expected, installed
+    )
 
 
 def assert_editable(script, *args):
@@ -42,8 +39,9 @@ def assert_editable(script, *args):
     # corresponding .egg-link file installed.
     # TODO: Implement a more rigorous way to test for editable installations.
     egg_links = set("{}.egg-link".format(arg) for arg in args)
-    assert egg_links <= set(os.listdir(script.site_packages_path)), \
-        "{!r} not all found in {!r}".format(args, script.site_packages_path)
+    assert egg_links <= set(
+        os.listdir(script.site_packages_path)
+    ), "{!r} not all found in {!r}".format(args, script.site_packages_path)
 
 
 def test_new_resolver_can_install(script):
@@ -53,10 +51,13 @@ def test_new_resolver_can_install(script):
         "0.1.0",
     )
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "simple"
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "simple",
     )
     assert_installed(script, simple="0.1.0")
 
@@ -68,10 +69,13 @@ def test_new_resolver_can_install_with_version(script):
         "0.1.0",
     )
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "simple==0.1.0"
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "simple==0.1.0",
     )
     assert_installed(script, simple="0.1.0")
 
@@ -88,10 +92,13 @@ def test_new_resolver_picks_latest_version(script):
         "0.2.0",
     )
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "simple"
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "simple",
     )
     assert_installed(script, simple="0.2.0")
 
@@ -108,18 +115,24 @@ def test_new_resolver_picks_installed_version(script):
         "0.2.0",
     )
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "simple==0.1.0"
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "simple==0.1.0",
     )
     assert_installed(script, simple="0.1.0")
 
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "simple"
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "simple",
     )
     assert "Collecting" not in result.stdout, "Should not fetch new version"
     assert_installed(script, simple="0.1.0")
@@ -137,17 +150,22 @@ def test_new_resolver_picks_installed_version_if_no_match_found(script):
         "0.2.0",
     )
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "simple==0.1.0"
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "simple==0.1.0",
     )
     assert_installed(script, simple="0.1.0")
 
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "simple"
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "simple",
     )
     assert "Collecting" not in result.stdout, "Should not fetch new version"
     assert_installed(script, simple="0.1.0")
@@ -166,10 +184,13 @@ def test_new_resolver_installs_dependencies(script):
         "0.1.0",
     )
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "base"
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "base",
     )
     assert_installed(script, base="0.1.0", dep="0.1.0")
 
@@ -187,10 +208,14 @@ def test_new_resolver_ignore_dependencies(script):
         "0.1.0",
     )
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index", "--no-deps",
-        "--find-links", script.scratch_path,
-        "base"
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--no-deps",
+        "--find-links",
+        script.scratch_path,
+        "base",
     )
     assert_installed(script, base="0.1.0")
     assert_not_installed(script, "dep")
@@ -219,10 +244,14 @@ def test_new_resolver_installs_extras(tmpdir, script, root_dep):
         "0.1.0",
     )
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "-r", req_file,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "-r",
+        req_file,
     )
     assert_installed(script, base="0.1.0", dep="0.1.0")
 
@@ -243,11 +272,15 @@ def test_new_resolver_installs_extras_deprecated(tmpdir, script):
         "0.1.0",
     )
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "-r", req_file,
-        expect_stderr=True
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "-r",
+        req_file,
+        expect_stderr=True,
     )
     assert "DEPRECATION: Extras after version" in result.stderr
     assert_installed(script, base="0.1.0", dep="0.1.0")
@@ -266,9 +299,12 @@ def test_new_resolver_installs_extras_warn_missing(script):
         "0.1.0",
     )
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "base[add,missing]",
         expect_stderr=True,
     )
@@ -280,9 +316,12 @@ def test_new_resolver_installs_extras_warn_missing(script):
 def test_new_resolver_installed_message(script):
     create_basic_wheel_for_package(script, "A", "1.0")
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "A",
         expect_stderr=False,
     )
@@ -292,9 +331,12 @@ def test_new_resolver_installed_message(script):
 def test_new_resolver_no_dist_message(script):
     create_basic_wheel_for_package(script, "A", "1.0")
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "B",
         expect_error=True,
         expect_stderr=True,
@@ -305,8 +347,9 @@ def test_new_resolver_no_dist_message(script):
     #        requirement xxx (from versions: none)
     # ERROR: No matching distribution found for xxx
 
-    assert "Could not find a version that satisfies the requirement B" \
-        in result.stderr, str(result)
+    assert (
+        "Could not find a version that satisfies the requirement B" in result.stderr
+    ), str(result)
     assert "No matching distribution found for B" in result.stderr, str(result)
 
 
@@ -323,11 +366,15 @@ def test_new_resolver_installs_editable(script):
         version="0.1.0",
     )
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "base",
-        "--editable", source_dir,
+        "--editable",
+        source_dir,
     )
     assert_installed(script, base="0.1.0", dep="0.1.0")
     assert_editable(script, "dep")
@@ -339,7 +386,6 @@ def test_new_resolver_installs_editable(script):
         # Something impossible to satisfy.
         ("<2", False, "0.1.0"),
         ("<2", True, "0.2.0"),
-
         # Something guaranteed to satisfy.
         (">=2", False, "0.2.0"),
         (">=2", True, "0.2.0"),
@@ -374,7 +420,8 @@ def test_new_resolver_requires_python(
         "--use-feature=2020-resolver",
         "--no-cache-dir",
         "--no-index",
-        "--find-links", script.scratch_path,
+        "--find-links",
+        script.scratch_path,
     ]
     if ignore_requires_python:
         args.append("--ignore-requires-python")
@@ -393,9 +440,12 @@ def test_new_resolver_requires_python_error(script):
         requires_python="<2",
     )
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "base",
         expect_error=True,
     )
@@ -421,24 +471,28 @@ def test_new_resolver_installed(script):
     )
 
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "base",
     )
     assert "Requirement already satisfied" not in result.stdout, str(result)
 
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "base~=0.1.0",
     )
-    assert "Requirement already satisfied: base~=0.1.0" in result.stdout, \
-        str(result)
+    assert "Requirement already satisfied: base~=0.1.0" in result.stdout, str(result)
     result.did_not_update(
-        script.site_packages / "base",
-        message="base 0.1.0 reinstalled"
+        script.site_packages / "base", message="base 0.1.0 reinstalled"
     )
 
 
@@ -451,23 +505,29 @@ def test_new_resolver_ignore_installed(script):
     satisfied_output = "Requirement already satisfied"
 
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "base",
     )
     assert satisfied_output not in result.stdout, str(result)
 
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index", "--ignore-installed",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--ignore-installed",
+        "--find-links",
+        script.scratch_path,
         "base",
     )
     assert satisfied_output not in result.stdout, str(result)
     result.did_update(
-        script.site_packages / "base",
-        message="base 0.1.0 not reinstalled"
+        script.site_packages / "base", message="base 0.1.0 not reinstalled"
     )
 
 
@@ -492,19 +552,26 @@ def test_new_resolver_only_builds_sdists_when_needed(script):
     )
     # We only ever need to check dep 0.2.0 as it's the latest version
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "base"
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "base",
     )
     assert_installed(script, base="0.1.0", dep="0.2.0")
 
     # We merge criteria here, as we have two "dep" requirements
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "base", "dep"
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "base",
+        "dep",
     )
     assert_installed(script, base="0.1.0", dep="0.2.0")
 
@@ -514,26 +581,29 @@ def test_new_resolver_install_different_version(script):
     create_basic_wheel_for_package(script, "base", "0.2.0")
 
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "base==0.1.0",
     )
 
     # This should trigger an uninstallation of base.
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "base==0.2.0",
     )
 
     assert "Uninstalling base-0.1.0" in result.stdout, str(result)
     assert "Successfully uninstalled base-0.1.0" in result.stdout, str(result)
-    result.did_update(
-        script.site_packages / "base",
-        message="base not upgraded"
-    )
+    result.did_update(script.site_packages / "base", message="base not upgraded")
     assert_installed(script, base="0.2.0")
 
 
@@ -541,28 +611,31 @@ def test_new_resolver_force_reinstall(script):
     create_basic_wheel_for_package(script, "base", "0.1.0")
 
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "base==0.1.0",
     )
 
     # This should trigger an uninstallation of base due to --force-reinstall,
     # even though the installed version matches.
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "--force-reinstall",
         "base==0.1.0",
     )
 
     assert "Uninstalling base-0.1.0" in result.stdout, str(result)
     assert "Successfully uninstalled base-0.1.0" in result.stdout, str(result)
-    result.did_update(
-        script.site_packages / "base",
-        message="base not reinstalled"
-    )
+    result.did_update(script.site_packages / "base", message="base not reinstalled")
     assert_installed(script, base="0.1.0")
 
 
@@ -589,9 +662,12 @@ def test_new_resolver_handles_prerelease(
     for version in available_versions:
         create_basic_wheel_for_package(script, "pkg", version)
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         *pip_args
     )
     assert_installed(script, pkg=expected_version)
@@ -604,16 +680,19 @@ def test_new_resolver_handles_prerelease(
         (["dep; os_name == 'nonexist_os'"], ["pkg"]),
         # This tests the marker is picked up from a root dependency.
         ([], ["pkg", "dep; os_name == 'nonexist_os'"]),
-    ]
+    ],
 )
 def test_new_reolver_skips_marker(script, pkg_deps, root_deps):
     create_basic_wheel_for_package(script, "pkg", "1.0", depends=pkg_deps)
     create_basic_wheel_for_package(script, "dep", "1.0")
 
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         *root_deps
     )
     assert_installed(script, pkg="1.0")
@@ -627,7 +706,7 @@ def test_new_reolver_skips_marker(script, pkg_deps, root_deps):
         # This also tests the pkg constraint don't get merged with the
         # requirement prematurely. (pypa/pip#8134)
         ["pkg<2.0"],
-    ]
+    ],
 )
 def test_new_resolver_constraints(script, constraints):
     create_basic_wheel_for_package(script, "pkg", "1.0")
@@ -636,11 +715,15 @@ def test_new_resolver_constraints(script, constraints):
     constraints_file = script.scratch_path / "constraints.txt"
     constraints_file.write_text("\n".join(constraints))
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "-c", constraints_file,
-        "pkg"
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "-c",
+        constraints_file,
+        "pkg",
     )
     assert_installed(script, pkg="1.0")
     assert_not_installed(script, "constraint_only")
@@ -652,11 +735,15 @@ def test_new_resolver_constraint_no_specifier(script):
     constraints_file = script.scratch_path / "constraints.txt"
     constraints_file.write_text("pkg")
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "-c", constraints_file,
-        "pkg"
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "-c",
+        constraints_file,
+        "pkg",
     )
     assert_installed(script, pkg="1.0")
 
@@ -683,10 +770,14 @@ def test_new_resolver_constraint_reject_invalid(script, constraint, error):
     constraints_file = script.scratch_path / "constraints.txt"
     constraints_file.write_text(constraint)
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "-c", constraints_file,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "-c",
+        constraints_file,
         "pkg",
         expect_error=True,
         expect_stderr=True,
@@ -702,11 +793,15 @@ def test_new_resolver_constraint_on_dependency(script):
     constraints_file = script.scratch_path / "constraints.txt"
     constraints_file.write_text("dep==2.0")
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "-c", constraints_file,
-        "base"
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "-c",
+        constraints_file,
+        "base",
     )
     assert_installed(script, base="1.0")
     assert_installed(script, dep="2.0")
@@ -719,9 +814,12 @@ def test_new_resolver_constraint_on_path(script):
     constraints_txt = script.scratch_path / "constraints.txt"
     constraints_txt.write_text("foo==1.0")
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "-c", constraints_txt,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "-c",
+        constraints_txt,
         str(script.scratch_path),
         expect_error=True,
     )
@@ -745,10 +843,14 @@ def test_new_resolver_constraint_only_marker_match(script):
     constraints_txt.write_text(constrants_content)
 
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "-c", constraints_txt,
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "-c",
+        constraints_txt,
+        "--find-links",
+        script.scratch_path,
         "pkg",
     )
     assert_installed(script, pkg="1.0")
@@ -758,9 +860,12 @@ def test_new_resolver_upgrade_needs_option(script):
     # Install pkg 1.0.0
     create_basic_wheel_for_package(script, "pkg", "1.0.0")
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "pkg",
     )
 
@@ -769,9 +874,12 @@ def test_new_resolver_upgrade_needs_option(script):
 
     # This should not upgrade because we don't specify --upgrade
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "pkg",
     )
 
@@ -780,19 +888,19 @@ def test_new_resolver_upgrade_needs_option(script):
 
     # This should upgrade
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "--upgrade",
         "PKG",  # Deliberately uppercase to check canonicalization
     )
 
     assert "Uninstalling pkg-1.0.0" in result.stdout, str(result)
     assert "Successfully uninstalled pkg-1.0.0" in result.stdout, str(result)
-    result.did_update(
-        script.site_packages / "pkg",
-        message="pkg not upgraded"
-    )
+    result.did_update(script.site_packages / "pkg", message="pkg not upgraded")
     assert_installed(script, pkg="2.0.0")
 
 
@@ -800,9 +908,12 @@ def test_new_resolver_upgrade_strategy(script):
     create_basic_wheel_for_package(script, "base", "1.0.0", depends=["dep"])
     create_basic_wheel_for_package(script, "dep", "1.0.0")
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "base",
     )
 
@@ -814,9 +925,12 @@ def test_new_resolver_upgrade_strategy(script):
     create_basic_wheel_for_package(script, "dep", "2.0.0")
 
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "--upgrade",
         "base",
     )
@@ -828,10 +942,14 @@ def test_new_resolver_upgrade_strategy(script):
 
     create_basic_wheel_for_package(script, "base", "3.0.0", depends=["dep"])
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "--upgrade", "--upgrade-strategy=eager",
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "--upgrade",
+        "--upgrade-strategy=eager",
         "base",
     )
 
@@ -847,8 +965,7 @@ class TestExtraMerge(object):
     """
 
     def _local_with_setup(script, name, version, requires, extras):
-        """Create the package as a local source directory to install from path.
-        """
+        """Create the package as a local source directory to install from path."""
         return create_test_package_with_setup(
             script,
             name=name,
@@ -858,8 +975,7 @@ def _local_with_setup(script, name, version, requires, extras):
         )
 
     def _direct_wheel(script, name, version, requires, extras):
-        """Create the package as a wheel to install from path directly.
-        """
+        """Create the package as a wheel to install from path directly."""
         return create_basic_wheel_for_package(
             script,
             name=name,
@@ -869,8 +985,7 @@ def _direct_wheel(script, name, version, requires, extras):
         )
 
     def _wheel_from_index(script, name, version, requires, extras):
-        """Create the package as a wheel to install from index.
-        """
+        """Create the package as a wheel to install from index."""
         create_basic_wheel_for_package(
             script,
             name=name,
@@ -889,7 +1004,10 @@ def _wheel_from_index(script, name, version, requires, extras):
         ],
     )
     def test_new_resolver_extra_merge_in_package(
-        self, monkeypatch, script, pkg_builder,
+        self,
+        monkeypatch,
+        script,
+        pkg_builder,
     ):
         create_basic_wheel_for_package(script, "depdev", "1.0.0")
         create_basic_wheel_for_package(
@@ -907,9 +1025,12 @@ def test_new_resolver_extra_merge_in_package(
         )
 
         script.pip(
-            "install", "--use-feature=2020-resolver",
-            "--no-cache-dir", "--no-index",
-            "--find-links", script.scratch_path,
+            "install",
+            "--use-feature=2020-resolver",
+            "--no-cache-dir",
+            "--no-index",
+            "--find-links",
+            script.scratch_path,
             requirement + "[dev]",
         )
         assert_installed(script, pkg="1.0.0", dep="1.0.0", depdev="1.0.0")
@@ -937,7 +1058,10 @@ def test_new_resolver_build_directory_error_zazo_19(script):
         can delete this. Please delete it and try again.
     """
     create_basic_wheel_for_package(
-        script, "pkg_a", "3.0.0", depends=["pkg-b<2"],
+        script,
+        "pkg_a",
+        "3.0.0",
+        depends=["pkg-b<2"],
     )
     create_basic_wheel_for_package(script, "pkg_a", "2.0.0")
     create_basic_wheel_for_package(script, "pkg_a", "1.0.0")
@@ -946,10 +1070,14 @@ def test_new_resolver_build_directory_error_zazo_19(script):
     create_basic_sdist_for_package(script, "pkg_b", "1.0.0")
 
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "pkg-a", "pkg-b",
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "pkg-a",
+        "pkg-b",
     )
     assert_installed(script, pkg_a="3.0.0", pkg_b="1.0.0")
 
@@ -959,17 +1087,23 @@ def test_new_resolver_upgrade_same_version(script):
     create_basic_wheel_for_package(script, "pkg", "1")
 
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "pkg",
     )
     assert_installed(script, pkg="2")
 
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "--upgrade",
         "pkg",
     )
@@ -983,9 +1117,12 @@ def test_new_resolver_local_and_req(script):
         version="0.1.0",
     )
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        source_dir, "pkg!=0.1.0",
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        source_dir,
+        "pkg!=0.1.0",
         expect_error=True,
     )
 
@@ -1010,7 +1147,8 @@ def test_new_resolver_no_deps_checks_requires_python(script):
         "--no-cache-dir",
         "--no-index",
         "--no-deps",
-        "--find-links", script.scratch_path,
+        "--find-links",
+        script.scratch_path,
         "base",
         expect_error=True,
     )
diff --git a/tests/functional/test_new_resolver_errors.py b/tests/functional/test_new_resolver_errors.py
index 267f2130710..c9a6b3f59be 100644
--- a/tests/functional/test_new_resolver_errors.py
+++ b/tests/functional/test_new_resolver_errors.py
@@ -5,20 +5,30 @@ def test_new_resolver_conflict_requirements_file(tmpdir, script):
     create_basic_wheel_for_package(script, "base", "1.0")
     create_basic_wheel_for_package(script, "base", "2.0")
     create_basic_wheel_for_package(
-        script, "pkga", "1.0", depends=["base==1.0"],
+        script,
+        "pkga",
+        "1.0",
+        depends=["base==1.0"],
     )
     create_basic_wheel_for_package(
-        script, "pkgb", "1.0", depends=["base==2.0"],
+        script,
+        "pkgb",
+        "1.0",
+        depends=["base==2.0"],
     )
 
     req_file = tmpdir.joinpath("requirements.txt")
     req_file.write_text("pkga\npkgb")
 
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
-        "-r", req_file,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
+        "-r",
+        req_file,
         expect_error=True,
     )
 
diff --git a/tests/functional/test_new_resolver_hashes.py b/tests/functional/test_new_resolver_hashes.py
index 4b13ebc307d..449fa7e1d27 100644
--- a/tests/functional/test_new_resolver_hashes.py
+++ b/tests/functional/test_new_resolver_hashes.py
@@ -4,13 +4,11 @@
 import pytest
 
 from pip._internal.utils.urls import path_to_url
-from tests.lib import (
-    create_basic_sdist_for_package,
-    create_basic_wheel_for_package,
-)
+from tests.lib import create_basic_sdist_for_package, create_basic_wheel_for_package
 
 _FindLinks = collections.namedtuple(
-    "_FindLinks", "index_html sdist_hash wheel_hash",
+    "_FindLinks",
+    "index_html sdist_hash wheel_hash",
 )
 
 
@@ -79,9 +77,11 @@ def test_new_resolver_hash_intersect(script, requirements_template, message):
         "--no-cache-dir",
         "--no-deps",
         "--no-index",
-        "--find-links", find_links.index_html,
+        "--find-links",
+        find_links.index_html,
         "--verbose",
-        "--requirement", requirements_txt,
+        "--requirement",
+        requirements_txt,
     )
 
     assert message.format(name=u"base") in result.stdout, str(result)
@@ -112,10 +112,13 @@ def test_new_resolver_hash_intersect_from_constraint(script):
         "--no-cache-dir",
         "--no-deps",
         "--no-index",
-        "--find-links", find_links.index_html,
+        "--find-links",
+        find_links.index_html,
         "--verbose",
-        "--constraint", constraints_txt,
-        "--requirement", requirements_txt,
+        "--constraint",
+        constraints_txt,
+        "--requirement",
+        requirements_txt,
     )
 
     message = (
@@ -143,7 +146,9 @@ def test_new_resolver_hash_intersect_from_constraint(script):
     ids=["both-requirements", "one-each"],
 )
 def test_new_resolver_hash_intersect_empty(
-    script, requirements_template, constraints_template,
+    script,
+    requirements_template,
+    constraints_template,
 ):
     find_links = _create_find_links(script)
 
@@ -169,9 +174,12 @@ def test_new_resolver_hash_intersect_empty(
         "--no-cache-dir",
         "--no-deps",
         "--no-index",
-        "--find-links", find_links.index_html,
-        "--constraint", constraints_txt,
-        "--requirement", requirements_txt,
+        "--find-links",
+        find_links.index_html,
+        "--constraint",
+        constraints_txt,
+        "--requirement",
+        requirements_txt,
         expect_error=True,
     )
 
@@ -200,8 +208,10 @@ def test_new_resolver_hash_intersect_empty_from_constraint(script):
         "--no-cache-dir",
         "--no-deps",
         "--no-index",
-        "--find-links", find_links.index_html,
-        "--constraint", constraints_txt,
+        "--find-links",
+        find_links.index_html,
+        "--constraint",
+        constraints_txt,
         "base==0.1.0",
         expect_error=True,
     )
diff --git a/tests/functional/test_new_resolver_target.py b/tests/functional/test_new_resolver_target.py
index 6189e1cb5bc..fe5276daf07 100644
--- a/tests/functional/test_new_resolver_target.py
+++ b/tests/functional/test_new_resolver_target.py
@@ -7,7 +7,6 @@
 
 @pytest.fixture()
 def make_fake_wheel(script):
-
     def _make_fake_wheel(wheel_tag):
         wheel_house = script.scratch_path.joinpath("wheelhouse")
         wheel_house.mkdir()
@@ -37,10 +36,13 @@ def test_new_resolver_target_checks_compatibility_failure(
 ):
     fake_wheel_tag = "fakepy1-fakeabi-fakeplat"
     args = [
-        "install", "--use-feature=2020-resolver",
+        "install",
+        "--use-feature=2020-resolver",
         "--only-binary=:all:",
-        "--no-cache-dir", "--no-index",
-        "--target", str(script.scratch_path.joinpath("target")),
+        "--no-cache-dir",
+        "--no-index",
+        "--target",
+        str(script.scratch_path.joinpath("target")),
         make_fake_wheel(fake_wheel_tag),
     ]
     if implementation:
@@ -58,7 +60,7 @@ def test_new_resolver_target_checks_compatibility_failure(
         abi,
         platform,
     )
-    wheel_tag_matches = (args_tag == fake_wheel_tag)
+    wheel_tag_matches = args_tag == fake_wheel_tag
 
     result = script.pip(*args, expect_error=(not wheel_tag_matches))
 
diff --git a/tests/functional/test_new_resolver_user.py b/tests/functional/test_new_resolver_user.py
index 2aae3eb16cb..7d583f881da 100644
--- a/tests/functional/test_new_resolver_user.py
+++ b/tests/functional/test_new_resolver_user.py
@@ -10,9 +10,12 @@
 def test_new_resolver_install_user(script):
     create_basic_wheel_for_package(script, "base", "0.1.0")
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "--user",
         "base",
     )
@@ -28,15 +31,21 @@ def test_new_resolver_install_user_satisfied_by_global_site(script):
     create_basic_wheel_for_package(script, "base", "1.0.0")
 
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "base==1.0.0",
     )
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "--user",
         "base==1.0.0",
     )
@@ -54,17 +63,23 @@ def test_new_resolver_install_user_conflict_in_user_site(script):
     create_basic_wheel_for_package(script, "base", "2.0.0")
 
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "--user",
         "base==2.0.0",
     )
 
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "--user",
         "base==1.0.0",
     )
@@ -82,15 +97,21 @@ def test_new_resolver_install_user_in_virtualenv_with_conflict_fails(script):
     create_basic_wheel_for_package(script, "base", "2.0.0")
 
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "base==2.0.0",
     )
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "--user",
         "base==1.0.0",
         expect_error=True,
@@ -109,13 +130,15 @@ def patch_dist_in_site_packages(virtualenv):
     # install to the usersite because it will lack sys.path precedence..."
     # error: Monkey patch `dist_in_site_packages` in the resolver module so
     # it's possible to install a conflicting distribution in the user site.
-    virtualenv.sitecustomize = textwrap.dedent("""
+    virtualenv.sitecustomize = textwrap.dedent(
+        """
         def dist_in_site_packages(dist):
             return False
 
         from pip._internal.resolution.resolvelib import factory
         factory.dist_in_site_packages = dist_in_site_packages
-    """)
+    """
+    )
 
 
 @pytest.mark.incompatible_with_test_venv
@@ -128,15 +151,21 @@ def test_new_resolver_install_user_reinstall_global_site(script):
     create_basic_wheel_for_package(script, "base", "1.0.0")
 
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "base==1.0.0",
     )
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "--user",
         "--force-reinstall",
         "base==1.0.0",
@@ -159,16 +188,22 @@ def test_new_resolver_install_user_conflict_in_global_site(script):
     create_basic_wheel_for_package(script, "base", "2.0.0")
 
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "base==1.0.0",
     )
 
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "--user",
         "base==2.0.0",
     )
@@ -191,24 +226,33 @@ def test_new_resolver_install_user_conflict_in_global_and_user_sites(script):
     create_basic_wheel_for_package(script, "base", "2.0.0")
 
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "base==2.0.0",
     )
     script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "--user",
         "--force-reinstall",
         "base==2.0.0",
     )
 
     result = script.pip(
-        "install", "--use-feature=2020-resolver",
-        "--no-cache-dir", "--no-index",
-        "--find-links", script.scratch_path,
+        "install",
+        "--use-feature=2020-resolver",
+        "--no-cache-dir",
+        "--no-index",
+        "--find-links",
+        script.scratch_path,
         "--user",
         "base==1.0.0",
     )
diff --git a/tests/functional/test_no_color.py b/tests/functional/test_no_color.py
index 48ed3ff7848..09f5a7c0f27 100644
--- a/tests/functional/test_no_color.py
+++ b/tests/functional/test_no_color.py
@@ -8,8 +8,7 @@
 
 
 def test_no_color(script):
-    """Ensure colour output disabled when --no-color is passed.
-    """
+    """Ensure colour output disabled when --no-color is passed."""
     # Using 'script' in this test allows for transparently testing pip's output
     # since pip is smart enough to disable colour output when piped, which is
     # not the behaviour we want to be testing here.
@@ -19,14 +18,17 @@ def test_no_color(script):
     #
     # This test will stay until someone has the time to rewrite it.
     command = (
-        'script --flush --quiet --return /tmp/pip-test-no-color.txt '
+        "script --flush --quiet --return /tmp/pip-test-no-color.txt "
         '--command "pip uninstall {} noSuchPackage"'
     )
 
     def get_run_output(option):
         cmd = command.format(option)
         proc = subprocess.Popen(
-            cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+            cmd,
+            shell=True,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
         )
         proc.communicate()
         if proc.returncode:
@@ -40,5 +42,6 @@ def get_run_output(option):
             os.unlink("/tmp/pip-test-no-color.txt")
 
     assert "\x1b" in get_run_output(option=""), "Expected color in output"
-    assert "\x1b" not in get_run_output(option="--no-color"), \
-        "Expected no color in output"
+    assert "\x1b" not in get_run_output(
+        option="--no-color"
+    ), "Expected no color in output"
diff --git a/tests/functional/test_pep517.py b/tests/functional/test_pep517.py
index bcad4793672..c30582a9723 100644
--- a/tests/functional/test_pep517.py
+++ b/tests/functional/test_pep517.py
@@ -8,15 +8,15 @@
 
 def make_project(tmpdir, requires=None, backend=None, backend_path=None):
     requires = requires or []
-    project_dir = tmpdir / 'project'
+    project_dir = tmpdir / "project"
     project_dir.mkdir()
-    buildsys = {'requires': requires}
+    buildsys = {"requires": requires}
     if backend:
-        buildsys['build-backend'] = backend
+        buildsys["build-backend"] = backend
     if backend_path:
-        buildsys['backend-path'] = backend_path
-    data = toml.dumps({'build-system': buildsys})
-    project_dir.joinpath('pyproject.toml').write_text(data)
+        buildsys["backend-path"] = backend_path
+    data = toml.dumps({"build-system": buildsys})
+    project_dir.joinpath("pyproject.toml").write_text(data)
     return project_dir
 
 
@@ -28,10 +28,10 @@ def test_backend(tmpdir, data):
     req.load_pyproject_toml()
     env = BuildEnvironment()
     finder = make_test_finder(find_links=[data.backends])
-    env.install_requirements(finder, ["dummy_backend"], 'normal', "Installing")
+    env.install_requirements(finder, ["dummy_backend"], "normal", "Installing")
     conflicting, missing = env.check_requirements(["dummy_backend"])
     assert not conflicting and not missing
-    assert hasattr(req.pep517_backend, 'build_wheel')
+    assert hasattr(req.pep517_backend, "build_wheel")
     with env:
         assert req.pep517_backend.build_wheel("dir") == "Backend called"
 
@@ -48,16 +48,14 @@ def build_wheel(
 
 def test_backend_path(tmpdir, data):
     """Check we can call a backend inside the project"""
-    project_dir = make_project(
-        tmpdir, backend="dummy_backend", backend_path=['.']
-    )
-    (project_dir / 'dummy_backend.py').write_text(dummy_backend_code)
+    project_dir = make_project(tmpdir, backend="dummy_backend", backend_path=["."])
+    (project_dir / "dummy_backend.py").write_text(dummy_backend_code)
     req = InstallRequirement(None, None)
     req.source_dir = project_dir  # make req believe it has been unpacked
     req.load_pyproject_toml()
 
     env = BuildEnvironment()
-    assert hasattr(req.pep517_backend, 'build_wheel')
+    assert hasattr(req.pep517_backend, "build_wheel")
     with env:
         assert req.pep517_backend.build_wheel("dir") == "Backend called"
 
@@ -65,9 +63,9 @@ def test_backend_path(tmpdir, data):
 def test_backend_path_and_dep(tmpdir, data):
     """Check we can call a requirement's backend successfully"""
     project_dir = make_project(
-        tmpdir, backend="dummy_internal_backend", backend_path=['.']
+        tmpdir, backend="dummy_internal_backend", backend_path=["."]
     )
-    (project_dir / 'dummy_internal_backend.py').write_text(
+    (project_dir / "dummy_internal_backend.py").write_text(
         "from dummy_backend import build_wheel"
     )
     req = InstallRequirement(None, None)
@@ -75,9 +73,9 @@ def test_backend_path_and_dep(tmpdir, data):
     req.load_pyproject_toml()
     env = BuildEnvironment()
     finder = make_test_finder(find_links=[data.backends])
-    env.install_requirements(finder, ["dummy_backend"], 'normal', "Installing")
+    env.install_requirements(finder, ["dummy_backend"], "normal", "Installing")
 
-    assert hasattr(req.pep517_backend, 'build_wheel')
+    assert hasattr(req.pep517_backend, "build_wheel")
     with env:
         assert req.pep517_backend.build_wheel("dir") == "Backend called"
 
@@ -85,170 +83,172 @@ def test_backend_path_and_dep(tmpdir, data):
 def test_pep517_install(script, tmpdir, data):
     """Check we can build with a custom backend"""
     project_dir = make_project(
-        tmpdir, requires=['test_backend'],
-        backend="test_backend"
+        tmpdir, requires=["test_backend"], backend="test_backend"
     )
-    result = script.pip(
-        'install', '--no-index', '-f', data.backends, project_dir
-    )
-    result.assert_installed('project', editable=False)
+    result = script.pip("install", "--no-index", "-f", data.backends, project_dir)
+    result.assert_installed("project", editable=False)
 
 
 def test_pep517_install_with_reqs(script, tmpdir, data):
     """Backend generated requirements are installed in the build env"""
     project_dir = make_project(
-        tmpdir, requires=['test_backend'],
-        backend="test_backend"
+        tmpdir, requires=["test_backend"], backend="test_backend"
     )
     project_dir.joinpath("backend_reqs.txt").write_text("simplewheel")
     result = script.pip(
-        'install', '--no-index',
-        '-f', data.backends,
-        '-f', data.packages,
-        project_dir
+        "install", "--no-index", "-f", data.backends, "-f", data.packages, project_dir
     )
-    result.assert_installed('project', editable=False)
+    result.assert_installed("project", editable=False)
 
 
 def test_no_use_pep517_without_setup_py(script, tmpdir, data):
     """Using --no-use-pep517 requires setup.py"""
     project_dir = make_project(
-        tmpdir, requires=['test_backend'],
-        backend="test_backend"
+        tmpdir, requires=["test_backend"], backend="test_backend"
     )
     result = script.pip(
-        'install', '--no-index', '--no-use-pep517',
-        '-f', data.backends,
+        "install",
+        "--no-index",
+        "--no-use-pep517",
+        "-f",
+        data.backends,
         project_dir,
-        expect_error=True
+        expect_error=True,
     )
-    assert 'project does not have a setup.py' in result.stderr
+    assert "project does not have a setup.py" in result.stderr
 
 
 def test_conflicting_pep517_backend_requirements(script, tmpdir, data):
     project_dir = make_project(
-        tmpdir, requires=['test_backend', 'simplewheel==1.0'],
-        backend="test_backend"
+        tmpdir, requires=["test_backend", "simplewheel==1.0"], backend="test_backend"
     )
     project_dir.joinpath("backend_reqs.txt").write_text("simplewheel==2.0")
     result = script.pip(
-        'install', '--no-index',
-        '-f', data.backends,
-        '-f', data.packages,
+        "install",
+        "--no-index",
+        "-f",
+        data.backends,
+        "-f",
+        data.packages,
         project_dir,
-        expect_error=True
+        expect_error=True,
     )
     msg = (
-        'Some build dependencies for {url} conflict with the backend '
-        'dependencies: simplewheel==1.0 is incompatible with '
-        'simplewheel==2.0.'.format(url=path_to_url(project_dir)))
-    assert (
-        result.returncode != 0 and
-        msg in result.stderr
-    ), str(result)
+        "Some build dependencies for {url} conflict with the backend "
+        "dependencies: simplewheel==1.0 is incompatible with "
+        "simplewheel==2.0.".format(url=path_to_url(project_dir))
+    )
+    assert result.returncode != 0 and msg in result.stderr, str(result)
 
 
 def test_pep517_backend_requirements_already_satisfied(script, tmpdir, data):
     project_dir = make_project(
-        tmpdir, requires=['test_backend', 'simplewheel==1.0'],
-        backend="test_backend"
+        tmpdir, requires=["test_backend", "simplewheel==1.0"], backend="test_backend"
     )
     project_dir.joinpath("backend_reqs.txt").write_text("simplewheel")
     result = script.pip(
-        'install', '--no-index',
-        '-f', data.backends,
-        '-f', data.packages,
+        "install",
+        "--no-index",
+        "-f",
+        data.backends,
+        "-f",
+        data.packages,
         project_dir,
     )
-    assert 'Installing backend dependencies:' not in result.stdout
+    assert "Installing backend dependencies:" not in result.stdout
 
 
 def test_pep517_install_with_no_cache_dir(script, tmpdir, data):
-    """Check builds with a custom backends work, even with no cache.
-    """
+    """Check builds with a custom backends work, even with no cache."""
     project_dir = make_project(
-        tmpdir, requires=['test_backend'],
-        backend="test_backend"
+        tmpdir, requires=["test_backend"], backend="test_backend"
     )
     result = script.pip(
-        'install', '--no-cache-dir', '--no-index', '-f', data.backends,
+        "install",
+        "--no-cache-dir",
+        "--no-index",
+        "-f",
+        data.backends,
         project_dir,
     )
-    result.assert_installed('project', editable=False)
+    result.assert_installed("project", editable=False)
 
 
 def make_pyproject_with_setup(tmpdir, build_system=True, set_backend=True):
-    project_dir = tmpdir / 'project'
+    project_dir = tmpdir / "project"
     project_dir.mkdir()
-    setup_script = (
-        'from setuptools import setup\n'
-    )
+    setup_script = "from setuptools import setup\n"
     expect_script_dir_on_path = True
     if build_system:
         buildsys = {
-            'requires': ['setuptools', 'wheel'],
+            "requires": ["setuptools", "wheel"],
         }
         if set_backend:
-            buildsys['build-backend'] = 'setuptools.build_meta'
+            buildsys["build-backend"] = "setuptools.build_meta"
             expect_script_dir_on_path = False
-        project_data = toml.dumps({'build-system': buildsys})
+        project_data = toml.dumps({"build-system": buildsys})
     else:
-        project_data = ''
+        project_data = ""
 
     if expect_script_dir_on_path:
-        setup_script += (
-            'from pep517_test import __version__\n'
-        )
+        setup_script += "from pep517_test import __version__\n"
     else:
         setup_script += (
-            'try:\n'
-            '    import pep517_test\n'
-            'except ImportError:\n'
-            '    pass\n'
-            'else:\n'
+            "try:\n"
+            "    import pep517_test\n"
+            "except ImportError:\n"
+            "    pass\n"
+            "else:\n"
             '    raise RuntimeError("Source dir incorrectly on sys.path")\n'
         )
 
-    setup_script += (
-        'setup(name="pep517_test", version="0.1", packages=["pep517_test"])'
-    )
+    setup_script += 'setup(name="pep517_test", version="0.1", packages=["pep517_test"])'
 
-    project_dir.joinpath('pyproject.toml').write_text(project_data)
-    project_dir.joinpath('setup.py').write_text(setup_script)
+    project_dir.joinpath("pyproject.toml").write_text(project_data)
+    project_dir.joinpath("setup.py").write_text(setup_script)
     package_dir = project_dir / "pep517_test"
     package_dir.mkdir()
-    package_dir.joinpath('__init__.py').write_text('__version__ = "0.1"')
+    package_dir.joinpath("__init__.py").write_text('__version__ = "0.1"')
     return project_dir, "pep517_test"
 
 
 def test_no_build_system_section(script, tmpdir, data, common_wheels):
-    """Check builds with setup.py, pyproject.toml, but no build-system section.
-    """
+    """Check builds with setup.py, pyproject.toml, but no build-system section."""
     project_dir, name = make_pyproject_with_setup(tmpdir, build_system=False)
     result = script.pip(
-        'install', '--no-cache-dir', '--no-index', '-f', common_wheels,
+        "install",
+        "--no-cache-dir",
+        "--no-index",
+        "-f",
+        common_wheels,
         project_dir,
     )
     result.assert_installed(name, editable=False)
 
 
 def test_no_build_backend_entry(script, tmpdir, data, common_wheels):
-    """Check builds with setup.py, pyproject.toml, but no build-backend entry.
-    """
+    """Check builds with setup.py, pyproject.toml, but no build-backend entry."""
     project_dir, name = make_pyproject_with_setup(tmpdir, set_backend=False)
     result = script.pip(
-        'install', '--no-cache-dir', '--no-index', '-f', common_wheels,
+        "install",
+        "--no-cache-dir",
+        "--no-index",
+        "-f",
+        common_wheels,
         project_dir,
     )
     result.assert_installed(name, editable=False)
 
 
 def test_explicit_setuptools_backend(script, tmpdir, data, common_wheels):
-    """Check builds with setup.py, pyproject.toml, and a build-backend entry.
-    """
+    """Check builds with setup.py, pyproject.toml, and a build-backend entry."""
     project_dir, name = make_pyproject_with_setup(tmpdir)
     result = script.pip(
-        'install', '--no-cache-dir', '--no-index', '-f', common_wheels,
+        "install",
+        "--no-cache-dir",
+        "--no-index",
+        "-f",
+        common_wheels,
         project_dir,
     )
     result.assert_installed(name, editable=False)
@@ -260,11 +260,15 @@ def test_pep517_and_build_options(script, tmpdir, data, common_wheels):
     """Backend generated requirements are installed in the build env"""
     project_dir, name = make_pyproject_with_setup(tmpdir)
     result = script.pip(
-        'wheel', '--wheel-dir', tmpdir,
-        '--build-option', 'foo',
-        '-f', common_wheels,
+        "wheel",
+        "--wheel-dir",
+        tmpdir,
+        "--build-option",
+        "foo",
+        "-f",
+        common_wheels,
         project_dir,
-        expect_error=True
+        expect_error=True,
     )
-    assert 'Cannot build wheel' in result.stderr
-    assert 'when --build-option is present' in result.stderr
+    assert "Cannot build wheel" in result.stderr
+    assert "when --build-option is present" in result.stderr
diff --git a/tests/functional/test_requests.py b/tests/functional/test_requests.py
index f8eef787c95..3921c39fbc2 100644
--- a/tests/functional/test_requests.py
+++ b/tests/functional/test_requests.py
@@ -4,14 +4,15 @@
 @pytest.mark.skipif
 def test_timeout(script):
     result = script.pip(
-        "--timeout", "0.01", "install", "-vvv", "INITools",
+        "--timeout",
+        "0.01",
+        "install",
+        "-vvv",
+        "INITools",
         expect_error=True,
     )
     assert (
         "Could not fetch URL https://pypi.org/simple/INITools/: "
         "timed out" in result.stdout
     )
-    assert (
-        "Could not fetch URL https://pypi.org/simple/: "
-        "timed out" in result.stdout
-    )
+    assert "Could not fetch URL https://pypi.org/simple/: " "timed out" in result.stdout
diff --git a/tests/functional/test_search.py b/tests/functional/test_search.py
index 5918b4f64f9..804b0bb1a15 100644
--- a/tests/functional/test_search.py
+++ b/tests/functional/test_search.py
@@ -5,14 +5,10 @@
 
 from pip._internal.cli.status_codes import NO_MATCHES_FOUND, SUCCESS
 from pip._internal.commands import create_command
-from pip._internal.commands.search import (
-    highest_version,
-    print_results,
-    transform_hits,
-)
+from pip._internal.commands.search import highest_version, print_results, transform_hits
 from tests.lib import pyversion
 
-if pyversion >= '3':
+if pyversion >= "3":
     VERBOSE_FALSE = False
 else:
     VERBOSE_FALSE = 0
@@ -23,8 +19,8 @@ def test_version_compare():
     Test version comparison.
 
     """
-    assert highest_version(['1.0', '2.0', '0.1']) == '2.0'
-    assert highest_version(['1.0a1', '1.0']) == '1.0'
+    assert highest_version(["1.0", "2.0", "0.1"]) == "2.0"
+    assert highest_version(["1.0a1", "1.0"]) == "1.0"
 
 
 def test_pypi_xml_transformation():
@@ -34,32 +30,32 @@ def test_pypi_xml_transformation():
     """
     pypi_hits = [
         {
-            'name': 'foo',
-            'summary': 'foo summary',
-            'version': '1.0',
+            "name": "foo",
+            "summary": "foo summary",
+            "version": "1.0",
         },
         {
-            'name': 'foo',
-            'summary': 'foo summary v2',
-            'version': '2.0',
+            "name": "foo",
+            "summary": "foo summary v2",
+            "version": "2.0",
         },
         {
-            '_pypi_ordering': 50,
-            'name': 'bar',
-            'summary': 'bar summary',
-            'version': '1.0',
+            "_pypi_ordering": 50,
+            "name": "bar",
+            "summary": "bar summary",
+            "version": "1.0",
         },
     ]
     expected = [
         {
-            'versions': ['1.0', '2.0'],
-            'name': 'foo',
-            'summary': 'foo summary v2',
+            "versions": ["1.0", "2.0"],
+            "name": "foo",
+            "summary": "foo summary v2",
         },
         {
-            'versions': ['1.0'],
-            'name': 'bar',
-            'summary': 'bar summary',
+            "versions": ["1.0"],
+            "name": "bar",
+            "summary": "bar summary",
         },
     ]
     assert transform_hits(pypi_hits) == expected
@@ -71,39 +67,39 @@ def test_basic_search(script):
     End to end test of search command.
 
     """
-    output = script.pip('search', 'pip')
+    output = script.pip("search", "pip")
     assert (
-        'The PyPA recommended tool for installing '
-        'Python packages.' in output.stdout
+        "The PyPA recommended tool for installing " "Python packages." in output.stdout
     )
 
 
 @pytest.mark.network
 @pytest.mark.skip(
-    reason=("Warehouse search behavior is different and no longer returns "
-            "multiple results. See "
-            "https://github.com/pypa/warehouse/issues/3717 for more "
-            "information."),
+    reason=(
+        "Warehouse search behavior is different and no longer returns "
+        "multiple results. See "
+        "https://github.com/pypa/warehouse/issues/3717 for more "
+        "information."
+    ),
 )
 def test_multiple_search(script):
     """
     Test searching for multiple packages at once.
 
     """
-    output = script.pip('search', 'pip', 'INITools')
+    output = script.pip("search", "pip", "INITools")
     assert (
-        'The PyPA recommended tool for installing '
-        'Python packages.' in output.stdout
+        "The PyPA recommended tool for installing " "Python packages." in output.stdout
     )
-    assert 'Tools for parsing and using INI-style files' in output.stdout
+    assert "Tools for parsing and using INI-style files" in output.stdout
 
 
 def test_search_missing_argument(script):
     """
     Test missing required argument for search
     """
-    result = script.pip('search', expect_error=True)
-    assert 'ERROR: Missing required argument (search query).' in result.stderr
+    result = script.pip("search", expect_error=True)
+    assert "ERROR: Missing required argument (search query)." in result.stderr
 
 
 @pytest.mark.network
@@ -111,7 +107,7 @@ def test_run_method_should_return_success_when_find_packages():
     """
     Test SearchCommand.run for found package
     """
-    command = create_command('search')
+    command = create_command("search")
     cmdline = "--index=https://pypi.org/pypi pip"
     with command.main_context():
         options, args = command.parse_args(cmdline.split())
@@ -124,7 +120,7 @@ def test_run_method_should_return_no_matches_found_when_does_not_find_pkgs():
     """
     Test SearchCommand.run for no matches
     """
-    command = create_command('search')
+    command = create_command("search")
     cmdline = "--index=https://pypi.org/pypi nonexistentpackage"
     with command.main_context():
         options, args = command.parse_args(cmdline.split())
@@ -137,7 +133,7 @@ def test_search_should_exit_status_code_zero_when_find_packages(script):
     """
     Test search exit status code for package found
     """
-    result = script.pip('search', 'pip')
+    result = script.pip("search", "pip")
     assert result.returncode == SUCCESS
 
 
@@ -146,7 +142,7 @@ def test_search_exit_status_code_when_finds_no_package(script):
     """
     Test search exit status code for no matches
     """
-    result = script.pip('search', 'nonexistentpackage', expect_error=True)
+    result = script.pip("search", "nonexistentpackage", expect_error=True)
     assert result.returncode == NO_MATCHES_FOUND, result.returncode
 
 
@@ -156,26 +152,24 @@ def test_latest_prerelease_install_message(caplog, monkeypatch):
     """
     hits = [
         {
-            'name': 'ni',
-            'summary': 'For knights who say Ni!',
-            'versions': ['1.0.0', '1.0.1a']
+            "name": "ni",
+            "summary": "For knights who say Ni!",
+            "versions": ["1.0.0", "1.0.1a"],
         }
     ]
 
     installed_package = pretend.stub(project_name="ni")
-    monkeypatch.setattr("pip._vendor.pkg_resources.working_set",
-                        [installed_package])
+    monkeypatch.setattr("pip._vendor.pkg_resources.working_set", [installed_package])
 
     dist = pretend.stub(version="1.0.0")
     get_dist = pretend.call_recorder(lambda x: dist)
-    monkeypatch.setattr("pip._internal.commands.search.get_distribution",
-                        get_dist)
+    monkeypatch.setattr("pip._internal.commands.search.get_distribution", get_dist)
     with caplog.at_level(logging.INFO):
         print_results(hits)
 
     message = caplog.records[-1].getMessage()
     assert 'pre-release; install with "pip install --pre"' in message
-    assert get_dist.calls == [pretend.call('ni')]
+    assert get_dist.calls == [pretend.call("ni")]
 
 
 def test_search_print_results_should_contain_latest_versions(caplog):
@@ -184,20 +178,20 @@ def test_search_print_results_should_contain_latest_versions(caplog):
     """
     hits = [
         {
-            'name': 'testlib1',
-            'summary': 'Test library 1.',
-            'versions': ['1.0.5', '1.0.3']
+            "name": "testlib1",
+            "summary": "Test library 1.",
+            "versions": ["1.0.5", "1.0.3"],
         },
         {
-            'name': 'testlib2',
-            'summary': 'Test library 1.',
-            'versions': ['2.0.1', '2.0.3']
-        }
+            "name": "testlib2",
+            "summary": "Test library 1.",
+            "versions": ["2.0.1", "2.0.3"],
+        },
     ]
 
     with caplog.at_level(logging.INFO):
         print_results(hits)
 
     log_messages = sorted([r.getMessage() for r in caplog.records])
-    assert log_messages[0].startswith('testlib1 (1.0.5)')
-    assert log_messages[1].startswith('testlib2 (2.0.3)')
+    assert log_messages[0].startswith("testlib1 (1.0.5)")
+    assert log_messages[1].startswith("testlib2 (2.0.3)")
diff --git a/tests/functional/test_show.py b/tests/functional/test_show.py
index c19228b566c..8a75608c5f0 100644
--- a/tests/functional/test_show.py
+++ b/tests/functional/test_show.py
@@ -12,13 +12,13 @@ def test_basic_show(script):
     """
     Test end to end test for show command.
     """
-    result = script.pip('show', 'pip')
+    result = script.pip("show", "pip")
     lines = result.stdout.splitlines()
     assert len(lines) == 10
-    assert 'Name: pip' in lines
-    assert 'Version: {}'.format(__version__) in lines
-    assert any(line.startswith('Location: ') for line in lines)
-    assert 'Requires: ' in lines
+    assert "Name: pip" in lines
+    assert "Version: {}".format(__version__) in lines
+    assert any(line.startswith("Location: ") for line in lines)
+    assert "Requires: " in lines
 
 
 def test_show_with_files_not_found(script, data):
@@ -26,29 +26,29 @@ def test_show_with_files_not_found(script, data):
     Test for show command with installed files listing enabled and
     installed-files.txt not found.
     """
-    editable = data.packages.joinpath('SetupPyUTF8')
-    script.pip('install', '-e', editable)
-    result = script.pip('show', '-f', 'SetupPyUTF8')
+    editable = data.packages.joinpath("SetupPyUTF8")
+    script.pip("install", "-e", editable)
+    result = script.pip("show", "-f", "SetupPyUTF8")
     lines = result.stdout.splitlines()
     assert len(lines) == 12
-    assert 'Name: SetupPyUTF8' in lines
-    assert 'Version: 0.0.0' in lines
-    assert any(line.startswith('Location: ') for line in lines)
-    assert 'Requires: ' in lines
-    assert 'Files:' in lines
-    assert 'Cannot locate installed-files.txt' in lines
+    assert "Name: SetupPyUTF8" in lines
+    assert "Version: 0.0.0" in lines
+    assert any(line.startswith("Location: ") for line in lines)
+    assert "Requires: " in lines
+    assert "Files:" in lines
+    assert "Cannot locate installed-files.txt" in lines
 
 
 def test_show_with_files_from_wheel(script, data):
     """
     Test that a wheel's files can be listed
     """
-    wheel_file = data.packages.joinpath('simple.dist-0.1-py2.py3-none-any.whl')
-    script.pip('install', '--no-index', wheel_file)
-    result = script.pip('show', '-f', 'simple.dist')
+    wheel_file = data.packages.joinpath("simple.dist-0.1-py2.py3-none-any.whl")
+    script.pip("install", "--no-index", wheel_file)
+    result = script.pip("show", "-f", "simple.dist")
     lines = result.stdout.splitlines()
-    assert 'Name: simple.dist' in lines
-    assert 'Cannot locate installed-files.txt' not in lines[6], lines[6]
+    assert "Name: simple.dist" in lines
+    assert "Cannot locate installed-files.txt" not in lines[6], lines[6]
     assert re.search(r"Files:\n(  .+\n)+", result.stdout)
 
 
@@ -57,10 +57,10 @@ def test_show_with_all_files(script):
     """
     Test listing all files in the show command.
     """
-    script.pip('install', 'initools==0.2')
-    result = script.pip('show', '--files', 'initools')
+    script.pip("install", "initools==0.2")
+    result = script.pip("show", "--files", "initools")
     lines = result.stdout.splitlines()
-    assert 'Cannot locate installed-files.txt' not in lines[6], lines[6]
+    assert "Cannot locate installed-files.txt" not in lines[6], lines[6]
     assert re.search(r"Files:\n(  .+\n)+", result.stdout)
 
 
@@ -68,15 +68,15 @@ def test_missing_argument(script):
     """
     Test show command with no arguments.
     """
-    result = script.pip('show', expect_error=True)
-    assert 'ERROR: Please provide a package name or names.' in result.stderr
+    result = script.pip("show", expect_error=True)
+    assert "ERROR: Please provide a package name or names." in result.stderr
 
 
 def test_find_package_not_found():
     """
     Test trying to get info about a nonexistent package.
     """
-    result = search_packages_info(['abcd3'])
+    result = search_packages_info(["abcd3"])
     assert len(list(result)) == 0
 
 
@@ -89,8 +89,8 @@ def test_report_single_not_found(script):
     # Also, the following should report an error as there are no results
     # to print. Consequently, there is no need to pass
     # allow_stderr_warning=True since this is implied by expect_error=True.
-    result = script.pip('show', 'Abcd-3', expect_error=True)
-    assert 'WARNING: Package(s) not found: Abcd-3' in result.stderr
+    result = script.pip("show", "Abcd-3", expect_error=True)
+    assert "WARNING: Package(s) not found: Abcd-3" in result.stderr
     assert not result.stdout.splitlines()
 
 
@@ -99,13 +99,11 @@ def test_report_mixed_not_found(script):
     Test passing a mixture of found and not-found names.
     """
     # We test passing non-canonicalized names.
-    result = script.pip(
-        'show', 'Abcd3', 'A-B-C', 'pip', allow_stderr_warning=True
-    )
-    assert 'WARNING: Package(s) not found: A-B-C, Abcd3' in result.stderr
+    result = script.pip("show", "Abcd3", "A-B-C", "pip", allow_stderr_warning=True)
+    assert "WARNING: Package(s) not found: A-B-C, Abcd3" in result.stderr
     lines = result.stdout.splitlines()
     assert len(lines) == 10
-    assert 'Name: pip' in lines
+    assert "Name: pip" in lines
 
 
 def test_search_any_case():
@@ -113,9 +111,9 @@ def test_search_any_case():
     Search for a package in any case.
 
     """
-    result = list(search_packages_info(['PIP']))
+    result = list(search_packages_info(["PIP"]))
     assert len(result) == 1
-    assert result[0]['name'] == 'pip'
+    assert result[0]["name"] == "pip"
 
 
 def test_more_than_one_package():
@@ -123,7 +121,7 @@ def test_more_than_one_package():
     Search for more than one package.
 
     """
-    result = list(search_packages_info(['pIp', 'pytest', 'Virtualenv']))
+    result = list(search_packages_info(["pIp", "pytest", "Virtualenv"]))
     assert len(result) == 3
 
 
@@ -131,9 +129,9 @@ def test_show_verbose_with_classifiers(script):
     """
     Test that classifiers can be listed
     """
-    result = script.pip('show', 'pip', '--verbose')
+    result = script.pip("show", "pip", "--verbose")
     lines = result.stdout.splitlines()
-    assert 'Name: pip' in lines
+    assert "Name: pip" in lines
     assert re.search(r"Classifiers:\n(  .+\n)+", result.stdout)
     assert "Intended Audience :: Developers" in result.stdout
 
@@ -142,36 +140,45 @@ def test_show_verbose_installer(script, data):
     """
     Test that the installer is shown (this currently needs a wheel install)
     """
-    wheel_file = data.packages.joinpath('simple.dist-0.1-py2.py3-none-any.whl')
-    script.pip('install', '--no-index', wheel_file)
-    result = script.pip('show', '--verbose', 'simple.dist')
+    wheel_file = data.packages.joinpath("simple.dist-0.1-py2.py3-none-any.whl")
+    script.pip("install", "--no-index", wheel_file)
+    result = script.pip("show", "--verbose", "simple.dist")
     lines = result.stdout.splitlines()
-    assert 'Name: simple.dist' in lines
-    assert 'Installer: pip' in lines
+    assert "Name: simple.dist" in lines
+    assert "Installer: pip" in lines
 
 
 def test_show_verbose(script):
     """
     Test end to end test for verbose show command.
     """
-    result = script.pip('show', '--verbose', 'pip')
+    result = script.pip("show", "--verbose", "pip")
     lines = result.stdout.splitlines()
-    assert any(line.startswith('Metadata-Version: ') for line in lines)
-    assert any(line.startswith('Installer: ') for line in lines)
-    assert 'Entry-points:' in lines
-    assert 'Classifiers:' in lines
+    assert any(line.startswith("Metadata-Version: ") for line in lines)
+    assert any(line.startswith("Installer: ") for line in lines)
+    assert "Entry-points:" in lines
+    assert "Classifiers:" in lines
 
 
 def test_all_fields(script):
     """
     Test that all the fields are present
     """
-    result = script.pip('show', 'pip')
+    result = script.pip("show", "pip")
     lines = result.stdout.splitlines()
-    expected = {'Name', 'Version', 'Summary', 'Home-page', 'Author',
-                'Author-email', 'License', 'Location', 'Requires',
-                'Required-by'}
-    actual = {re.sub(':.*$', '', line) for line in lines}
+    expected = {
+        "Name",
+        "Version",
+        "Summary",
+        "Home-page",
+        "Author",
+        "Author-email",
+        "License",
+        "Location",
+        "Requires",
+        "Required-by",
+    }
+    actual = {re.sub(":.*$", "", line) for line in lines}
     assert actual == expected
 
 
@@ -179,7 +186,7 @@ def test_pip_show_is_short(script):
     """
     Test that pip show stays short
     """
-    result = script.pip('show', 'pip')
+    result = script.pip("show", "pip")
     lines = result.stdout.splitlines()
     assert len(lines) <= 10
 
@@ -188,19 +195,17 @@ def test_pip_show_divider(script, data):
     """
     Expect a divider between packages
     """
-    script.pip('install', 'pip-test-package', '--no-index',
-               '-f', data.packages)
-    result = script.pip('show', 'pip', 'pip-test-package')
+    script.pip("install", "pip-test-package", "--no-index", "-f", data.packages)
+    result = script.pip("show", "pip", "pip-test-package")
     lines = result.stdout.splitlines()
     assert "---" in lines
 
 
 def test_package_name_is_canonicalized(script, data):
-    script.pip('install', 'pip-test-package', '--no-index', '-f',
-               data.packages)
+    script.pip("install", "pip-test-package", "--no-index", "-f", data.packages)
 
-    dash_show_result = script.pip('show', 'pip-test-package')
-    underscore_upper_show_result = script.pip('show', 'pip-test_Package')
+    dash_show_result = script.pip("show", "pip-test-package")
+    underscore_upper_show_result = script.pip("show", "pip-test_Package")
 
     assert underscore_upper_show_result.returncode == 0
     assert underscore_upper_show_result.stdout == dash_show_result.stdout
@@ -210,16 +215,14 @@ def test_show_required_by_packages_basic(script, data):
     """
     Test that installed packages that depend on this package are shown
     """
-    editable_path = os.path.join(data.src, 'requires_simple')
-    script.pip(
-        'install', '--no-index', '-f', data.find_links, editable_path
-    )
+    editable_path = os.path.join(data.src, "requires_simple")
+    script.pip("install", "--no-index", "-f", data.find_links, editable_path)
 
-    result = script.pip('show', 'simple')
+    result = script.pip("show", "simple")
     lines = result.stdout.splitlines()
 
-    assert 'Name: simple' in lines
-    assert 'Required-by: requires-simple' in lines
+    assert "Name: simple" in lines
+    assert "Required-by: requires-simple" in lines
 
 
 def test_show_required_by_packages_capitalized(script, data):
@@ -227,16 +230,14 @@ def test_show_required_by_packages_capitalized(script, data):
     Test that the installed packages which depend on a package are shown
     where the package has a capital letter
     """
-    editable_path = os.path.join(data.src, 'requires_capitalized')
-    script.pip(
-        'install', '--no-index', '-f', data.find_links, editable_path
-    )
+    editable_path = os.path.join(data.src, "requires_capitalized")
+    script.pip("install", "--no-index", "-f", data.find_links, editable_path)
 
-    result = script.pip('show', 'simple')
+    result = script.pip("show", "simple")
     lines = result.stdout.splitlines()
 
-    assert 'Name: simple' in lines
-    assert 'Required-by: Requires-Capitalized' in lines
+    assert "Name: simple" in lines
+    assert "Required-by: Requires-Capitalized" in lines
 
 
 def test_show_required_by_packages_requiring_capitalized(script, data):
@@ -245,21 +246,17 @@ def test_show_required_by_packages_requiring_capitalized(script, data):
     where the package has a name with a mix of
     lower and upper case letters
     """
-    required_package_path = os.path.join(data.src, 'requires_capitalized')
-    script.pip(
-        'install', '--no-index', '-f', data.find_links, required_package_path
-    )
-    editable_path = os.path.join(data.src, 'requires_requires_capitalized')
-    script.pip(
-        'install', '--no-index', '-f', data.find_links, editable_path
-    )
+    required_package_path = os.path.join(data.src, "requires_capitalized")
+    script.pip("install", "--no-index", "-f", data.find_links, required_package_path)
+    editable_path = os.path.join(data.src, "requires_requires_capitalized")
+    script.pip("install", "--no-index", "-f", data.find_links, editable_path)
 
-    result = script.pip('show', 'Requires_Capitalized')
+    result = script.pip("show", "Requires_Capitalized")
     lines = result.stdout.splitlines()
     print(lines)
 
-    assert 'Name: Requires-Capitalized' in lines
-    assert 'Required-by: requires-requires-capitalized' in lines
+    assert "Name: Requires-Capitalized" in lines
+    assert "Required-by: requires-requires-capitalized" in lines
 
 
 def test_show_skip_work_dir_pkg(script):
@@ -269,14 +266,12 @@ def test_show_skip_work_dir_pkg(script):
     """
 
     # Create a test package and create .egg-info dir
-    pkg_path = create_test_package_with_setup(
-        script, name='simple', version='1.0')
-    script.run('python', 'setup.py', 'egg_info',
-               expect_stderr=True, cwd=pkg_path)
+    pkg_path = create_test_package_with_setup(script, name="simple", version="1.0")
+    script.run("python", "setup.py", "egg_info", expect_stderr=True, cwd=pkg_path)
 
     # Show should not include package simple when run from package directory
-    result = script.pip('show', 'simple', expect_error=True, cwd=pkg_path)
-    assert 'WARNING: Package(s) not found: simple' in result.stderr
+    result = script.pip("show", "simple", expect_error=True, cwd=pkg_path)
+    assert "WARNING: Package(s) not found: simple" in result.stderr
 
 
 def test_show_include_work_dir_pkg(script):
@@ -286,15 +281,13 @@ def test_show_include_work_dir_pkg(script):
     """
 
     # Create a test package and create .egg-info dir
-    pkg_path = create_test_package_with_setup(
-        script, name='simple', version='1.0')
-    script.run('python', 'setup.py', 'egg_info',
-               expect_stderr=True, cwd=pkg_path)
+    pkg_path = create_test_package_with_setup(script, name="simple", version="1.0")
+    script.run("python", "setup.py", "egg_info", expect_stderr=True, cwd=pkg_path)
 
-    script.environ.update({'PYTHONPATH': pkg_path})
+    script.environ.update({"PYTHONPATH": pkg_path})
 
     # Show should include package simple when run from package directory,
     # when package directory is in PYTHONPATH
-    result = script.pip('show', 'simple', cwd=pkg_path)
+    result = script.pip("show", "simple", cwd=pkg_path)
     lines = result.stdout.splitlines()
-    assert 'Name: simple' in lines
+    assert "Name: simple" in lines
diff --git a/tests/functional/test_uninstall.py b/tests/functional/test_uninstall.py
index 5def6587174..d06b5c9b410 100644
--- a/tests/functional/test_uninstall.py
+++ b/tests/functional/test_uninstall.py
@@ -13,11 +13,7 @@
 
 from pip._internal.req.constructors import install_req_from_line
 from pip._internal.utils.misc import rmtree
-from tests.lib import (
-    assert_all_changes,
-    create_test_package_with_setup,
-    need_svn,
-)
+from tests.lib import assert_all_changes, create_test_package_with_setup, need_svn
 from tests.lib.local_repos import local_checkout, local_repo
 
 
@@ -27,13 +23,13 @@ def test_basic_uninstall(script):
     Test basic install and uninstall.
 
     """
-    result = script.pip('install', 'INITools==0.2')
-    result.did_create(join(script.site_packages, 'initools'))
+    result = script.pip("install", "INITools==0.2")
+    result.did_create(join(script.site_packages, "initools"))
     # the import forces the generation of __pycache__ if the version of python
     # supports it
-    script.run('python', '-c', "import initools")
-    result2 = script.pip('uninstall', 'INITools', '-y')
-    assert_all_changes(result, result2, [script.venv / 'build', 'cache'])
+    script.run("python", "-c", "import initools")
+    result2 = script.pip("uninstall", "INITools", "-y")
+    assert_all_changes(result, result2, [script.venv / "build", "cache"])
 
 
 def test_basic_uninstall_distutils(script):
@@ -42,20 +38,24 @@ def test_basic_uninstall_distutils(script):
 
     """
     script.scratch_path.joinpath("distutils_install").mkdir()
-    pkg_path = script.scratch_path / 'distutils_install'
-    pkg_path.joinpath("setup.py").write_text(textwrap.dedent("""
+    pkg_path = script.scratch_path / "distutils_install"
+    pkg_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
         from distutils.core import setup
         setup(
             name='distutils-install',
             version='0.1',
         )
-    """))
-    result = script.run('python', pkg_path / 'setup.py', 'install')
-    result = script.pip('list', '--format=json')
-    assert {"name": "distutils-install", "version": "0.1"} \
-        in json.loads(result.stdout)
-    result = script.pip('uninstall', 'distutils_install', '-y',
-                        expect_stderr=True, expect_error=True)
+    """
+        )
+    )
+    result = script.run("python", pkg_path / "setup.py", "install")
+    result = script.pip("list", "--format=json")
+    assert {"name": "distutils-install", "version": "0.1"} in json.loads(result.stdout)
+    result = script.pip(
+        "uninstall", "distutils_install", "-y", expect_stderr=True, expect_error=True
+    )
     assert (
         "Cannot uninstall 'distutils-install'. It is a distutils installed "
         "project and thus we cannot accurately determine which files belong "
@@ -69,15 +69,15 @@ def test_basic_uninstall_with_scripts(script):
     Uninstall an easy_installed package with scripts.
 
     """
-    result = script.easy_install('PyLogo', expect_stderr=True)
-    easy_install_pth = script.site_packages / 'easy-install.pth'
-    pylogo = sys.platform == 'win32' and 'pylogo' or 'PyLogo'
-    assert(pylogo in result.files_updated[easy_install_pth].bytes)
-    result2 = script.pip('uninstall', 'pylogo', '-y')
+    result = script.easy_install("PyLogo", expect_stderr=True)
+    easy_install_pth = script.site_packages / "easy-install.pth"
+    pylogo = sys.platform == "win32" and "pylogo" or "PyLogo"
+    assert pylogo in result.files_updated[easy_install_pth].bytes
+    result2 = script.pip("uninstall", "pylogo", "-y")
     assert_all_changes(
         result,
         result2,
-        [script.venv / 'build', 'cache', easy_install_pth],
+        [script.venv / "build", "cache", easy_install_pth],
     )
 
 
@@ -87,19 +87,19 @@ def test_uninstall_easy_install_after_import(script):
     Uninstall an easy_installed package after it's been imported
 
     """
-    result = script.easy_install('INITools==0.2', expect_stderr=True)
+    result = script.easy_install("INITools==0.2", expect_stderr=True)
     # the import forces the generation of __pycache__ if the version of python
     # supports it
-    script.run('python', '-c', "import initools")
-    result2 = script.pip('uninstall', 'INITools', '-y')
+    script.run("python", "-c", "import initools")
+    result2 = script.pip("uninstall", "INITools", "-y")
     assert_all_changes(
         result,
         result2,
         [
-            script.venv / 'build',
-            'cache',
-            script.site_packages / 'easy-install.pth',
-        ]
+            script.venv / "build",
+            "cache",
+            script.site_packages / "easy-install.pth",
+        ],
     )
 
 
@@ -110,26 +110,25 @@ def test_uninstall_trailing_newline(script):
     lacks a trailing newline
 
     """
-    script.easy_install('INITools==0.2', expect_stderr=True)
-    script.easy_install('PyLogo', expect_stderr=True)
-    easy_install_pth = script.site_packages_path / 'easy-install.pth'
+    script.easy_install("INITools==0.2", expect_stderr=True)
+    script.easy_install("PyLogo", expect_stderr=True)
+    easy_install_pth = script.site_packages_path / "easy-install.pth"
 
     # trim trailing newline from easy-install.pth
     with open(easy_install_pth) as f:
         pth_before = f.read()
 
-    with open(easy_install_pth, 'w') as f:
+    with open(easy_install_pth, "w") as f:
         f.write(pth_before.rstrip())
 
     # uninstall initools
-    script.pip('uninstall', 'INITools', '-y')
+    script.pip("uninstall", "INITools", "-y")
     with open(easy_install_pth) as f:
         pth_after = f.read()
 
     # verify that only initools is removed
     before_without_initools = [
-        line for line in pth_before.splitlines()
-        if 'initools' not in line.lower()
+        line for line in pth_before.splitlines() if "initools" not in line.lower()
     ]
     lines_after = pth_after.splitlines()
 
@@ -143,14 +142,14 @@ def test_basic_uninstall_namespace_package(script):
     the namespace and everything in it.
 
     """
-    result = script.pip('install', 'pd.requires==0.0.3')
-    result.did_create(join(script.site_packages, 'pd'))
-    result2 = script.pip('uninstall', 'pd.find', '-y')
-    assert join(script.site_packages, 'pd') not in result2.files_deleted, (
-        sorted(result2.files_deleted.keys())
+    result = script.pip("install", "pd.requires==0.0.3")
+    result.did_create(join(script.site_packages, "pd"))
+    result2 = script.pip("uninstall", "pd.find", "-y")
+    assert join(script.site_packages, "pd") not in result2.files_deleted, sorted(
+        result2.files_deleted.keys()
     )
-    assert join(script.site_packages, 'pd', 'find') in result2.files_deleted, (
-        sorted(result2.files_deleted.keys())
+    assert join(script.site_packages, "pd", "find") in result2.files_deleted, sorted(
+        result2.files_deleted.keys()
     )
 
 
@@ -165,65 +164,66 @@ def test_uninstall_overlapping_package(script, data):
     parent_pkg = data.packages.joinpath("parent-0.1.tar.gz")
     child_pkg = data.packages.joinpath("child-0.1.tar.gz")
 
-    result1 = script.pip('install', parent_pkg)
-    result1.did_create(join(script.site_packages, 'parent'))
-    result2 = script.pip('install', child_pkg)
-    result2.did_create(join(script.site_packages, 'child'))
-    result2.did_create(normpath(
-        join(script.site_packages, 'parent/plugins/child_plugin.py')
-    ))
+    result1 = script.pip("install", parent_pkg)
+    result1.did_create(join(script.site_packages, "parent"))
+    result2 = script.pip("install", child_pkg)
+    result2.did_create(join(script.site_packages, "child"))
+    result2.did_create(
+        normpath(join(script.site_packages, "parent/plugins/child_plugin.py"))
+    )
     # The import forces the generation of __pycache__ if the version of python
     #  supports it
-    script.run('python', '-c', "import parent.plugins.child_plugin, child")
-    result3 = script.pip('uninstall', '-y', 'child')
-    assert join(script.site_packages, 'child') in result3.files_deleted, (
-        sorted(result3.files_created.keys())
+    script.run("python", "-c", "import parent.plugins.child_plugin, child")
+    result3 = script.pip("uninstall", "-y", "child")
+    assert join(script.site_packages, "child") in result3.files_deleted, sorted(
+        result3.files_created.keys()
     )
-    assert normpath(
-        join(script.site_packages, 'parent/plugins/child_plugin.py')
-    ) in result3.files_deleted, sorted(result3.files_deleted.keys())
-    assert join(script.site_packages, 'parent') not in result3.files_deleted, (
-        sorted(result3.files_deleted.keys())
+    assert (
+        normpath(join(script.site_packages, "parent/plugins/child_plugin.py"))
+        in result3.files_deleted
+    ), sorted(result3.files_deleted.keys())
+    assert join(script.site_packages, "parent") not in result3.files_deleted, sorted(
+        result3.files_deleted.keys()
     )
     # Additional check: uninstalling 'child' should return things to the
     # previous state, without unintended side effects.
     assert_all_changes(result2, result3, [])
 
 
-@pytest.mark.parametrize("console_scripts",
-                         ["test_ = distutils_install",
-                          "test_:test_ = distutils_install"])
+@pytest.mark.parametrize(
+    "console_scripts", ["test_ = distutils_install", "test_:test_ = distutils_install"]
+)
 def test_uninstall_entry_point_colon_in_name(script, console_scripts):
     """
     Test uninstall package with two or more entry points in the same section,
     whose name contain a colon.
     """
-    pkg_name = 'ep_install'
+    pkg_name = "ep_install"
     pkg_path = create_test_package_with_setup(
         script,
         name=pkg_name,
-        version='0.1',
-        entry_points={"console_scripts": [console_scripts, ],
-                      "pip_test.ep":
-                      ["ep:name1 = distutils_install",
-                       "ep:name2 = distutils_install"]
-                      }
-    )
-    script_name = script.bin_path.joinpath(
-        console_scripts.split('=')[0].strip()
+        version="0.1",
+        entry_points={
+            "console_scripts": [
+                console_scripts,
+            ],
+            "pip_test.ep": [
+                "ep:name1 = distutils_install",
+                "ep:name2 = distutils_install",
+            ],
+        },
     )
-    if sys.platform == 'win32':
-        script_name += '.exe'
-    result = script.pip('install', pkg_path)
+    script_name = script.bin_path.joinpath(console_scripts.split("=")[0].strip())
+    if sys.platform == "win32":
+        script_name += ".exe"
+    result = script.pip("install", pkg_path)
     assert script_name.exists()
-    result = script.pip('list', '--format=json')
-    assert {"name": "ep-install", "version": "0.1"} \
-        in json.loads(result.stdout)
-    script.pip('uninstall', 'ep_install', '-y')
+    result = script.pip("list", "--format=json")
+    assert {"name": "ep-install", "version": "0.1"} in json.loads(result.stdout)
+    script.pip("uninstall", "ep_install", "-y")
     assert not script_name.exists()
-    result2 = script.pip('list', '--format=json')
-    assert {"name": "ep-install", "version": "0.1"} \
-        not in json.loads(result2.stdout)
+    result2 = script.pip("list", "--format=json")
+    assert {"name": "ep-install", "version": "0.1"} not in json.loads(result2.stdout)
 
 
 def test_uninstall_gui_scripts(script):
@@ -234,15 +234,19 @@ def test_uninstall_gui_scripts(script):
     pkg_path = create_test_package_with_setup(
         script,
         name=pkg_name,
-        version='0.1',
-        entry_points={"gui_scripts": ["test_ = distutils_install", ], }
+        version="0.1",
+        entry_points={
+            "gui_scripts": [
+                "test_ = distutils_install",
+            ],
+        },
     )
-    script_name = script.bin_path.joinpath('test_')
-    if sys.platform == 'win32':
-        script_name += '.exe'
-    script.pip('install', pkg_path)
+    script_name = script.bin_path.joinpath("test_")
+    if sys.platform == "win32":
+        script_name += ".exe"
+    script.pip("install", pkg_path)
     assert script_name.exists()
-    script.pip('uninstall', pkg_name, '-y')
+    script.pip("uninstall", pkg_name, "-y")
     assert not script_name.exists()
 
 
@@ -253,14 +257,14 @@ def test_uninstall_console_scripts(script):
     """
     pkg_path = create_test_package_with_setup(
         script,
-        name='discover',
-        version='0.1',
-        entry_points={'console_scripts': ['discover = discover:main']},
+        name="discover",
+        version="0.1",
+        entry_points={"console_scripts": ["discover = discover:main"]},
     )
-    result = script.pip('install', pkg_path)
-    result.did_create(script.bin / 'discover' + script.exe)
-    result2 = script.pip('uninstall', 'discover', '-y')
-    assert_all_changes(result, result2, [script.venv / 'build', 'cache'])
+    result = script.pip("install", pkg_path)
+    result.did_create(script.bin / "discover" + script.exe)
+    result2 = script.pip("uninstall", "discover", "-y")
+    assert_all_changes(result, result2, [script.venv / "build", "cache"])
 
 
 def test_uninstall_console_scripts_uppercase_name(script):
@@ -269,20 +273,20 @@ def test_uninstall_console_scripts_uppercase_name(script):
     """
     pkg_path = create_test_package_with_setup(
         script,
-        name='ep_install',
-        version='0.1',
+        name="ep_install",
+        version="0.1",
         entry_points={
             "console_scripts": [
                 "Test = distutils_install",
             ],
         },
     )
-    script_name = script.bin_path.joinpath('Test' + script.exe)
+    script_name = script.bin_path.joinpath("Test" + script.exe)
 
-    script.pip('install', pkg_path)
+    script.pip("install", pkg_path)
     assert script_name.exists()
 
-    script.pip('uninstall', 'ep_install', '-y')
+    script.pip("uninstall", "ep_install", "-y")
     assert not script_name.exists()
 
 
@@ -293,17 +297,17 @@ def test_uninstall_easy_installed_console_scripts(script):
     """
     # setuptools >= 42.0.0 deprecates easy_install and prints a warning when
     # used
-    result = script.easy_install('discover', allow_stderr_warning=True)
-    result.did_create(script.bin / 'discover' + script.exe)
-    result2 = script.pip('uninstall', 'discover', '-y')
+    result = script.easy_install("discover", allow_stderr_warning=True)
+    result.did_create(script.bin / "discover" + script.exe)
+    result2 = script.pip("uninstall", "discover", "-y")
     assert_all_changes(
         result,
         result2,
         [
-            script.venv / 'build',
-            'cache',
-            script.site_packages / 'easy-install.pth',
-        ]
+            script.venv / "build",
+            "cache",
+            script.site_packages / "easy-install.pth",
+        ],
     )
 
 
@@ -315,22 +319,22 @@ def test_uninstall_editable_from_svn(script, tmpdir):
     Test uninstalling an editable installation from svn.
     """
     result = script.pip(
-        'install', '-e',
-        '{checkout}#egg=initools'.format(
-            checkout=local_checkout(
-                'svn+http://svn.colorstudy.com/INITools', tmpdir)
+        "install",
+        "-e",
+        "{checkout}#egg=initools".format(
+            checkout=local_checkout("svn+http://svn.colorstudy.com/INITools", tmpdir)
         ),
     )
-    result.assert_installed('INITools')
-    result2 = script.pip('uninstall', '-y', 'initools')
-    assert (script.venv / 'src' / 'initools' in result2.files_after)
+    result.assert_installed("INITools")
+    result2 = script.pip("uninstall", "-y", "initools")
+    assert script.venv / "src" / "initools" in result2.files_after
     assert_all_changes(
         result,
         result2,
         [
-            script.venv / 'src',
-            script.venv / 'build',
-            script.site_packages / 'easy-install.pth'
+            script.venv / "src",
+            script.venv / "build",
+            script.site_packages / "easy-install.pth",
         ],
     )
 
@@ -342,7 +346,7 @@ def test_uninstall_editable_with_source_outside_venv(script, tmpdir):
     """
     try:
         temp = mkdtemp()
-        temp_pkg_dir = join(temp, 'pip-test-package')
+        temp_pkg_dir = join(temp, "pip-test-package")
         _test_uninstall_editable_with_source_outside_venv(
             script,
             tmpdir,
@@ -353,23 +357,24 @@ def test_uninstall_editable_with_source_outside_venv(script, tmpdir):
 
 
 def _test_uninstall_editable_with_source_outside_venv(
-    script, tmpdir, temp_pkg_dir,
+    script,
+    tmpdir,
+    temp_pkg_dir,
 ):
     result = script.run(
-        'git', 'clone',
-        local_repo('git+git://github.com/pypa/pip-test-package', tmpdir),
+        "git",
+        "clone",
+        local_repo("git+git://github.com/pypa/pip-test-package", tmpdir),
         temp_pkg_dir,
         expect_stderr=True,
     )
-    result2 = script.pip('install', '-e', temp_pkg_dir)
-    result2.did_create(join(
-        script.site_packages, 'pip-test-package.egg-link'
-    ))
-    result3 = script.pip('uninstall', '-y', 'pip-test-package')
+    result2 = script.pip("install", "-e", temp_pkg_dir)
+    result2.did_create(join(script.site_packages, "pip-test-package.egg-link"))
+    result3 = script.pip("uninstall", "-y", "pip-test-package")
     assert_all_changes(
         result,
         result3,
-        [script.venv / 'build', script.site_packages / 'easy-install.pth'],
+        [script.venv / "build", script.site_packages / "easy-install.pth"],
     )
 
 
@@ -382,18 +387,22 @@ def test_uninstall_from_reqs_file(script, tmpdir):
 
     """
     local_svn_url = local_checkout(
-        'svn+http://svn.colorstudy.com/INITools', tmpdir,
+        "svn+http://svn.colorstudy.com/INITools",
+        tmpdir,
     )
     script.scratch_path.joinpath("test-req.txt").write_text(
-        textwrap.dedent("""
+        textwrap.dedent(
+            """
             -e {url}#egg=initools
             # and something else to test out:
             PyLogo<0.4
-        """).format(url=local_svn_url)
+        """
+        ).format(url=local_svn_url)
     )
-    result = script.pip('install', '-r', 'test-req.txt')
+    result = script.pip("install", "-r", "test-req.txt")
     script.scratch_path.joinpath("test-req.txt").write_text(
-        textwrap.dedent("""
+        textwrap.dedent(
+            """
             # -f, -i, and --extra-index-url should all be ignored by uninstall
             -f http://www.example.com
             -i http://www.example.com
@@ -402,17 +411,18 @@ def test_uninstall_from_reqs_file(script, tmpdir):
             -e {url}#egg=initools
             # and something else to test out:
             PyLogo<0.4
-        """).format(url=local_svn_url)
+        """
+        ).format(url=local_svn_url)
     )
-    result2 = script.pip('uninstall', '-r', 'test-req.txt', '-y')
+    result2 = script.pip("uninstall", "-r", "test-req.txt", "-y")
     assert_all_changes(
         result,
         result2,
         [
-            script.venv / 'build',
-            script.venv / 'src',
-            script.scratch / 'test-req.txt',
-            script.site_packages / 'easy-install.pth',
+            script.venv / "build",
+            script.venv / "src",
+            script.scratch / "test-req.txt",
+            script.site_packages / "easy-install.pth",
         ],
     )
 
@@ -428,14 +438,11 @@ def test_uninstallpathset_no_paths(caplog):
 
     caplog.set_level(logging.INFO)
 
-    test_dist = get_distribution('pip')
+    test_dist = get_distribution("pip")
     uninstall_set = UninstallPathSet(test_dist)
     uninstall_set.remove()  # with no files added to set
 
-    assert (
-        "Can't uninstall 'pip'. No files were found to uninstall."
-        in caplog.text
-    )
+    assert "Can't uninstall 'pip'. No files were found to uninstall." in caplog.text
 
 
 def test_uninstall_non_local_distutils(caplog, monkeypatch, tmpdir):
@@ -464,10 +471,10 @@ def test_uninstall_wheel(script, data):
     Test uninstalling a wheel
     """
     package = data.packages.joinpath("simple.dist-0.1-py2.py3-none-any.whl")
-    result = script.pip('install', package, '--no-index')
-    dist_info_folder = script.site_packages / 'simple.dist-0.1.dist-info'
+    result = script.pip("install", package, "--no-index")
+    dist_info_folder = script.site_packages / "simple.dist-0.1.dist-info"
     result.did_create(dist_info_folder)
-    result2 = script.pip('uninstall', 'simple.dist', '-y')
+    result2 = script.pip("uninstall", "simple.dist", "-y")
     assert_all_changes(result, result2, [])
 
 
@@ -478,17 +485,17 @@ def test_uninstall_with_symlink(script, data, tmpdir):
     https://github.com/pypa/pip/issues/6892
     """
     package = data.packages.joinpath("simple.dist-0.1-py2.py3-none-any.whl")
-    script.pip('install', package, '--no-index')
+    script.pip("install", package, "--no-index")
     symlink_target = tmpdir / "target"
     symlink_target.mkdir()
     symlink_source = script.site_packages / "symlink"
     (script.base_path / symlink_source).symlink_to(symlink_target)
     st_mode = symlink_target.stat().st_mode
-    distinfo_path = script.site_packages_path / 'simple.dist-0.1.dist-info'
-    record_path = distinfo_path / 'RECORD'
+    distinfo_path = script.site_packages_path / "simple.dist-0.1.dist-info"
+    record_path = distinfo_path / "RECORD"
     with open(record_path, "a") as f:
         f.write("symlink,,\n")
-    uninstall_result = script.pip('uninstall', 'simple.dist', '-y')
+    uninstall_result = script.pip("uninstall", "simple.dist", "-y")
     assert symlink_source in uninstall_result.files_deleted
     assert symlink_target.stat().st_mode == st_mode
 
@@ -496,22 +503,20 @@ def test_uninstall_with_symlink(script, data, tmpdir):
 def test_uninstall_setuptools_develop_install(script, data):
     """Try uninstall after setup.py develop followed of setup.py install"""
     pkg_path = data.packages.joinpath("FSPkg")
-    script.run('python', 'setup.py', 'develop',
-               expect_stderr=True, cwd=pkg_path)
-    script.run('python', 'setup.py', 'install',
-               expect_stderr=True, cwd=pkg_path)
-    list_result = script.pip('list', '--format=json')
-    assert {"name": os.path.normcase("FSPkg"), "version": "0.1.dev0"} \
-        in json.loads(list_result.stdout), str(list_result)
+    script.run("python", "setup.py", "develop", expect_stderr=True, cwd=pkg_path)
+    script.run("python", "setup.py", "install", expect_stderr=True, cwd=pkg_path)
+    list_result = script.pip("list", "--format=json")
+    assert {"name": os.path.normcase("FSPkg"), "version": "0.1.dev0"} in json.loads(
+        list_result.stdout
+    ), str(list_result)
     # Uninstall both develop and install
-    uninstall = script.pip('uninstall', 'FSPkg', '-y')
-    assert any(filename.endswith('.egg')
-               for filename in uninstall.files_deleted.keys())
-    uninstall2 = script.pip('uninstall', 'FSPkg', '-y')
-    assert join(
-        script.site_packages, 'FSPkg.egg-link'
-    ) in uninstall2.files_deleted, list(uninstall2.files_deleted.keys())
-    list_result2 = script.pip('list', '--format=json')
+    uninstall = script.pip("uninstall", "FSPkg", "-y")
+    assert any(filename.endswith(".egg") for filename in uninstall.files_deleted.keys())
+    uninstall2 = script.pip("uninstall", "FSPkg", "-y")
+    assert (
+        join(script.site_packages, "FSPkg.egg-link") in uninstall2.files_deleted
+    ), list(uninstall2.files_deleted.keys())
+    list_result2 = script.pip("list", "--format=json")
     assert "FSPkg" not in {p["name"] for p in json.loads(list_result2.stdout)}
 
 
@@ -520,26 +525,24 @@ def test_uninstall_editable_and_pip_install(script, data):
     # SETUPTOOLS_SYS_PATH_TECHNIQUE=raw removes the assumption that `-e`
     # installs are always higher priority than regular installs.
     # This becomes the default behavior in setuptools 25.
-    script.environ['SETUPTOOLS_SYS_PATH_TECHNIQUE'] = 'raw'
+    script.environ["SETUPTOOLS_SYS_PATH_TECHNIQUE"] = "raw"
 
     pkg_path = data.packages.joinpath("FSPkg")
-    script.pip('install', '-e', '.',
-               expect_stderr=True, cwd=pkg_path)
+    script.pip("install", "-e", ".", expect_stderr=True, cwd=pkg_path)
     # ensure both are installed with --ignore-installed:
-    script.pip('install', '--ignore-installed', '.',
-               expect_stderr=True, cwd=pkg_path)
-    list_result = script.pip('list', '--format=json')
-    assert {"name": "FSPkg", "version": "0.1.dev0"} \
-        in json.loads(list_result.stdout)
+    script.pip("install", "--ignore-installed", ".", expect_stderr=True, cwd=pkg_path)
+    list_result = script.pip("list", "--format=json")
+    assert {"name": "FSPkg", "version": "0.1.dev0"} in json.loads(list_result.stdout)
     # Uninstall both develop and install
-    uninstall = script.pip('uninstall', 'FSPkg', '-y')
-    assert not any(filename.endswith('.egg-link')
-                   for filename in uninstall.files_deleted.keys())
-    uninstall2 = script.pip('uninstall', 'FSPkg', '-y')
-    assert join(
-        script.site_packages, 'FSPkg.egg-link'
-    ) in uninstall2.files_deleted, list(uninstall2.files_deleted.keys())
-    list_result2 = script.pip('list', '--format=json')
+    uninstall = script.pip("uninstall", "FSPkg", "-y")
+    assert not any(
+        filename.endswith(".egg-link") for filename in uninstall.files_deleted.keys()
+    )
+    uninstall2 = script.pip("uninstall", "FSPkg", "-y")
+    assert (
+        join(script.site_packages, "FSPkg.egg-link") in uninstall2.files_deleted
+    ), list(uninstall2.files_deleted.keys())
+    list_result2 = script.pip("list", "--format=json")
     assert "FSPkg" not in {p["name"] for p in json.loads(list_result2.stdout)}
 
 
@@ -549,52 +552,53 @@ def test_uninstall_editable_and_pip_install_easy_install_remove(script, data):
     # SETUPTOOLS_SYS_PATH_TECHNIQUE=raw removes the assumption that `-e`
     # installs are always higher priority than regular installs.
     # This becomes the default behavior in setuptools 25.
-    script.environ['SETUPTOOLS_SYS_PATH_TECHNIQUE'] = 'raw'
+    script.environ["SETUPTOOLS_SYS_PATH_TECHNIQUE"] = "raw"
 
     # Rename easy-install.pth to pip-test.pth
-    easy_install_pth = join(script.site_packages_path, 'easy-install.pth')
-    pip_test_pth = join(script.site_packages_path, 'pip-test.pth')
+    easy_install_pth = join(script.site_packages_path, "easy-install.pth")
+    pip_test_pth = join(script.site_packages_path, "pip-test.pth")
     os.rename(easy_install_pth, pip_test_pth)
 
     # Install FSPkg
     pkg_path = data.packages.joinpath("FSPkg")
-    script.pip('install', '-e', '.',
-               expect_stderr=True, cwd=pkg_path)
+    script.pip("install", "-e", ".", expect_stderr=True, cwd=pkg_path)
 
     # Rename easy-install.pth to pip-test-fspkg.pth
-    pip_test_fspkg_pth = join(script.site_packages_path, 'pip-test-fspkg.pth')
+    pip_test_fspkg_pth = join(script.site_packages_path, "pip-test-fspkg.pth")
     os.rename(easy_install_pth, pip_test_fspkg_pth)
 
     # Confirm that FSPkg is installed
-    list_result = script.pip('list', '--format=json')
-    assert {"name": "FSPkg", "version": "0.1.dev0"} \
-        in json.loads(list_result.stdout)
+    list_result = script.pip("list", "--format=json")
+    assert {"name": "FSPkg", "version": "0.1.dev0"} in json.loads(list_result.stdout)
 
     # Remove pip-test-fspkg.pth
     os.remove(pip_test_fspkg_pth)
 
     # Uninstall will fail with given warning
-    uninstall = script.pip('uninstall', 'FSPkg', '-y')
+    uninstall = script.pip("uninstall", "FSPkg", "-y")
     assert "Cannot remove entries from nonexistent file" in uninstall.stderr
 
-    assert join(
-        script.site_packages, 'FSPkg.egg-link'
-    ) in uninstall.files_deleted, list(uninstall.files_deleted.keys())
+    assert (
+        join(script.site_packages, "FSPkg.egg-link") in uninstall.files_deleted
+    ), list(uninstall.files_deleted.keys())
 
     # Confirm that FSPkg is uninstalled
-    list_result = script.pip('list', '--format=json')
-    assert {"name": "FSPkg", "version": "0.1.dev0"} \
-        not in json.loads(list_result.stdout)
+    list_result = script.pip("list", "--format=json")
+    assert {"name": "FSPkg", "version": "0.1.dev0"} not in json.loads(
+        list_result.stdout
+    )
 
     # Rename pip-test.pth back to easy-install.pth
     os.rename(pip_test_pth, easy_install_pth)
 
 
 def test_uninstall_ignores_missing_packages(script, data):
-    """Uninstall of a non existent package prints a warning and exits cleanly
-    """
+    """Uninstall of a non existent package prints a warning and exits cleanly"""
     result = script.pip(
-        'uninstall', '-y', 'non-existent-pkg', expect_stderr=True,
+        "uninstall",
+        "-y",
+        "non-existent-pkg",
+        expect_stderr=True,
     )
 
     assert "Skipping non-existent-pkg as it is not installed." in result.stderr
@@ -602,9 +606,13 @@ def test_uninstall_ignores_missing_packages(script, data):
 
 
 def test_uninstall_ignores_missing_packages_and_uninstalls_rest(script, data):
-    script.pip_install_local('simple')
+    script.pip_install_local("simple")
     result = script.pip(
-        'uninstall', '-y', 'non-existent-pkg', 'simple', expect_stderr=True,
+        "uninstall",
+        "-y",
+        "non-existent-pkg",
+        "simple",
+        expect_stderr=True,
     )
 
     assert "Skipping non-existent-pkg as it is not installed." in result.stderr
diff --git a/tests/functional/test_uninstall_user.py b/tests/functional/test_uninstall_user.py
index 2dbf032ac38..edaa550df44 100644
--- a/tests/functional/test_uninstall_user.py
+++ b/tests/functional/test_uninstall_user.py
@@ -12,41 +12,41 @@
 
 @pytest.mark.incompatible_with_test_venv
 class Tests_UninstallUserSite:
-
     @pytest.mark.network
     def test_uninstall_from_usersite(self, script):
         """
         Test uninstall from usersite
         """
-        result1 = script.pip('install', '--user', 'INITools==0.3')
-        result2 = script.pip('uninstall', '-y', 'INITools')
-        assert_all_changes(result1, result2, [script.venv / 'build', 'cache'])
+        result1 = script.pip("install", "--user", "INITools==0.3")
+        result2 = script.pip("uninstall", "-y", "INITools")
+        assert_all_changes(result1, result2, [script.venv / "build", "cache"])
 
-    def test_uninstall_from_usersite_with_dist_in_global_site(
-            self, virtualenv, script):
+    def test_uninstall_from_usersite_with_dist_in_global_site(self, virtualenv, script):
         """
         Test uninstall from usersite (with same dist in global site)
         """
         _patch_dist_in_site_packages(virtualenv)
 
-        script.pip_install_local('pip-test-package==0.1', '--no-binary=:all:')
+        script.pip_install_local("pip-test-package==0.1", "--no-binary=:all:")
 
         result2 = script.pip_install_local(
-            '--user', 'pip-test-package==0.1.1', '--no-binary=:all:')
-        result3 = script.pip('uninstall', '-vy', 'pip-test-package')
+            "--user", "pip-test-package==0.1.1", "--no-binary=:all:"
+        )
+        result3 = script.pip("uninstall", "-vy", "pip-test-package")
 
         # uninstall console is mentioning user scripts, but not global scripts
         assert normcase(script.user_bin_path) in result3.stdout, str(result3)
         assert normcase(script.bin_path) not in result3.stdout, str(result3)
 
         # uninstall worked
-        assert_all_changes(result2, result3, [script.venv / 'build', 'cache'])
+        assert_all_changes(result2, result3, [script.venv / "build", "cache"])
 
         # site still has 0.2 (can't look in result1; have to check)
         # keep checking for egg-info because no-binary implies setup.py install
         egg_info_folder = (
-            script.base_path / script.site_packages /
-            'pip_test_package-0.1-py{pyversion}.egg-info'.format(**globals())
+            script.base_path
+            / script.site_packages
+            / "pip_test_package-0.1-py{pyversion}.egg-info".format(**globals())
         )
         assert isdir(egg_info_folder)
 
@@ -58,22 +58,20 @@ def test_uninstall_editable_from_usersite(self, script, data):
 
         # install
         to_install = data.packages.joinpath("FSPkg")
-        result1 = script.pip(
-            'install', '--user', '-e', to_install
-        )
-        egg_link = script.user_site / 'FSPkg.egg-link'
+        result1 = script.pip("install", "--user", "-e", to_install)
+        egg_link = script.user_site / "FSPkg.egg-link"
         result1.did_create(egg_link)
 
         # uninstall
-        result2 = script.pip('uninstall', '-y', 'FSPkg')
+        result2 = script.pip("uninstall", "-y", "FSPkg")
         assert not isfile(script.base_path / egg_link)
 
         assert_all_changes(
             result1,
             result2,
             [
-                script.venv / 'build',
-                'cache',
-                script.user_site / 'easy-install.pth',
-            ]
+                script.venv / "build",
+                "cache",
+                script.user_site / "easy-install.pth",
+            ],
         )
diff --git a/tests/functional/test_vcs_bazaar.py b/tests/functional/test_vcs_bazaar.py
index d928da8b364..7228b94e4d2 100644
--- a/tests/functional/test_vcs_bazaar.py
+++ b/tests/functional/test_vcs_bazaar.py
@@ -18,8 +18,8 @@
 
 
 @pytest.mark.skipif(
-    'TRAVIS' not in os.environ,
-    reason='Bazaar is only required under Travis')
+    "TRAVIS" not in os.environ, reason="Bazaar is only required under Travis"
+)
 def test_ensure_bzr_available():
     """Make sure that bzr is available when running in Travis."""
     assert is_bzr_installed()
@@ -28,40 +28,45 @@ def test_ensure_bzr_available():
 @need_bzr
 def test_export(script, tmpdir):
     """Test that a Bazaar branch can be exported."""
-    source_dir = tmpdir / 'test-source'
+    source_dir = tmpdir / "test-source"
     source_dir.mkdir()
 
-    create_file(source_dir / 'test_file', 'something')
+    create_file(source_dir / "test_file", "something")
 
-    _vcs_add(script, str(source_dir), vcs='bazaar')
+    _vcs_add(script, str(source_dir), vcs="bazaar")
 
-    export_dir = str(tmpdir / 'export')
-    url = hide_url('bzr+' + _test_path_to_file_url(source_dir))
+    export_dir = str(tmpdir / "export")
+    url = hide_url("bzr+" + _test_path_to_file_url(source_dir))
     Bazaar().export(export_dir, url=url)
 
-    assert os.listdir(export_dir) == ['test_file']
+    assert os.listdir(export_dir) == ["test_file"]
 
 
 @need_bzr
 def test_export_rev(script, tmpdir):
     """Test that a Bazaar branch can be exported, specifying a rev."""
-    source_dir = tmpdir / 'test-source'
+    source_dir = tmpdir / "test-source"
     source_dir.mkdir()
 
     # Create a single file that is changed by two revisions.
-    create_file(source_dir / 'test_file', 'something initial')
-    _vcs_add(script, str(source_dir), vcs='bazaar')
+    create_file(source_dir / "test_file", "something initial")
+    _vcs_add(script, str(source_dir), vcs="bazaar")
 
-    create_file(source_dir / 'test_file', 'something new')
+    create_file(source_dir / "test_file", "something new")
     script.run(
-        'bzr', 'commit', '-q',
-        '--author', 'pip <distutils-sig@python.org>',
-        '-m', 'change test file', cwd=source_dir,
+        "bzr",
+        "commit",
+        "-q",
+        "--author",
+        "pip <distutils-sig@python.org>",
+        "-m",
+        "change test file",
+        cwd=source_dir,
     )
 
-    export_dir = tmpdir / 'export'
-    url = hide_url('bzr+' + _test_path_to_file_url(source_dir) + '@1')
+    export_dir = tmpdir / "export"
+    url = hide_url("bzr+" + _test_path_to_file_url(source_dir) + "@1")
     Bazaar().export(str(export_dir), url=url)
 
-    with open(export_dir / 'test_file', 'r') as f:
-        assert f.read() == 'something initial'
+    with open(export_dir / "test_file", "r") as f:
+        assert f.read() == "something initial"
diff --git a/tests/functional/test_vcs_git.py b/tests/functional/test_vcs_git.py
index 8b07ae6673b..0d13061d23b 100644
--- a/tests/functional/test_vcs_git.py
+++ b/tests/functional/test_vcs_git.py
@@ -17,24 +17,28 @@ def test_get_backend_for_scheme():
 
 def get_head_sha(script, dest):
     """Return the HEAD sha."""
-    result = script.run('git', 'rev-parse', 'HEAD', cwd=dest)
+    result = script.run("git", "rev-parse", "HEAD", cwd=dest)
     sha = result.stdout.strip()
 
     return sha
 
 
 def checkout_ref(script, repo_dir, ref):
-    script.run('git', 'checkout', ref, cwd=repo_dir)
+    script.run("git", "checkout", ref, cwd=repo_dir)
 
 
 def checkout_new_branch(script, repo_dir, branch):
     script.run(
-        'git', 'checkout', '-b', branch, cwd=repo_dir,
+        "git",
+        "checkout",
+        "-b",
+        branch,
+        cwd=repo_dir,
     )
 
 
 def do_commit(script, dest):
-    _git_commit(script, dest, message='test commit', allow_empty=True)
+    _git_commit(script, dest, message="test commit", allow_empty=True)
     return get_head_sha(script, dest)
 
 
@@ -56,43 +60,43 @@ def test_git_dir_ignored(tmpdir):
     """
     Test that a GIT_DIR environment variable is ignored.
     """
-    repo_path = tmpdir / 'test-repo'
+    repo_path = tmpdir / "test-repo"
     repo_path.mkdir()
     repo_dir = str(repo_path)
 
-    env = {'GIT_DIR': 'foo'}
+    env = {"GIT_DIR": "foo"}
     # If GIT_DIR is not ignored, then os.listdir() will return ['foo'].
-    Git.run_command(['init', repo_dir], cwd=repo_dir, extra_environ=env)
-    assert os.listdir(repo_dir) == ['.git']
+    Git.run_command(["init", repo_dir], cwd=repo_dir, extra_environ=env)
+    assert os.listdir(repo_dir) == [".git"]
 
 
 def test_git_work_tree_ignored(tmpdir):
     """
     Test that a GIT_WORK_TREE environment variable is ignored.
     """
-    repo_path = tmpdir / 'test-repo'
+    repo_path = tmpdir / "test-repo"
     repo_path.mkdir()
     repo_dir = str(repo_path)
 
-    Git.run_command(['init', repo_dir], cwd=repo_dir)
+    Git.run_command(["init", repo_dir], cwd=repo_dir)
     # Choose a directory relative to the cwd that does not exist.
     # If GIT_WORK_TREE is not ignored, then the command will error out
     # with: "fatal: This operation must be run in a work tree".
-    env = {'GIT_WORK_TREE': 'foo'}
-    Git.run_command(['status', repo_dir], extra_environ=env, cwd=repo_dir)
+    env = {"GIT_WORK_TREE": "foo"}
+    Git.run_command(["status", repo_dir], extra_environ=env, cwd=repo_dir)
 
 
 def test_get_remote_url(script, tmpdir):
-    source_dir = tmpdir / 'source'
+    source_dir = tmpdir / "source"
     source_dir.mkdir()
     source_url = _test_path_to_file_url(source_dir)
 
     source_dir = str(source_dir)
-    script.run('git', 'init', cwd=source_dir)
+    script.run("git", "init", cwd=source_dir)
     do_commit(script, source_dir)
 
-    repo_dir = str(tmpdir / 'repo')
-    script.run('git', 'clone', source_url, repo_dir)
+    repo_dir = str(tmpdir / "repo")
+    script.run("git", "clone", source_url, repo_dir)
 
     remote_url = Git.get_remote_url(repo_dir)
     assert remote_url == source_url
@@ -102,11 +106,11 @@ def test_get_remote_url__no_remote(script, tmpdir):
     """
     Test a repo with no remote.
     """
-    repo_dir = tmpdir / 'temp-repo'
+    repo_dir = tmpdir / "temp-repo"
     repo_dir.mkdir()
     repo_dir = str(repo_dir)
 
-    script.run('git', 'init', cwd=repo_dir)
+    script.run("git", "init", cwd=repo_dir)
 
     with pytest.raises(RemoteNotFoundError):
         Git.get_remote_url(repo_dir)
@@ -115,15 +119,15 @@ def test_get_remote_url__no_remote(script, tmpdir):
 def test_get_current_branch(script):
     repo_dir = str(script.scratch_path)
 
-    script.run('git', 'init', cwd=repo_dir)
+    script.run("git", "init", cwd=repo_dir)
     sha = do_commit(script, repo_dir)
 
-    assert Git.get_current_branch(repo_dir) == 'master'
+    assert Git.get_current_branch(repo_dir) == "master"
 
     # Switch to a branch with the same SHA as "master" but whose name
     # is alphabetically after.
-    checkout_new_branch(script, repo_dir, 'release')
-    assert Git.get_current_branch(repo_dir) == 'release'
+    checkout_new_branch(script, repo_dir, "release")
+    assert Git.get_current_branch(repo_dir) == "release"
 
     # Also test the detached HEAD case.
     checkout_ref(script, repo_dir, sha)
@@ -136,23 +140,23 @@ def test_get_current_branch__branch_and_tag_same_name(script, tmpdir):
     and tag have the same name.
     """
     repo_dir = str(tmpdir)
-    script.run('git', 'init', cwd=repo_dir)
+    script.run("git", "init", cwd=repo_dir)
     do_commit(script, repo_dir)
-    checkout_new_branch(script, repo_dir, 'dev')
+    checkout_new_branch(script, repo_dir, "dev")
     # Create a tag with the same name as the branch.
-    script.run('git', 'tag', 'dev', cwd=repo_dir)
+    script.run("git", "tag", "dev", cwd=repo_dir)
 
-    assert Git.get_current_branch(repo_dir) == 'dev'
+    assert Git.get_current_branch(repo_dir) == "dev"
 
     # Now try with the tag checked out.
-    checkout_ref(script, repo_dir, 'refs/tags/dev')
+    checkout_ref(script, repo_dir, "refs/tags/dev")
     assert Git.get_current_branch(repo_dir) is None
 
 
 def test_get_revision_sha(script):
     repo_dir = str(script.scratch_path)
 
-    script.run('git', 'init', cwd=repo_dir)
+    script.run("git", "init", cwd=repo_dir)
     shas = add_commits(script, repo_dir, count=3)
 
     tag_sha = shas[0]
@@ -160,45 +164,46 @@ def test_get_revision_sha(script):
     head_sha = shas[2]
     assert head_sha == shas[-1]
 
-    origin_ref = 'refs/remotes/origin/origin-branch'
-    generic_ref = 'refs/generic-ref'
+    origin_ref = "refs/remotes/origin/origin-branch"
+    generic_ref = "refs/generic-ref"
 
+    script.run("git", "branch", "local-branch", head_sha, cwd=repo_dir)
+    script.run("git", "tag", "v1.0", tag_sha, cwd=repo_dir)
+    script.run("git", "update-ref", origin_ref, origin_sha, cwd=repo_dir)
     script.run(
-        'git', 'branch', 'local-branch', head_sha, cwd=repo_dir
+        "git",
+        "update-ref",
+        "refs/remotes/upstream/upstream-branch",
+        head_sha,
+        cwd=repo_dir,
     )
-    script.run('git', 'tag', 'v1.0', tag_sha, cwd=repo_dir)
-    script.run('git', 'update-ref', origin_ref, origin_sha, cwd=repo_dir)
-    script.run(
-        'git', 'update-ref', 'refs/remotes/upstream/upstream-branch',
-        head_sha, cwd=repo_dir
-    )
-    script.run('git', 'update-ref', generic_ref, head_sha, cwd=repo_dir)
+    script.run("git", "update-ref", generic_ref, head_sha, cwd=repo_dir)
 
     # Test two tags pointing to the same sha.
-    script.run('git', 'tag', 'v2.0', tag_sha, cwd=repo_dir)
+    script.run("git", "tag", "v2.0", tag_sha, cwd=repo_dir)
     # Test tags sharing the same suffix as another tag, both before and
     # after the suffix alphabetically.
-    script.run('git', 'tag', 'aaa/v1.0', head_sha, cwd=repo_dir)
-    script.run('git', 'tag', 'zzz/v1.0', head_sha, cwd=repo_dir)
+    script.run("git", "tag", "aaa/v1.0", head_sha, cwd=repo_dir)
+    script.run("git", "tag", "zzz/v1.0", head_sha, cwd=repo_dir)
 
-    check_rev(repo_dir, 'v1.0', (tag_sha, False))
-    check_rev(repo_dir, 'v2.0', (tag_sha, False))
-    check_rev(repo_dir, 'origin-branch', (origin_sha, True))
+    check_rev(repo_dir, "v1.0", (tag_sha, False))
+    check_rev(repo_dir, "v2.0", (tag_sha, False))
+    check_rev(repo_dir, "origin-branch", (origin_sha, True))
 
     ignored_names = [
         # Local branches should be ignored.
-        'local-branch',
+        "local-branch",
         # Non-origin remote branches should be ignored.
-        'upstream-branch',
+        "upstream-branch",
         # Generic refs should be ignored.
-        'generic-ref',
+        "generic-ref",
         # Fully spelled-out refs should be ignored.
         origin_ref,
         generic_ref,
         # Test passing a valid commit hash.
         tag_sha,
         # Test passing a non-existent name.
-        'does-not-exist',
+        "does-not-exist",
     ]
     for name in ignored_names:
         check_rev(repo_dir, name, (None, False))
@@ -209,32 +214,24 @@ def test_is_commit_id_equal(script):
     Test Git.is_commit_id_equal().
     """
     version_pkg_path = _create_test_package(script)
-    script.run('git', 'branch', 'branch0.1', cwd=version_pkg_path)
-    commit = script.run(
-        'git', 'rev-parse', 'HEAD',
-        cwd=version_pkg_path
-    ).stdout.strip()
+    script.run("git", "branch", "branch0.1", cwd=version_pkg_path)
+    commit = script.run("git", "rev-parse", "HEAD", cwd=version_pkg_path).stdout.strip()
 
     assert Git.is_commit_id_equal(version_pkg_path, commit)
     assert not Git.is_commit_id_equal(version_pkg_path, commit[:7])
-    assert not Git.is_commit_id_equal(version_pkg_path, 'branch0.1')
-    assert not Git.is_commit_id_equal(version_pkg_path, 'abc123')
+    assert not Git.is_commit_id_equal(version_pkg_path, "branch0.1")
+    assert not Git.is_commit_id_equal(version_pkg_path, "abc123")
     # Also check passing a None value.
     assert not Git.is_commit_id_equal(version_pkg_path, None)
 
 
 def test_is_immutable_rev_checkout(script):
     version_pkg_path = _create_test_package(script)
-    commit = script.run(
-        'git', 'rev-parse', 'HEAD',
-        cwd=version_pkg_path
-    ).stdout.strip()
+    commit = script.run("git", "rev-parse", "HEAD", cwd=version_pkg_path).stdout.strip()
     assert Git().is_immutable_rev_checkout(
         "git+https://g.c/o/r@" + commit, version_pkg_path
     )
-    assert not Git().is_immutable_rev_checkout(
-        "git+https://g.c/o/r", version_pkg_path
-    )
+    assert not Git().is_immutable_rev_checkout("git+https://g.c/o/r", version_pkg_path)
     assert not Git().is_immutable_rev_checkout(
         "git+https://g.c/o/r@master", version_pkg_path
     )
@@ -267,9 +264,7 @@ def test_resolve_commit_not_on_branch(script, tmp_path):
     # create a commit
     repo_file.write_text(u"..")
     script.run("git", "commit", "-a", "-m", "commit 1", cwd=str(repo_path))
-    commit = script.run(
-        "git", "rev-parse", "HEAD", cwd=str(repo_path)
-    ).stdout.strip()
+    commit = script.run("git", "rev-parse", "HEAD", cwd=str(repo_path)).stdout.strip()
 
     # make sure our commit is not on a branch
     script.run("git", "checkout", "master", cwd=str(repo_path))
diff --git a/tests/functional/test_warning.py b/tests/functional/test_warning.py
index ff228421e66..5a3502cc957 100644
--- a/tests/functional/test_warning.py
+++ b/tests/functional/test_warning.py
@@ -8,8 +8,10 @@
 
 @pytest.fixture
 def warnings_demo(tmpdir):
-    demo = tmpdir.joinpath('warnings_demo.py')
-    demo.write_text(textwrap.dedent('''
+    demo = tmpdir.joinpath("warnings_demo.py")
+    demo.write_text(
+        textwrap.dedent(
+            """
         from logging import basicConfig
         from pip._internal.utils import deprecation
 
@@ -17,20 +19,22 @@ def warnings_demo(tmpdir):
         basicConfig()
 
         deprecation.deprecated("deprecated!", replacement=None, gone_in=None)
-    '''))
+    """
+        )
+    )
     return demo
 
 
 def test_deprecation_warnings_are_correct(script, warnings_demo):
-    result = script.run('python', warnings_demo, expect_stderr=True)
-    expected = 'WARNING:pip._internal.deprecations:DEPRECATION: deprecated!\n'
+    result = script.run("python", warnings_demo, expect_stderr=True)
+    expected = "WARNING:pip._internal.deprecations:DEPRECATION: deprecated!\n"
     assert result.stderr == expected
 
 
 def test_deprecation_warnings_can_be_silenced(script, warnings_demo):
-    script.environ['PYTHONWARNINGS'] = 'ignore'
-    result = script.run('python', warnings_demo)
-    assert result.stderr == ''
+    script.environ["PYTHONWARNINGS"] = "ignore"
+    result = script.run("python", warnings_demo)
+    assert result.stderr == ""
 
 
 DEPRECATION_TEXT = "drop support for Python 2.7"
@@ -53,7 +57,7 @@ def test_flag_does_nothing_if_python_version_is_not_2(script):
 def test_version_warning_is_shown_if_python_version_is_2(script):
     result = script.pip("debug", allow_stderr_warning=True)
     assert DEPRECATION_TEXT in result.stderr, str(result)
-    if platform.python_implementation() == 'CPython':
+    if platform.python_implementation() == "CPython":
         assert CPYTHON_DEPRECATION_TEXT in result.stderr, str(result)
     else:
         assert CPYTHON_DEPRECATION_TEXT not in result.stderr, str(result)
diff --git a/tests/functional/test_wheel.py b/tests/functional/test_wheel.py
index 0b58c923785..9046710a14c 100644
--- a/tests/functional/test_wheel.py
+++ b/tests/functional/test_wheel.py
@@ -16,8 +16,8 @@ def auto_with_wheel(with_wheel):
 
 
 def add_files_to_dist_directory(folder):
-    (folder / 'dist').mkdir(parents=True)
-    (folder / 'dist' / 'a_name-0.0.1.tar.gz').write_text("hello")
+    (folder / "dist").mkdir(parents=True)
+    (folder / "dist" / "a_name-0.0.1.tar.gz").write_text("hello")
     # Not adding a wheel file since that confuses setuptools' backend.
     # (folder / 'dist' / 'a_name-0.0.1-py2.py3-none-any.whl').write_text(
     #     "hello"
@@ -28,7 +28,7 @@ def test_wheel_exit_status_code_when_no_requirements(script):
     """
     Test wheel exit status code when no requirements specified
     """
-    result = script.pip('wheel', expect_error=True)
+    result = script.pip("wheel", expect_error=True)
     assert "You must give at least one requirement to wheel" in result.stderr
     assert result.returncode == ERROR
 
@@ -38,7 +38,7 @@ def test_wheel_exit_status_code_when_blank_requirements_file(script):
     Test wheel exit status code when blank requirements file specified
     """
     script.scratch_path.joinpath("blank.txt").write_text("\n")
-    script.pip('wheel', '-r', 'blank.txt')
+    script.pip("wheel", "-r", "blank.txt")
 
 
 def test_pip_wheel_success(script, data):
@@ -46,18 +46,22 @@ def test_pip_wheel_success(script, data):
     Test 'pip wheel' success.
     """
     result = script.pip(
-        'wheel', '--no-index', '-f', data.find_links,
-        'simple==3.0',
+        "wheel",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "simple==3.0",
     )
-    wheel_file_name = 'simple-3.0-py{pyversion[0]}-none-any.whl' \
-        .format(**globals())
+    wheel_file_name = "simple-3.0-py{pyversion[0]}-none-any.whl".format(**globals())
     wheel_file_path = script.scratch / wheel_file_name
     assert re.search(
         r"Created wheel for simple: "
-        r"filename={filename} size=\d+ sha256=[A-Fa-f0-9]{{64}}"
-        .format(filename=re.escape(wheel_file_name)), result.stdout)
-    assert re.search(
-        r"^\s+Stored in directory: ", result.stdout, re.M)
+        r"filename={filename} size=\d+ sha256=[A-Fa-f0-9]{{64}}".format(
+            filename=re.escape(wheel_file_name)
+        ),
+        result.stdout,
+    )
+    assert re.search(r"^\s+Stored in directory: ", result.stdout, re.M)
     result.did_create(wheel_file_path)
     assert "Successfully built simple" in result.stdout, result.stdout
 
@@ -67,11 +71,13 @@ def test_pip_wheel_build_cache(script, data):
     Test 'pip wheel' builds and caches.
     """
     result = script.pip(
-        'wheel', '--no-index', '-f', data.find_links,
-        'simple==3.0',
+        "wheel",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "simple==3.0",
     )
-    wheel_file_name = 'simple-3.0-py{pyversion[0]}-none-any.whl' \
-        .format(**globals())
+    wheel_file_name = "simple-3.0-py{pyversion[0]}-none-any.whl".format(**globals())
     wheel_file_path = script.scratch / wheel_file_name
     result.did_create(wheel_file_path)
     assert "Successfully built simple" in result.stdout, result.stdout
@@ -80,8 +86,11 @@ def test_pip_wheel_build_cache(script, data):
     # pip wheel again and test that no build occurs since
     # we get the wheel from cache
     result = script.pip(
-        'wheel', '--no-index', '-f', data.find_links,
-        'simple==3.0',
+        "wheel",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "simple==3.0",
     )
     result.did_create(wheel_file_path)
     assert "Successfully built simple" not in result.stdout, result.stdout
@@ -92,9 +101,13 @@ def test_basic_pip_wheel_downloads_wheels(script, data):
     Test 'pip wheel' downloads wheels
     """
     result = script.pip(
-        'wheel', '--no-index', '-f', data.find_links, 'simple.dist',
+        "wheel",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "simple.dist",
     )
-    wheel_file_name = 'simple.dist-0.1-py2.py3-none-any.whl'
+    wheel_file_name = "simple.dist-0.1-py2.py3-none-any.whl"
     wheel_file_path = script.scratch / wheel_file_name
     result.did_create(wheel_file_path)
     assert "Saved" in result.stdout, result.stdout
@@ -105,20 +118,29 @@ def test_pip_wheel_build_relative_cachedir(script, data):
     Test 'pip wheel' builds and caches with a non-absolute cache directory.
     """
     result = script.pip(
-        'wheel', '--no-index', '-f', data.find_links,
-        '--cache-dir', './cache',
-        'simple==3.0',
+        "wheel",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "--cache-dir",
+        "./cache",
+        "simple==3.0",
     )
     assert result.returncode == 0
 
 
 def test_pip_wheel_builds_when_no_binary_set(script, data):
-    data.packages.joinpath('simple-3.0-py2.py3-none-any.whl').touch()
+    data.packages.joinpath("simple-3.0-py2.py3-none-any.whl").touch()
     # Check that the wheel package is ignored
     res = script.pip(
-        'wheel', '--no-index', '--no-binary', ':all:',
-        '-f', data.find_links,
-        'simple==3.0')
+        "wheel",
+        "--no-index",
+        "--no-binary",
+        ":all:",
+        "-f",
+        data.find_links,
+        "simple==3.0",
+    )
     assert "Building wheel for simple" in str(res), str(res)
 
 
@@ -129,10 +151,13 @@ def test_pip_wheel_readonly_cache(script, data, tmpdir):
     os.chmod(cache_dir, 0o400)  # read-only cache
     # Check that the wheel package is ignored
     res = script.pip(
-        'wheel', '--no-index',
-        '-f', data.find_links,
-        '--cache-dir', cache_dir,
-        'simple==3.0',
+        "wheel",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "--cache-dir",
+        cache_dir,
+        "simple==3.0",
         allow_stderr_warning=True,
     )
     assert res.returncode == 0
@@ -143,13 +168,11 @@ def test_pip_wheel_builds_editable_deps(script, data):
     """
     Test 'pip wheel' finds and builds dependencies of editables
     """
-    editable_path = os.path.join(data.src, 'requires_simple')
+    editable_path = os.path.join(data.src, "requires_simple")
     result = script.pip(
-        'wheel', '--no-index', '-f', data.find_links,
-        '-e', editable_path
+        "wheel", "--no-index", "-f", data.find_links, "-e", editable_path
     )
-    wheel_file_name = 'simple-1.0-py{pyversion[0]}-none-any.whl' \
-        .format(**globals())
+    wheel_file_name = "simple-1.0-py{pyversion[0]}-none-any.whl".format(**globals())
     wheel_file_path = script.scratch / wheel_file_name
     result.did_create(wheel_file_path)
 
@@ -158,13 +181,13 @@ def test_pip_wheel_builds_editable(script, data):
     """
     Test 'pip wheel' builds an editable package
     """
-    editable_path = os.path.join(data.src, 'simplewheel-1.0')
+    editable_path = os.path.join(data.src, "simplewheel-1.0")
     result = script.pip(
-        'wheel', '--no-index', '-f', data.find_links,
-        '-e', editable_path
+        "wheel", "--no-index", "-f", data.find_links, "-e", editable_path
+    )
+    wheel_file_name = "simplewheel-1.0-py{pyversion[0]}-none-any.whl".format(
+        **globals()
     )
-    wheel_file_name = 'simplewheel-1.0-py{pyversion[0]}-none-any.whl' \
-        .format(**globals())
     wheel_file_path = script.scratch / wheel_file_name
     result.did_create(wheel_file_path)
 
@@ -174,12 +197,16 @@ def test_pip_wheel_fail(script, data):
     Test 'pip wheel' failure.
     """
     result = script.pip(
-        'wheel', '--no-index', '-f', data.find_links,
-        'wheelbroken==0.1',
+        "wheel",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "wheelbroken==0.1",
         expect_error=True,
     )
-    wheel_file_name = 'wheelbroken-0.1-py{pyversion[0]}-none-any.whl' \
-        .format(**globals())
+    wheel_file_name = "wheelbroken-0.1-py{pyversion[0]}-none-any.whl".format(
+        **globals()
+    )
     wheel_file_path = script.scratch / wheel_file_name
     result.did_not_create(wheel_file_path)
     assert "FakeError" in result.stderr, result.stderr
@@ -195,11 +222,15 @@ def test_no_clean_option_blocks_cleaning_after_wheel(
     """
     Test --no-clean option blocks cleaning after wheel build
     """
-    build = script.venv_path / 'build'
+    build = script.venv_path / "build"
     result = script.pip(
-        'wheel', '--no-clean', '--no-index', '--build', build,
-        '--find-links={data.find_links}'.format(**locals()),
-        'simple',
+        "wheel",
+        "--no-clean",
+        "--no-index",
+        "--build",
+        build,
+        "--find-links={data.find_links}".format(**locals()),
+        "simple",
         expect_temp=True,
         # TODO: allow_stderr_warning is used for the --build deprecation,
         #       remove it when removing support for --build
@@ -207,7 +238,7 @@ def test_no_clean_option_blocks_cleaning_after_wheel(
     )
 
     if not use_new_resolver:
-        build = build / 'simple'
+        build = build / "simple"
         message = "build/simple should still exist {}".format(result)
         assert exists(build), message
 
@@ -219,11 +250,13 @@ def test_pip_wheel_source_deps(script, data):
     """
     # 'requires_source' is a wheel that depends on the 'source' project
     result = script.pip(
-        'wheel', '--no-index', '-f', data.find_links,
-        'requires_source',
+        "wheel",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "requires_source",
     )
-    wheel_file_name = 'source-1.0-py{pyversion[0]}-none-any.whl' \
-        .format(**globals())
+    wheel_file_name = "source-1.0-py{pyversion[0]}-none-any.whl".format(**globals())
     wheel_file_path = script.scratch / wheel_file_name
     result.did_create(wheel_file_path)
     assert "Successfully built source" in result.stdout, result.stdout
@@ -240,24 +273,25 @@ def test_pip_wheel_fail_cause_of_previous_build_dir(
     """
 
     # Given that I have a previous build dir of the `simple` package
-    build = script.venv_path / 'build' / 'simple'
+    build = script.venv_path / "build" / "simple"
     os.makedirs(build)
-    build.joinpath('setup.py').write_text('#')
+    build.joinpath("setup.py").write_text("#")
 
     # When I call pip trying to install things again
     result = script.pip(
-        'wheel', '--no-index',
-        '--find-links={data.find_links}'.format(**locals()),
-        '--build', script.venv_path / 'build',
-        'simple==3.0',
+        "wheel",
+        "--no-index",
+        "--find-links={data.find_links}".format(**locals()),
+        "--build",
+        script.venv_path / "build",
+        "simple==3.0",
         expect_error=(not use_new_resolver),
         expect_temp=(not use_new_resolver),
         expect_stderr=True,
     )
 
     assert (
-        "The -b/--build/--build-dir/--build-directory "
-        "option is deprecated."
+        "The -b/--build/--build-dir/--build-directory " "option is deprecated."
     ) in result.stderr
 
     # Then I see that the error code is the right one
@@ -269,15 +303,21 @@ def test_wheel_package_with_latin1_setup(script, data):
     """Create a wheel from a package with latin-1 encoded setup.py."""
 
     pkg_to_wheel = data.packages.joinpath("SetupPyLatin1")
-    result = script.pip('wheel', pkg_to_wheel)
-    assert 'Successfully built SetupPyUTF8' in result.stdout
+    result = script.pip("wheel", pkg_to_wheel)
+    assert "Successfully built SetupPyUTF8" in result.stdout
 
 
 def test_pip_wheel_with_pep518_build_reqs(script, data, common_wheels):
-    result = script.pip('wheel', '--no-index', '-f', data.find_links,
-                        '-f', common_wheels, 'pep518==3.0',)
-    wheel_file_name = 'pep518-3.0-py{pyversion[0]}-none-any.whl' \
-        .format(**globals())
+    result = script.pip(
+        "wheel",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "-f",
+        common_wheels,
+        "pep518==3.0",
+    )
+    wheel_file_name = "pep518-3.0-py{pyversion[0]}-none-any.whl".format(**globals())
     wheel_file_path = script.scratch / wheel_file_name
     result.did_create(wheel_file_path)
     assert "Successfully built pep518" in result.stdout, result.stdout
@@ -285,13 +325,16 @@ def test_pip_wheel_with_pep518_build_reqs(script, data, common_wheels):
 
 
 def test_pip_wheel_with_pep518_build_reqs_no_isolation(script, data):
-    script.pip_install_local('simplewheel==2.0')
+    script.pip_install_local("simplewheel==2.0")
     result = script.pip(
-        'wheel', '--no-index', '-f', data.find_links,
-        '--no-build-isolation', 'pep518==3.0',
+        "wheel",
+        "--no-index",
+        "-f",
+        data.find_links,
+        "--no-build-isolation",
+        "pep518==3.0",
     )
-    wheel_file_name = 'pep518-3.0-py{pyversion[0]}-none-any.whl' \
-        .format(**globals())
+    wheel_file_name = "pep518-3.0-py{pyversion[0]}-none-any.whl".format(**globals())
     wheel_file_path = script.scratch / wheel_file_name
     result.did_create(wheel_file_path)
     assert "Successfully built pep518" in result.stdout, result.stdout
@@ -299,60 +342,60 @@ def test_pip_wheel_with_pep518_build_reqs_no_isolation(script, data):
 
 
 def test_pip_wheel_with_user_set_in_config(script, data, common_wheels):
-    config_file = script.scratch_path / 'pip.conf'
-    script.environ['PIP_CONFIG_FILE'] = str(config_file)
+    config_file = script.scratch_path / "pip.conf"
+    script.environ["PIP_CONFIG_FILE"] = str(config_file)
     config_file.write_text("[install]\nuser = true")
     result = script.pip(
-        'wheel', data.src / 'withpyproject',
-        '--no-index', '-f', common_wheels
+        "wheel", data.src / "withpyproject", "--no-index", "-f", common_wheels
     )
     assert "Successfully built withpyproject" in result.stdout, result.stdout
 
 
-@pytest.mark.skipif(sys.platform.startswith('win'),
-                    reason='The empty extension module does not work on Win')
+@pytest.mark.skipif(
+    sys.platform.startswith("win"),
+    reason="The empty extension module does not work on Win",
+)
 def test_pip_wheel_ext_module_with_tmpdir_inside(script, data, common_wheels):
-    tmpdir = data.src / 'extension/tmp'
+    tmpdir = data.src / "extension/tmp"
     tmpdir.mkdir()
-    script.environ['TMPDIR'] = str(tmpdir)
+    script.environ["TMPDIR"] = str(tmpdir)
 
     # To avoid a test dependency on a C compiler, we set the env vars to "noop"
     # The .c source is empty anyway
-    script.environ['CC'] = script.environ['LDSHARED'] = str('true')
+    script.environ["CC"] = script.environ["LDSHARED"] = str("true")
 
     result = script.pip(
-        'wheel', data.src / 'extension',
-        '--no-index', '-f', common_wheels
+        "wheel", data.src / "extension", "--no-index", "-f", common_wheels
     )
     assert "Successfully built extension" in result.stdout, result.stdout
 
 
 @pytest.mark.network
 def test_pep517_wheels_are_not_confused_with_other_files(script, tmpdir, data):
-    """Check correct wheels are copied. (#6196)
-    """
-    pkg_to_wheel = data.src / 'withpyproject'
+    """Check correct wheels are copied. (#6196)"""
+    pkg_to_wheel = data.src / "withpyproject"
     add_files_to_dist_directory(pkg_to_wheel)
 
-    result = script.pip('wheel', pkg_to_wheel, '-w', script.scratch_path)
+    result = script.pip("wheel", pkg_to_wheel, "-w", script.scratch_path)
     assert "Installing build dependencies" in result.stdout, result.stdout
 
-    wheel_file_name = 'withpyproject-0.0.1-py{pyversion[0]}-none-any.whl' \
-        .format(**globals())
+    wheel_file_name = "withpyproject-0.0.1-py{pyversion[0]}-none-any.whl".format(
+        **globals()
+    )
     wheel_file_path = script.scratch / wheel_file_name
     result.did_create(wheel_file_path)
 
 
 def test_legacy_wheels_are_not_confused_with_other_files(script, tmpdir, data):
-    """Check correct wheels are copied. (#6196)
-    """
-    pkg_to_wheel = data.src / 'simplewheel-1.0'
+    """Check correct wheels are copied. (#6196)"""
+    pkg_to_wheel = data.src / "simplewheel-1.0"
     add_files_to_dist_directory(pkg_to_wheel)
 
-    result = script.pip('wheel', pkg_to_wheel, '-w', script.scratch_path)
+    result = script.pip("wheel", pkg_to_wheel, "-w", script.scratch_path)
     assert "Installing build dependencies" not in result.stdout, result.stdout
 
-    wheel_file_name = 'simplewheel-1.0-py{pyversion[0]}-none-any.whl' \
-        .format(**globals())
+    wheel_file_name = "simplewheel-1.0-py{pyversion[0]}-none-any.whl".format(
+        **globals()
+    )
     wheel_file_path = script.scratch / wheel_file_name
     result.did_create(wheel_file_path)
diff --git a/tests/functional/test_yaml.py b/tests/functional/test_yaml.py
index e22a01ace91..3322519c43b 100644
--- a/tests/functional/test_yaml.py
+++ b/tests/functional/test_yaml.py
@@ -22,12 +22,12 @@ def generate_yaml_tests(directory):
 
         # Strip the parts of the directory to only get a name without
         # extension and resolver directory
-        base_name = str(yml_file)[len(str(directory)) + 1:-4]
+        base_name = str(yml_file)[len(str(directory)) + 1 : -4]
 
         base = data.get("base", {})
         cases = data["cases"]
 
-        for resolver in 'old', 'new':
+        for resolver in "old", "new":
             for i, case_template in enumerate(cases):
                 case = base.copy()
                 case.update(case_template)
@@ -39,7 +39,7 @@ def generate_yaml_tests(directory):
                 case[":resolver:"] = resolver
 
                 skip = case.pop("skip", False)
-                assert skip in [False, True, 'old', 'new']
+                assert skip in [False, True, "old", "new"]
                 if skip is True or skip == resolver:
                     case = pytest.param(case, marks=pytest.mark.xfail)
 
@@ -60,7 +60,6 @@ def id_func(param):
 
 
 def convert_to_dict(string):
-
     def stripping_split(my_str, splitwith, count=None):
         if count is None:
             return [x.strip() for x in my_str.strip().split(splitwith)]
@@ -85,14 +84,13 @@ def stripping_split(my_str, splitwith, count=None):
 
 
 def handle_request(script, action, requirement, options, new_resolver=False):
-    if action == 'install':
-        args = ['install']
+    if action == "install":
+        args = ["install"]
         if new_resolver:
             args.append("--use-feature=2020-resolver")
-        args.extend(["--no-index", "--find-links",
-                     path_to_url(script.scratch_path)])
-    elif action == 'uninstall':
-        args = ['uninstall', '--yes']
+        args.extend(["--no-index", "--find-links", path_to_url(script.scratch_path)])
+    elif action == "uninstall":
+        args = ["uninstall", "--yes"]
     else:
         raise "Did not excpet action: {!r}".format(action)
 
@@ -106,18 +104,17 @@ def handle_request(script, action, requirement, options, new_resolver=False):
     args.extend(options)
     args.append("--verbose")
 
-    result = script.pip(*args,
-                        allow_stderr_error=True,
-                        allow_stderr_warning=True,
-                        allow_error=True)
+    result = script.pip(
+        *args, allow_stderr_error=True, allow_stderr_warning=True, allow_error=True
+    )
 
     # Check which packages got installed
     state = []
     for path in os.listdir(script.site_packages_path):
         if path.endswith(".dist-info"):
-            name, version = (
-                os.path.basename(path)[:-len(".dist-info")]
-            ).rsplit("-", 1)
+            name, version = (os.path.basename(path)[: -len(".dist-info")]).rsplit(
+                "-", 1
+            )
             # TODO: information about extras.
             state.append(" ".join((name, version)))
 
@@ -125,11 +122,11 @@ def handle_request(script, action, requirement, options, new_resolver=False):
 
 
 def check_error(error, result):
-    return_code = error.get('code')
+    return_code = error.get("code")
     if return_code:
         assert result.returncode == return_code
 
-    stderr = error.get('stderr')
+    stderr = error.get("stderr")
     if not stderr:
         return
 
@@ -142,8 +139,7 @@ def check_error(error, result):
 
     for patter in patters:
         match = re.search(patter, result.stderr, re.I)
-        assert match, 'regex %r not found in stderr: %r' % (
-            stderr, result.stderr)
+        assert match, "regex %r not found in stderr: %r" % (stderr, result.stderr)
 
 
 @pytest.mark.yaml
@@ -155,9 +151,9 @@ def test_yaml_based(script, case):
     requests = case.get("request", [])
     responses = case.get("response", [])
 
-    assert len(requests) == len(responses), (
-        "Expected requests and responses counts to be same"
-    )
+    assert len(requests) == len(
+        responses
+    ), "Expected requests and responses counts to be same"
 
     # Create a custom index of all the packages that are supposed to be
     # available
@@ -173,30 +169,34 @@ def test_yaml_based(script, case):
     # use scratch path for index
     for request, response in zip(requests, responses):
 
-        for action in 'install', 'uninstall':
+        for action in "install", "uninstall":
             if action in request:
                 break
         else:
             raise "Unsupported request {!r}".format(request)
 
         # Perform the requested action
-        effect = handle_request(script, action,
-                                request[action],
-                                request.get('options', '').split(),
-                                case[':resolver:'] == 'new')
-        result = effect['result']
+        effect = handle_request(
+            script,
+            action,
+            request[action],
+            request.get("options", "").split(),
+            case[":resolver:"] == "new",
+        )
+        result = effect["result"]
 
         if 0:  # for analyzing output easier
-            with open(DATA_DIR.parent / "yaml" /
-                      case[':name:'].replace('*', '-'), 'w') as fo:
+            with open(
+                DATA_DIR.parent / "yaml" / case[":name:"].replace("*", "-"), "w"
+            ) as fo:
                 fo.write("=== RETURNCODE = %d\n" % result.returncode)
                 fo.write("=== STDERR ===:\n%s\n" % result.stderr)
 
-        if 'state' in response:
-            assert effect['state'] == (response['state'] or []), str(result)
+        if "state" in response:
+            assert effect["state"] == (response["state"] or []), str(result)
 
-        error = response.get('error')
-        if error and case[":resolver:"] == 'new' and sys.platform != 'win32':
+        error = response.get("error")
+        if error and case[":resolver:"] == "new" and sys.platform != "win32":
             # Note: we currently skip running these tests on Windows, as they
             # were failing due to different error codes.  There should not
             # be a reason for not running these this check on Windows.
diff --git a/tests/lib/__init__.py b/tests/lib/__init__.py
index 07569d814f4..fedba1a984a 100644
--- a/tests/lib/__init__.py
+++ b/tests/lib/__init__.py
@@ -57,12 +57,12 @@ def path_to_url(path):
     path = os.path.normpath(os.path.abspath(path))
     drive, path = os.path.splitdrive(path)
     filepath = path.split(os.path.sep)
-    url = '/'.join(filepath)
+    url = "/".join(filepath)
     if drive:
         # Note: match urllib.request.pathname2url's
         # behavior: uppercase the drive letter.
-        return 'file:///' + drive.upper() + url
-    return 'file://' + url
+        return "file:///" + drive.upper() + url
+    return "file://" + url
 
 
 def _test_path_to_file_url(path):
@@ -72,12 +72,11 @@ def _test_path_to_file_url(path):
     Args:
       path: a tests.lib.path.Path object.
     """
-    return 'file://' + path.resolve().replace('\\', '/')
+    return "file://" + path.resolve().replace("\\", "/")
 
 
 def create_file(path, contents=None):
-    """Create a file on the path, with the given contents
-    """
+    """Create a file on the path, with the given contents"""
     from pip._internal.utils.misc import ensure_dir
 
     ensure_dir(os.path.dirname(path))
@@ -103,7 +102,7 @@ def make_test_search_scope(
 def make_test_link_collector(
     find_links=None,  # type: Optional[List[str]]
     index_urls=None,  # type: Optional[List[str]]
-    session=None,     # type: Optional[PipSession]
+    session=None,  # type: Optional[PipSession]
 ):
     # type: (...) -> LinkCollector
     """
@@ -124,8 +123,8 @@ def make_test_finder(
     find_links=None,  # type: Optional[List[str]]
     index_urls=None,  # type: Optional[List[str]]
     allow_all_prereleases=False,  # type: bool
-    session=None,                 # type: Optional[PipSession]
-    target_python=None,           # type: Optional[TargetPython]
+    session=None,  # type: Optional[PipSession]
+    target_python=None,  # type: Optional[TargetPython]
 ):
     # type: (...) -> PackageFinder
     """
@@ -229,51 +228,59 @@ class TestFailure(AssertionError):
     """
     An "assertion" failed during testing.
     """
+
     pass
 
 
 class TestPipResult(object):
-
     def __init__(self, impl, verbose=False):
         self._impl = impl
 
         if verbose:
             print(self.stdout)
             if self.stderr:
-                print('======= stderr ========')
+                print("======= stderr ========")
                 print(self.stderr)
-                print('=======================')
+                print("=======================")
 
     def __getattr__(self, attr):
         return getattr(self._impl, attr)
 
-    if sys.platform == 'win32':
+    if sys.platform == "win32":
 
         @property
         def stdout(self):
-            return self._impl.stdout.replace('\r\n', '\n')
+            return self._impl.stdout.replace("\r\n", "\n")
 
         @property
         def stderr(self):
-            return self._impl.stderr.replace('\r\n', '\n')
+            return self._impl.stderr.replace("\r\n", "\n")
 
         def __str__(self):
-            return str(self._impl).replace('\r\n', '\n')
+            return str(self._impl).replace("\r\n", "\n")
+
     else:
         # Python doesn't automatically forward __str__ through __getattr__
 
         def __str__(self):
             return str(self._impl)
 
-    def assert_installed(self, pkg_name, editable=True, with_files=None,
-                         without_files=None, without_egg_link=False,
-                         use_user_site=False, sub_dir=False):
+    def assert_installed(
+        self,
+        pkg_name,
+        editable=True,
+        with_files=None,
+        without_files=None,
+        without_egg_link=False,
+        use_user_site=False,
+        sub_dir=False,
+    ):
         with_files = with_files or []
         without_files = without_files or []
         e = self.test_env
 
         if editable:
-            pkg_dir = e.venv / 'src' / pkg_name.lower()
+            pkg_dir = e.venv / "src" / pkg_name.lower()
             # If package was installed in a sub directory
             if sub_dir:
                 pkg_dir = pkg_dir / sub_dir
@@ -282,78 +289,86 @@ def assert_installed(self, pkg_name, editable=True, with_files=None,
             pkg_dir = e.site_packages / pkg_name
 
         if use_user_site:
-            egg_link_path = e.user_site / pkg_name + '.egg-link'
+            egg_link_path = e.user_site / pkg_name + ".egg-link"
         else:
-            egg_link_path = e.site_packages / pkg_name + '.egg-link'
+            egg_link_path = e.site_packages / pkg_name + ".egg-link"
 
         if without_egg_link:
             if egg_link_path in self.files_created:
                 raise TestFailure(
-                    'unexpected egg link file created: '
-                    '{egg_link_path!r}\n{self}'
-                    .format(**locals())
+                    "unexpected egg link file created: "
+                    "{egg_link_path!r}\n{self}".format(**locals())
                 )
         else:
             if egg_link_path not in self.files_created:
                 raise TestFailure(
-                    'expected egg link file missing: '
-                    '{egg_link_path!r}\n{self}'
-                    .format(**locals())
+                    "expected egg link file missing: "
+                    "{egg_link_path!r}\n{self}".format(**locals())
                 )
 
             egg_link_file = self.files_created[egg_link_path]
-            egg_link_contents = egg_link_file.bytes.replace(os.linesep, '\n')
+            egg_link_contents = egg_link_file.bytes.replace(os.linesep, "\n")
 
             # FIXME: I don't understand why there's a trailing . here
-            if not (egg_link_contents.endswith('\n.') and
-                    egg_link_contents[:-2].endswith(pkg_dir)):
-                raise TestFailure(textwrap.dedent(
-                    u'''\
+            if not (
+                egg_link_contents.endswith("\n.")
+                and egg_link_contents[:-2].endswith(pkg_dir)
+            ):
+                raise TestFailure(
+                    textwrap.dedent(
+                        u"""\
                     Incorrect egg_link file {egg_link_file!r}
                     Expected ending: {expected_ending!r}
                     ------- Actual contents -------
                     {egg_link_contents!r}
-                    -------------------------------'''.format(
-                        expected_ending=pkg_dir + '\n.',
-                        **locals())
-                ))
+                    -------------------------------""".format(
+                            expected_ending=pkg_dir + "\n.", **locals()
+                        )
+                    )
+                )
 
         if use_user_site:
-            pth_file = e.user_site / 'easy-install.pth'
+            pth_file = e.user_site / "easy-install.pth"
         else:
-            pth_file = e.site_packages / 'easy-install.pth'
+            pth_file = e.site_packages / "easy-install.pth"
 
         if (pth_file in self.files_updated) == without_egg_link:
             raise TestFailure(
-                '{pth_file} unexpectedly {maybe}updated by install'.format(
-                    maybe=not without_egg_link and 'not ' or '',
-                    **locals()))
+                "{pth_file} unexpectedly {maybe}updated by install".format(
+                    maybe=not without_egg_link and "not " or "", **locals()
+                )
+            )
 
         if (pkg_dir in self.files_created) == (curdir in without_files):
-            raise TestFailure(textwrap.dedent('''\
+            raise TestFailure(
+                textwrap.dedent(
+                    """\
             expected package directory {pkg_dir!r} {maybe}to be created
             actually created:
             {files}
-            ''').format(
-                pkg_dir=pkg_dir,
-                maybe=curdir in without_files and 'not ' or '',
-                files=sorted(self.files_created.keys()),
-            ))
+            """
+                ).format(
+                    pkg_dir=pkg_dir,
+                    maybe=curdir in without_files and "not " or "",
+                    files=sorted(self.files_created.keys()),
+                )
+            )
 
         for f in with_files:
             normalized_path = os.path.normpath(pkg_dir / f)
             if normalized_path not in self.files_created:
                 raise TestFailure(
-                    'Package directory {pkg_dir!r} missing '
-                    'expected content {f!r}'.format(**locals())
+                    "Package directory {pkg_dir!r} missing "
+                    "expected content {f!r}".format(**locals())
                 )
 
         for f in without_files:
             normalized_path = os.path.normpath(pkg_dir / f)
             if normalized_path in self.files_created:
                 raise TestFailure(
-                    'Package directory {pkg_dir!r} has unexpected content {f}'
-                    .format(**locals())
+                    "Package directory {pkg_dir!r} has unexpected content {f}".format(
+                        **locals()
+                    )
                 )
 
     def did_create(self, path, message=None):
@@ -370,8 +385,7 @@ def did_not_update(self, path, message=None):
 
 
 def _one_or_both(a, b):
-    """Returns f"{a}\n{b}" if a is truthy, else returns str(b).
-    """
+    """Returns f"{a}\n{b}" if a is truthy, else returns str(b)."""
     if not a:
         return str(b)
 
@@ -382,15 +396,19 @@ def make_check_stderr_message(stderr, line, reason):
     """
     Create an exception message to use inside check_stderr().
     """
-    return dedent("""\
+    return dedent(
+        """\
     {reason}:
      Caused by line: {line!r}
      Complete stderr: {stderr}
-    """).format(stderr=stderr, line=line, reason=reason)
+    """
+    ).format(stderr=stderr, line=line, reason=reason)
 
 
 def _check_stderr(
-    stderr, allow_stderr_warning, allow_stderr_error,
+    stderr,
+    allow_stderr_warning,
+    allow_stderr_error,
 ):
     """
     Check the given stderr for logged warnings and errors.
@@ -411,29 +429,29 @@ def _check_stderr(
         # sent directly to stderr and so bypass any configured log formatter.
         # The "--- Logging error ---" string is used in Python 3.4+, and
         # "Logged from file " is used in Python 2.
-        if (line.startswith('--- Logging error ---') or
-                line.startswith('Logged from file ')):
-            reason = 'stderr has a logging error, which is never allowed'
+        if line.startswith("--- Logging error ---") or line.startswith(
+            "Logged from file "
+        ):
+            reason = "stderr has a logging error, which is never allowed"
             msg = make_check_stderr_message(stderr, line=line, reason=reason)
             raise RuntimeError(msg)
         if allow_stderr_error:
             continue
 
-        if line.startswith('ERROR: '):
+        if line.startswith("ERROR: "):
             reason = (
-                'stderr has an unexpected error '
-                '(pass allow_stderr_error=True to permit this)'
+                "stderr has an unexpected error "
+                "(pass allow_stderr_error=True to permit this)"
             )
             msg = make_check_stderr_message(stderr, line=line, reason=reason)
             raise RuntimeError(msg)
         if allow_stderr_warning:
             continue
 
-        if (line.startswith('WARNING: ') or
-                line.startswith(DEPRECATION_MSG_PREFIX)):
+        if line.startswith("WARNING: ") or line.startswith(DEPRECATION_MSG_PREFIX):
             reason = (
-                'stderr has an unexpected warning '
-                '(pass allow_stderr_warning=True to permit this)'
+                "stderr has an unexpected warning "
+                "(pass allow_stderr_warning=True to permit this)"
             )
             msg = make_check_stderr_message(stderr, line=line, reason=reason)
             raise RuntimeError(msg)
@@ -453,7 +471,7 @@ class PipTestEnvironment(TestFileEnvironment):
     # a name of the form xxxx_path and relative paths have a name that
     # does not end in '_path'.
 
-    exe = sys.platform == 'win32' and '.exe' or ''
+    exe = sys.platform == "win32" and ".exe" or ""
     verbose = False
 
     def __init__(self, base_path, *args, **kwargs):
@@ -470,16 +488,16 @@ def __init__(self, base_path, *args, **kwargs):
         self.user_base_path = self.venv_path.joinpath("user")
         self.user_site_path = self.venv_path.joinpath(
             "user",
-            site.USER_SITE[len(site.USER_BASE) + 1:],
+            site.USER_SITE[len(site.USER_BASE) + 1 :],
         )
-        if sys.platform == 'win32':
+        if sys.platform == "win32":
             if sys.version_info >= (3, 5):
                 scripts_base = Path(
-                    os.path.normpath(self.user_site_path.joinpath('..'))
+                    os.path.normpath(self.user_site_path.joinpath(".."))
                 )
             else:
                 scripts_base = self.user_base_path
-            self.user_bin_path = scripts_base.joinpath('Scripts')
+            self.user_bin_path = scripts_base.joinpath("Scripts")
         else:
             self.user_bin_path = self.user_base_path.joinpath(
                 os.path.relpath(self.bin_path, self.venv_path)
@@ -505,18 +523,27 @@ def __init__(self, base_path, *args, **kwargs):
 
         # Whether all pip invocations should expect stderr
         # (useful for Python version deprecation)
-        self.pip_expect_warning = kwargs.pop('pip_expect_warning', None)
+        self.pip_expect_warning = kwargs.pop("pip_expect_warning", None)
 
         # Call the TestFileEnvironment __init__
         super(PipTestEnvironment, self).__init__(base_path, *args, **kwargs)
 
         # Expand our absolute path directories into relative
-        for name in ["base", "venv", "bin", "lib", "site_packages",
-                     "user_base", "user_site", "user_bin", "scratch"]:
+        for name in [
+            "base",
+            "venv",
+            "bin",
+            "lib",
+            "site_packages",
+            "user_base",
+            "user_site",
+            "user_bin",
+            "scratch",
+        ]:
             real_name = "{name}_path".format(**locals())
-            relative_path = Path(os.path.relpath(
-                getattr(self, real_name), self.base_path
-            ))
+            relative_path = Path(
+                os.path.relpath(getattr(self, real_name), self.base_path)
+            )
             setattr(self, name, relative_path)
 
         # Make sure temp_path is a Path object
@@ -530,7 +557,7 @@ def __init__(self, base_path, *args, **kwargs):
         self.user_site_path.joinpath("easy-install.pth").touch()
 
     def _ignore_file(self, fn):
-        if fn.endswith('__pycache__') or fn.endswith(".pyc"):
+        if fn.endswith("__pycache__") or fn.endswith(".pyc"):
             result = True
         else:
             result = super(PipTestEnvironment, self)._ignore_file(fn)
@@ -541,7 +568,7 @@ def _find_traverse(self, path, result):
         # results because of venv `lib64 -> lib/` symlink on Linux.
         full = os.path.join(self.base_path, path)
         if os.path.isdir(full) and os.path.islink(full):
-            if not self.temp_path or path != 'tmp':
+            if not self.temp_path or path != "tmp":
                 result[path] = FoundDir(self.base_path, path)
         else:
             super(PipTestEnvironment, self)._find_traverse(path, result)
@@ -567,50 +594,48 @@ def run(self, *args, **kw):
             compatibility.
         """
         if self.verbose:
-            print('>> running {args} {kw}'.format(**locals()))
+            print(">> running {args} {kw}".format(**locals()))
 
-        cwd = kw.pop('cwd', None)
-        run_from = kw.pop('run_from', None)
+        cwd = kw.pop("cwd", None)
+        run_from = kw.pop("run_from", None)
         assert not cwd or not run_from, "Don't use run_from; it's going away"
         cwd = cwd or run_from or self.cwd
-        if sys.platform == 'win32':
+        if sys.platform == "win32":
             # Partial fix for ScriptTest.run using `shell=True` on Windows.
-            args = [str(a).replace('^', '^^').replace('&', '^&') for a in args]
+            args = [str(a).replace("^", "^^").replace("&", "^&") for a in args]
 
         # Remove `allow_stderr_error`, `allow_stderr_warning` and
         # `allow_error` before calling run() because PipTestEnvironment
         # doesn't support them.
-        allow_stderr_error = kw.pop('allow_stderr_error', None)
-        allow_stderr_warning = kw.pop('allow_stderr_warning', None)
-        allow_error = kw.pop('allow_error', None)
+        allow_stderr_error = kw.pop("allow_stderr_error", None)
+        allow_stderr_warning = kw.pop("allow_stderr_warning", None)
+        allow_error = kw.pop("allow_error", None)
         if allow_error:
-            kw['expect_error'] = True
+            kw["expect_error"] = True
 
         # Propagate default values.
-        expect_error = kw.get('expect_error')
+        expect_error = kw.get("expect_error")
         if expect_error:
             # Then default to allowing logged errors.
             if allow_stderr_error is not None and not allow_stderr_error:
                 raise RuntimeError(
-                    'cannot pass allow_stderr_error=False with '
-                    'expect_error=True'
+                    "cannot pass allow_stderr_error=False with " "expect_error=True"
                 )
             allow_stderr_error = True
 
-        elif kw.get('expect_stderr'):
+        elif kw.get("expect_stderr"):
             # Then default to allowing logged warnings.
             if allow_stderr_warning is not None and not allow_stderr_warning:
                 raise RuntimeError(
-                    'cannot pass allow_stderr_warning=False with '
-                    'expect_stderr=True'
+                    "cannot pass allow_stderr_warning=False with " "expect_stderr=True"
                 )
             allow_stderr_warning = True
 
         if allow_stderr_error:
             if allow_stderr_warning is not None and not allow_stderr_warning:
                 raise RuntimeError(
-                    'cannot pass allow_stderr_warning=False with '
-                    'allow_stderr_error=True'
+                    "cannot pass allow_stderr_warning=False with "
+                    "allow_stderr_error=True"
                 )
 
         # Default values if not set.
@@ -621,7 +646,7 @@ def run(self, *args, **kw):
 
         # Pass expect_stderr=True to allow any stderr.  We do this because
         # we do our checking of stderr further on in check_stderr().
-        kw['expect_stderr'] = True
+        kw["expect_stderr"] = True
         result = super(PipTestEnvironment, self).run(cwd=cwd, *args, **kw)
 
         if expect_error and not allow_error:
@@ -630,7 +655,8 @@ def run(self, *args, **kw):
                 raise AssertionError("Script passed unexpectedly.")
 
         _check_stderr(
-            result.stderr, allow_stderr_error=allow_stderr_error,
+            result.stderr,
+            allow_stderr_error=allow_stderr_error,
             allow_stderr_warning=allow_stderr_warning,
         )
 
@@ -639,24 +665,27 @@ def run(self, *args, **kw):
     def pip(self, *args, **kwargs):
         __tracebackhide__ = True
         if self.pip_expect_warning:
-            kwargs['allow_stderr_warning'] = True
-        if kwargs.pop('use_module', True):
-            exe = 'python'
-            args = ('-m', 'pip') + args
+            kwargs["allow_stderr_warning"] = True
+        if kwargs.pop("use_module", True):
+            exe = "python"
+            args = ("-m", "pip") + args
         else:
-            exe = 'pip'
+            exe = "pip"
         return self.run(exe, *args, **kwargs)
 
     def pip_install_local(self, *args, **kwargs):
         return self.pip(
-            "install", "--no-index",
-            "--find-links", path_to_url(os.path.join(DATA_DIR, "packages")),
-            *args, **kwargs
+            "install",
+            "--no-index",
+            "--find-links",
+            path_to_url(os.path.join(DATA_DIR, "packages")),
+            *args,
+            **kwargs
         )
 
     def easy_install(self, *args, **kwargs):
-        args = ('-m', 'easy_install') + args
-        return self.run('python', *args, **kwargs)
+        args = ("-m", "easy_install") + args
+        return self.run("python", *args, **kwargs)
 
 
 # FIXME ScriptTest does something similar, but only within a single
@@ -694,15 +723,15 @@ def prefix_match(path, prefix):
         prefix = prefix.rstrip(os.path.sep) + os.path.sep
         return path.startswith(prefix)
 
-    start_keys = {k for k in start.keys()
-                  if not any([prefix_match(k, i) for i in ignore])}
-    end_keys = {k for k in end.keys()
-                if not any([prefix_match(k, i) for i in ignore])}
+    start_keys = {
+        k for k in start.keys() if not any([prefix_match(k, i) for i in ignore])
+    }
+    end_keys = {k for k in end.keys() if not any([prefix_match(k, i) for i in ignore])}
     deleted = {k: start[k] for k in start_keys.difference(end_keys)}
     created = {k: end[k] for k in end_keys.difference(start_keys)}
     updated = {}
     for k in start_keys.intersection(end_keys):
-        if (start[k].size != end[k].size):
+        if start[k].size != end[k].size:
             updated[k] = end[k]
     return dict(deleted=deleted, created=created, updated=updated)
 
@@ -731,8 +760,10 @@ def assert_all_changes(start_state, end_state, expected_changes):
 
     diff = diff_states(start_files, end_files, ignore=expected_changes)
     if list(diff.values()) != [{}, {}, {}]:
-        raise TestFailure('Unexpected changes:\n' + '\n'.join(
-            [k + ': ' + ', '.join(v.keys()) for k, v in diff.items()]))
+        raise TestFailure(
+            "Unexpected changes:\n"
+            + "\n".join([k + ": " + ", ".join(v.keys()) for k, v in diff.items()])
+        )
 
     # Don't throw away this potentially useful information
     return diff
@@ -743,14 +774,18 @@ def _create_main_file(dir_path, name=None, output=None):
     Create a module with a main() function that prints the given output.
     """
     if name is None:
-        name = 'version_pkg'
+        name = "version_pkg"
     if output is None:
-        output = '0.1'
-    text = textwrap.dedent("""\
+        output = "0.1"
+    text = textwrap.dedent(
+        """\
     def main():
         print({!r})
-    """.format(output))
-    filename = '{}.py'.format(name)
+    """.format(
+            output
+        )
+    )
+    filename = "{}.py".format(name)
     dir_path.joinpath(filename).write_text(text)
 
 
@@ -770,7 +805,7 @@ def _git_commit(
       message: an optional commit message.
     """
     if message is None:
-        message = 'test commit'
+        message = "test commit"
 
     args = []
 
@@ -781,100 +816,121 @@ def _git_commit(
         args.append("--all")
 
     new_args = [
-        'git', 'commit', '-q', '--author', 'pip <distutils-sig@python.org>',
+        "git",
+        "commit",
+        "-q",
+        "--author",
+        "pip <distutils-sig@python.org>",
     ]
     new_args.extend(args)
-    new_args.extend(['-m', message])
+    new_args.extend(["-m", message])
     env_or_script.run(*new_args, cwd=repo_dir)
 
 
-def _vcs_add(script, version_pkg_path, vcs='git'):
-    if vcs == 'git':
-        script.run('git', 'init', cwd=version_pkg_path)
-        script.run('git', 'add', '.', cwd=version_pkg_path)
-        _git_commit(script, version_pkg_path, message='initial version')
-    elif vcs == 'hg':
-        script.run('hg', 'init', cwd=version_pkg_path)
-        script.run('hg', 'add', '.', cwd=version_pkg_path)
+def _vcs_add(script, version_pkg_path, vcs="git"):
+    if vcs == "git":
+        script.run("git", "init", cwd=version_pkg_path)
+        script.run("git", "add", ".", cwd=version_pkg_path)
+        _git_commit(script, version_pkg_path, message="initial version")
+    elif vcs == "hg":
+        script.run("hg", "init", cwd=version_pkg_path)
+        script.run("hg", "add", ".", cwd=version_pkg_path)
         script.run(
-            'hg', 'commit', '-q',
-            '--user', 'pip <distutils-sig@python.org>',
-            '-m', 'initial version', cwd=version_pkg_path,
+            "hg",
+            "commit",
+            "-q",
+            "--user",
+            "pip <distutils-sig@python.org>",
+            "-m",
+            "initial version",
+            cwd=version_pkg_path,
         )
-    elif vcs == 'svn':
+    elif vcs == "svn":
         repo_url = _create_svn_repo(script, version_pkg_path)
         script.run(
-            'svn', 'checkout', repo_url, 'pip-test-package',
-            cwd=script.scratch_path
+            "svn", "checkout", repo_url, "pip-test-package", cwd=script.scratch_path
         )
-        checkout_path = script.scratch_path / 'pip-test-package'
+        checkout_path = script.scratch_path / "pip-test-package"
 
         # svn internally stores windows drives as uppercase; we'll match that.
-        checkout_path = checkout_path.replace('c:', 'C:')
+        checkout_path = checkout_path.replace("c:", "C:")
 
         version_pkg_path = checkout_path
-    elif vcs == 'bazaar':
-        script.run('bzr', 'init', cwd=version_pkg_path)
-        script.run('bzr', 'add', '.', cwd=version_pkg_path)
+    elif vcs == "bazaar":
+        script.run("bzr", "init", cwd=version_pkg_path)
+        script.run("bzr", "add", ".", cwd=version_pkg_path)
         script.run(
-            'bzr', 'whoami', 'pip <distutils-sig@python.org>',
-            cwd=version_pkg_path)
+            "bzr", "whoami", "pip <distutils-sig@python.org>", cwd=version_pkg_path
+        )
         script.run(
-            'bzr', 'commit', '-q',
-            '--author', 'pip <distutils-sig@python.org>',
-            '-m', 'initial version', cwd=version_pkg_path,
+            "bzr",
+            "commit",
+            "-q",
+            "--author",
+            "pip <distutils-sig@python.org>",
+            "-m",
+            "initial version",
+            cwd=version_pkg_path,
         )
     else:
-        raise ValueError('Unknown vcs: {vcs}'.format(**locals()))
+        raise ValueError("Unknown vcs: {vcs}".format(**locals()))
     return version_pkg_path
 
 
 def _create_test_package_with_subdirectory(script, subdirectory):
     script.scratch_path.joinpath("version_pkg").mkdir()
-    version_pkg_path = script.scratch_path / 'version_pkg'
+    version_pkg_path = script.scratch_path / "version_pkg"
     _create_main_file(version_pkg_path, name="version_pkg", output="0.1")
     version_pkg_path.joinpath("setup.py").write_text(
-        textwrap.dedent("""
+        textwrap.dedent(
+            """
     from setuptools import setup, find_packages
     setup(name='version_pkg',
           version='0.1',
           packages=find_packages(),
           py_modules=['version_pkg'],
           entry_points=dict(console_scripts=['version_pkg=version_pkg:main']))
-        """))
+        """
+        )
+    )
 
     subdirectory_path = version_pkg_path.joinpath(subdirectory)
     subdirectory_path.mkdir()
     _create_main_file(subdirectory_path, name="version_subpkg", output="0.1")
 
-    subdirectory_path.joinpath('setup.py').write_text(
-        textwrap.dedent("""
+    subdirectory_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
 from setuptools import setup, find_packages
 setup(name='version_subpkg',
       version='0.1',
       packages=find_packages(),
       py_modules=['version_subpkg'],
       entry_points=dict(console_scripts=['version_pkg=version_subpkg:main']))
-        """))
+        """
+        )
+    )
 
-    script.run('git', 'init', cwd=version_pkg_path)
-    script.run('git', 'add', '.', cwd=version_pkg_path)
-    _git_commit(script, version_pkg_path, message='initial version')
+    script.run("git", "init", cwd=version_pkg_path)
+    script.run("git", "add", ".", cwd=version_pkg_path)
+    _git_commit(script, version_pkg_path, message="initial version")
 
     return version_pkg_path
 
 
-def _create_test_package_with_srcdir(script, name='version_pkg', vcs='git'):
+def _create_test_package_with_srcdir(script, name="version_pkg", vcs="git"):
     script.scratch_path.joinpath(name).mkdir()
     version_pkg_path = script.scratch_path / name
-    subdir_path = version_pkg_path.joinpath('subdir')
+    subdir_path = version_pkg_path.joinpath("subdir")
     subdir_path.mkdir()
-    src_path = subdir_path.joinpath('src')
+    src_path = subdir_path.joinpath("src")
     src_path.mkdir()
-    pkg_path = src_path.joinpath('pkg')
+    pkg_path = src_path.joinpath("pkg")
     pkg_path.mkdir()
-    pkg_path.joinpath('__init__.py').write_text('')
-    subdir_path.joinpath("setup.py").write_text(textwrap.dedent("""
+    pkg_path.joinpath("__init__.py").write_text("")
+    subdir_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
         from setuptools import setup, find_packages
         setup(
             name='{name}',
@@ -882,15 +938,21 @@ def _create_test_package_with_srcdir(script, name='version_pkg', vcs='git'):
             packages=find_packages(),
             package_dir={{'': 'src'}},
         )
-    """.format(name=name)))
+    """.format(
+                name=name
+            )
+        )
+    )
     return _vcs_add(script, version_pkg_path, vcs)
 
 
-def _create_test_package(script, name='version_pkg', vcs='git'):
+def _create_test_package(script, name="version_pkg", vcs="git"):
     script.scratch_path.joinpath(name).mkdir()
     version_pkg_path = script.scratch_path / name
-    _create_main_file(version_pkg_path, name=name, output='0.1')
-    version_pkg_path.joinpath("setup.py").write_text(textwrap.dedent("""
+    _create_main_file(version_pkg_path, name=name, output="0.1")
+    version_pkg_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
         from setuptools import setup, find_packages
         setup(
             name='{name}',
@@ -899,33 +961,35 @@ def _create_test_package(script, name='version_pkg', vcs='git'):
             py_modules=['{name}'],
             entry_points=dict(console_scripts=['{name}={name}:main'])
         )
-    """.format(name=name)))
+    """.format(
+                name=name
+            )
+        )
+    )
     return _vcs_add(script, version_pkg_path, vcs)
 
 
 def _create_svn_repo(script, version_pkg_path):
-    repo_url = path_to_url(
-        script.scratch_path / 'pip-test-package-repo' / 'trunk')
+    repo_url = path_to_url(script.scratch_path / "pip-test-package-repo" / "trunk")
+    script.run("svnadmin", "create", "pip-test-package-repo", cwd=script.scratch_path)
     script.run(
-        'svnadmin', 'create', 'pip-test-package-repo',
-        cwd=script.scratch_path
-    )
-    script.run(
-        'svn', 'import', version_pkg_path, repo_url,
-        '-m', 'Initial import of pip-test-package',
-        cwd=script.scratch_path
+        "svn",
+        "import",
+        version_pkg_path,
+        repo_url,
+        "-m",
+        "Initial import of pip-test-package",
+        cwd=script.scratch_path,
     )
     return repo_url
 
 
 def _change_test_package_version(script, version_pkg_path):
     _create_main_file(
-        version_pkg_path, name='version_pkg', output='some different version'
+        version_pkg_path, name="version_pkg", output="some different version"
     )
     # Pass -a to stage the change to the main file.
-    _git_commit(
-        script, version_pkg_path, message='messed version', stage_modified=True
-    )
+    _git_commit(script, version_pkg_path, message="messed version", stage_modified=True)
 
 
 def assert_raises_regexp(exception, reg, run, *args, **kwargs):
@@ -950,21 +1014,25 @@ def requirements_file(contents, tmpdir):
     :param tmpdir: A Path to the folder in which to create the file
 
     """
-    path = tmpdir / 'reqs.txt'
+    path = tmpdir / "reqs.txt"
     path.write_text(contents)
     yield path
     path.unlink()
 
 
 def create_test_package_with_setup(script, **setup_kwargs):
-    assert 'name' in setup_kwargs, setup_kwargs
-    pkg_path = script.scratch_path / setup_kwargs['name']
+    assert "name" in setup_kwargs, setup_kwargs
+    pkg_path = script.scratch_path / setup_kwargs["name"]
     pkg_path.mkdir()
-    pkg_path.joinpath("setup.py").write_text(textwrap.dedent("""
+    pkg_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """
         from setuptools import setup
         kwargs = {setup_kwargs!r}
         setup(**kwargs)
-    """).format(**locals()))
+    """
+        ).format(**locals())
+    )
     return pkg_path
 
 
@@ -976,9 +1044,7 @@ def urlsafe_b64encode_nopad(data):
 def create_really_basic_wheel(name, version):
     # type: (str, str) -> bytes
     def digest(contents):
-        return "sha256={}".format(
-            urlsafe_b64encode_nopad(sha256(contents).digest())
-        )
+        return "sha256={}".format(urlsafe_b64encode_nopad(sha256(contents).digest()))
 
     def add_file(path, text):
         contents = text.encode("utf-8")
@@ -998,7 +1064,9 @@ def add_file(path, text):
                 Metadata-Version: 2.1
                 Name: {}
                 Version: {}
-                """.format(name, version)
+                """.format(
+                    name, version
+                )
             ),
         )
         z.writestr(record_path, "\n".join(",".join(r) for r in records))
@@ -1058,7 +1126,6 @@ def hello():
         metadata_updates=metadata_updates,
         extra_metadata_files={"top_level.txt": name},
         extra_files=extra_files,
-
         # Have an empty RECORD because we don't want to be checking hashes.
         record="",
     )
@@ -1067,9 +1134,7 @@ def hello():
     return archive_path
 
 
-def create_basic_sdist_for_package(
-    script, name, version, extra_files=None
-):
+def create_basic_sdist_for_package(script, name, version, extra_files=None):
     files = {
         "setup.py": """
             from setuptools import find_packages, setup
@@ -1078,17 +1143,13 @@ def create_basic_sdist_for_package(
     }
 
     # Some useful shorthands
-    archive_name = "{name}-{version}.tar.gz".format(
-        name=name, version=version
-    )
+    archive_name = "{name}-{version}.tar.gz".format(name=name, version=version)
 
     # Replace key-values with formatted values
     for key, value in list(files.items()):
         del files[key]
         key = key.format(name=name)
-        files[key] = textwrap.dedent(value).format(
-            name=name, version=version
-        ).strip()
+        files[key] = textwrap.dedent(value).format(name=name, version=version).strip()
 
     # Add new files after formatting
     if extra_files:
@@ -1105,7 +1166,7 @@ def create_basic_sdist_for_package(
     retval = script.scratch_path / archive_name
     generated = shutil.make_archive(
         retval,
-        'gztar',
+        "gztar",
         root_dir=script.temp_path,
         base_dir=text_type(os.curdir),
     )
@@ -1122,15 +1183,17 @@ def wrapper(fn):
         try:
             subprocess.check_output(check_cmd)
         except (OSError, subprocess.CalledProcessError):
-            return pytest.mark.skip(
-                reason='{name} is not available'.format(name=name))(fn)
+            return pytest.mark.skip(reason="{name} is not available".format(name=name))(
+                fn
+            )
         return fn
+
     return wrapper
 
 
 def is_bzr_installed():
     try:
-        subprocess.check_output(('bzr', 'version', '--short'))
+        subprocess.check_output(("bzr", "version", "--short"))
     except OSError:
         return False
     return True
@@ -1138,30 +1201,26 @@ def is_bzr_installed():
 
 def is_svn_installed():
     try:
-        subprocess.check_output(('svn', '--version'))
+        subprocess.check_output(("svn", "--version"))
     except OSError:
         return False
     return True
 
 
 def need_bzr(fn):
-    return pytest.mark.bzr(need_executable(
-        'Bazaar', ('bzr', 'version', '--short')
-    )(fn))
+    return pytest.mark.bzr(need_executable("Bazaar", ("bzr", "version", "--short"))(fn))
 
 
 def need_svn(fn):
-    return pytest.mark.svn(need_executable(
-        'Subversion', ('svn', '--version')
-    )(need_executable(
-        'Subversion Admin', ('svnadmin', '--version')
-    )(fn)))
+    return pytest.mark.svn(
+        need_executable("Subversion", ("svn", "--version"))(
+            need_executable("Subversion Admin", ("svnadmin", "--version"))(fn)
+        )
+    )
 
 
 def need_mercurial(fn):
-    return pytest.mark.mercurial(need_executable(
-        'Mercurial', ('hg', 'version')
-    )(fn))
+    return pytest.mark.mercurial(need_executable("Mercurial", ("hg", "version"))(fn))
 
 
 skip_if_python2 = pytest.mark.skipif(PY2, reason="Non-Python 2 only")
diff --git a/tests/lib/certs.py b/tests/lib/certs.py
index 7d86ee4c04e..a1c82c2cc49 100644
--- a/tests/lib/certs.py
+++ b/tests/lib/certs.py
@@ -15,13 +15,13 @@
 def make_tls_cert(hostname):
     # type: (Text) -> Tuple[x509.Certificate, rsa.RSAPrivateKey]
     key = rsa.generate_private_key(
-        public_exponent=65537,
-        key_size=2048,
-        backend=default_backend()
+        public_exponent=65537, key_size=2048, backend=default_backend()
+    )
+    subject = issuer = x509.Name(
+        [
+            x509.NameAttribute(NameOID.COMMON_NAME, hostname),
+        ]
     )
-    subject = issuer = x509.Name([
-        x509.NameAttribute(NameOID.COMMON_NAME, hostname),
-    ])
     cert = (
         x509.CertificateBuilder()
         .subject_name(subject)
diff --git a/tests/lib/configuration_helpers.py b/tests/lib/configuration_helpers.py
index 3e3692696a8..a4f7c051cdc 100644
--- a/tests/lib/configuration_helpers.py
+++ b/tests/lib/configuration_helpers.py
@@ -15,7 +15,6 @@
 
 
 class ConfigurationMixin(object):
-
     def setup(self):
         self.configuration = pip._internal.configuration.Configuration(
             isolated=False,
@@ -41,9 +40,7 @@ def overridden():
     @contextlib.contextmanager
     def tmpfile(self, contents):
         # Create a temporary file
-        fd, path = tempfile.mkstemp(
-            prefix="pip_", suffix="_config.ini", text=True
-        )
+        fd, path = tempfile.mkstemp(prefix="pip_", suffix="_config.ini", text=True)
         os.close(fd)
 
         contents = textwrap.dedent(contents).lstrip()
diff --git a/tests/lib/filesystem.py b/tests/lib/filesystem.py
index dc14b323e33..05e2db62cfd 100644
--- a/tests/lib/filesystem.py
+++ b/tests/lib/filesystem.py
@@ -43,6 +43,4 @@ def join(dirpath, dirnames, filenames):
             (join_dirpath(p) for p in filenames),
         )
 
-    return set(chain.from_iterable(
-        join(*dirinfo) for dirinfo in os.walk(base)
-    ))
+    return set(chain.from_iterable(join(*dirinfo) for dirinfo in os.walk(base)))
diff --git a/tests/lib/git_submodule_helpers.py b/tests/lib/git_submodule_helpers.py
index 34295a05dc9..6a4d2822fec 100644
--- a/tests/lib/git_submodule_helpers.py
+++ b/tests/lib/git_submodule_helpers.py
@@ -7,11 +7,11 @@
 
 def _create_test_package_submodule(env):
     env.scratch_path.joinpath("version_pkg_submodule").mkdir()
-    submodule_path = env.scratch_path / 'version_pkg_submodule'
-    env.run('touch', 'testfile', cwd=submodule_path)
-    env.run('git', 'init', cwd=submodule_path)
-    env.run('git', 'add', '.', cwd=submodule_path)
-    _git_commit(env, submodule_path, message='initial version / submodule')
+    submodule_path = env.scratch_path / "version_pkg_submodule"
+    env.run("touch", "testfile", cwd=submodule_path)
+    env.run("git", "init", cwd=submodule_path)
+    env.run("git", "add", ".", cwd=submodule_path)
+    _git_commit(env, submodule_path, message="initial version / submodule")
 
     return submodule_path
 
@@ -19,8 +19,8 @@ def _create_test_package_submodule(env):
 def _change_test_package_submodule(env, submodule_path):
     submodule_path.joinpath("testfile").write_text("this is a changed file")
     submodule_path.joinpath("testfile2").write_text("this is an added file")
-    env.run('git', 'add', '.', cwd=submodule_path)
-    _git_commit(env, submodule_path, message='submodule change')
+    env.run("git", "add", ".", cwd=submodule_path)
+    _git_commit(env, submodule_path, message="submodule change")
 
 
 def _pull_in_submodule_changes_to_module(env, module_path, rel_path):
@@ -29,11 +29,9 @@ def _pull_in_submodule_changes_to_module(env, module_path, rel_path):
       rel_path: the location of the submodule relative to the superproject.
     """
     submodule_path = module_path / rel_path
-    env.run('git', 'pull', '-q', 'origin', 'master', cwd=submodule_path)
+    env.run("git", "pull", "-q", "origin", "master", cwd=submodule_path)
     # Pass -a to stage the submodule changes that were just pulled in.
-    _git_commit(
-        env, module_path, message='submodule change', stage_modified=True
-    )
+    _git_commit(env, module_path, message="submodule change", stage_modified=True)
 
 
 def _create_test_package_with_submodule(env, rel_path):
@@ -42,33 +40,37 @@ def _create_test_package_with_submodule(env, rel_path):
       rel_path: the location of the submodule relative to the superproject.
     """
     env.scratch_path.joinpath("version_pkg").mkdir()
-    version_pkg_path = env.scratch_path / 'version_pkg'
+    version_pkg_path = env.scratch_path / "version_pkg"
     version_pkg_path.joinpath("testpkg").mkdir()
-    pkg_path = version_pkg_path / 'testpkg'
+    pkg_path = version_pkg_path / "testpkg"
 
     pkg_path.joinpath("__init__.py").write_text("# hello there")
     _create_main_file(pkg_path, name="version_pkg", output="0.1")
-    version_pkg_path.joinpath("setup.py").write_text(textwrap.dedent('''\
+    version_pkg_path.joinpath("setup.py").write_text(
+        textwrap.dedent(
+            """\
                         from setuptools import setup, find_packages
                         setup(name='version_pkg',
                               version='0.1',
                               packages=find_packages(),
                              )
-                        '''))
-    env.run('git', 'init', cwd=version_pkg_path)
-    env.run('git', 'add', '.', cwd=version_pkg_path)
-    _git_commit(env, version_pkg_path, message='initial version')
+                        """
+        )
+    )
+    env.run("git", "init", cwd=version_pkg_path)
+    env.run("git", "add", ".", cwd=version_pkg_path)
+    _git_commit(env, version_pkg_path, message="initial version")
 
     submodule_path = _create_test_package_submodule(env)
 
     env.run(
-        'git',
-        'submodule',
-        'add',
+        "git",
+        "submodule",
+        "add",
         submodule_path,
         rel_path,
         cwd=version_pkg_path,
     )
-    _git_commit(env, version_pkg_path, message='initial version w submodule')
+    _git_commit(env, version_pkg_path, message="initial version w submodule")
 
     return version_pkg_path, submodule_path
diff --git a/tests/lib/index.py b/tests/lib/index.py
index 0f507a0e7ff..b0877c9e61d 100644
--- a/tests/lib/index.py
+++ b/tests/lib/index.py
@@ -3,12 +3,12 @@
 
 
 def make_mock_candidate(version, yanked_reason=None, hex_digest=None):
-    url = 'https://example.com/pkg-{}.tar.gz'.format(version)
+    url = "https://example.com/pkg-{}.tar.gz".format(version)
     if hex_digest is not None:
         assert len(hex_digest) == 64
-        url += '#sha256={}'.format(hex_digest)
+        url += "#sha256={}".format(hex_digest)
 
     link = Link(url, yanked_reason=yanked_reason)
-    candidate = InstallationCandidate('mypackage', version, link)
+    candidate = InstallationCandidate("mypackage", version, link)
 
     return candidate
diff --git a/tests/lib/local_repos.py b/tests/lib/local_repos.py
index 2a41595f9f2..c95bc3a7ebc 100644
--- a/tests/lib/local_repos.py
+++ b/tests/lib/local_repos.py
@@ -19,16 +19,16 @@ def _create_svn_initools_repo(initools_dir):
     Create the SVN INITools repo.
     """
     directory = os.path.dirname(initools_dir)
-    subprocess.check_call('svnadmin create INITools'.split(), cwd=directory)
+    subprocess.check_call("svnadmin create INITools".split(), cwd=directory)
 
     filename, _ = urllib_request.urlretrieve(
-        'http://bitbucket.org/hltbra/pip-initools-dump/raw/8b55c908a320/'
-        'INITools_modified.dump'
+        "http://bitbucket.org/hltbra/pip-initools-dump/raw/8b55c908a320/"
+        "INITools_modified.dump"
     )
-    devnull = open(os.devnull, 'w')
+    devnull = open(os.devnull, "w")
     dump = open(filename)
     subprocess.check_call(
-        ['svnadmin', 'load', initools_dir],
+        ["svnadmin", "load", initools_dir],
         stdin=dump,
         stdout=devnull,
     )
@@ -39,7 +39,7 @@ def _create_svn_initools_repo(initools_dir):
 
 def local_checkout(
     remote_repo,  # type: str
-    temp_path,    # type: Path
+    temp_path,  # type: Path
 ):
     # type: (...) -> str
     """
@@ -47,27 +47,27 @@ def local_checkout(
         temp directory Path object unique to each test function invocation,
         created as a sub directory of the base temp directory.
     """
-    assert '+' in remote_repo
-    vcs_name = remote_repo.split('+', 1)[0]
+    assert "+" in remote_repo
+    vcs_name = remote_repo.split("+", 1)[0]
     repository_name = os.path.basename(remote_repo)
 
-    directory = temp_path.joinpath('cache')
+    directory = temp_path.joinpath("cache")
     repo_url_path = os.path.join(directory, repository_name)
     assert not os.path.exists(repo_url_path)
 
     if not os.path.exists(directory):
         os.mkdir(directory)
 
-    if vcs_name == 'svn':
-        assert repository_name == 'INITools'
+    if vcs_name == "svn":
+        assert repository_name == "INITools"
         _create_svn_initools_repo(repo_url_path)
-        repo_url_path = os.path.join(repo_url_path, 'trunk')
+        repo_url_path = os.path.join(repo_url_path, "trunk")
     else:
         vcs_backend = vcs.get_backend(vcs_name)
         vcs_backend.obtain(repo_url_path, url=hide_url(remote_repo))
 
-    return '{}+{}'.format(vcs_name, path_to_url(repo_url_path))
+    return "{}+{}".format(vcs_name, path_to_url(repo_url_path))
 
 
 def local_repo(remote_repo, temp_path):
-    return local_checkout(remote_repo, temp_path).split('+', 1)[1]
+    return local_checkout(remote_repo, temp_path).split("+", 1)[1]
diff --git a/tests/lib/options_helpers.py b/tests/lib/options_helpers.py
index 2354a818df8..a0525c0b3e6 100644
--- a/tests/lib/options_helpers.py
+++ b/tests/lib/options_helpers.py
@@ -7,7 +7,6 @@
 
 
 class FakeCommand(Command):
-
     def main(self, args):
         index_opts = cmdoptions.make_option_group(
             cmdoptions.index_group,
@@ -18,11 +17,12 @@ def main(self, args):
 
 
 class AddFakeCommandMixin(object):
-
     def setup(self):
-        commands_dict['fake'] = CommandInfo(
-            'tests.lib.options_helpers', 'FakeCommand', 'fake summary',
+        commands_dict["fake"] = CommandInfo(
+            "tests.lib.options_helpers",
+            "FakeCommand",
+            "fake summary",
         )
 
     def teardown(self):
-        commands_dict.pop('fake')
+        commands_dict.pop("fake")
diff --git a/tests/lib/path.py b/tests/lib/path.py
index d1ea6bc5e8d..6cb45081daf 100644
--- a/tests/lib/path.py
+++ b/tests/lib/path.py
@@ -15,7 +15,6 @@
     supports_fd = set()
 
 
-
 _base = six.text_type if os.path.supports_unicode_filenames else str
 
 
@@ -170,7 +169,7 @@ def joinpath(self, *parts):
 
     # TODO: Remove after removing inheritance from str.
     def join(self, *parts):
-        raise RuntimeError('Path.join is invalid, use joinpath instead.')
+        raise RuntimeError("Path.join is invalid, use joinpath instead.")
 
     def read_bytes(self):
         # type: () -> bytes
@@ -201,4 +200,5 @@ def symlink_to(self, target):
     def stat(self):
         return os.stat(self)
 
+
 curdir = Path(os.path.curdir)
diff --git a/tests/lib/requests_mocks.py b/tests/lib/requests_mocks.py
index e8e3e9c886e..cb90dddcc68 100644
--- a/tests/lib/requests_mocks.py
+++ b/tests/lib/requests_mocks.py
@@ -5,7 +5,6 @@
 
 
 class FakeStream(object):
-
     def __init__(self, contents):
         self._io = BytesIO(contents)
 
@@ -20,7 +19,6 @@ def release_conn(self):
 
 
 class MockResponse(object):
-
     def __init__(self, contents):
         self.raw = FakeStream(contents)
         self.content = contents
@@ -29,12 +27,11 @@ def __init__(self, contents):
         self.status_code = 200
         self.connection = None
         self.url = None
-        self.headers = {'Content-Length': len(contents)}
+        self.headers = {"Content-Length": len(contents)}
         self.history = []
 
 
 class MockConnection(object):
-
     def _send(self, req, **kwargs):
         raise NotImplementedError("_send must be overridden for tests")
 
@@ -46,7 +43,6 @@ def send(self, req, **kwargs):
 
 
 class MockRequest(object):
-
     def __init__(self, url):
         self.url = url
         self.headers = {}
diff --git a/tests/lib/server.py b/tests/lib/server.py
index ebbf120d3d7..a63cc8b37c0 100644
--- a/tests/lib/server.py
+++ b/tests/lib/server.py
@@ -41,16 +41,17 @@
     class MockServer(BaseWSGIServer):
         mock = Mock()  # type: Mock
 
+
 # Applies on Python 2 and Windows.
 if not hasattr(signal, "pthread_sigmask"):
     # We're not relying on this behavior anywhere currently, it's just best
     # practice.
     blocked_signals = nullcontext
 else:
+
     @contextmanager
     def blocked_signals():
-        """Block all signals for e.g. starting a worker thread.
-        """
+        """Block all signals for e.g. starting a worker thread."""
         # valid_signals() was added in Python 3.8 (and not using it results
         # in a warning on pthread_sigmask() call)
         try:
@@ -95,6 +96,7 @@ def _mock_wsgi_adapter(mock):
     """Uses a mock to record function arguments and provide
     the actual function that should respond.
     """
+
     def adapter(environ, start_response):
         # type: (Environ, StartResponse) -> Body
         responder = mock(environ, start_response)
@@ -146,8 +148,7 @@ def make_mock_server(**kwargs):
 @contextmanager
 def server_running(server):
     # type: (BaseWSGIServer) -> None
-    """Context manager for running the provided server in a separate thread.
-    """
+    """Context manager for running the provided server in a separate thread."""
     thread = threading.Thread(target=server.serve_forever)
     thread.daemon = True
     with blocked_signals():
@@ -166,45 +167,50 @@ def text_html_response(text):
     # type: (Text) -> Responder
     def responder(environ, start_response):
         # type: (Environ, StartResponse) -> Body
-        start_response("200 OK", [
-            ("Content-Type", "text/html; charset=UTF-8"),
-        ])
-        return [text.encode('utf-8')]
+        start_response(
+            "200 OK",
+            [
+                ("Content-Type", "text/html; charset=UTF-8"),
+            ],
+        )
+        return [text.encode("utf-8")]
 
     return responder
 
 
 def html5_page(text):
     # type: (Union[Text, str]) -> Text
-    return dedent(u"""
+    return (
+        dedent(
+            u"""
     <!DOCTYPE html>
     <html>
       <body>
         {}
       </body>
     </html>
-    """).strip().format(text)
+    """
+        )
+        .strip()
+        .format(text)
+    )
 
 
 def index_page(spec):
     # type: (Dict[str, str]) -> Responder
     def link(name, value):
-        return '<a href="{}">{}</a>'.format(
-            value, name
-        )
+        return '<a href="{}">{}</a>'.format(value, name)
 
-    links = ''.join(link(*kv) for kv in spec.items())
+    links = "".join(link(*kv) for kv in spec.items())
     return text_html_response(html5_page(links))
 
 
 def package_page(spec):
     # type: (Dict[str, str]) -> Responder
     def link(name, value):
-        return '<a href="{}">{}</a>'.format(
-            value, name
-        )
+        return '<a href="{}">{}</a>'.format(value, name)
 
-    links = ''.join(link(*kv) for kv in spec.items())
+    links = "".join(link(*kv) for kv in spec.items())
     return text_html_response(html5_page(links))
 
 
@@ -214,13 +220,14 @@ def responder(environ, start_response):
         # type: (Environ, StartResponse) -> Body
         size = os.stat(path).st_size
         start_response(
-            "200 OK", [
+            "200 OK",
+            [
                 ("Content-Type", "application/octet-stream"),
                 ("Content-Length", str(size)),
             ],
         )
 
-        with open(path, 'rb') as f:
+        with open(path, "rb") as f:
             return [f.read()]
 
     return responder
@@ -231,12 +238,13 @@ def responder(environ, start_response):
         # type: (Environ, StartResponse) -> Body
 
         start_response(
-            "401 Unauthorized", [
+            "401 Unauthorized",
+            [
                 ("WWW-Authenticate", "Basic"),
             ],
         )
 
-        with open(path, 'rb') as f:
+        with open(path, "rb") as f:
             return [f.read()]
 
     return responder
diff --git a/tests/lib/test_lib.py b/tests/lib/test_lib.py
index 9c00e9d1f0c..f647c1e6fe7 100644
--- a/tests/lib/test_lib.py
+++ b/tests/lib/test_lib.py
@@ -20,8 +20,8 @@ def assert_error_startswith(exc_type, expected_start):
     with pytest.raises(exc_type) as err:
         yield
 
-    assert str(err.value).startswith(expected_start), (
-        'full message: {}'.format(err.value)
+    assert str(err.value).startswith(expected_start), "full message: {}".format(
+        err.value
     )
 
 
@@ -33,7 +33,7 @@ def test_tmp_dir_exists_in_env(script):
     # need these tests to ensure the assert_no_temp feature of scripttest is
     # working
     script.assert_no_temp()  # this fails if env.tmp_path doesn't exist
-    assert script.environ['TMPDIR'] == script.temp_path
+    assert script.environ["TMPDIR"] == script.temp_path
     assert isdir(script.temp_path)
 
 
@@ -43,16 +43,16 @@ def test_correct_pip_version(script):
     """
     # output is like:
     # pip PIPVERSION from PIPDIRECTORY (python PYVERSION)
-    result = script.pip('--version')
+    result = script.pip("--version")
 
     # compare the directory tree of the invoked pip with that of this source
     # distribution
     pip_folder_outputed = re.match(
-        r'pip \d+(\.[\d]+)+(\.?(b|rc|dev|pre|post)\d+)? from (.*) '
-        r'\(python \d(.[\d])+\)$',
-        result.stdout
+        r"pip \d+(\.[\d]+)+(\.?(b|rc|dev|pre|post)\d+)? from (.*) "
+        r"\(python \d(.[\d])+\)$",
+        result.stdout,
     ).group(4)
-    pip_folder = join(SRC_DIR, 'src', 'pip')
+    pip_folder = join(SRC_DIR, "src", "pip")
 
     diffs = filecmp.dircmp(pip_folder, pip_folder_outputed)
 
@@ -61,32 +61,33 @@ def test_correct_pip_version(script):
     # primary resources other than .py files, this code will need
     # maintenance
     mismatch_py = [
-        x for x in diffs.left_only + diffs.right_only + diffs.diff_files
-        if x.endswith('.py')
+        x
+        for x in diffs.left_only + diffs.right_only + diffs.diff_files
+        if x.endswith(".py")
     ]
     assert not mismatch_py, (
-        'mismatched source files in {pip_folder!r} '
-        'and {pip_folder_outputed!r}: {mismatch_py!r}'.format(**locals())
+        "mismatched source files in {pip_folder!r} "
+        "and {pip_folder_outputed!r}: {mismatch_py!r}".format(**locals())
     )
 
 
 def test_as_import(script):
-    """ test that pip.__init__.py does not shadow
+    """test that pip.__init__.py does not shadow
     the command submodule with a dictionary
     """
     import pip._internal.commands.install as inst
+
     assert inst is not None
 
 
 class TestPipTestEnvironment:
-
     def run_stderr_with_prefix(self, script, prefix, **kwargs):
         """
         Call run() that prints stderr with the given prefix.
         """
-        text = '{}: hello, world\\n'.format(prefix)
+        text = "{}: hello, world\\n".format(prefix)
         command = 'import sys; sys.stderr.write("{}")'.format(text)
-        args = [sys.executable, '-c', command]
+        args = [sys.executable, "-c", command]
         script.run(*args, **kwargs)
 
     def run_with_log_command(self, script, sub_string, **kwargs):
@@ -98,14 +99,17 @@ def run_with_log_command(self, script, sub_string, **kwargs):
             "import logging; logging.basicConfig(level='INFO'); "
             "logging.getLogger().info('sub: {}', 'foo')"
         ).format(sub_string)
-        args = [sys.executable, '-c', command]
+        args = [sys.executable, "-c", command]
         script.run(*args, **kwargs)
 
-    @pytest.mark.parametrize('prefix', (
-        'DEBUG',
-        'INFO',
-        'FOO',
-    ))
+    @pytest.mark.parametrize(
+        "prefix",
+        (
+            "DEBUG",
+            "INFO",
+            "FOO",
+        ),
+    )
     def test_run__allowed_stderr(self, script, prefix):
         """
         Test calling run() with allowed stderr.
@@ -119,21 +123,28 @@ def test_run__allow_stderr_warning(self, script):
         """
         # Check that no error happens.
         self.run_stderr_with_prefix(
-            script, 'WARNING', allow_stderr_warning=True,
+            script,
+            "WARNING",
+            allow_stderr_warning=True,
         )
 
         # Check that an error still happens with ERROR.
-        expected_start = 'stderr has an unexpected error'
+        expected_start = "stderr has an unexpected error"
         with assert_error_startswith(RuntimeError, expected_start):
             self.run_stderr_with_prefix(
-                script, 'ERROR', allow_stderr_warning=True,
+                script,
+                "ERROR",
+                allow_stderr_warning=True,
             )
 
-    @pytest.mark.parametrize('prefix', (
-        'DEPRECATION',
-        'WARNING',
-        'ERROR',
-    ))
+    @pytest.mark.parametrize(
+        "prefix",
+        (
+            "DEPRECATION",
+            "WARNING",
+            "ERROR",
+        ),
+    )
     def test_run__allow_stderr_error(self, script, prefix):
         """
         Test passing allow_stderr_error=True.
@@ -141,11 +152,14 @@ def test_run__allow_stderr_error(self, script, prefix):
         # Check that no error happens.
         self.run_stderr_with_prefix(script, prefix, allow_stderr_error=True)
 
-    @pytest.mark.parametrize('prefix, expected_start', (
-        ('DEPRECATION', 'stderr has an unexpected warning'),
-        ('WARNING', 'stderr has an unexpected warning'),
-        ('ERROR', 'stderr has an unexpected error'),
-    ))
+    @pytest.mark.parametrize(
+        "prefix, expected_start",
+        (
+            ("DEPRECATION", "stderr has an unexpected warning"),
+            ("WARNING", "stderr has an unexpected warning"),
+            ("ERROR", "stderr has an unexpected error"),
+        ),
+    )
     def test_run__unexpected_stderr(self, script, prefix, expected_start):
         """
         Test calling run() with unexpected stderr output.
@@ -158,70 +172,72 @@ def test_run__logging_error(self, script):
         Test calling run() with an unexpected logging error.
         """
         # Pass a good substitution string.
-        self.run_with_log_command(script, sub_string='%r')
+        self.run_with_log_command(script, sub_string="%r")
 
-        expected_start = 'stderr has a logging error, which is never allowed'
+        expected_start = "stderr has a logging error, which is never allowed"
         with assert_error_startswith(RuntimeError, expected_start):
             # Pass a bad substitution string.  Also, pass
             # allow_stderr_error=True to check that the RuntimeError occurs
             # even under the stricter test condition of when we are allowing
             # other types of errors.
             self.run_with_log_command(
-                script, sub_string='{!r}', allow_stderr_error=True,
+                script,
+                sub_string="{!r}",
+                allow_stderr_error=True,
             )
 
     def test_run__allow_stderr_error_false_error_with_expect_error(
-        self, script,
+        self,
+        script,
     ):
         """
         Test passing allow_stderr_error=False with expect_error=True.
         """
-        expected_start = (
-            'cannot pass allow_stderr_error=False with expect_error=True'
-        )
+        expected_start = "cannot pass allow_stderr_error=False with expect_error=True"
         with assert_error_startswith(RuntimeError, expected_start):
-            script.run('python', allow_stderr_error=False, expect_error=True)
+            script.run("python", allow_stderr_error=False, expect_error=True)
 
     def test_run__allow_stderr_warning_false_error_with_expect_stderr(
-        self, script,
+        self,
+        script,
     ):
         """
         Test passing allow_stderr_warning=False with expect_stderr=True.
         """
         expected_start = (
-            'cannot pass allow_stderr_warning=False with expect_stderr=True'
+            "cannot pass allow_stderr_warning=False with expect_stderr=True"
         )
         with assert_error_startswith(RuntimeError, expected_start):
             script.run(
-                'python', allow_stderr_warning=False, expect_stderr=True,
+                "python",
+                allow_stderr_warning=False,
+                expect_stderr=True,
             )
 
-    @pytest.mark.parametrize('arg_name', (
-        'expect_error',
-        'allow_stderr_error',
-    ))
+    @pytest.mark.parametrize(
+        "arg_name",
+        (
+            "expect_error",
+            "allow_stderr_error",
+        ),
+    )
     def test_run__allow_stderr_warning_false_error(self, script, arg_name):
         """
         Test passing allow_stderr_warning=False when it is not allowed.
         """
-        kwargs = {'allow_stderr_warning': False, arg_name: True}
+        kwargs = {"allow_stderr_warning": False, arg_name: True}
         expected_start = (
-            'cannot pass allow_stderr_warning=False with '
-            'allow_stderr_error=True'
+            "cannot pass allow_stderr_warning=False with " "allow_stderr_error=True"
         )
         with assert_error_startswith(RuntimeError, expected_start):
-            script.run('python', **kwargs)
+            script.run("python", **kwargs)
 
     def test_run__expect_error_fails_when_zero_returncode(self, script):
-        expected_start = 'Script passed unexpectedly'
+        expected_start = "Script passed unexpectedly"
         with assert_error_startswith(AssertionError, expected_start):
-            script.run(
-                'python', expect_error=True
-            )
+            script.run("python", expect_error=True)
 
     def test_run__no_expect_error_fails_when_nonzero_returncode(self, script):
-        expected_start = 'Script returned code: 1'
+        expected_start = "Script returned code: 1"
         with assert_error_startswith(AssertionError, expected_start):
-            script.run(
-                'python', '-c', 'import sys; sys.exit(1)'
-            )
+            script.run("python", "-c", "import sys; sys.exit(1)")
diff --git a/tests/lib/test_wheel.py b/tests/lib/test_wheel.py
index a6f46cd899c..cab2788262d 100644
--- a/tests/lib/test_wheel.py
+++ b/tests/lib/test_wheel.py
@@ -166,19 +166,20 @@ def test_make_wheel_default_record():
         record_bytes = z.read("simple-0.1.0.dist-info/RECORD")
         record_text = ensure_text(record_bytes)
         record_rows = list(csv.reader(record_text.splitlines()))
-        records = {
-            row[0]: row[1:] for row in record_rows
-        }
+        records = {row[0]: row[1:] for row in record_rows}
 
         expected = {
             "simple/__init__.py": [
-                "sha256=ypeBEsobvcr6wjGzmiPcTaeG7_gUfE5yuYB3ha_uSLs", "1"
+                "sha256=ypeBEsobvcr6wjGzmiPcTaeG7_gUfE5yuYB3ha_uSLs",
+                "1",
             ],
             "simple-0.1.0.data/purelib/info.txt": [
-                "sha256=Ln0sA6lQeuJl7PW1NWiFpTOTogKdJBOUmXJloaJa78Y", "1"
+                "sha256=Ln0sA6lQeuJl7PW1NWiFpTOTogKdJBOUmXJloaJa78Y",
+                "1",
             ],
             "simple-0.1.0.dist-info/LICENSE": [
-                "sha256=PiPoFgA5WUoziU9lZOGxNIu9egCI1CxKy3PurtWcAJ0", "1"
+                "sha256=PiPoFgA5WUoziU9lZOGxNIu9egCI1CxKy3PurtWcAJ0",
+                "1",
             ],
             "simple-0.1.0.dist-info/RECORD": ["", ""],
         }
diff --git a/tests/lib/venv.py b/tests/lib/venv.py
index cc94e29f254..2e702b2c4bc 100644
--- a/tests/lib/venv.py
+++ b/tests/lib/venv.py
@@ -22,9 +22,9 @@ class VirtualEnvironment(object):
 
     def __init__(self, location, template=None, venv_type=None):
         assert template is None or venv_type is None
-        assert venv_type in (None, 'virtualenv', 'venv')
+        assert venv_type in (None, "virtualenv", "venv")
         self.location = Path(location)
-        self._venv_type = venv_type or template._venv_type or 'virtualenv'
+        self._venv_type = venv_type or template._venv_type or "virtualenv"
         self._user_site_packages = False
         self._template = template
         self._sitecustomize = None
@@ -34,12 +34,12 @@ def __init__(self, location, template=None, venv_type=None):
     def _update_paths(self):
         home, lib, inc, bin = _virtualenv.path_locations(self.location)
         self.bin = Path(bin)
-        self.site = Path(lib) / 'site-packages'
+        self.site = Path(lib) / "site-packages"
         # Workaround for https://github.com/pypa/virtualenv/issues/306
         if hasattr(sys, "pypy_version_info"):
-            version_fmt = '{0}' if six.PY3 else '{0}.{1}'
+            version_fmt = "{0}" if six.PY3 else "{0}.{1}"
             version_dir = version_fmt.format(*sys.version_info)
-            self.lib = Path(home, 'lib-python', version_dir)
+            self.lib = Path(home, "lib-python", version_dir)
         else:
             self.lib = Path(lib)
 
@@ -52,17 +52,15 @@ def _create(self, clear=False):
         if self._template:
             # On Windows, calling `_virtualenv.path_locations(target)`
             # will have created the `target` directory...
-            if sys.platform == 'win32' and self.location.exists():
+            if sys.platform == "win32" and self.location.exists():
                 self.location.rmdir()
             # Clone virtual environment from template.
-            shutil.copytree(
-                self._template.location, self.location, symlinks=True
-            )
+            shutil.copytree(self._template.location, self.location, symlinks=True)
             self._sitecustomize = self._template.sitecustomize
             self._user_site_packages = self._template.user_site_packages
         else:
             # Create a new virtual environment.
-            if self._venv_type == 'virtualenv':
+            if self._venv_type == "virtualenv":
                 _virtualenv.create_environment(
                     self.location,
                     no_pip=True,
@@ -70,7 +68,7 @@ def _create(self, clear=False):
                     no_setuptools=True,
                 )
                 self._fix_virtualenv_site_module()
-            elif self._venv_type == 'venv':
+            elif self._venv_type == "venv":
                 builder = _venv.EnvBuilder()
                 context = builder.ensure_directories(self.location)
                 builder.create_configuration(context)
@@ -81,46 +79,44 @@ def _create(self, clear=False):
 
     def _fix_virtualenv_site_module(self):
         # Patch `site.py` so user site work as expected.
-        site_py = self.lib / 'site.py'
+        site_py = self.lib / "site.py"
         with open(site_py) as fp:
             site_contents = fp.read()
         for pattern, replace in (
             (
                 # Ensure enabling user site does not result in adding
                 # the real site-packages' directory to `sys.path`.
+                ("\ndef virtual_addsitepackages(known_paths):\n"),
                 (
-                    '\ndef virtual_addsitepackages(known_paths):\n'
-                ),
-                (
-                    '\ndef virtual_addsitepackages(known_paths):\n'
-                    '    return known_paths\n'
+                    "\ndef virtual_addsitepackages(known_paths):\n"
+                    "    return known_paths\n"
                 ),
             ),
             (
                 # Fix sites ordering: user site must be added before system.
                 (
-                    '\n    paths_in_sys = addsitepackages(paths_in_sys)'
-                    '\n    paths_in_sys = addusersitepackages(paths_in_sys)\n'
+                    "\n    paths_in_sys = addsitepackages(paths_in_sys)"
+                    "\n    paths_in_sys = addusersitepackages(paths_in_sys)\n"
                 ),
                 (
-                    '\n    paths_in_sys = addusersitepackages(paths_in_sys)'
-                    '\n    paths_in_sys = addsitepackages(paths_in_sys)\n'
+                    "\n    paths_in_sys = addusersitepackages(paths_in_sys)"
+                    "\n    paths_in_sys = addsitepackages(paths_in_sys)\n"
                 ),
             ),
         ):
             assert pattern in site_contents
             site_contents = site_contents.replace(pattern, replace)
-        with open(site_py, 'w') as fp:
+        with open(site_py, "w") as fp:
             fp.write(site_contents)
         # Make sure bytecode is up-to-date too.
         assert compileall.compile_file(str(site_py), quiet=1, force=True)
 
     def _customize_site(self):
-        contents = ''
-        if self._venv_type == 'venv':
+        contents = ""
+        if self._venv_type == "venv":
             # Enable user site (before system).
             contents += textwrap.dedent(
-                '''
+                """
                 import os, site, sys
 
                 if not os.environ.get('PYTHONNOUSERSITE', False):
@@ -144,9 +140,10 @@ def _customize_site(self):
                     # Third, add back system-sites related paths.
                     for path in site.getsitepackages():
                         site.addsitedir(path)
-                ''').strip()
+                """
+            ).strip()
         if self._sitecustomize is not None:
-            contents += '\n' + self._sitecustomize
+            contents += "\n" + self._sitecustomize
         sitecustomize = self.site / "sitecustomize.py"
         sitecustomize.write_text(contents)
         # Make sure bytecode is up-to-date too.
@@ -176,11 +173,11 @@ def user_site_packages(self):
     @user_site_packages.setter
     def user_site_packages(self, value):
         self._user_site_packages = value
-        if self._venv_type == 'virtualenv':
+        if self._venv_type == "virtualenv":
             marker = self.lib / "no-global-site-packages.txt"
             if self._user_site_packages:
                 marker.unlink()
             else:
                 marker.touch()
-        elif self._venv_type == 'venv':
+        elif self._venv_type == "venv":
             self._customize_site()
diff --git a/tests/lib/wheel.py b/tests/lib/wheel.py
index d89a680a190..8af5fa8971f 100644
--- a/tests/lib/wheel.py
+++ b/tests/lib/wheel.py
@@ -34,9 +34,7 @@
 
     # path, digest, size
     RecordLike = Tuple[str, str, str]
-    RecordCallback = Callable[
-        [List["Record"]], Union[str, bytes, List[RecordLike]]
-    ]
+    RecordCallback = Callable[[List["Record"]], Union[str, bytes, List[RecordLike]]]
     # As would be used in metadata
     HeaderValue = Union[str, List[str]]
 
@@ -56,8 +54,8 @@ class Default(Enum):
     T = TypeVar("T")
 
     class Defaulted(Union[Default, T]):
-        """A type which may be defaulted.
-        """
+        """A type which may be defaulted."""
+
         pass
 
 
@@ -98,11 +96,13 @@ def make_metadata_file(
     if value is not _default:
         return File(path, ensure_binary(value))
 
-    metadata = CaseInsensitiveDict({
-        "Metadata-Version": "2.1",
-        "Name": name,
-        "Version": version,
-    })
+    metadata = CaseInsensitiveDict(
+        {
+            "Metadata-Version": "2.1",
+            "Name": name,
+            "Version": version,
+        }
+    )
     if updates is not _default:
         metadata.update(updates)
 
@@ -129,12 +129,14 @@ def make_wheel_metadata_file(
     if value is not _default:
         return File(path, ensure_binary(value))
 
-    metadata = CaseInsensitiveDict({
-        "Wheel-Version": "1.0",
-        "Generator": "pip-test-suite",
-        "Root-Is-Purelib": "true",
-        "Tag": ["-".join(parts) for parts in tags],
-    })
+    metadata = CaseInsensitiveDict(
+        {
+            "Wheel-Version": "1.0",
+            "Generator": "pip-test-suite",
+            "Root-Is-Purelib": "true",
+            "Tag": ["-".join(parts) for parts in tags],
+        }
+    )
 
     if updates is not _default:
         metadata.update(updates)
@@ -173,10 +175,7 @@ def make_entry_points_file(
 
 def make_files(files):
     # type: (Dict[str, AnyStr]) -> List[File]
-    return [
-        File(name, ensure_binary(contents))
-        for name, contents in iteritems(files)
-    ]
+    return [File(name, ensure_binary(contents)) for name, contents in iteritems(files)]
 
 
 def make_metadata_files(name, version, files):
@@ -204,9 +203,7 @@ def urlsafe_b64encode_nopad(data):
 
 def digest(contents):
     # type: (bytes) -> str
-    return "sha256={}".format(
-        urlsafe_b64encode_nopad(sha256(contents).digest())
-    )
+    return "sha256={}".format(urlsafe_b64encode_nopad(sha256(contents).digest()))
 
 
 def record_file_maker_wrapper(
@@ -220,9 +217,7 @@ def record_file_maker_wrapper(
     records = []  # type: List[Record]
     for file in files:
         records.append(
-            Record(
-                file.name, digest(file.contents), str(len(file.contents))
-            )
+            Record(file.name, digest(file.contents), str(len(file.contents)))
         )
         yield file
 
@@ -251,19 +246,20 @@ def record_file_maker_wrapper(
 
 def wheel_name(name, version, pythons, abis, platforms):
     # type: (str, str, str, str, str) -> str
-    stem = "-".join([
-        name,
-        version,
-        ".".join(pythons),
-        ".".join(abis),
-        ".".join(platforms),
-    ])
+    stem = "-".join(
+        [
+            name,
+            version,
+            ".".join(pythons),
+            ".".join(abis),
+            ".".join(platforms),
+        ]
+    )
     return "{}.whl".format(stem)
 
 
 class WheelBuilder(object):
-    """A wheel that can be saved or converted to several formats.
-    """
+    """A wheel that can be saved or converted to several formats."""
 
     def __init__(self, name, files):
         # type: (str, List[File]) -> None
@@ -391,9 +387,7 @@ def make_wheel(
     tags = list(itertools.product(pythons, abis, platforms))
 
     possible_files = [
-        make_metadata_file(
-            name, version, metadata, metadata_updates, metadata_body
-        ),
+        make_metadata_file(name, version, metadata, metadata_updates, metadata_body),
         make_wheel_metadata_file(
             name, version, wheel_metadata, tags, wheel_metadata_updates
         ),
@@ -404,9 +398,7 @@ def make_wheel(
         possible_files.extend(make_files(extra_files))
 
     if extra_metadata_files is not _default:
-        possible_files.extend(
-            make_metadata_files(name, version, extra_metadata_files)
-        )
+        possible_files.extend(make_metadata_files(name, version, extra_metadata_files))
 
     if extra_data_files is not _default:
         possible_files.extend(make_data_files(name, version, extra_data_files))
diff --git a/tests/unit/resolution_resolvelib/conftest.py b/tests/unit/resolution_resolvelib/conftest.py
index 87f5d129cbd..8d2e9e7d3f7 100644
--- a/tests/unit/resolution_resolvelib/conftest.py
+++ b/tests/unit/resolution_resolvelib/conftest.py
@@ -4,6 +4,7 @@
 from pip._internal.commands.install import InstallCommand
 from pip._internal.index.collector import LinkCollector
 from pip._internal.index.package_finder import PackageFinder
+
 # from pip._internal.models.index import PyPI
 from pip._internal.models.search_scope import SearchScope
 from pip._internal.models.selection_prefs import SelectionPreferences
@@ -40,7 +41,7 @@ def preparer(finder):
                     req_tracker=tracker,
                     session=session,
                     finder=finder,
-                    use_user_site=False
+                    use_user_site=False,
                 )
 
                 yield preparer
diff --git a/tests/unit/resolution_resolvelib/test_requirement.py b/tests/unit/resolution_resolvelib/test_requirement.py
index a03edb6f7c2..847f9f92ced 100644
--- a/tests/unit/resolution_resolvelib/test_requirement.py
+++ b/tests/unit/resolution_resolvelib/test_requirement.py
@@ -63,8 +63,7 @@ def test_new_resolver_correct_number_of_matches(test_cases, factory):
 
 
 def test_new_resolver_candidates_match_requirement(test_cases, factory):
-    """Candidates returned from find_candidates should satisfy the requirement
-    """
+    """Candidates returned from find_candidates should satisfy the requirement"""
     for spec, _, _ in test_cases:
         req = factory.make_requirement_from_spec(spec, comes_from=None)
         for c in factory.find_candidates([req], Constraint.empty()):
@@ -77,4 +76,4 @@ def test_new_resolver_full_resolve(factory, provider):
     req = factory.make_requirement_from_spec("simplewheel", comes_from=None)
     r = Resolver(provider, BaseReporter())
     result = r.resolve([req])
-    assert set(result.mapping.keys()) == {'simplewheel'}
+    assert set(result.mapping.keys()) == {"simplewheel"}
diff --git a/tests/unit/resolution_resolvelib/test_resolver.py b/tests/unit/resolution_resolvelib/test_resolver.py
index 0f240ec6ce4..4ebbd80a9dc 100644
--- a/tests/unit/resolution_resolvelib/test_resolver.py
+++ b/tests/unit/resolution_resolvelib/test_resolver.py
@@ -30,8 +30,7 @@ def resolver(preparer, finder):
 
 
 def _make_graph(edges):
-    """Build graph from edge declarations.
-    """
+    """Build graph from edge declarations."""
 
     graph = DirectedGraph()
     for parent, child in edges:
diff --git a/tests/unit/test_appdirs.py b/tests/unit/test_appdirs.py
index e129c0c0b83..819013f4ca8 100644
--- a/tests/unit/test_appdirs.py
+++ b/tests/unit/test_appdirs.py
@@ -10,7 +10,6 @@
 
 
 class TestUserCacheDir:
-
     def test_user_cache_dir_win(self, monkeypatch):
         @pretend.call_recorder
         def _get_win_folder(base):
@@ -25,8 +24,10 @@ def _get_win_folder(base):
         monkeypatch.setattr(_appdirs, "system", "win32")
         monkeypatch.setattr(os, "path", ntpath)
 
-        assert (appdirs.user_cache_dir("pip") ==
-                "C:\\Users\\test\\AppData\\Local\\pip\\Cache")
+        assert (
+            appdirs.user_cache_dir("pip")
+            == "C:\\Users\\test\\AppData\\Local\\pip\\Cache"
+        )
         assert _get_win_folder.calls == [pretend.call("CSIDL_LOCAL_APPDATA")]
 
     def test_user_cache_dir_osx(self, monkeypatch):
@@ -66,7 +67,7 @@ def test_user_cache_dir_linux_home_slash(self, monkeypatch):
         assert appdirs.user_cache_dir("pip") == "/.cache/pip"
 
     def test_user_cache_dir_unicode(self, monkeypatch):
-        if sys.platform != 'win32':
+        if sys.platform != "win32":
             return
 
         def my_get_win_folder(csidl_name):
@@ -77,16 +78,16 @@ def my_get_win_folder(csidl_name):
         # Do not use the isinstance expression directly in the
         # assert statement, as the Unicode characters in the result
         # cause pytest to fail with an internal error on Python 2.7
-        result_is_str = isinstance(appdirs.user_cache_dir('test'), str)
+        result_is_str = isinstance(appdirs.user_cache_dir("test"), str)
         assert result_is_str, "user_cache_dir did not return a str"
 
         # Test against regression #3463
         from pip._internal.cli.main_parser import create_main_parser
+
         create_main_parser().print_help()  # This should not crash
 
 
 class TestSiteConfigDirs:
-
     def test_site_config_dirs_win(self, monkeypatch):
         @pretend.call_recorder
         def _get_win_folder(base):
@@ -110,8 +111,7 @@ def test_site_config_dirs_osx(self, monkeypatch):
         monkeypatch.setenv("HOME", "/home/test")
         monkeypatch.setattr(sys, "platform", "darwin")
 
-        assert appdirs.site_config_dirs("pip") == \
-            ["/Library/Application Support/pip"]
+        assert appdirs.site_config_dirs("pip") == ["/Library/Application Support/pip"]
 
     def test_site_config_dirs_linux(self, monkeypatch):
         monkeypatch.setattr(_appdirs, "system", "linux2")
@@ -119,36 +119,32 @@ def test_site_config_dirs_linux(self, monkeypatch):
         monkeypatch.delenv("XDG_CONFIG_DIRS", raising=False)
         monkeypatch.setattr(sys, "platform", "linux2")
 
-        assert appdirs.site_config_dirs("pip") == [
-            '/etc/xdg/pip',
-            '/etc'
-        ]
+        assert appdirs.site_config_dirs("pip") == ["/etc/xdg/pip", "/etc"]
 
     def test_site_config_dirs_linux_override(self, monkeypatch):
         monkeypatch.setattr(_appdirs, "system", "linux2")
         monkeypatch.setattr(os, "path", posixpath)
-        monkeypatch.setattr(os, "pathsep", ':')
+        monkeypatch.setattr(os, "pathsep", ":")
         monkeypatch.setenv("XDG_CONFIG_DIRS", "/spam:/etc:/etc/xdg")
         monkeypatch.setattr(sys, "platform", "linux2")
 
         assert appdirs.site_config_dirs("pip") == [
-            '/spam/pip',
-            '/etc/pip',
-            '/etc/xdg/pip',
-            '/etc'
+            "/spam/pip",
+            "/etc/pip",
+            "/etc/xdg/pip",
+            "/etc",
         ]
 
     def test_site_config_dirs_linux_empty(self, monkeypatch):
         monkeypatch.setattr(_appdirs, "system", "linux2")
         monkeypatch.setattr(os, "path", posixpath)
-        monkeypatch.setattr(os, "pathsep", ':')
+        monkeypatch.setattr(os, "pathsep", ":")
         monkeypatch.setenv("XDG_CONFIG_DIRS", "")
         monkeypatch.setattr(sys, "platform", "linux2")
-        assert appdirs.site_config_dirs("pip") == ['/etc/xdg/pip', '/etc']
+        assert appdirs.site_config_dirs("pip") == ["/etc/xdg/pip", "/etc"]
 
 
 class TestUserConfigDir:
-
     def test_user_config_dir_win_no_roaming(self, monkeypatch):
         @pretend.call_recorder
         def _get_win_folder(base):
@@ -164,8 +160,8 @@ def _get_win_folder(base):
         monkeypatch.setattr(os, "path", ntpath)
 
         assert (
-            appdirs.user_config_dir("pip", roaming=False) ==
-            "C:\\Users\\test\\AppData\\Local\\pip"
+            appdirs.user_config_dir("pip", roaming=False)
+            == "C:\\Users\\test\\AppData\\Local\\pip"
         )
         assert _get_win_folder.calls == [pretend.call("CSIDL_LOCAL_APPDATA")]
 
@@ -183,8 +179,9 @@ def _get_win_folder(base):
         monkeypatch.setattr(_appdirs, "system", "win32")
         monkeypatch.setattr(os, "path", ntpath)
 
-        assert (appdirs.user_config_dir("pip") ==
-                "C:\\Users\\test\\AppData\\Roaming\\pip")
+        assert (
+            appdirs.user_config_dir("pip") == "C:\\Users\\test\\AppData\\Roaming\\pip"
+        )
         assert _get_win_folder.calls == [pretend.call("CSIDL_APPDATA")]
 
     def test_user_config_dir_osx(self, monkeypatch):
@@ -193,12 +190,13 @@ def test_user_config_dir_osx(self, monkeypatch):
         monkeypatch.setenv("HOME", "/home/test")
         monkeypatch.setattr(sys, "platform", "darwin")
 
-        if os.path.isdir('/home/test/Library/Application Support/'):
-            assert (appdirs.user_config_dir("pip") ==
-                    "/home/test/Library/Application Support/pip")
+        if os.path.isdir("/home/test/Library/Application Support/"):
+            assert (
+                appdirs.user_config_dir("pip")
+                == "/home/test/Library/Application Support/pip"
+            )
         else:
-            assert (appdirs.user_config_dir("pip") ==
-                    "/home/test/.config/pip")
+            assert appdirs.user_config_dir("pip") == "/home/test/.config/pip"
 
     def test_user_config_dir_linux(self, monkeypatch):
         monkeypatch.setattr(_appdirs, "system", "linux2")
diff --git a/tests/unit/test_base_command.py b/tests/unit/test_base_command.py
index 8ba3d9e2526..0b3f10a1bab 100644
--- a/tests/unit/test_base_command.py
+++ b/tests/unit/test_base_command.py
@@ -13,16 +13,17 @@
 
 @pytest.fixture
 def fixed_time(utc):
-    with patch('time.time', lambda: 1547704837.040001):
+    with patch("time.time", lambda: 1547704837.040001):
         yield
 
 
 class FakeCommand(Command):
 
-    _name = 'fake'
+    _name = "fake"
 
     def __init__(self, run_func=None, error=False):
         if error:
+
             def run_func():
                 raise SystemExit(1)
 
@@ -43,21 +44,19 @@ def run(self, options, args):
 
 
 class FakeCommandWithUnicode(FakeCommand):
-    _name = 'fake_unicode'
+    _name = "fake_unicode"
 
     def run(self, options, args):
         logging.getLogger("pip.tests").info(b"bytes here \xE9")
-        logging.getLogger("pip.tests").info(
-            b"unicode here \xC3\xA9".decode("utf-8")
-        )
+        logging.getLogger("pip.tests").info(b"unicode here \xC3\xA9".decode("utf-8"))
 
 
 class TestCommand(object):
-
     def call_main(self, capsys, args):
         """
         Call command.main(), and return the command's stderr.
         """
+
         def raise_broken_stdout():
             raise BrokenStdoutLoggingError()
 
@@ -74,19 +73,19 @@ def test_raise_broken_stdout(self, capsys):
         """
         stderr = self.call_main(capsys, [])
 
-        assert stderr.rstrip() == 'ERROR: Pipe to stdout was broken'
+        assert stderr.rstrip() == "ERROR: Pipe to stdout was broken"
 
     def test_raise_broken_stdout__debug_logging(self, capsys):
         """
         Test raising BrokenStdoutLoggingError with debug logging enabled.
         """
-        stderr = self.call_main(capsys, ['-v'])
+        stderr = self.call_main(capsys, ["-v"])
 
-        assert 'ERROR: Pipe to stdout was broken' in stderr
-        assert 'Traceback (most recent call last):' in stderr
+        assert "ERROR: Pipe to stdout was broken" in stderr
+        assert "Traceback (most recent call last):" in stderr
 
 
-@patch('pip._internal.cli.req_command.Command.handle_pip_version_check')
+@patch("pip._internal.cli.req_command.Command.handle_pip_version_check")
 def test_handle_pip_version_check_called(mock_handle_version_check):
     """
     Check that Command.handle_pip_version_check() is called.
@@ -99,28 +98,28 @@ def test_handle_pip_version_check_called(mock_handle_version_check):
 def test_log_command_success(fixed_time, tmpdir):
     """Test the --log option logs when command succeeds."""
     cmd = FakeCommand()
-    log_path = tmpdir.joinpath('log')
-    cmd.main(['fake', '--log', log_path])
+    log_path = tmpdir.joinpath("log")
+    cmd.main(["fake", "--log", log_path])
     with open(log_path) as f:
-        assert f.read().rstrip() == '2019-01-17T06:00:37,040 fake'
+        assert f.read().rstrip() == "2019-01-17T06:00:37,040 fake"
 
 
 def test_log_command_error(fixed_time, tmpdir):
     """Test the --log option logs when command fails."""
     cmd = FakeCommand(error=True)
-    log_path = tmpdir.joinpath('log')
-    cmd.main(['fake', '--log', log_path])
+    log_path = tmpdir.joinpath("log")
+    cmd.main(["fake", "--log", log_path])
     with open(log_path) as f:
-        assert f.read().startswith('2019-01-17T06:00:37,040 fake')
+        assert f.read().startswith("2019-01-17T06:00:37,040 fake")
 
 
 def test_log_file_command_error(fixed_time, tmpdir):
     """Test the --log-file option logs (when there's an error)."""
     cmd = FakeCommand(error=True)
-    log_file_path = tmpdir.joinpath('log_file')
-    cmd.main(['fake', '--log-file', log_file_path])
+    log_file_path = tmpdir.joinpath("log_file")
+    cmd.main(["fake", "--log-file", log_file_path])
     with open(log_file_path) as f:
-        assert f.read().startswith('2019-01-17T06:00:37,040 fake')
+        assert f.read().startswith("2019-01-17T06:00:37,040 fake")
 
 
 def test_log_unicode_messages(fixed_time, tmpdir):
@@ -128,8 +127,8 @@ def test_log_unicode_messages(fixed_time, tmpdir):
     don't break logging.
     """
     cmd = FakeCommandWithUnicode()
-    log_path = tmpdir.joinpath('log')
-    cmd.main(['fake_unicode', '--log', log_path])
+    log_path = tmpdir.joinpath("log")
+    cmd.main(["fake_unicode", "--log", log_path])
 
 
 @pytest.mark.no_auto_tempdir_manager
@@ -151,9 +150,7 @@ def assert_helpers_set(options, args):
 not_deleted = "not_deleted"
 
 
-@pytest.mark.parametrize("kind,exists", [
-    (not_deleted, True), ("deleted", False)
-])
+@pytest.mark.parametrize("kind,exists", [(not_deleted, True), ("deleted", False)])
 @pytest.mark.no_auto_tempdir_manager
 def test_base_command_global_tempdir_cleanup(kind, exists):
     assert temp_dir._tempdir_manager is None
@@ -174,9 +171,7 @@ def create_temp_dirs(options, args):
     assert os.path.exists(Holder.value) == exists
 
 
-@pytest.mark.parametrize("kind,exists", [
-    (not_deleted, True), ("deleted", False)
-])
+@pytest.mark.parametrize("kind,exists", [(not_deleted, True), ("deleted", False)])
 @pytest.mark.no_auto_tempdir_manager
 def test_base_command_local_tempdir_cleanup(kind, exists):
     assert temp_dir._tempdir_manager is None
diff --git a/tests/unit/test_build_env.py b/tests/unit/test_build_env.py
index 1f3b88b4d87..fede5bcf30a 100644
--- a/tests/unit/test_build_env.py
+++ b/tests/unit/test_build_env.py
@@ -7,16 +7,14 @@
 
 
 def indent(text, prefix):
-    return '\n'.join((prefix if line else '') + line
-                     for line in text.split('\n'))
+    return "\n".join((prefix if line else "") + line for line in text.split("\n"))
 
 
-def run_with_build_env(script, setup_script_contents,
-                       test_script_contents=None):
-    build_env_script = script.scratch_path / 'build_env.py'
+def run_with_build_env(script, setup_script_contents, test_script_contents=None):
+    build_env_script = script.scratch_path / "build_env.py"
     build_env_script.write_text(
         dedent(
-            '''
+            """
             from __future__ import print_function
             import subprocess
             import sys
@@ -45,22 +43,25 @@ def run_with_build_env(script, setup_script_contents,
 
             with global_tempdir_manager():
                 build_env = BuildEnvironment()
-            '''.format(scratch=str(script.scratch_path))) +
-        indent(dedent(setup_script_contents), '    ') +
-        indent(
+            """.format(
+                scratch=str(script.scratch_path)
+            )
+        )
+        + indent(dedent(setup_script_contents), "    ")
+        + indent(
             dedent(
-                '''
+                """
                 if len(sys.argv) > 1:
                     with build_env:
                         subprocess.check_call((sys.executable, sys.argv[1]))
-                '''
+                """
             ),
-            '    '
+            "    ",
         )
     )
-    args = ['python', build_env_script]
+    args = ["python", build_env_script]
     if test_script_contents is not None:
-        test_script = script.scratch_path / 'test.py'
+        test_script = script.scratch_path / "test.py"
         test_script.write_text(dedent(test_script_contents))
         args.append(test_script)
     return script.run(*args)
@@ -68,41 +69,41 @@ def run_with_build_env(script, setup_script_contents,
 
 def test_build_env_allow_empty_requirements_install():
     build_env = BuildEnvironment()
-    for prefix in ('normal', 'overlay'):
+    for prefix in ("normal", "overlay"):
         build_env.install_requirements(None, [], prefix, None)
 
 
 def test_build_env_allow_only_one_install(script):
-    create_basic_wheel_for_package(script, 'foo', '1.0')
-    create_basic_wheel_for_package(script, 'bar', '1.0')
+    create_basic_wheel_for_package(script, "foo", "1.0")
+    create_basic_wheel_for_package(script, "bar", "1.0")
     finder = make_test_finder(find_links=[script.scratch_path])
     build_env = BuildEnvironment()
-    for prefix in ('normal', 'overlay'):
+    for prefix in ("normal", "overlay"):
         build_env.install_requirements(
-            finder, ['foo'], prefix,
-            'installing foo in {prefix}'.format(**locals()))
+            finder, ["foo"], prefix, "installing foo in {prefix}".format(**locals())
+        )
         with pytest.raises(AssertionError):
             build_env.install_requirements(
-                finder, ['bar'], prefix,
-                'installing bar in {prefix}'.format(**locals()))
+                finder, ["bar"], prefix, "installing bar in {prefix}".format(**locals())
+            )
         with pytest.raises(AssertionError):
             build_env.install_requirements(
-                finder, [], prefix,
-                'installing in {prefix}'.format(**locals()))
+                finder, [], prefix, "installing in {prefix}".format(**locals())
+            )
 
 
 def test_build_env_requirements_check(script):
 
-    create_basic_wheel_for_package(script, 'foo', '2.0')
-    create_basic_wheel_for_package(script, 'bar', '1.0')
-    create_basic_wheel_for_package(script, 'bar', '3.0')
-    create_basic_wheel_for_package(script, 'other', '0.5')
+    create_basic_wheel_for_package(script, "foo", "2.0")
+    create_basic_wheel_for_package(script, "bar", "1.0")
+    create_basic_wheel_for_package(script, "bar", "3.0")
+    create_basic_wheel_for_package(script, "other", "0.5")
 
-    script.pip_install_local('-f', script.scratch_path, 'foo', 'bar', 'other')
+    script.pip_install_local("-f", script.scratch_path, "foo", "bar", "other")
 
     run_with_build_env(
         script,
-        '''
+        """
         r = build_env.check_requirements(['foo', 'bar', 'other'])
         assert r == (set(), {'foo', 'bar', 'other'}), repr(r)
 
@@ -111,11 +112,12 @@ def test_build_env_requirements_check(script):
 
         r = build_env.check_requirements(['foo>3.0', 'bar>=2.5'])
         assert r == (set(), {'foo>3.0', 'bar>=2.5'}), repr(r)
-        ''')
+        """,
+    )
 
     run_with_build_env(
         script,
-        '''
+        """
         build_env.install_requirements(finder, ['foo', 'bar==3.0'], 'normal',
                                        'installing foo in normal')
 
@@ -127,11 +129,12 @@ def test_build_env_requirements_check(script):
 
         r = build_env.check_requirements(['foo>3.0', 'bar>=2.5'])
         assert r == ({('foo==2.0', 'foo>3.0')}, set()), repr(r)
-        ''')
+        """,
+    )
 
     run_with_build_env(
         script,
-        '''
+        """
         build_env.install_requirements(finder, ['foo', 'bar==3.0'], 'normal',
                                        'installing foo in normal')
         build_env.install_requirements(finder, ['bar==1.0'], 'overlay',
@@ -146,55 +149,56 @@ def test_build_env_requirements_check(script):
         r = build_env.check_requirements(['foo>3.0', 'bar>=2.5'])
         assert r == ({('bar==1.0', 'bar>=2.5'), ('foo==2.0', 'foo>3.0')}, \
             set()), repr(r)
-        ''')
+        """,
+    )
 
 
 def test_build_env_overlay_prefix_has_priority(script):
-    create_basic_wheel_for_package(script, 'pkg', '2.0')
-    create_basic_wheel_for_package(script, 'pkg', '4.3')
+    create_basic_wheel_for_package(script, "pkg", "2.0")
+    create_basic_wheel_for_package(script, "pkg", "4.3")
     result = run_with_build_env(
         script,
-        '''
+        """
         build_env.install_requirements(finder, ['pkg==2.0'], 'overlay',
                                        'installing pkg==2.0 in overlay')
         build_env.install_requirements(finder, ['pkg==4.3'], 'normal',
                                        'installing pkg==4.3 in normal')
-        ''',
-        '''
+        """,
+        """
         from __future__ import print_function
 
         print(__import__('pkg').__version__)
-        ''')
-    assert result.stdout.strip() == '2.0', str(result)
+        """,
+    )
+    assert result.stdout.strip() == "2.0", str(result)
 
 
 @pytest.mark.incompatible_with_test_venv
 def test_build_env_isolation(script):
 
     # Create dummy `pkg` wheel.
-    pkg_whl = create_basic_wheel_for_package(script, 'pkg', '1.0')
+    pkg_whl = create_basic_wheel_for_package(script, "pkg", "1.0")
 
     # Install it to site packages.
     script.pip_install_local(pkg_whl)
 
     # And a copy in the user site.
-    script.pip_install_local('--ignore-installed', '--user', pkg_whl)
+    script.pip_install_local("--ignore-installed", "--user", pkg_whl)
 
     # And to another directory available through a .pth file.
-    target = script.scratch_path / 'pth_install'
-    script.pip_install_local('-t', target, pkg_whl)
-    (script.site_packages_path / 'build_requires.pth').write_text(
-        str(target) + '\n'
-    )
+    target = script.scratch_path / "pth_install"
+    script.pip_install_local("-t", target, pkg_whl)
+    (script.site_packages_path / "build_requires.pth").write_text(str(target) + "\n")
 
     # And finally to yet another directory available through PYTHONPATH.
-    target = script.scratch_path / 'pypath_install'
-    script.pip_install_local('-t', target, pkg_whl)
+    target = script.scratch_path / "pypath_install"
+    script.pip_install_local("-t", target, pkg_whl)
     script.environ["PYTHONPATH"] = target
 
     run_with_build_env(
-        script, '',
-        r'''
+        script,
+        "",
+        r"""
         from __future__ import print_function
         from distutils.sysconfig import get_python_lib
         import sys
@@ -213,4 +217,5 @@ def test_build_env_isolation(script):
                     })), file=sys.stderr)
             print('sys.path:\n  ' + '\n  '.join(sys.path), file=sys.stderr)
             sys.exit(1)
-        ''')
+        """,
+    )
diff --git a/tests/unit/test_cache.py b/tests/unit/test_cache.py
index a289fb59890..571a80a75b1 100644
--- a/tests/unit/test_cache.py
+++ b/tests/unit/test_cache.py
@@ -67,9 +67,7 @@ def test_get_path_for_link_legacy(tmpdir):
     ensure_dir(legacy_path)
     with open(os.path.join(legacy_path, "test-1.0.0-pyx-none-any.whl"), "w"):
         pass
-    expected_candidates = {
-        "test-1.0.0-pyx-none-any.whl", "test-1.0.0-pyz-none-any.whl"
-    }
+    expected_candidates = {"test-1.0.0-pyx-none-any.whl", "test-1.0.0-pyz-none-any.whl"}
     candidates = {c[0] for c in wc._get_candidates(link, "test")}
     assert candidates == expected_candidates
 
@@ -86,9 +84,8 @@ def test_get_with_legacy_entry_only(tmpdir):
     with open(os.path.join(legacy_path, "test-1.0.0-py3-none-any.whl"), "w"):
         pass
     cached_link = wc.get(link, "test", [Tag("py3", "none", "any")])
-    assert (
-        os.path.normcase(os.path.dirname(cached_link.file_path)) ==
-        os.path.normcase(legacy_path)
+    assert os.path.normcase(os.path.dirname(cached_link.file_path)) == os.path.normcase(
+        legacy_path
     )
 
 
@@ -106,10 +103,6 @@ def test_get_cache_entry(tmpdir):
         pass
     other_link = Link("https://g.c/o/r/other")
     supported_tags = [Tag("py3", "none", "any")]
-    assert (
-        wc.get_cache_entry(persi_link, "persi", supported_tags).persistent
-    )
-    assert (
-        not wc.get_cache_entry(ephem_link, "ephem", supported_tags).persistent
-    )
+    assert wc.get_cache_entry(persi_link, "persi", supported_tags).persistent
+    assert not wc.get_cache_entry(ephem_link, "ephem", supported_tags).persistent
     assert wc.get_cache_entry(other_link, "other", supported_tags) is None
diff --git a/tests/unit/test_check.py b/tests/unit/test_check.py
index 1d1921484ea..8cfcafa58d6 100644
--- a/tests/unit/test_check.py
+++ b/tests/unit/test_check.py
@@ -7,7 +7,6 @@
 
 
 class TestInstalledDistributionsCall(object):
-
     def test_passes_correct_default_kwargs(self, monkeypatch):
         my_mock = mock.MagicMock(return_value=[])
         monkeypatch.setattr(check, "get_installed_distributions", my_mock)
diff --git a/tests/unit/test_cmdoptions.py b/tests/unit/test_cmdoptions.py
index 150570e716e..9bb63007d63 100644
--- a/tests/unit/test_cmdoptions.py
+++ b/tests/unit/test_cmdoptions.py
@@ -3,22 +3,25 @@
 from pip._internal.cli.cmdoptions import _convert_python_version
 
 
-@pytest.mark.parametrize('value, expected', [
-    ('', (None, None)),
-    ('2', ((2,), None)),
-    ('3', ((3,), None)),
-    ('3.7', ((3, 7), None)),
-    ('3.7.3', ((3, 7, 3), None)),
-    # Test strings without dots of length bigger than 1.
-    ('34', ((3, 4), None)),
-    # Test a 2-digit minor version.
-    ('310', ((3, 10), None)),
-    # Test some values that fail to parse.
-    ('ab', ((), 'each version part must be an integer')),
-    ('3a', ((), 'each version part must be an integer')),
-    ('3.7.a', ((), 'each version part must be an integer')),
-    ('3.7.3.1', ((), 'at most three version parts are allowed')),
-])
+@pytest.mark.parametrize(
+    "value, expected",
+    [
+        ("", (None, None)),
+        ("2", ((2,), None)),
+        ("3", ((3,), None)),
+        ("3.7", ((3, 7), None)),
+        ("3.7.3", ((3, 7, 3), None)),
+        # Test strings without dots of length bigger than 1.
+        ("34", ((3, 4), None)),
+        # Test a 2-digit minor version.
+        ("310", ((3, 10), None)),
+        # Test some values that fail to parse.
+        ("ab", ((), "each version part must be an integer")),
+        ("3a", ((), "each version part must be an integer")),
+        ("3.7.a", ((), "each version part must be an integer")),
+        ("3.7.3.1", ((), "at most three version parts are allowed")),
+    ],
+)
 def test_convert_python_version(value, expected):
     actual = _convert_python_version(value)
-    assert actual == expected, 'actual: {!r}'.format(actual)
+    assert actual == expected, "actual: {!r}".format(actual)
diff --git a/tests/unit/test_collector.py b/tests/unit/test_collector.py
index fa1057b640e..c1d2325649a 100644
--- a/tests/unit/test_collector.py
+++ b/tests/unit/test_collector.py
@@ -57,24 +57,29 @@ def test_get_html_response_archive_to_naive_scheme(url):
     ],
 )
 @mock.patch("pip._internal.index.collector.raise_for_status")
-def test_get_html_response_archive_to_http_scheme(mock_raise_for_status, url,
-                                                  content_type):
+def test_get_html_response_archive_to_http_scheme(
+    mock_raise_for_status, url, content_type
+):
     """
     `_get_html_response()` should send a HEAD request on an archive-like URL
     if the scheme supports it, and raise `_NotHTML` if the response isn't HTML.
     """
     session = mock.Mock(PipSession)
-    session.head.return_value = mock.Mock(**{
-        "request.method": "HEAD",
-        "headers": {"Content-Type": content_type},
-    })
+    session.head.return_value = mock.Mock(
+        **{
+            "request.method": "HEAD",
+            "headers": {"Content-Type": content_type},
+        }
+    )
 
     with pytest.raises(_NotHTML) as ctx:
         _get_html_response(url, session=session)
 
-    session.assert_has_calls([
-        mock.call.head(url, allow_redirects=True),
-    ])
+    session.assert_has_calls(
+        [
+            mock.call.head(url, allow_redirects=True),
+        ]
+    )
     mock_raise_for_status.assert_called_once_with(session.head.return_value)
     assert ctx.value.args == (content_type, "HEAD")
 
@@ -96,12 +101,12 @@ def test_get_html_page_invalid_content_type_archive(caplog, url):
     session = mock.Mock(PipSession)
 
     assert _get_html_page(link, session=session) is None
-    assert ('pip._internal.index.collector',
-            logging.WARNING,
-            'Skipping page {} because it looks like an archive, and cannot '
-            'be checked by a HTTP HEAD request.'.format(
-                url)) \
-        in caplog.record_tuples
+    assert (
+        "pip._internal.index.collector",
+        logging.WARNING,
+        "Skipping page {} because it looks like an archive, and cannot "
+        "be checked by a HTTP HEAD request.".format(url),
+    ) in caplog.record_tuples
 
 
 @pytest.mark.parametrize(
@@ -112,18 +117,18 @@ def test_get_html_page_invalid_content_type_archive(caplog, url):
     ],
 )
 @mock.patch("pip._internal.index.collector.raise_for_status")
-def test_get_html_response_archive_to_http_scheme_is_html(
-    mock_raise_for_status, url
-):
+def test_get_html_response_archive_to_http_scheme_is_html(mock_raise_for_status, url):
     """
     `_get_html_response()` should work with archive-like URLs if the HEAD
     request is responded with text/html.
     """
     session = mock.Mock(PipSession)
-    session.head.return_value = mock.Mock(**{
-        "request.method": "HEAD",
-        "headers": {"Content-Type": "text/html"},
-    })
+    session.head.return_value = mock.Mock(
+        **{
+            "request.method": "HEAD",
+            "headers": {"Content-Type": "text/html"},
+        }
+    )
     session.get.return_value = mock.Mock(headers={"Content-Type": "text/html"})
 
     resp = _get_html_response(url, session=session)
@@ -131,13 +136,17 @@ def test_get_html_response_archive_to_http_scheme_is_html(
     assert resp is not None
     assert session.mock_calls == [
         mock.call.head(url, allow_redirects=True),
-        mock.call.get(url, headers={
-            "Accept": "text/html", "Cache-Control": "max-age=0",
-        }),
+        mock.call.get(
+            url,
+            headers={
+                "Accept": "text/html",
+                "Cache-Control": "max-age=0",
+            },
+        ),
     ]
     assert mock_raise_for_status.mock_calls == [
         mock.call(session.head.return_value),
-        mock.call(resp)
+        mock.call(resp),
     ]
 
 
@@ -158,26 +167,33 @@ def test_get_html_response_no_head(mock_raise_for_status, url):
     session = mock.Mock(PipSession)
 
     # Mock the headers dict to ensure it is accessed.
-    session.get.return_value = mock.Mock(headers=mock.Mock(**{
-        "get.return_value": "text/html",
-    }))
+    session.get.return_value = mock.Mock(
+        headers=mock.Mock(
+            **{
+                "get.return_value": "text/html",
+            }
+        )
+    )
 
     resp = _get_html_response(url, session=session)
 
     assert resp is not None
     assert session.head.call_count == 0
     assert session.get.mock_calls == [
-        mock.call(url, headers={
-            "Accept": "text/html", "Cache-Control": "max-age=0",
-        }),
+        mock.call(
+            url,
+            headers={
+                "Accept": "text/html",
+                "Cache-Control": "max-age=0",
+            },
+        ),
         mock.call().headers.get("Content-Type", ""),
     ]
     mock_raise_for_status.assert_called_once_with(resp)
 
 
 @mock.patch("pip._internal.index.collector.raise_for_status")
-def test_get_html_response_dont_log_clear_text_password(mock_raise_for_status,
-                                                        caplog):
+def test_get_html_response_dont_log_clear_text_password(mock_raise_for_status, caplog):
     """
     `_get_html_response()` should redact the password from the index URL
     in its DEBUG log message.
@@ -185,9 +201,13 @@ def test_get_html_response_dont_log_clear_text_password(mock_raise_for_status,
     session = mock.Mock(PipSession)
 
     # Mock the headers dict to ensure it is accessed.
-    session.get.return_value = mock.Mock(headers=mock.Mock(**{
-        "get.return_value": "text/html",
-    }))
+    session.get.return_value = mock.Mock(
+        headers=mock.Mock(
+            **{
+                "get.return_value": "text/html",
+            }
+        )
+    )
 
     caplog.set_level(logging.DEBUG)
 
@@ -200,7 +220,7 @@ def test_get_html_response_dont_log_clear_text_password(mock_raise_for_status,
 
     assert len(caplog.records) == 1
     record = caplog.records[0]
-    assert record.levelname == 'DEBUG'
+    assert record.levelname == "DEBUG"
     assert record.message.splitlines() == [
         "Getting page https://user:****@example.com/simple/",
     ]
@@ -211,15 +231,13 @@ def test_get_html_response_dont_log_clear_text_password(mock_raise_for_status,
     [
         (b"<html></html>", "https://example.com/", "https://example.com/"),
         (
-            b"<html><head>"
-            b"<base href=\"https://foo.example.com/\">"
-            b"</head></html>",
+            b"<html><head>" b'<base href="https://foo.example.com/">' b"</head></html>",
             "https://example.com/",
             "https://foo.example.com/",
         ),
         (
             b"<html><head>"
-            b"<base><base href=\"https://foo.example.com/\">"
+            b'<base><base href="https://foo.example.com/">'
             b"</head></html>",
             "https://example.com/",
             "https://foo.example.com/",
@@ -228,68 +246,70 @@ def test_get_html_response_dont_log_clear_text_password(mock_raise_for_status,
 )
 def test_determine_base_url(html, url, expected):
     document = html5lib.parse(
-        html, transport_encoding=None, namespaceHTMLElements=False,
+        html,
+        transport_encoding=None,
+        namespaceHTMLElements=False,
     )
     assert _determine_base_url(document, url) == expected
 
 
 @pytest.mark.parametrize(
-    ('path', 'expected'),
+    ("path", "expected"),
     [
         # Test a character that needs quoting.
-        ('a b', 'a%20b'),
+        ("a b", "a%20b"),
         # Test an unquoted "@".
-        ('a @ b', 'a%20@%20b'),
+        ("a @ b", "a%20@%20b"),
         # Test multiple unquoted "@".
-        ('a @ @ b', 'a%20@%20@%20b'),
+        ("a @ @ b", "a%20@%20@%20b"),
         # Test a quoted "@".
-        ('a %40 b', 'a%20%40%20b'),
+        ("a %40 b", "a%20%40%20b"),
         # Test a quoted "@" before an unquoted "@".
-        ('a %40b@ c', 'a%20%40b@%20c'),
+        ("a %40b@ c", "a%20%40b@%20c"),
         # Test a quoted "@" after an unquoted "@".
-        ('a @b%40 c', 'a%20@b%40%20c'),
+        ("a @b%40 c", "a%20@b%40%20c"),
         # Test alternating quoted and unquoted "@".
-        ('a %40@b %40@c %40', 'a%20%40@b%20%40@c%20%40'),
+        ("a %40@b %40@c %40", "a%20%40@b%20%40@c%20%40"),
         # Test an unquoted "/".
-        ('a / b', 'a%20/%20b'),
+        ("a / b", "a%20/%20b"),
         # Test multiple unquoted "/".
-        ('a / / b', 'a%20/%20/%20b'),
+        ("a / / b", "a%20/%20/%20b"),
         # Test a quoted "/".
-        ('a %2F b', 'a%20%2F%20b'),
+        ("a %2F b", "a%20%2F%20b"),
         # Test a quoted "/" before an unquoted "/".
-        ('a %2Fb/ c', 'a%20%2Fb/%20c'),
+        ("a %2Fb/ c", "a%20%2Fb/%20c"),
         # Test a quoted "/" after an unquoted "/".
-        ('a /b%2F c', 'a%20/b%2F%20c'),
+        ("a /b%2F c", "a%20/b%2F%20c"),
         # Test alternating quoted and unquoted "/".
-        ('a %2F/b %2F/c %2F', 'a%20%2F/b%20%2F/c%20%2F'),
+        ("a %2F/b %2F/c %2F", "a%20%2F/b%20%2F/c%20%2F"),
         # Test normalizing non-reserved quoted characters "[" and "]"
-        ('a %5b %5d b', 'a%20%5B%20%5D%20b'),
+        ("a %5b %5d b", "a%20%5B%20%5D%20b"),
         # Test normalizing a reserved quoted "/"
-        ('a %2f b', 'a%20%2F%20b'),
-    ]
+        ("a %2f b", "a%20%2F%20b"),
+    ],
 )
-@pytest.mark.parametrize('is_local_path', [True, False])
+@pytest.mark.parametrize("is_local_path", [True, False])
 def test_clean_url_path(path, expected, is_local_path):
     assert _clean_url_path(path, is_local_path=is_local_path) == expected
 
 
 @pytest.mark.parametrize(
-    ('path', 'expected'),
+    ("path", "expected"),
     [
         # Test a VCS path with a Windows drive letter and revision.
         pytest.param(
-            '/T:/with space/repo.git@1.0',
-            '///T:/with%20space/repo.git@1.0',
+            "/T:/with space/repo.git@1.0",
+            "///T:/with%20space/repo.git@1.0",
             marks=pytest.mark.skipif("sys.platform != 'win32'"),
         ),
         # Test a VCS path with a Windows drive letter and revision,
         # running on non-windows platform.
         pytest.param(
-            '/T:/with space/repo.git@1.0',
-            '/T%3A/with%20space/repo.git@1.0',
+            "/T:/with space/repo.git@1.0",
+            "/T%3A/with%20space/repo.git@1.0",
             marks=pytest.mark.skipif("sys.platform == 'win32'"),
         ),
-    ]
+    ],
 )
 def test_clean_url_path_with_local_path(path, expected):
     actual = _clean_url_path(path, is_local_path=True)
@@ -300,41 +320,63 @@ def test_clean_url_path_with_local_path(path, expected):
     ("url", "clean_url"),
     [
         # URL with hostname and port. Port separator should not be quoted.
-        ("https://localhost.localdomain:8181/path/with space/",
-         "https://localhost.localdomain:8181/path/with%20space/"),
+        (
+            "https://localhost.localdomain:8181/path/with space/",
+            "https://localhost.localdomain:8181/path/with%20space/",
+        ),
         # URL that is already properly quoted. The quoting `%`
         # characters should not be quoted again.
-        ("https://localhost.localdomain:8181/path/with%20quoted%20space/",
-         "https://localhost.localdomain:8181/path/with%20quoted%20space/"),
+        (
+            "https://localhost.localdomain:8181/path/with%20quoted%20space/",
+            "https://localhost.localdomain:8181/path/with%20quoted%20space/",
+        ),
         # URL with IPv4 address and port.
-        ("https://127.0.0.1:8181/path/with space/",
-         "https://127.0.0.1:8181/path/with%20space/"),
+        (
+            "https://127.0.0.1:8181/path/with space/",
+            "https://127.0.0.1:8181/path/with%20space/",
+        ),
         # URL with IPv6 address and port. The `[]` brackets around the
         # IPv6 address should not be quoted.
-        ("https://[fd00:0:0:236::100]:8181/path/with space/",
-         "https://[fd00:0:0:236::100]:8181/path/with%20space/"),
+        (
+            "https://[fd00:0:0:236::100]:8181/path/with space/",
+            "https://[fd00:0:0:236::100]:8181/path/with%20space/",
+        ),
         # URL with query. The leading `?` should not be quoted.
-        ("https://localhost.localdomain:8181/path/with/query?request=test",
-         "https://localhost.localdomain:8181/path/with/query?request=test"),
+        (
+            "https://localhost.localdomain:8181/path/with/query?request=test",
+            "https://localhost.localdomain:8181/path/with/query?request=test",
+        ),
         # URL with colon in the path portion.
-        ("https://localhost.localdomain:8181/path:/with:/colon",
-         "https://localhost.localdomain:8181/path%3A/with%3A/colon"),
+        (
+            "https://localhost.localdomain:8181/path:/with:/colon",
+            "https://localhost.localdomain:8181/path%3A/with%3A/colon",
+        ),
         # URL with something that looks like a drive letter, but is
         # not. The `:` should be quoted.
-        ("https://localhost.localdomain/T:/path/",
-         "https://localhost.localdomain/T%3A/path/"),
+        (
+            "https://localhost.localdomain/T:/path/",
+            "https://localhost.localdomain/T%3A/path/",
+        ),
         # URL with a quoted "/" in the path portion.
-        ("https://example.com/access%2Ftoken/path/",
-         "https://example.com/access%2Ftoken/path/"),
+        (
+            "https://example.com/access%2Ftoken/path/",
+            "https://example.com/access%2Ftoken/path/",
+        ),
         # VCS URL containing revision string.
-        ("git+ssh://example.com/path to/repo.git@1.0#egg=my-package-1.0",
-         "git+ssh://example.com/path%20to/repo.git@1.0#egg=my-package-1.0"),
+        (
+            "git+ssh://example.com/path to/repo.git@1.0#egg=my-package-1.0",
+            "git+ssh://example.com/path%20to/repo.git@1.0#egg=my-package-1.0",
+        ),
         # VCS URL with a quoted "#" in the revision string.
-        ("git+https://example.com/repo.git@hash%23symbol#egg=my-package-1.0",
-         "git+https://example.com/repo.git@hash%23symbol#egg=my-package-1.0"),
+        (
+            "git+https://example.com/repo.git@hash%23symbol#egg=my-package-1.0",
+            "git+https://example.com/repo.git@hash%23symbol#egg=my-package-1.0",
+        ),
         # VCS URL with a quoted "@" in the revision string.
-        ("git+https://example.com/repo.git@at%40 space#egg=my-package-1.0",
-         "git+https://example.com/repo.git@at%40%20space#egg=my-package-1.0"),
+        (
+            "git+https://example.com/repo.git@at%40 space#egg=my-package-1.0",
+            "git+https://example.com/repo.git@at%40%20space#egg=my-package-1.0",
+        ),
         # URL with Windows drive letter. The `:` after the drive
         # letter should not be quoted. The trailing `/` should be
         # removed.
@@ -363,45 +405,49 @@ def test_clean_url_path_with_local_path(path, expected):
             "git+file:/T%3A/with%20space/repo.git@1.0#egg=my-package-1.0",
             marks=pytest.mark.skipif("sys.platform == 'win32'"),
         ),
-    ]
+    ],
 )
 def test_clean_link(url, clean_url):
     assert _clean_link(url) == clean_url
 
 
-@pytest.mark.parametrize('anchor_html, expected', [
-    # Test not present.
-    ('<a href="/pkg1-1.0.tar.gz"></a>', None),
-    # Test present with no value.
-    ('<a href="/pkg2-1.0.tar.gz" data-yanked></a>', ''),
-    # Test the empty string.
-    ('<a href="/pkg3-1.0.tar.gz" data-yanked=""></a>', ''),
-    # Test a non-empty string.
-    ('<a href="/pkg4-1.0.tar.gz" data-yanked="error"></a>', 'error'),
-    # Test a value with an escaped character.
-    ('<a href="/pkg4-1.0.tar.gz" data-yanked="version &lt 1"></a>',
-        'version < 1'),
-    # Test a yanked reason with a non-ascii character.
-    (u'<a href="/pkg-1.0.tar.gz" data-yanked="curlyquote \u2018"></a>',
-        u'curlyquote \u2018'),
-])
+@pytest.mark.parametrize(
+    "anchor_html, expected",
+    [
+        # Test not present.
+        ('<a href="/pkg1-1.0.tar.gz"></a>', None),
+        # Test present with no value.
+        ('<a href="/pkg2-1.0.tar.gz" data-yanked></a>', ""),
+        # Test the empty string.
+        ('<a href="/pkg3-1.0.tar.gz" data-yanked=""></a>', ""),
+        # Test a non-empty string.
+        ('<a href="/pkg4-1.0.tar.gz" data-yanked="error"></a>', "error"),
+        # Test a value with an escaped character.
+        ('<a href="/pkg4-1.0.tar.gz" data-yanked="version &lt 1"></a>', "version < 1"),
+        # Test a yanked reason with a non-ascii character.
+        (
+            u'<a href="/pkg-1.0.tar.gz" data-yanked="curlyquote \u2018"></a>',
+            u"curlyquote \u2018",
+        ),
+    ],
+)
 def test_parse_links__yanked_reason(anchor_html, expected):
     html = (
         # Mark this as a unicode string for Python 2 since anchor_html
         # can contain non-ascii.
         u'<html><head><meta charset="utf-8"><head>'
-        '<body>{}</body></html>'
+        "<body>{}</body></html>"
     ).format(anchor_html)
-    html_bytes = html.encode('utf-8')
+    html_bytes = html.encode("utf-8")
     page = HTMLPage(
         html_bytes,
         encoding=None,
         # parse_links() is cached by url, so we inject a random uuid to ensure
         # the page content isn't cached.
-        url='https://example.com/simple-{}/'.format(uuid.uuid4()),
+        url="https://example.com/simple-{}/".format(uuid.uuid4()),
     )
     links = list(parse_links(page))
-    link, = links
+    (link,) = links
     actual = link.yanked_reason
     assert actual == expected
 
@@ -412,9 +458,9 @@ def test_parse_links_caches_same_page_by_url():
         '<html><head><meta charset="utf-8"><head>'
         '<body><a href="/pkg1-1.0.tar.gz"></a></body></html>'
     )
-    html_bytes = html.encode('utf-8')
+    html_bytes = html.encode("utf-8")
 
-    url = 'https://example.com/simple/'
+    url = "https://example.com/simple/"
 
     page_1 = HTMLPage(
         html_bytes,
@@ -424,7 +470,7 @@ def test_parse_links_caches_same_page_by_url():
     # Make a second page with zero content, to ensure that it's not accessed,
     # because the page was cached by url.
     page_2 = HTMLPage(
-        b'',
+        b"",
         encoding=None,
         url=url,
     )
@@ -432,7 +478,7 @@ def test_parse_links_caches_same_page_by_url():
     # cached, even for the same url. We modify the page content slightly to
     # verify that the result is not cached.
     page_3 = HTMLPage(
-        re.sub(b'pkg1', b'pkg2', html_bytes),
+        re.sub(b"pkg1", b"pkg2", html_bytes),
         encoding=None,
         url=url,
         cache_link_parsing=False,
@@ -440,7 +486,7 @@ def test_parse_links_caches_same_page_by_url():
 
     parsed_links_1 = list(parse_links(page_1))
     assert len(parsed_links_1) == 1
-    assert 'pkg1' in parsed_links_1[0].url
+    assert "pkg1" in parsed_links_1[0].url
 
     parsed_links_2 = list(parse_links(page_2))
     assert parsed_links_2 == parsed_links_1
@@ -448,47 +494,41 @@ def test_parse_links_caches_same_page_by_url():
     parsed_links_3 = list(parse_links(page_3))
     assert len(parsed_links_3) == 1
     assert parsed_links_3 != parsed_links_1
-    assert 'pkg2' in parsed_links_3[0].url
+    assert "pkg2" in parsed_links_3[0].url
 
 
 @mock.patch("pip._internal.index.collector.raise_for_status")
 def test_request_http_error(mock_raise_for_status, caplog):
     caplog.set_level(logging.DEBUG)
-    link = Link('http://localhost')
+    link = Link("http://localhost")
     session = Mock(PipSession)
     session.get.return_value = Mock()
-    mock_raise_for_status.side_effect = NetworkConnectionError('Http error')
+    mock_raise_for_status.side_effect = NetworkConnectionError("Http error")
     assert _get_html_page(link, session=session) is None
-    assert (
-        'Could not fetch URL http://localhost: Http error - skipping'
-        in caplog.text
-    )
+    assert "Could not fetch URL http://localhost: Http error - skipping" in caplog.text
 
 
 def test_request_retries(caplog):
     caplog.set_level(logging.DEBUG)
-    link = Link('http://localhost')
+    link = Link("http://localhost")
     session = Mock(PipSession)
-    session.get.side_effect = requests.exceptions.RetryError('Retry error')
+    session.get.side_effect = requests.exceptions.RetryError("Retry error")
     assert _get_html_page(link, session=session) is None
-    assert (
-        'Could not fetch URL http://localhost: Retry error - skipping'
-        in caplog.text
-    )
+    assert "Could not fetch URL http://localhost: Retry error - skipping" in caplog.text
 
 
 def test_make_html_page():
-    headers = {'Content-Type': 'text/html; charset=UTF-8'}
+    headers = {"Content-Type": "text/html; charset=UTF-8"}
     response = pretend.stub(
-        content=b'<content>',
-        url='https://example.com/index.html',
+        content=b"<content>",
+        url="https://example.com/index.html",
         headers=headers,
     )
 
     actual = _make_html_page(response)
-    assert actual.content == b'<content>'
-    assert actual.encoding == 'UTF-8'
-    assert actual.url == 'https://example.com/index.html'
+    assert actual.content == b"<content>"
+    assert actual.encoding == "UTF-8"
+    assert actual.url == "https://example.com/index.html"
 
 
 @pytest.mark.parametrize(
@@ -525,47 +565,51 @@ def test_get_html_page_invalid_scheme(caplog, url, vcs_scheme):
     ],
 )
 @mock.patch("pip._internal.index.collector.raise_for_status")
-def test_get_html_page_invalid_content_type(mock_raise_for_status,
-                                            caplog, content_type):
+def test_get_html_page_invalid_content_type(
+    mock_raise_for_status, caplog, content_type
+):
     """`_get_html_page()` should warn if an invalid content-type is given.
     Only text/html is allowed.
     """
     caplog.set_level(logging.DEBUG)
-    url = 'https://pypi.org/simple/pip'
+    url = "https://pypi.org/simple/pip"
     link = Link(url)
 
     session = mock.Mock(PipSession)
-    session.get.return_value = mock.Mock(**{
-        "request.method": "GET",
-        "headers": {"Content-Type": content_type},
-    })
+    session.get.return_value = mock.Mock(
+        **{
+            "request.method": "GET",
+            "headers": {"Content-Type": content_type},
+        }
+    )
     assert _get_html_page(link, session=session) is None
     mock_raise_for_status.assert_called_once_with(session.get.return_value)
-    assert ('pip._internal.index.collector',
-            logging.WARNING,
-            'Skipping page {} because the GET request got Content-Type: {}.'
-            'The only supported Content-Type is text/html'.format(
-                url, content_type)) \
-        in caplog.record_tuples
+    assert (
+        "pip._internal.index.collector",
+        logging.WARNING,
+        "Skipping page {} because the GET request got Content-Type: {}."
+        "The only supported Content-Type is text/html".format(url, content_type),
+    ) in caplog.record_tuples
 
 
 def make_fake_html_response(url):
     """
     Create a fake requests.Response object.
     """
-    html = dedent(u"""\
+    html = dedent(
+        u"""\
     <html><head><meta name="api-version" value="2" /></head>
     <body>
     <a href="/abc-1.0.tar.gz#md5=000000000">abc-1.0.tar.gz</a>
     </body></html>
-    """)
-    content = html.encode('utf-8')
+    """
+    )
+    content = html.encode("utf-8")
     return pretend.stub(content=content, url=url, headers={})
 
 
 def test_get_html_page_directory_append_index(tmpdir):
-    """`_get_html_page()` should append "index.html" to a directory URL.
-    """
+    """`_get_html_page()` should append "index.html" to a directory URL."""
     dirpath = tmpdir / "something"
     dirpath.mkdir()
     dir_url = "file:///{}".format(
@@ -581,7 +625,7 @@ def test_get_html_page_directory_append_index(tmpdir):
         actual = _get_html_page(Link(dir_url), session=session)
         assert mock_func.mock_calls == [
             mock.call(expected_url, session=session),
-        ], 'actual calls: {}'.format(mock_func.mock_calls)
+        ], "actual calls: {}".format(mock_func.mock_calls)
 
         assert actual.content == fake_response.content
         assert actual.encoding is None
@@ -591,14 +635,14 @@ def test_get_html_page_directory_append_index(tmpdir):
 def test_remove_duplicate_links():
     links = [
         # We choose Links that will test that ordering is preserved.
-        Link('https://example.com/2'),
-        Link('https://example.com/1'),
-        Link('https://example.com/2'),
+        Link("https://example.com/2"),
+        Link("https://example.com/1"),
+        Link("https://example.com/2"),
     ]
     actual = _remove_duplicate_links(links)
     assert actual == [
-        Link('https://example.com/2'),
-        Link('https://example.com/1'),
+        Link("https://example.com/2"),
+        Link("https://example.com/1"),
     ]
 
 
@@ -626,7 +670,7 @@ def test_group_locations__non_existing_path():
     """
     Test that a non-existing path is ignored.
     """
-    files, urls = group_locations([os.path.join('this', 'doesnt', 'exist')])
+    files, urls = group_locations([os.path.join("this", "doesnt", "exist")])
     assert not urls and not files, "nothing should have been found"
 
 
@@ -636,16 +680,15 @@ def check_links_include(links, names):
     given names, a link whose URL has a base name matching that name.
     """
     for name in names:
-        assert any(link.url.endswith(name) for link in links), (
-            'name {!r} not among links: {}'.format(name, links)
-        )
+        assert any(
+            link.url.endswith(name) for link in links
+        ), "name {!r} not among links: {}".format(name, links)
 
 
 class TestLinkCollector(object):
-
-    @patch('pip._internal.index.collector._get_html_response')
+    @patch("pip._internal.index.collector._get_html_response")
     def test_fetch_page(self, mock_get_html_response):
-        url = 'https://pypi.org/simple/twine/'
+        url = "https://pypi.org/simple/twine/"
 
         fake_response = make_fake_html_response(url)
         mock_get_html_response.return_value = fake_response
@@ -662,7 +705,8 @@ def test_fetch_page(self, mock_get_html_response):
         # Also check that the right session object was passed to
         # _get_html_response().
         mock_get_html_response.assert_called_once_with(
-            url, session=link_collector.session,
+            url,
+            session=link_collector.session,
         )
 
     def test_collect_links(self, caplog, data):
@@ -674,43 +718,48 @@ def test_collect_links(self, caplog, data):
             # is skipped.
             index_urls=[PyPI.simple_url, PyPI.simple_url],
         )
-        actual = link_collector.collect_links('twine')
+        actual = link_collector.collect_links("twine")
 
         # Spot-check the CollectedLinks return value.
         assert len(actual.files) > 20
-        check_links_include(actual.files, names=['simple-1.0.tar.gz'])
+        check_links_include(actual.files, names=["simple-1.0.tar.gz"])
 
         assert len(actual.find_links) == 1
-        check_links_include(actual.find_links, names=['packages'])
+        check_links_include(actual.find_links, names=["packages"])
         # Check that find-links URLs are marked as cacheable.
         assert actual.find_links[0].cache_link_parsing
 
-        assert actual.project_urls == [Link('https://pypi.org/simple/twine/')]
+        assert actual.project_urls == [Link("https://pypi.org/simple/twine/")]
         # Check that index URLs are marked as *un*cacheable.
         assert not actual.project_urls[0].cache_link_parsing
 
-        expected_message = dedent("""\
+        expected_message = dedent(
+            """\
         1 location(s) to search for versions of twine:
-        * https://pypi.org/simple/twine/""")
+        * https://pypi.org/simple/twine/"""
+        )
         assert caplog.record_tuples == [
-            ('pip._internal.index.collector', logging.DEBUG, expected_message),
+            ("pip._internal.index.collector", logging.DEBUG, expected_message),
         ]
 
 
 @pytest.mark.parametrize(
-    'find_links, no_index, suppress_no_index, expected', [
-        (['link1'], False, False,
-         (['link1'], ['default_url', 'url1', 'url2'])),
-        (['link1'], False, True, (['link1'], ['default_url', 'url1', 'url2'])),
-        (['link1'], True, False, (['link1'], [])),
+    "find_links, no_index, suppress_no_index, expected",
+    [
+        (["link1"], False, False, (["link1"], ["default_url", "url1", "url2"])),
+        (["link1"], False, True, (["link1"], ["default_url", "url1", "url2"])),
+        (["link1"], True, False, (["link1"], [])),
         # Passing suppress_no_index=True suppresses no_index=True.
-        (['link1'], True, True, (['link1'], ['default_url', 'url1', 'url2'])),
+        (["link1"], True, True, (["link1"], ["default_url", "url1", "url2"])),
         # Test options.find_links=False.
-        (False, False, False, ([], ['default_url', 'url1', 'url2'])),
+        (False, False, False, ([], ["default_url", "url1", "url2"])),
     ],
 )
 def test_link_collector_create(
-    find_links, no_index, suppress_no_index, expected,
+    find_links,
+    no_index,
+    suppress_no_index,
+    expected,
 ):
     """
     :param expected: the expected (find_links, index_urls) values.
@@ -719,12 +768,14 @@ def test_link_collector_create(
     session = PipSession()
     options = pretend.stub(
         find_links=find_links,
-        index_url='default_url',
-        extra_index_urls=['url1', 'url2'],
+        index_url="default_url",
+        extra_index_urls=["url1", "url2"],
         no_index=no_index,
     )
     link_collector = LinkCollector.create(
-        session, options=options, suppress_no_index=suppress_no_index,
+        session,
+        options=options,
+        suppress_no_index=suppress_no_index,
     )
 
     assert link_collector.session is session
@@ -734,16 +785,17 @@ def test_link_collector_create(
     assert search_scope.index_urls == expected_index_urls
 
 
-@patch('pip._internal.utils.misc.expanduser')
+@patch("pip._internal.utils.misc.expanduser")
 def test_link_collector_create_find_links_expansion(
-    mock_expanduser, tmpdir,
+    mock_expanduser,
+    tmpdir,
 ):
     """
     Test "~" expansion in --find-links paths.
     """
     # This is a mock version of expanduser() that expands "~" to the tmpdir.
     def expand_path(path):
-        if path.startswith('~/'):
+        if path.startswith("~/"):
             path = os.path.join(tmpdir, path[2:])
         return path
 
@@ -751,14 +803,14 @@ def expand_path(path):
 
     session = PipSession()
     options = pretend.stub(
-        find_links=['~/temp1', '~/temp2'],
-        index_url='default_url',
+        find_links=["~/temp1", "~/temp2"],
+        index_url="default_url",
         extra_index_urls=[],
         no_index=False,
     )
     # Only create temp2 and not temp1 to test that "~" expansion only occurs
     # when the directory exists.
-    temp2_dir = os.path.join(tmpdir, 'temp2')
+    temp2_dir = os.path.join(tmpdir, "temp2")
     os.mkdir(temp2_dir)
 
     link_collector = LinkCollector.create(session, options=options)
@@ -766,5 +818,5 @@ def expand_path(path):
     search_scope = link_collector.search_scope
     # Only ~/temp2 gets expanded. Also, the path is normalized when expanded.
     expected_temp2_dir = os.path.normcase(temp2_dir)
-    assert search_scope.find_links == ['~/temp1', expected_temp2_dir]
-    assert search_scope.index_urls == ['default_url']
+    assert search_scope.find_links == ["~/temp1", expected_temp2_dir]
+    assert search_scope.index_urls == ["default_url"]
diff --git a/tests/unit/test_command_install.py b/tests/unit/test_command_install.py
index 7b6b38de0fa..78a12da7ca8 100644
--- a/tests/unit/test_command_install.py
+++ b/tests/unit/test_command_install.py
@@ -14,33 +14,35 @@
 
 
 class TestDecideUserInstall:
-    @patch('site.ENABLE_USER_SITE', True)
-    @patch('pip._internal.commands.install.site_packages_writable')
+    @patch("site.ENABLE_USER_SITE", True)
+    @patch("pip._internal.commands.install.site_packages_writable")
     def test_prefix_and_target(self, sp_writable):
         sp_writable.return_value = False
 
-        assert decide_user_install(
-            use_user_site=None, prefix_path='foo'
-        ) is False
+        assert decide_user_install(use_user_site=None, prefix_path="foo") is False
 
-        assert decide_user_install(
-            use_user_site=None, target_dir='bar'
-        ) is False
+        assert decide_user_install(use_user_site=None, target_dir="bar") is False
 
     @pytest.mark.parametrize(
-        "enable_user_site,site_packages_writable,result", [
+        "enable_user_site,site_packages_writable,result",
+        [
             (True, True, False),
             (True, False, True),
             (False, True, False),
             (False, False, False),
-        ])
+        ],
+    )
     def test_most_cases(
-        self, enable_user_site, site_packages_writable, result, monkeypatch,
+        self,
+        enable_user_site,
+        site_packages_writable,
+        result,
+        monkeypatch,
     ):
-        monkeypatch.setattr('site.ENABLE_USER_SITE', enable_user_site)
+        monkeypatch.setattr("site.ENABLE_USER_SITE", enable_user_site)
         monkeypatch.setattr(
-            'pip._internal.commands.install.site_packages_writable',
-            lambda **kw: site_packages_writable
+            "pip._internal.commands.install.site_packages_writable",
+            lambda **kw: site_packages_writable,
         )
         assert decide_user_install(use_user_site=None) is result
 
@@ -58,8 +60,7 @@ def test_rejection_for_location_requirement_options():
 
     bad_named_req_options = ["--home=/wow"]
     bad_named_req = InstallRequirement(
-        Requirement("hello"), "requirements.txt",
-        install_options=bad_named_req_options
+        Requirement("hello"), "requirements.txt", install_options=bad_named_req_options
     )
 
     bad_unnamed_req_options = ["--install-lib=/lib"]
@@ -79,37 +80,75 @@ def test_rejection_for_location_requirement_options():
     assert "['--home'] from hello (from requirements.txt)" in str(e.value)
 
 
-@pytest.mark.parametrize('error, show_traceback, using_user_site, expected', [
-    # show_traceback = True, using_user_site = True
-    (EnvironmentError("Illegal byte sequence"), True, True, 'Could not install'
-        ' packages due to an EnvironmentError.\n'),
-    (EnvironmentError(errno.EACCES, "No file permission"), True, True, 'Could'
-        ' not install packages due to an EnvironmentError.\nCheck the'
-        ' permissions.\n'),
-    # show_traceback = True, using_user_site = False
-    (EnvironmentError("Illegal byte sequence"), True, False, 'Could not'
-        ' install packages due to an EnvironmentError.\n'),
-    (EnvironmentError(errno.EACCES, "No file permission"), True, False, 'Could'
-        ' not install packages due to an EnvironmentError.\nConsider using the'
-        ' `--user` option or check the permissions.\n'),
-    # show_traceback = False, using_user_site = True
-    (EnvironmentError("Illegal byte sequence"), False, True, 'Could not'
-        ' install packages due to an EnvironmentError: Illegal byte'
-        ' sequence\n'),
-    (EnvironmentError(errno.EACCES, "No file permission"), False, True, 'Could'
-        ' not install packages due to an EnvironmentError: [Errno 13] No file'
-        ' permission\nCheck the permissions.\n'),
-    # show_traceback = False, using_user_site = False
-    (EnvironmentError("Illegal byte sequence"), False, False, 'Could not'
-        ' install packages due to an EnvironmentError: Illegal byte sequence'
-        '\n'),
-    (EnvironmentError(errno.EACCES, "No file permission"), False, False,
-        'Could not install packages due to an EnvironmentError: [Errno 13] No'
-        ' file permission\nConsider using the `--user` option or check the'
-        ' permissions.\n'),
-])
-def test_create_env_error_message(
-    error, show_traceback, using_user_site, expected
-):
+@pytest.mark.parametrize(
+    "error, show_traceback, using_user_site, expected",
+    [
+        # show_traceback = True, using_user_site = True
+        (
+            EnvironmentError("Illegal byte sequence"),
+            True,
+            True,
+            "Could not install" " packages due to an EnvironmentError.\n",
+        ),
+        (
+            EnvironmentError(errno.EACCES, "No file permission"),
+            True,
+            True,
+            "Could"
+            " not install packages due to an EnvironmentError.\nCheck the"
+            " permissions.\n",
+        ),
+        # show_traceback = True, using_user_site = False
+        (
+            EnvironmentError("Illegal byte sequence"),
+            True,
+            False,
+            "Could not" " install packages due to an EnvironmentError.\n",
+        ),
+        (
+            EnvironmentError(errno.EACCES, "No file permission"),
+            True,
+            False,
+            "Could"
+            " not install packages due to an EnvironmentError.\nConsider using the"
+            " `--user` option or check the permissions.\n",
+        ),
+        # show_traceback = False, using_user_site = True
+        (
+            EnvironmentError("Illegal byte sequence"),
+            False,
+            True,
+            "Could not"
+            " install packages due to an EnvironmentError: Illegal byte"
+            " sequence\n",
+        ),
+        (
+            EnvironmentError(errno.EACCES, "No file permission"),
+            False,
+            True,
+            "Could"
+            " not install packages due to an EnvironmentError: [Errno 13] No file"
+            " permission\nCheck the permissions.\n",
+        ),
+        # show_traceback = False, using_user_site = False
+        (
+            EnvironmentError("Illegal byte sequence"),
+            False,
+            False,
+            "Could not"
+            " install packages due to an EnvironmentError: Illegal byte sequence"
+            "\n",
+        ),
+        (
+            EnvironmentError(errno.EACCES, "No file permission"),
+            False,
+            False,
+            "Could not install packages due to an EnvironmentError: [Errno 13] No"
+            " file permission\nConsider using the `--user` option or check the"
+            " permissions.\n",
+        ),
+    ],
+)
+def test_create_env_error_message(error, show_traceback, using_user_site, expected):
     msg = create_env_error_message(error, show_traceback, using_user_site)
     assert msg == expected
diff --git a/tests/unit/test_commands.py b/tests/unit/test_commands.py
index 7fae427c697..2c2df49f2dd 100644
--- a/tests/unit/test_commands.py
+++ b/tests/unit/test_commands.py
@@ -10,7 +10,7 @@
 
 # These are the expected names of the commands whose classes inherit from
 # IndexGroupCommand.
-EXPECTED_INDEX_GROUP_COMMANDS = ['download', 'install', 'list', 'wheel']
+EXPECTED_INDEX_GROUP_COMMANDS = ["download", "install", "list", "wheel"]
 
 
 def check_commands(pred, expected):
@@ -19,7 +19,7 @@ def check_commands(pred, expected):
     """
     commands = [create_command(name) for name in sorted(commands_dict)]
     actual = [command.name for command in commands if pred(command)]
-    assert actual == expected, 'actual: {}'.format(actual)
+    assert actual == expected, "actual: {}".format(actual)
 
 
 def test_commands_dict__order():
@@ -29,11 +29,11 @@ def test_commands_dict__order():
     names = list(commands_dict)
     # A spot-check is sufficient to check that commands_dict encodes an
     # ordering.
-    assert names[0] == 'install'
-    assert names[-1] == 'help'
+    assert names[0] == "install"
+    assert names[-1] == "help"
 
 
-@pytest.mark.parametrize('name', list(commands_dict))
+@pytest.mark.parametrize("name", list(commands_dict))
 def test_create_command(name):
     """Test creating an instance of each available command."""
     command = create_command(name)
@@ -45,10 +45,11 @@ def test_session_commands():
     """
     Test which commands inherit from SessionCommandMixin.
     """
+
     def is_session_command(command):
         return isinstance(command, SessionCommandMixin)
 
-    expected = ['download', 'install', 'list', 'search', 'uninstall', 'wheel']
+    expected = ["download", "install", "list", "search", "uninstall", "wheel"]
     check_commands(is_session_command, expected)
 
 
@@ -56,6 +57,7 @@ def test_index_group_commands():
     """
     Test the commands inheriting from IndexGroupCommand.
     """
+
     def is_index_group_command(command):
         return isinstance(command, IndexGroupCommand)
 
@@ -64,14 +66,14 @@ def is_index_group_command(command):
     # Also check that the commands inheriting from IndexGroupCommand are
     # exactly the commands with the --no-index option.
     def has_option_no_index(command):
-        return command.parser.has_option('--no-index')
+        return command.parser.has_option("--no-index")
 
     check_commands(has_option_no_index, EXPECTED_INDEX_GROUP_COMMANDS)
 
 
-@pytest.mark.parametrize('command_name', EXPECTED_INDEX_GROUP_COMMANDS)
+@pytest.mark.parametrize("command_name", EXPECTED_INDEX_GROUP_COMMANDS)
 @pytest.mark.parametrize(
-    'disable_pip_version_check, no_index, expected_called',
+    "disable_pip_version_check, no_index, expected_called",
     [
         # pip_self_version_check() is only called when both
         # disable_pip_version_check and no_index are False.
@@ -81,9 +83,12 @@ def has_option_no_index(command):
         (True, True, False),
     ],
 )
-@patch('pip._internal.cli.req_command.pip_self_version_check')
+@patch("pip._internal.cli.req_command.pip_self_version_check")
 def test_index_group_handle_pip_version_check(
-    mock_version_check, command_name, disable_pip_version_check, no_index,
+    mock_version_check,
+    command_name,
+    disable_pip_version_check,
+    no_index,
     expected_called,
 ):
     """
@@ -107,7 +112,8 @@ def test_requirement_commands():
     """
     Test which commands inherit from RequirementCommand.
     """
+
     def is_requirement_command(command):
         return isinstance(command, RequirementCommand)
 
-    check_commands(is_requirement_command, ['download', 'install', 'wheel'])
+    check_commands(is_requirement_command, ["download", "install", "wheel"])
diff --git a/tests/unit/test_compat.py b/tests/unit/test_compat.py
index 1b7a482a2a3..ad9abdb1062 100644
--- a/tests/unit/test_compat.py
+++ b/tests/unit/test_compat.py
@@ -34,7 +34,7 @@ def test_get_path_uid_symlink(tmpdir):
     f = tmpdir / "symlink" / "somefile"
     f.parent.mkdir()
     f.write_text("content")
-    fs = f + '_link'
+    fs = f + "_link"
     os.symlink(f, fs)
     with pytest.raises(OSError):
         get_path_uid(fs)
@@ -47,50 +47,56 @@ def test_get_path_uid_symlink_without_NOFOLLOW(tmpdir, monkeypatch):
     f = tmpdir / "symlink" / "somefile"
     f.parent.mkdir()
     f.write_text("content")
-    fs = f + '_link'
+    fs = f + "_link"
     os.symlink(f, fs)
     with pytest.raises(OSError):
         get_path_uid(fs)
 
 
-@pytest.mark.parametrize('data, expected', [
-    ('abc', u'abc'),
-    # Test text (unicode in Python 2) input.
-    (u'abc', u'abc'),
-    # Test text input with non-ascii characters.
-    (u'déf', u'déf'),
-])
+@pytest.mark.parametrize(
+    "data, expected",
+    [
+        ("abc", u"abc"),
+        # Test text (unicode in Python 2) input.
+        (u"abc", u"abc"),
+        # Test text input with non-ascii characters.
+        (u"déf", u"déf"),
+    ],
+)
 def test_str_to_display(data, expected):
     actual = str_to_display(data)
     assert actual == expected, (
         # Show the encoding for easier troubleshooting.
-        'encoding: {!r}'.format(locale.getpreferredencoding())
+        "encoding: {!r}".format(locale.getpreferredencoding())
     )
 
 
-@pytest.mark.parametrize('data, encoding, expected', [
-    # Test str input with non-ascii characters.
-    ('déf', 'utf-8', u'déf'),
-    # Test bytes input with non-ascii characters:
-    (u'déf'.encode('utf-8'), 'utf-8', u'déf'),
-    # Test a Windows encoding.
-    (u'déf'.encode('cp1252'), 'cp1252', u'déf'),
-    # Test a Windows encoding with incompatibly encoded text.
-    (u'déf'.encode('utf-8'), 'cp1252', u'déf'),
-])
+@pytest.mark.parametrize(
+    "data, encoding, expected",
+    [
+        # Test str input with non-ascii characters.
+        ("déf", "utf-8", u"déf"),
+        # Test bytes input with non-ascii characters:
+        (u"déf".encode("utf-8"), "utf-8", u"déf"),
+        # Test a Windows encoding.
+        (u"déf".encode("cp1252"), "cp1252", u"déf"),
+        # Test a Windows encoding with incompatibly encoded text.
+        (u"déf".encode("utf-8"), "cp1252", u"déf"),
+    ],
+)
 def test_str_to_display__encoding(monkeypatch, data, encoding, expected):
-    monkeypatch.setattr(locale, 'getpreferredencoding', lambda: encoding)
+    monkeypatch.setattr(locale, "getpreferredencoding", lambda: encoding)
     actual = str_to_display(data)
     assert actual == expected, (
         # Show the encoding for easier troubleshooting.
-        'encoding: {!r}'.format(locale.getpreferredencoding())
+        "encoding: {!r}".format(locale.getpreferredencoding())
     )
 
 
 def test_str_to_display__decode_error(monkeypatch, caplog):
-    monkeypatch.setattr(locale, 'getpreferredencoding', lambda: 'utf-8')
+    monkeypatch.setattr(locale, "getpreferredencoding", lambda: "utf-8")
     # Encode with an incompatible encoding.
-    data = u'ab'.encode('utf-16')
+    data = u"ab".encode("utf-16")
     actual = str_to_display(data)
     # Keep the expected value endian safe
     if sys.byteorder == "little":
@@ -100,22 +106,19 @@ def test_str_to_display__decode_error(monkeypatch, caplog):
 
     assert actual == expected, (
         # Show the encoding for easier troubleshooting.
-        'encoding: {!r}'.format(locale.getpreferredencoding())
+        "encoding: {!r}".format(locale.getpreferredencoding())
     )
     assert len(caplog.records) == 1
     record = caplog.records[0]
-    assert record.levelname == 'WARNING'
-    assert record.message == (
-        'Bytes object does not appear to be encoded as utf-8'
-    )
+    assert record.levelname == "WARNING"
+    assert record.message == ("Bytes object does not appear to be encoded as utf-8")
 
 
 def test_console_to_str(monkeypatch):
     some_bytes = b"a\xE9\xC3\xE9b"
-    encodings = ('ascii', 'utf-8', 'iso-8859-1', 'iso-8859-5',
-                 'koi8_r', 'cp850')
+    encodings = ("ascii", "utf-8", "iso-8859-1", "iso-8859-5", "koi8_r", "cp850")
     for e in encodings:
-        monkeypatch.setattr(locale, 'getpreferredencoding', lambda: e)
+        monkeypatch.setattr(locale, "getpreferredencoding", lambda: e)
         result = console_to_str(some_bytes)
         assert result.startswith("a")
         assert result.endswith("b")
@@ -125,21 +128,24 @@ def test_console_to_str_warning(monkeypatch):
     some_bytes = b"a\xE9b"
 
     def check_warning(msg, *args, **kwargs):
-        assert 'does not appear to be encoded as' in msg
-        assert args[0] == 'Subprocess output'
+        assert "does not appear to be encoded as" in msg
+        assert args[0] == "Subprocess output"
 
-    monkeypatch.setattr(locale, 'getpreferredencoding', lambda: 'utf-8')
-    monkeypatch.setattr(pip_compat.logger, 'warning', check_warning)
+    monkeypatch.setattr(locale, "getpreferredencoding", lambda: "utf-8")
+    monkeypatch.setattr(pip_compat.logger, "warning", check_warning)
     console_to_str(some_bytes)
 
 
-@pytest.mark.parametrize("home,path,expanded", [
-    ("/Users/test", "~", "/Users/test"),
-    ("/Users/test", "~/.cache", "/Users/test/.cache"),
-    # Verify that we are not affected by https://bugs.python.org/issue14768
-    ("/", "~", "/"),
-    ("/", "~/.cache", "/.cache"),
-])
+@pytest.mark.parametrize(
+    "home,path,expanded",
+    [
+        ("/Users/test", "~", "/Users/test"),
+        ("/Users/test", "~/.cache", "/Users/test/.cache"),
+        # Verify that we are not affected by https://bugs.python.org/issue14768
+        ("/", "~", "/"),
+        ("/", "~/.cache", "/.cache"),
+    ],
+)
 def test_expanduser(home, path, expanded, monkeypatch):
     monkeypatch.setenv("HOME", home)
     monkeypatch.setenv("USERPROFILE", home)
diff --git a/tests/unit/test_configuration.py b/tests/unit/test_configuration.py
index 0a45fc136d5..de18091b2bd 100644
--- a/tests/unit/test_configuration.py
+++ b/tests/unit/test_configuration.py
@@ -10,7 +10,6 @@
 
 
 class TestConfigurationLoading(ConfigurationMixin):
-
     def test_global_loading(self):
         self.patch_configuration(kinds.GLOBAL, {"test.hello": "1"})
 
@@ -39,8 +38,9 @@ def test_environment_config_loading(self, monkeypatch):
             monkeypatch.setenv("PIP_CONFIG_FILE", config_file)
 
             self.configuration.load()
-            assert self.configuration.get_value("test.hello") == "4", \
-                self.configuration._config
+            assert (
+                self.configuration.get_value("test.hello") == "4"
+            ), self.configuration._config
 
     def test_environment_var_loading(self, monkeypatch):
         monkeypatch.setenv("PIP_HELLO", "5")
@@ -76,9 +76,8 @@ def test_environment_config_errors_if_malformed(self, monkeypatch):
 
         assert "section header" in str(err.value)  # error kind
         assert "1" in str(err.value)  # line number
-        assert (  # file name
-            config_file in str(err.value) or
-            repr(config_file) in str(err.value)
+        assert config_file in str(err.value) or repr(config_file) in str(  # file name
+            err.value
         )
 
 
@@ -190,9 +189,7 @@ def test_site_modification(self):
 
         # get the path to site config file
         assert mymock.call_count == 1
-        assert mymock.call_args[0][0] == (
-            get_configuration_files()[kinds.SITE][0]
-        )
+        assert mymock.call_args[0][0] == (get_configuration_files()[kinds.SITE][0])
 
     def test_user_modification(self):
         # get the path to local config file
@@ -225,6 +222,4 @@ def test_global_modification(self):
 
         # get the path to user config file
         assert mymock.call_count == 1
-        assert mymock.call_args[0][0] == (
-            get_configuration_files()[kinds.GLOBAL][-1]
-        )
+        assert mymock.call_args[0][0] == (get_configuration_files()[kinds.GLOBAL][-1])
diff --git a/tests/unit/test_direct_url.py b/tests/unit/test_direct_url.py
index ee6b7fbf4ea..97b412aa8e7 100644
--- a/tests/unit/test_direct_url.py
+++ b/tests/unit/test_direct_url.py
@@ -30,9 +30,7 @@ def test_to_json():
 def test_archive_info():
     direct_url_dict = {
         "url": "file:///home/user/archive.tgz",
-        "archive_info": {
-            "hash": "sha1=1b8c5bc61a86f377fea47b4276c8c8a5842d2220"
-        },
+        "archive_info": {"hash": "sha1=1b8c5bc61a86f377fea47b4276c8c8a5842d2220"},
     }
     direct_url = DirectUrl.from_dict(direct_url_dict)
     assert isinstance(direct_url.info, ArchiveInfo)
@@ -71,47 +69,31 @@ def test_vcs_info():
     assert direct_url.url == direct_url_dict["url"]
     assert direct_url.info.vcs == "git"
     assert direct_url.info.requested_revision == "master"
-    assert (
-        direct_url.info.commit_id == "1b8c5bc61a86f377fea47b4276c8c8a5842d2220"
-    )
+    assert direct_url.info.commit_id == "1b8c5bc61a86f377fea47b4276c8c8a5842d2220"
     assert direct_url.to_dict() == direct_url_dict
 
 
 def test_parsing_validation():
-    with pytest.raises(
-        DirectUrlValidationError, match="url must have a value"
-    ):
+    with pytest.raises(DirectUrlValidationError, match="url must have a value"):
         DirectUrl.from_dict({"dir_info": {}})
     with pytest.raises(
         DirectUrlValidationError,
         match="missing one of archive_info, dir_info, vcs_info",
     ):
         DirectUrl.from_dict({"url": "http://..."})
-    with pytest.raises(
-        DirectUrlValidationError, match="unexpected type for editable"
-    ):
-        DirectUrl.from_dict(
-            {"url": "http://...", "dir_info": {"editable": "false"}}
-        )
-    with pytest.raises(
-        DirectUrlValidationError, match="unexpected type for hash"
-    ):
+    with pytest.raises(DirectUrlValidationError, match="unexpected type for editable"):
+        DirectUrl.from_dict({"url": "http://...", "dir_info": {"editable": "false"}})
+    with pytest.raises(DirectUrlValidationError, match="unexpected type for hash"):
         DirectUrl.from_dict({"url": "http://...", "archive_info": {"hash": 1}})
-    with pytest.raises(
-        DirectUrlValidationError, match="unexpected type for vcs"
-    ):
+    with pytest.raises(DirectUrlValidationError, match="unexpected type for vcs"):
         DirectUrl.from_dict({"url": "http://...", "vcs_info": {"vcs": None}})
-    with pytest.raises(
-        DirectUrlValidationError, match="commit_id must have a value"
-    ):
+    with pytest.raises(DirectUrlValidationError, match="commit_id must have a value"):
         DirectUrl.from_dict({"url": "http://...", "vcs_info": {"vcs": "git"}})
     with pytest.raises(
         DirectUrlValidationError,
         match="more than one of archive_info, dir_info, vcs_info",
     ):
-        DirectUrl.from_dict(
-            {"url": "http://...", "dir_info": {}, "archive_info": {}}
-        )
+        DirectUrl.from_dict({"url": "http://...", "dir_info": {}, "archive_info": {}})
 
 
 def test_redact_url():
@@ -130,22 +112,16 @@ def _redact_archive(url):
         return direct_url.redacted_url
 
     assert (
-        _redact_git("https://user:password@g.c/u/p.git@branch#egg=pkg") ==
-        "https://g.c/u/p.git@branch#egg=pkg"
-    )
-    assert (
-        _redact_git("https://${USER}:password@g.c/u/p.git") ==
-        "https://g.c/u/p.git"
-    )
-    assert (
-        _redact_archive("file://${U}:${PIP_PASSWORD}@g.c/u/p.tgz") ==
-        "file://${U}:${PIP_PASSWORD}@g.c/u/p.tgz"
+        _redact_git("https://user:password@g.c/u/p.git@branch#egg=pkg")
+        == "https://g.c/u/p.git@branch#egg=pkg"
     )
+    assert _redact_git("https://${USER}:password@g.c/u/p.git") == "https://g.c/u/p.git"
     assert (
-        _redact_git("https://${PIP_TOKEN}@g.c/u/p.git") ==
-        "https://${PIP_TOKEN}@g.c/u/p.git"
+        _redact_archive("file://${U}:${PIP_PASSWORD}@g.c/u/p.tgz")
+        == "file://${U}:${PIP_PASSWORD}@g.c/u/p.tgz"
     )
     assert (
-        _redact_git("ssh://git@g.c/u/p.git") ==
-        "ssh://git@g.c/u/p.git"
+        _redact_git("https://${PIP_TOKEN}@g.c/u/p.git")
+        == "https://${PIP_TOKEN}@g.c/u/p.git"
     )
+    assert _redact_git("ssh://git@g.c/u/p.git") == "ssh://git@g.c/u/p.git"
diff --git a/tests/unit/test_direct_url_helpers.py b/tests/unit/test_direct_url_helpers.py
index 55cd5855b93..d2821cae02c 100644
--- a/tests/unit/test_direct_url_helpers.py
+++ b/tests/unit/test_direct_url_helpers.py
@@ -25,20 +25,20 @@ def test_as_pep440_requirement_archive():
     )
     direct_url.validate()
     assert (
-        direct_url_as_pep440_direct_reference(direct_url, "pkg") ==
-        "pkg @ file:///home/user/archive.tgz"
+        direct_url_as_pep440_direct_reference(direct_url, "pkg")
+        == "pkg @ file:///home/user/archive.tgz"
     )
     direct_url.subdirectory = "subdir"
     direct_url.validate()
     assert (
-        direct_url_as_pep440_direct_reference(direct_url, "pkg") ==
-        "pkg @ file:///home/user/archive.tgz#subdirectory=subdir"
+        direct_url_as_pep440_direct_reference(direct_url, "pkg")
+        == "pkg @ file:///home/user/archive.tgz#subdirectory=subdir"
     )
     direct_url.info.hash = "sha1=1b8c5bc61a86f377fea47b4276c8c8a5842d2220"
     direct_url.validate()
     assert (
-        direct_url_as_pep440_direct_reference(direct_url, "pkg") ==
-        "pkg @ file:///home/user/archive.tgz"
+        direct_url_as_pep440_direct_reference(direct_url, "pkg")
+        == "pkg @ file:///home/user/archive.tgz"
         "#sha1=1b8c5bc61a86f377fea47b4276c8c8a5842d2220&subdirectory=subdir"
     )
 
@@ -50,29 +50,27 @@ def test_as_pep440_requirement_dir():
     )
     direct_url.validate()
     assert (
-        direct_url_as_pep440_direct_reference(direct_url, "pkg") ==
-        "pkg @ file:///home/user/project"
+        direct_url_as_pep440_direct_reference(direct_url, "pkg")
+        == "pkg @ file:///home/user/project"
     )
 
 
 def test_as_pep440_requirement_vcs():
     direct_url = DirectUrl(
         url="https:///g.c/u/p.git",
-        info=VcsInfo(
-            vcs="git", commit_id="1b8c5bc61a86f377fea47b4276c8c8a5842d2220"
-        )
+        info=VcsInfo(vcs="git", commit_id="1b8c5bc61a86f377fea47b4276c8c8a5842d2220"),
     )
     direct_url.validate()
     assert (
-        direct_url_as_pep440_direct_reference(direct_url, "pkg") ==
-        "pkg @ git+https:///g.c/u/p.git"
+        direct_url_as_pep440_direct_reference(direct_url, "pkg")
+        == "pkg @ git+https:///g.c/u/p.git"
         "@1b8c5bc61a86f377fea47b4276c8c8a5842d2220"
     )
     direct_url.subdirectory = "subdir"
     direct_url.validate()
     assert (
-        direct_url_as_pep440_direct_reference(direct_url, "pkg") ==
-        "pkg @ git+https:///g.c/u/p.git"
+        direct_url_as_pep440_direct_reference(direct_url, "pkg")
+        == "pkg @ git+https:///g.c/u/p.git"
         "@1b8c5bc61a86f377fea47b4276c8c8a5842d2220#subdirectory=subdir"
     )
 
@@ -94,28 +92,22 @@ def test_from_link_vcs(mock_get_backend_for_scheme):
     direct_url = _direct_url_from_link(Link("git+https://g.c/u/p.git@branch"))
     assert direct_url.url == "https://g.c/u/p.git"
     assert direct_url.info.requested_revision == "branch"
-    direct_url = _direct_url_from_link(
-        Link("git+https://g.c/u/p.git@branch#egg=pkg")
-    )
+    direct_url = _direct_url_from_link(Link("git+https://g.c/u/p.git@branch#egg=pkg"))
     assert direct_url.url == "https://g.c/u/p.git"
     assert direct_url.info.requested_revision == "branch"
-    direct_url = _direct_url_from_link(
-        Link("git+https://token@g.c/u/p.git")
-    )
+    direct_url = _direct_url_from_link(Link("git+https://token@g.c/u/p.git"))
     assert direct_url.to_dict()["url"] == "https://g.c/u/p.git"
 
 
 def test_from_link_vcs_with_source_dir_obtains_commit_id(script, tmpdir):
-    repo_path = tmpdir / 'test-repo'
+    repo_path = tmpdir / "test-repo"
     repo_path.mkdir()
     repo_dir = str(repo_path)
-    script.run('git', 'init', cwd=repo_dir)
+    script.run("git", "init", cwd=repo_dir)
     (repo_path / "somefile").touch()
-    script.run('git', 'add', '.', cwd=repo_dir)
-    script.run('git', 'commit', '-m', 'commit msg', cwd=repo_dir)
-    commit_id = script.run(
-        'git', 'rev-parse', 'HEAD', cwd=repo_dir
-    ).stdout.strip()
+    script.run("git", "add", ".", cwd=repo_dir)
+    script.run("git", "commit", "-m", "commit msg", cwd=repo_dir)
+    commit_id = script.run("git", "rev-parse", "HEAD", cwd=repo_dir).stdout.strip()
     direct_url = direct_url_from_link(
         Link("git+https://g.c/u/p.git"), source_dir=repo_dir
     )
@@ -136,15 +128,10 @@ def test_from_link_archive():
     assert direct_url.url == "https://g.c/archive.tgz"
     assert isinstance(direct_url.info, ArchiveInfo)
     direct_url = direct_url_from_link(
-        Link(
-            "https://g.c/archive.tgz"
-            "#sha1=1b8c5bc61a86f377fea47b4276c8c8a5842d2220"
-        )
+        Link("https://g.c/archive.tgz" "#sha1=1b8c5bc61a86f377fea47b4276c8c8a5842d2220")
     )
     assert isinstance(direct_url.info, ArchiveInfo)
-    assert (
-        direct_url.info.hash == "sha1=1b8c5bc61a86f377fea47b4276c8c8a5842d2220"
-    )
+    assert direct_url.info.hash == "sha1=1b8c5bc61a86f377fea47b4276c8c8a5842d2220"
 
 
 def test_from_link_dir(tmpdir):
@@ -187,9 +174,7 @@ def test_dist_get_direct_url_bad_metadata():
 def test_dist_get_direct_url_valid_metadata():
     dist = MagicMock()
     dist.has_metadata.return_value = True
-    dist.get_metadata.return_value = (
-        '{"url": "https://e.c/p.tgz", "archive_info": {}}'
-    )
+    dist.get_metadata.return_value = '{"url": "https://e.c/p.tgz", "archive_info": {}}'
     direct_url = dist_get_direct_url(dist)
     dist.get_metadata.assert_called_with(DIRECT_URL_METADATA_NAME)
     assert direct_url.url == "https://e.c/p.tgz"
diff --git a/tests/unit/test_finder.py b/tests/unit/test_finder.py
index 853af723b5a..739c661bb5f 100644
--- a/tests/unit/test_finder.py
+++ b/tests/unit/test_finder.py
@@ -8,10 +8,7 @@
 from pkg_resources import parse_version
 
 import pip._internal.utils.compatibility_tags
-from pip._internal.exceptions import (
-    BestVersionAlreadyInstalled,
-    DistributionNotFound,
-)
+from pip._internal.exceptions import BestVersionAlreadyInstalled, DistributionNotFound
 from pip._internal.index.package_finder import (
     CandidateEvaluator,
     InstallationCandidate,
@@ -63,10 +60,10 @@ def test_no_partial_name_match(data):
 def test_tilde():
     """Finder can accept a path with ~ in it and will normalize it."""
     patched_exists = patch(
-        'pip._internal.index.collector.os.path.exists', return_value=True
+        "pip._internal.index.collector.os.path.exists", return_value=True
     )
     with patched_exists:
-        finder = make_test_finder(find_links=['~/python-pkgs'])
+        finder = make_test_finder(find_links=["~/python-pkgs"])
     req = install_req_from_line("gmpy")
     with pytest.raises(DistributionNotFound):
         finder.find_requirement(req, False)
@@ -84,7 +81,7 @@ def test_duplicates_sort_ok(data):
 
 def test_finder_detects_latest_find_links(data):
     """Test PackageFinder detects latest using find-links"""
-    req = install_req_from_line('simple', None)
+    req = install_req_from_line("simple", None)
     finder = make_test_finder(find_links=[data.find_links])
     found = finder.find_requirement(req, False)
     assert found.link.url.endswith("simple-3.0.tar.gz")
@@ -92,7 +89,7 @@ def test_finder_detects_latest_find_links(data):
 
 def test_incorrect_case_file_index(data):
     """Test PackageFinder detects latest using wrong case"""
-    req = install_req_from_line('dinner', None)
+    req = install_req_from_line("dinner", None)
     finder = make_test_finder(index_urls=[data.find_links3])
     found = finder.find_requirement(req, False)
     assert found.link.url.endswith("Dinner-2.0.tar.gz")
@@ -101,13 +98,13 @@ def test_incorrect_case_file_index(data):
 @pytest.mark.network
 def test_finder_detects_latest_already_satisfied_find_links(data):
     """Test PackageFinder detects latest already satisfied using find-links"""
-    req = install_req_from_line('simple', None)
+    req = install_req_from_line("simple", None)
     # the latest simple in local pkgs is 3.0
     latest_version = "3.0"
     satisfied_by = Mock(
         location="/path",
         parsed_version=parse_version(latest_version),
-        version=latest_version
+        version=latest_version,
     )
     req.satisfied_by = satisfied_by
     finder = make_test_finder(find_links=[data.find_links])
@@ -119,7 +116,7 @@ def test_finder_detects_latest_already_satisfied_find_links(data):
 @pytest.mark.network
 def test_finder_detects_latest_already_satisfied_pypi_links():
     """Test PackageFinder detects latest already satisfied using pypi links"""
-    req = install_req_from_line('initools', None)
+    req = install_req_from_line("initools", None)
     # the latest initools on PyPI is 0.3.1
     latest_version = "0.3.1"
     satisfied_by = Mock(
@@ -135,7 +132,6 @@ def test_finder_detects_latest_already_satisfied_pypi_links():
 
 
 class TestWheel:
-
     def test_skip_invalid_wheel_link(self, caplog, data):
         """
         Test if PackageFinder skips invalid wheel filenames
@@ -148,7 +144,7 @@ def test_skip_invalid_wheel_link(self, caplog, data):
         with pytest.raises(DistributionNotFound):
             finder.find_requirement(req, True)
 
-        assert 'Skipping link: invalid wheel filename:' in caplog.text
+        assert "Skipping link: invalid wheel filename:" in caplog.text
 
     def test_not_find_wheel_not_supported(self, data, monkeypatch):
         """
@@ -173,15 +169,13 @@ def test_find_wheel_supported(self, data, monkeypatch):
         monkeypatch.setattr(
             pip._internal.utils.compatibility_tags,
             "get_supported",
-            lambda **kw: [('py2', 'none', 'any')],
+            lambda **kw: [("py2", "none", "any")],
         )
 
         req = install_req_from_line("simple.dist")
         finder = make_test_finder(find_links=[data.find_links])
         found = finder.find_requirement(req, True)
-        assert (
-            found.link.url.endswith("simple.dist-0.1-py2.py3-none-any.whl")
-        ), found
+        assert found.link.url.endswith("simple.dist-0.1-py2.py3-none-any.whl"), found
 
     def test_wheel_over_sdist_priority(self, data):
         """
@@ -191,15 +185,14 @@ def test_wheel_over_sdist_priority(self, data):
         req = install_req_from_line("priority")
         finder = make_test_finder(find_links=[data.find_links])
         found = finder.find_requirement(req, True)
-        assert found.link.url.endswith("priority-1.0-py2.py3-none-any.whl"), \
-            found
+        assert found.link.url.endswith("priority-1.0-py2.py3-none-any.whl"), found
 
     def test_existing_over_wheel_priority(self, data):
         """
         Test existing install has priority over wheels.
         `test_link_sorting` also covers this at a lower level
         """
-        req = install_req_from_line('priority', None)
+        req = install_req_from_line("priority", None)
         latest_version = "1.0"
         satisfied_by = Mock(
             location="/path",
@@ -217,36 +210,38 @@ def test_link_sorting(self):
         Test link sorting
         """
         links = [
-            InstallationCandidate("simple", "2.0", Link('simple-2.0.tar.gz')),
+            InstallationCandidate("simple", "2.0", Link("simple-2.0.tar.gz")),
             InstallationCandidate(
                 "simple",
                 "1.0",
-                Link('simple-1.0-pyT-none-TEST.whl'),
+                Link("simple-1.0-pyT-none-TEST.whl"),
             ),
             InstallationCandidate(
                 "simple",
-                '1.0',
-                Link('simple-1.0-pyT-TEST-any.whl'),
+                "1.0",
+                Link("simple-1.0-pyT-TEST-any.whl"),
             ),
             InstallationCandidate(
                 "simple",
-                '1.0',
-                Link('simple-1.0-pyT-none-any.whl'),
+                "1.0",
+                Link("simple-1.0-pyT-none-any.whl"),
             ),
             InstallationCandidate(
                 "simple",
-                '1.0',
-                Link('simple-1.0.tar.gz'),
+                "1.0",
+                Link("simple-1.0.tar.gz"),
             ),
         ]
         valid_tags = [
-            Tag('pyT', 'none', 'TEST'),
-            Tag('pyT', 'TEST', 'any'),
-            Tag('pyT', 'none', 'any'),
+            Tag("pyT", "none", "TEST"),
+            Tag("pyT", "TEST", "any"),
+            Tag("pyT", "none", "any"),
         ]
         specifier = SpecifierSet()
         evaluator = CandidateEvaluator(
-            'my-project', supported_tags=valid_tags, specifier=specifier,
+            "my-project",
+            supported_tags=valid_tags,
+            specifier=specifier,
         )
         sort_key = evaluator._sort_key
         results = sorted(links, key=sort_key, reverse=True)
@@ -273,7 +268,7 @@ def test_link_sorting_wheels_with_build_tags(self):
                 Link("simplewheel-1.0-py2.py3-none-any.whl"),
             ),
         ]
-        candidate_evaluator = CandidateEvaluator.create('my-project')
+        candidate_evaluator = CandidateEvaluator.create("my-project")
         sort_key = candidate_evaluator._sort_key
         results = sorted(links, key=sort_key, reverse=True)
         results2 = sorted(reversed(links), key=sort_key, reverse=True)
@@ -282,16 +277,17 @@ def test_link_sorting_wheels_with_build_tags(self):
 
 def test_finder_priority_file_over_page(data):
     """Test PackageFinder prefers file links over equivalent page links"""
-    req = install_req_from_line('gmpy==1.15', None)
+    req = install_req_from_line("gmpy==1.15", None)
     finder = make_test_finder(
         find_links=[data.find_links],
         index_urls=["http://pypi.org/simple/"],
     )
     all_versions = finder.find_all_candidates(req.name)
     # 1 file InstallationCandidate followed by all https ones
-    assert all_versions[0].link.scheme == 'file'
-    assert all(version.link.scheme == 'https'
-               for version in all_versions[1:]), all_versions
+    assert all_versions[0].link.scheme == "file"
+    assert all(
+        version.link.scheme == "https" for version in all_versions[1:]
+    ), all_versions
 
     found = finder.find_requirement(req, False)
     assert found.link.url.startswith("file://")
@@ -299,27 +295,27 @@ def test_finder_priority_file_over_page(data):
 
 def test_finder_priority_nonegg_over_eggfragments():
     """Test PackageFinder prefers non-egg links over "#egg=" links"""
-    req = install_req_from_line('bar==1.0', None)
-    links = ['http://foo/bar.py#egg=bar-1.0', 'http://foo/bar-1.0.tar.gz']
+    req = install_req_from_line("bar==1.0", None)
+    links = ["http://foo/bar.py#egg=bar-1.0", "http://foo/bar-1.0.tar.gz"]
 
     finder = make_no_network_finder(links)
     all_versions = finder.find_all_candidates(req.name)
-    assert all_versions[0].link.url.endswith('tar.gz')
-    assert all_versions[1].link.url.endswith('#egg=bar-1.0')
+    assert all_versions[0].link.url.endswith("tar.gz")
+    assert all_versions[1].link.url.endswith("#egg=bar-1.0")
 
     found = finder.find_requirement(req, False)
 
-    assert found.link.url.endswith('tar.gz')
+    assert found.link.url.endswith("tar.gz")
 
     links.reverse()
 
     finder = make_no_network_finder(links)
     all_versions = finder.find_all_candidates(req.name)
-    assert all_versions[0].link.url.endswith('tar.gz')
-    assert all_versions[1].link.url.endswith('#egg=bar-1.0')
+    assert all_versions[0].link.url.endswith("tar.gz")
+    assert all_versions[1].link.url.endswith("#egg=bar-1.0")
     found = finder.find_requirement(req, False)
 
-    assert found.link.url.endswith('tar.gz')
+    assert found.link.url.endswith("tar.gz")
 
 
 def test_finder_only_installs_stable_releases(data):
@@ -363,11 +359,11 @@ def test_finder_only_installs_data_require(data):
     finder = make_test_finder(index_urls=[data.index_url("datarequire")])
     links = finder.find_all_candidates("fakepackage")
 
-    expected = ['1.0.0', '9.9.9']
+    expected = ["1.0.0", "9.9.9"]
     if (2, 7) < sys.version_info < (3,):
-        expected.append('2.7.0')
+        expected.append("2.7.0")
     elif sys.version_info > (3, 3):
-        expected.append('3.3.0')
+        expected.append("3.3.0")
 
     assert {str(v.version) for v in links} == set(expected)
 
@@ -436,83 +432,90 @@ def test_finder_installs_pre_releases_with_version_spec():
 
 
 class TestLinkEvaluator(object):
-
     def make_test_link_evaluator(self, formats):
         target_python = TargetPython()
         return LinkEvaluator(
-            project_name='pytest',
-            canonical_name='pytest',
+            project_name="pytest",
+            canonical_name="pytest",
             formats=formats,
             target_python=target_python,
             allow_yanked=True,
         )
 
-    @pytest.mark.parametrize('url, expected_version', [
-        ('http:/yo/pytest-1.0.tar.gz', '1.0'),
-        ('http:/yo/pytest-1.0-py2.py3-none-any.whl', '1.0'),
-    ])
+    @pytest.mark.parametrize(
+        "url, expected_version",
+        [
+            ("http:/yo/pytest-1.0.tar.gz", "1.0"),
+            ("http:/yo/pytest-1.0-py2.py3-none-any.whl", "1.0"),
+        ],
+    )
     def test_evaluate_link__match(self, url, expected_version):
         """Test that 'pytest' archives match for 'pytest'"""
         link = Link(url)
-        evaluator = self.make_test_link_evaluator(formats=['source', 'binary'])
+        evaluator = self.make_test_link_evaluator(formats=["source", "binary"])
         actual = evaluator.evaluate_link(link)
         assert actual == (True, expected_version)
 
-    @pytest.mark.parametrize('url, expected_msg', [
-        # TODO: Uncomment this test case when #1217 is fixed.
-        # 'http:/yo/pytest-xdist-1.0.tar.gz',
-        ('http:/yo/pytest2-1.0.tar.gz',
-         'Missing project version for pytest'),
-        ('http:/yo/pytest_xdist-1.0-py2.py3-none-any.whl',
-         'wrong project name (not pytest)'),
-    ])
+    @pytest.mark.parametrize(
+        "url, expected_msg",
+        [
+            # TODO: Uncomment this test case when #1217 is fixed.
+            # 'http:/yo/pytest-xdist-1.0.tar.gz',
+            ("http:/yo/pytest2-1.0.tar.gz", "Missing project version for pytest"),
+            (
+                "http:/yo/pytest_xdist-1.0-py2.py3-none-any.whl",
+                "wrong project name (not pytest)",
+            ),
+        ],
+    )
     def test_evaluate_link__substring_fails(self, url, expected_msg):
         """Test that 'pytest<something> archives won't match for 'pytest'."""
         link = Link(url)
-        evaluator = self.make_test_link_evaluator(formats=['source', 'binary'])
+        evaluator = self.make_test_link_evaluator(formats=["source", "binary"])
         actual = evaluator.evaluate_link(link)
         assert actual == (False, expected_msg)
 
 
 def test_process_project_url(data):
-    project_name = 'simple'
-    index_url = data.index_url('simple')
-    project_url = Link('{}/{}'.format(index_url, project_name))
+    project_name = "simple"
+    index_url = data.index_url("simple")
+    project_url = Link("{}/{}".format(index_url, project_name))
     finder = make_test_finder(index_urls=[index_url])
     link_evaluator = finder.make_link_evaluator(project_name)
     actual = finder.process_project_url(
-        project_url, link_evaluator=link_evaluator,
+        project_url,
+        link_evaluator=link_evaluator,
     )
 
     assert len(actual) == 1
     package_link = actual[0]
-    assert package_link.name == 'simple'
-    assert str(package_link.version) == '1.0'
+    assert package_link.name == "simple"
+    assert str(package_link.version) == "1.0"
 
 
 def test_find_all_candidates_nothing():
     """Find nothing without anything"""
     finder = make_test_finder()
-    assert not finder.find_all_candidates('pip')
+    assert not finder.find_all_candidates("pip")
 
 
 def test_find_all_candidates_find_links(data):
     finder = make_test_finder(find_links=[data.find_links])
-    versions = finder.find_all_candidates('simple')
-    assert [str(v.version) for v in versions] == ['3.0', '2.0', '1.0']
+    versions = finder.find_all_candidates("simple")
+    assert [str(v.version) for v in versions] == ["3.0", "2.0", "1.0"]
 
 
 def test_find_all_candidates_index(data):
-    finder = make_test_finder(index_urls=[data.index_url('simple')])
-    versions = finder.find_all_candidates('simple')
-    assert [str(v.version) for v in versions] == ['1.0']
+    finder = make_test_finder(index_urls=[data.index_url("simple")])
+    versions = finder.find_all_candidates("simple")
+    assert [str(v.version) for v in versions] == ["1.0"]
 
 
 def test_find_all_candidates_find_links_and_index(data):
     finder = make_test_finder(
         find_links=[data.find_links],
-        index_urls=[data.index_url('simple')],
+        index_urls=[data.index_url("simple")],
     )
-    versions = finder.find_all_candidates('simple')
+    versions = finder.find_all_candidates("simple")
     # first the find-links versions then the page versions
-    assert [str(v.version) for v in versions] == ['3.0', '2.0', '1.0', '1.0']
+    assert [str(v.version) for v in versions] == ["3.0", "2.0", "1.0", "1.0"]
diff --git a/tests/unit/test_format_control.py b/tests/unit/test_format_control.py
index 0e152798184..6118d3a7c13 100644
--- a/tests/unit/test_format_control.py
+++ b/tests/unit/test_format_control.py
@@ -6,9 +6,8 @@
 
 
 class SimpleCommand(Command):
-
     def __init__(self):
-        super(SimpleCommand, self).__init__('fake', 'fake summary')
+        super(SimpleCommand, self).__init__("fake", "fake summary")
 
     def add_options(self):
         self.cmd_opts.add_option(cmdoptions.no_binary())
@@ -20,38 +19,36 @@ def run(self, options, args):
 
 def test_no_binary_overrides():
     cmd = SimpleCommand()
-    cmd.main(['fake', '--only-binary=:all:', '--no-binary=fred'])
-    format_control = FormatControl({'fred'}, {':all:'})
+    cmd.main(["fake", "--only-binary=:all:", "--no-binary=fred"])
+    format_control = FormatControl({"fred"}, {":all:"})
     assert cmd.options.format_control == format_control
 
 
 def test_only_binary_overrides():
     cmd = SimpleCommand()
-    cmd.main(['fake', '--no-binary=:all:', '--only-binary=fred'])
-    format_control = FormatControl({':all:'}, {'fred'})
+    cmd.main(["fake", "--no-binary=:all:", "--only-binary=fred"])
+    format_control = FormatControl({":all:"}, {"fred"})
     assert cmd.options.format_control == format_control
 
 
 def test_none_resets():
     cmd = SimpleCommand()
-    cmd.main(['fake', '--no-binary=:all:', '--no-binary=:none:'])
+    cmd.main(["fake", "--no-binary=:all:", "--no-binary=:none:"])
     format_control = FormatControl(set(), set())
     assert cmd.options.format_control == format_control
 
 
 def test_none_preserves_other_side():
     cmd = SimpleCommand()
-    cmd.main(
-        ['fake', '--no-binary=:all:', '--only-binary=fred',
-         '--no-binary=:none:'])
-    format_control = FormatControl(set(), {'fred'})
+    cmd.main(["fake", "--no-binary=:all:", "--only-binary=fred", "--no-binary=:none:"])
+    format_control = FormatControl(set(), {"fred"})
     assert cmd.options.format_control == format_control
 
 
 def test_comma_separated_values():
     cmd = SimpleCommand()
-    cmd.main(['fake', '--no-binary=1,2,3'])
-    format_control = FormatControl({'1', '2', '3'}, set())
+    cmd.main(["fake", "--no-binary=1,2,3"])
+    format_control = FormatControl({"1", "2", "3"}, set())
     assert cmd.options.format_control == format_control
 
 
@@ -61,8 +58,8 @@ def test_comma_separated_values():
         ({"fred"}, set(), "fred", frozenset(["source"])),
         ({"fred"}, {":all:"}, "fred", frozenset(["source"])),
         (set(), {"fred"}, "fred", frozenset(["binary"])),
-        ({":all:"}, {"fred"}, "fred", frozenset(["binary"]))
-    ]
+        ({":all:"}, {"fred"}, "fred", frozenset(["binary"])),
+    ],
 )
 def test_fmt_ctl_matches(no_binary, only_binary, argument, expected):
     fmt = FormatControl(no_binary, only_binary)
diff --git a/tests/unit/test_index.py b/tests/unit/test_index.py
index 2ae847ae0b7..b1958ac325d 100644
--- a/tests/unit/test_index.py
+++ b/tests/unit/test_index.py
@@ -26,15 +26,18 @@
 from tests.lib.index import make_mock_candidate
 
 
-@pytest.mark.parametrize('requires_python, expected', [
-    ('== 3.6.4', False),
-    ('== 3.6.5', True),
-    # Test an invalid Requires-Python value.
-    ('invalid', True),
-])
+@pytest.mark.parametrize(
+    "requires_python, expected",
+    [
+        ("== 3.6.4", False),
+        ("== 3.6.5", True),
+        # Test an invalid Requires-Python value.
+        ("invalid", True),
+    ],
+)
 def test_check_link_requires_python(requires_python, expected):
     version_info = (3, 6, 5)
-    link = Link('https://example.com', requires_python=requires_python)
+    link = Link("https://example.com", requires_python=requires_python)
     actual = _check_link_requires_python(link, version_info)
     assert actual == expected
 
@@ -46,29 +49,43 @@ def check_caplog(caplog, expected_level, expected_message):
     assert record.message == expected_message
 
 
-@pytest.mark.parametrize('ignore_requires_python, expected', [
-    (None, (
-        False, 'DEBUG',
-        "Link requires a different Python (3.6.5 not in: '== 3.6.4'): "
-        "https://example.com"
-    )),
-    (True, (
-        True, 'DEBUG',
-        "Ignoring failed Requires-Python check (3.6.5 not in: '== 3.6.4') "
-        "for link: https://example.com"
-    )),
-])
+@pytest.mark.parametrize(
+    "ignore_requires_python, expected",
+    [
+        (
+            None,
+            (
+                False,
+                "DEBUG",
+                "Link requires a different Python (3.6.5 not in: '== 3.6.4'): "
+                "https://example.com",
+            ),
+        ),
+        (
+            True,
+            (
+                True,
+                "DEBUG",
+                "Ignoring failed Requires-Python check (3.6.5 not in: '== 3.6.4') "
+                "for link: https://example.com",
+            ),
+        ),
+    ],
+)
 def test_check_link_requires_python__incompatible_python(
-    caplog, ignore_requires_python, expected,
+    caplog,
+    ignore_requires_python,
+    expected,
 ):
     """
     Test an incompatible Python.
     """
     expected_return, expected_level, expected_message = expected
-    link = Link('https://example.com', requires_python='== 3.6.4')
+    link = Link("https://example.com", requires_python="== 3.6.4")
     caplog.set_level(logging.DEBUG)
     actual = _check_link_requires_python(
-        link, version_info=(3, 6, 5),
+        link,
+        version_info=(3, 6, 5),
         ignore_requires_python=ignore_requires_python,
     )
     assert actual == expected_return
@@ -80,74 +97,84 @@ def test_check_link_requires_python__invalid_requires(caplog):
     """
     Test the log message for an invalid Requires-Python.
     """
-    link = Link('https://example.com', requires_python='invalid')
+    link = Link("https://example.com", requires_python="invalid")
     caplog.set_level(logging.DEBUG)
     actual = _check_link_requires_python(link, version_info=(3, 6, 5))
     assert actual
 
     expected_message = (
-        "Ignoring invalid Requires-Python ('invalid') for link: "
-        "https://example.com"
+        "Ignoring invalid Requires-Python ('invalid') for link: " "https://example.com"
     )
-    check_caplog(caplog, 'DEBUG', expected_message)
+    check_caplog(caplog, "DEBUG", expected_message)
 
 
 class TestLinkEvaluator:
-
     @pytest.mark.parametrize(
-        'py_version_info,ignore_requires_python,expected', [
-            ((3, 6, 5), None, (True, '1.12')),
+        "py_version_info,ignore_requires_python,expected",
+        [
+            ((3, 6, 5), None, (True, "1.12")),
             # Test an incompatible Python.
             ((3, 6, 4), None, (False, None)),
             # Test an incompatible Python with ignore_requires_python=True.
-            ((3, 6, 4), True, (True, '1.12')),
+            ((3, 6, 4), True, (True, "1.12")),
         ],
     )
     def test_evaluate_link(
-        self, py_version_info, ignore_requires_python, expected,
+        self,
+        py_version_info,
+        ignore_requires_python,
+        expected,
     ):
         target_python = TargetPython(py_version_info=py_version_info)
         evaluator = LinkEvaluator(
-            project_name='twine',
-            canonical_name='twine',
-            formats={'source'},
+            project_name="twine",
+            canonical_name="twine",
+            formats={"source"},
             target_python=target_python,
             allow_yanked=True,
             ignore_requires_python=ignore_requires_python,
         )
         link = Link(
-            'https://example.com/#egg=twine-1.12',
-            requires_python='== 3.6.5',
+            "https://example.com/#egg=twine-1.12",
+            requires_python="== 3.6.5",
         )
         actual = evaluator.evaluate_link(link)
         assert actual == expected
 
-    @pytest.mark.parametrize('yanked_reason, allow_yanked, expected', [
-        (None, True, (True, '1.12')),
-        (None, False, (True, '1.12')),
-        ('', True, (True, '1.12')),
-        ('', False, (False, 'yanked for reason: <none given>')),
-        ('bad metadata', True, (True, '1.12')),
-        ('bad metadata', False,
-         (False, 'yanked for reason: bad metadata')),
-        # Test a unicode string with a non-ascii character.
-        (u'curly quote: \u2018', True, (True, '1.12')),
-        (u'curly quote: \u2018', False,
-         (False, u'yanked for reason: curly quote: \u2018')),
-    ])
+    @pytest.mark.parametrize(
+        "yanked_reason, allow_yanked, expected",
+        [
+            (None, True, (True, "1.12")),
+            (None, False, (True, "1.12")),
+            ("", True, (True, "1.12")),
+            ("", False, (False, "yanked for reason: <none given>")),
+            ("bad metadata", True, (True, "1.12")),
+            ("bad metadata", False, (False, "yanked for reason: bad metadata")),
+            # Test a unicode string with a non-ascii character.
+            (u"curly quote: \u2018", True, (True, "1.12")),
+            (
+                u"curly quote: \u2018",
+                False,
+                (False, u"yanked for reason: curly quote: \u2018"),
+            ),
+        ],
+    )
     def test_evaluate_link__allow_yanked(
-        self, yanked_reason, allow_yanked, expected,
+        self,
+        yanked_reason,
+        allow_yanked,
+        expected,
     ):
         target_python = TargetPython(py_version_info=(3, 6, 4))
         evaluator = LinkEvaluator(
-            project_name='twine',
-            canonical_name='twine',
-            formats={'source'},
+            project_name="twine",
+            canonical_name="twine",
+            formats={"source"},
             target_python=target_python,
             allow_yanked=allow_yanked,
         )
         link = Link(
-            'https://example.com/#egg=twine-1.12',
+            "https://example.com/#egg=twine-1.12",
             yanked_reason=yanked_reason,
         )
         actual = evaluator.evaluate_link(link)
@@ -161,38 +188,41 @@ def test_evaluate_link__incompatible_wheel(self):
         # Set the valid tags to an empty list to make sure nothing matches.
         target_python._valid_tags = []
         evaluator = LinkEvaluator(
-            project_name='sample',
-            canonical_name='sample',
-            formats={'binary'},
+            project_name="sample",
+            canonical_name="sample",
+            formats={"binary"},
             target_python=target_python,
             allow_yanked=True,
         )
-        link = Link('https://example.com/sample-1.0-py2.py3-none-any.whl')
+        link = Link("https://example.com/sample-1.0-py2.py3-none-any.whl")
         actual = evaluator.evaluate_link(link)
-        expected = (
-            False, "none of the wheel's tags match: py2-none-any, py3-none-any"
-        )
+        expected = (False, "none of the wheel's tags match: py2-none-any, py3-none-any")
         assert actual == expected
 
 
-@pytest.mark.parametrize('hex_digest, expected_versions', [
-    (None, ['1.0', '1.1', '1.2']),
-    (64 * 'a', ['1.0', '1.1']),
-    (64 * 'b', ['1.0', '1.2']),
-    (64 * 'c', ['1.0', '1.1', '1.2']),
-])
+@pytest.mark.parametrize(
+    "hex_digest, expected_versions",
+    [
+        (None, ["1.0", "1.1", "1.2"]),
+        (64 * "a", ["1.0", "1.1"]),
+        (64 * "b", ["1.0", "1.2"]),
+        (64 * "c", ["1.0", "1.1", "1.2"]),
+    ],
+)
 def test_filter_unallowed_hashes(hex_digest, expected_versions):
     candidates = [
-        make_mock_candidate('1.0'),
-        make_mock_candidate('1.1', hex_digest=(64 * 'a')),
-        make_mock_candidate('1.2', hex_digest=(64 * 'b')),
+        make_mock_candidate("1.0"),
+        make_mock_candidate("1.1", hex_digest=(64 * "a")),
+        make_mock_candidate("1.2", hex_digest=(64 * "b")),
     ]
     hashes_data = {
-        'sha256': [hex_digest],
+        "sha256": [hex_digest],
     }
     hashes = Hashes(hashes_data)
     actual = filter_unallowed_hashes(
-        candidates, hashes=hashes, project_name='my-project',
+        candidates,
+        hashes=hashes,
+        project_name="my-project",
     )
 
     actual_versions = [str(candidate.version) for candidate in actual]
@@ -205,11 +235,13 @@ def test_filter_unallowed_hashes__no_hashes(caplog):
     caplog.set_level(logging.DEBUG)
 
     candidates = [
-        make_mock_candidate('1.0'),
-        make_mock_candidate('1.1'),
+        make_mock_candidate("1.0"),
+        make_mock_candidate("1.1"),
     ]
     actual = filter_unallowed_hashes(
-        candidates, hashes=Hashes(), project_name='my-project',
+        candidates,
+        hashes=Hashes(),
+        project_name="my-project",
     )
 
     # Check that the return value is a copy.
@@ -220,7 +252,7 @@ def test_filter_unallowed_hashes__no_hashes(caplog):
         "Given no hashes to check 2 links for project 'my-project': "
         "discarding no candidates"
     )
-    check_caplog(caplog, 'DEBUG', expected_message)
+    check_caplog(caplog, "DEBUG", expected_message)
 
 
 def test_filter_unallowed_hashes__log_message_with_match(caplog):
@@ -229,19 +261,25 @@ def test_filter_unallowed_hashes__log_message_with_match(caplog):
     # Test 1 match, 2 non-matches, 3 no hashes so all 3 values will be
     # different.
     candidates = [
-        make_mock_candidate('1.0'),
-        make_mock_candidate('1.1',),
-        make_mock_candidate('1.2',),
-        make_mock_candidate('1.3', hex_digest=(64 * 'a')),
-        make_mock_candidate('1.4', hex_digest=(64 * 'b')),
-        make_mock_candidate('1.5', hex_digest=(64 * 'c')),
+        make_mock_candidate("1.0"),
+        make_mock_candidate(
+            "1.1",
+        ),
+        make_mock_candidate(
+            "1.2",
+        ),
+        make_mock_candidate("1.3", hex_digest=(64 * "a")),
+        make_mock_candidate("1.4", hex_digest=(64 * "b")),
+        make_mock_candidate("1.5", hex_digest=(64 * "c")),
     ]
     hashes_data = {
-        'sha256': [64 * 'a', 64 * 'd'],
+        "sha256": [64 * "a", 64 * "d"],
     }
     hashes = Hashes(hashes_data)
     actual = filter_unallowed_hashes(
-        candidates, hashes=hashes, project_name='my-project',
+        candidates,
+        hashes=hashes,
+        project_name="my-project",
     )
     assert len(actual) == 4
 
@@ -253,23 +291,25 @@ def test_filter_unallowed_hashes__log_message_with_match(caplog):
         "  https://example.com/pkg-1.5.tar.gz#sha256="
         "cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc"
     )
-    check_caplog(caplog, 'DEBUG', expected_message)
+    check_caplog(caplog, "DEBUG", expected_message)
 
 
 def test_filter_unallowed_hashes__log_message_with_no_match(caplog):
     caplog.set_level(logging.DEBUG)
 
     candidates = [
-        make_mock_candidate('1.0'),
-        make_mock_candidate('1.1', hex_digest=(64 * 'b')),
-        make_mock_candidate('1.2', hex_digest=(64 * 'c')),
+        make_mock_candidate("1.0"),
+        make_mock_candidate("1.1", hex_digest=(64 * "b")),
+        make_mock_candidate("1.2", hex_digest=(64 * "c")),
     ]
     hashes_data = {
-        'sha256': [64 * 'a', 64 * 'd'],
+        "sha256": [64 * "a", 64 * "d"],
     }
     hashes = Hashes(hashes_data)
     actual = filter_unallowed_hashes(
-        candidates, hashes=hashes, project_name='my-project',
+        candidates,
+        hashes=hashes,
+        project_name="my-project",
     )
     assert len(actual) == 3
 
@@ -277,23 +317,25 @@ def test_filter_unallowed_hashes__log_message_with_no_match(caplog):
         "Checked 3 links for project 'my-project' against 2 hashes "
         "(0 matches, 1 no digest): discarding no candidates"
     )
-    check_caplog(caplog, 'DEBUG', expected_message)
+    check_caplog(caplog, "DEBUG", expected_message)
 
 
 class TestCandidateEvaluator:
-
-    @pytest.mark.parametrize('allow_all_prereleases, prefer_binary', [
-        (False, False),
-        (False, True),
-        (True, False),
-        (True, True),
-    ])
+    @pytest.mark.parametrize(
+        "allow_all_prereleases, prefer_binary",
+        [
+            (False, False),
+            (False, True),
+            (True, False),
+            (True, True),
+        ],
+    )
     def test_create(self, allow_all_prereleases, prefer_binary):
         target_python = TargetPython()
-        target_python._valid_tags = [('py36', 'none', 'any')]
+        target_python._valid_tags = [("py36", "none", "any")]
         specifier = SpecifierSet()
         evaluator = CandidateEvaluator.create(
-            project_name='my-project',
+            project_name="my-project",
             target_python=target_python,
             allow_all_prereleases=allow_all_prereleases,
             prefer_binary=prefer_binary,
@@ -302,13 +344,13 @@ def test_create(self, allow_all_prereleases, prefer_binary):
         assert evaluator._allow_all_prereleases == allow_all_prereleases
         assert evaluator._prefer_binary == prefer_binary
         assert evaluator._specifier is specifier
-        assert evaluator._supported_tags == [('py36', 'none', 'any')]
+        assert evaluator._supported_tags == [("py36", "none", "any")]
 
     def test_create__target_python_none(self):
         """
         Test passing target_python=None.
         """
-        evaluator = CandidateEvaluator.create('my-project')
+        evaluator = CandidateEvaluator.create("my-project")
         expected_tags = get_supported()
         assert evaluator._supported_tags == expected_tags
 
@@ -316,52 +358,55 @@ def test_create__specifier_none(self):
         """
         Test passing specifier=None.
         """
-        evaluator = CandidateEvaluator.create('my-project')
+        evaluator = CandidateEvaluator.create("my-project")
         expected_specifier = SpecifierSet()
         assert evaluator._specifier == expected_specifier
 
     def test_get_applicable_candidates(self):
-        specifier = SpecifierSet('<= 1.11')
-        versions = ['1.10', '1.11', '1.12']
-        candidates = [
-            make_mock_candidate(version) for version in versions
-        ]
+        specifier = SpecifierSet("<= 1.11")
+        versions = ["1.10", "1.11", "1.12"]
+        candidates = [make_mock_candidate(version) for version in versions]
         evaluator = CandidateEvaluator.create(
-            'my-project',
+            "my-project",
             specifier=specifier,
         )
         actual = evaluator.get_applicable_candidates(candidates)
         expected_applicable = candidates[:2]
         assert [str(c.version) for c in expected_applicable] == [
-            '1.10',
-            '1.11',
+            "1.10",
+            "1.11",
         ]
         assert actual == expected_applicable
 
-    @pytest.mark.parametrize('specifier, expected_versions', [
-        # Test no version constraint.
-        (SpecifierSet(), ['1.0', '1.2']),
-        # Test a version constraint that excludes the candidate whose
-        # hash matches.  Then the non-allowed hash is a candidate.
-        (SpecifierSet('<= 1.1'), ['1.0', '1.1']),
-    ])
+    @pytest.mark.parametrize(
+        "specifier, expected_versions",
+        [
+            # Test no version constraint.
+            (SpecifierSet(), ["1.0", "1.2"]),
+            # Test a version constraint that excludes the candidate whose
+            # hash matches.  Then the non-allowed hash is a candidate.
+            (SpecifierSet("<= 1.1"), ["1.0", "1.1"]),
+        ],
+    )
     def test_get_applicable_candidates__hashes(
-        self, specifier, expected_versions,
+        self,
+        specifier,
+        expected_versions,
     ):
         """
         Test a non-None hashes value.
         """
         candidates = [
-            make_mock_candidate('1.0'),
-            make_mock_candidate('1.1', hex_digest=(64 * 'a')),
-            make_mock_candidate('1.2', hex_digest=(64 * 'b')),
+            make_mock_candidate("1.0"),
+            make_mock_candidate("1.1", hex_digest=(64 * "a")),
+            make_mock_candidate("1.2", hex_digest=(64 * "b")),
         ]
         hashes_data = {
-            'sha256': [64 * 'b'],
+            "sha256": [64 * "b"],
         }
         hashes = Hashes(hashes_data)
         evaluator = CandidateEvaluator.create(
-            'my-project',
+            "my-project",
             specifier=specifier,
             hashes=hashes,
         )
@@ -370,13 +415,11 @@ def test_get_applicable_candidates__hashes(
         assert actual_versions == expected_versions
 
     def test_compute_best_candidate(self):
-        specifier = SpecifierSet('<= 1.11')
-        versions = ['1.10', '1.11', '1.12']
-        candidates = [
-            make_mock_candidate(version) for version in versions
-        ]
+        specifier = SpecifierSet("<= 1.11")
+        versions = ["1.10", "1.11", "1.12"]
+        candidates = [make_mock_candidate(version) for version in versions]
         evaluator = CandidateEvaluator.create(
-            'my-project',
+            "my-project",
             specifier=specifier,
         )
         result = evaluator.compute_best_candidate(candidates)
@@ -384,8 +427,8 @@ def test_compute_best_candidate(self):
         assert result._candidates == candidates
         expected_applicable = candidates[:2]
         assert [str(c.version) for c in expected_applicable] == [
-            '1.10',
-            '1.11',
+            "1.10",
+            "1.11",
         ]
         assert result._applicable_candidates == expected_applicable
 
@@ -395,13 +438,11 @@ def test_compute_best_candidate__none_best(self):
         """
         Test returning a None best candidate.
         """
-        specifier = SpecifierSet('<= 1.10')
-        versions = ['1.11', '1.12']
-        candidates = [
-            make_mock_candidate(version) for version in versions
-        ]
+        specifier = SpecifierSet("<= 1.10")
+        versions = ["1.11", "1.12"]
+        candidates = [make_mock_candidate(version) for version in versions]
         evaluator = CandidateEvaluator.create(
-            'my-project',
+            "my-project",
             specifier=specifier,
         )
         result = evaluator.compute_best_candidate(candidates)
@@ -410,41 +451,47 @@ def test_compute_best_candidate__none_best(self):
         assert result._applicable_candidates == []
         assert result.best_candidate is None
 
-    @pytest.mark.parametrize('hex_digest, expected', [
-        # Test a link with no hash.
-        (None, 0),
-        # Test a link with an allowed hash.
-        (64 * 'a', 1),
-        # Test a link with a hash that isn't allowed.
-        (64 * 'b', 0),
-    ])
+    @pytest.mark.parametrize(
+        "hex_digest, expected",
+        [
+            # Test a link with no hash.
+            (None, 0),
+            # Test a link with an allowed hash.
+            (64 * "a", 1),
+            # Test a link with a hash that isn't allowed.
+            (64 * "b", 0),
+        ],
+    )
     def test_sort_key__hash(self, hex_digest, expected):
         """
         Test the effect of the link's hash on _sort_key()'s return value.
         """
-        candidate = make_mock_candidate('1.0', hex_digest=hex_digest)
+        candidate = make_mock_candidate("1.0", hex_digest=hex_digest)
         hashes_data = {
-            'sha256': [64 * 'a'],
+            "sha256": [64 * "a"],
         }
         hashes = Hashes(hashes_data)
-        evaluator = CandidateEvaluator.create('my-project', hashes=hashes)
+        evaluator = CandidateEvaluator.create("my-project", hashes=hashes)
         sort_value = evaluator._sort_key(candidate)
         # The hash is reflected in the first element of the tuple.
         actual = sort_value[0]
         assert actual == expected
 
-    @pytest.mark.parametrize('yanked_reason, expected', [
-        # Test a non-yanked file.
-        (None, 0),
-        # Test a yanked file (has a lower value than non-yanked).
-        ('bad metadata', -1),
-    ])
+    @pytest.mark.parametrize(
+        "yanked_reason, expected",
+        [
+            # Test a non-yanked file.
+            (None, 0),
+            # Test a yanked file (has a lower value than non-yanked).
+            ("bad metadata", -1),
+        ],
+    )
     def test_sort_key__is_yanked(self, yanked_reason, expected):
         """
         Test the effect of is_yanked on _sort_key()'s return value.
         """
-        candidate = make_mock_candidate('1.0', yanked_reason=yanked_reason)
-        evaluator = CandidateEvaluator.create('my-project')
+        candidate = make_mock_candidate("1.0", yanked_reason=yanked_reason)
+        evaluator = CandidateEvaluator.create("my-project")
         sort_value = evaluator._sort_key(candidate)
         # Yanked / non-yanked is reflected in the second element of the tuple.
         actual = sort_value[1]
@@ -454,44 +501,49 @@ def test_sort_best_candidate__no_candidates(self):
         """
         Test passing an empty list.
         """
-        evaluator = CandidateEvaluator.create('my-project')
+        evaluator = CandidateEvaluator.create("my-project")
         actual = evaluator.sort_best_candidate([])
         assert actual is None
 
     def test_sort_best_candidate__best_yanked_but_not_all(
-        self, caplog,
+        self,
+        caplog,
     ):
         """
         Test the best candidates being yanked, but not all.
         """
         caplog.set_level(logging.INFO)
         candidates = [
-            make_mock_candidate('4.0', yanked_reason='bad metadata #4'),
+            make_mock_candidate("4.0", yanked_reason="bad metadata #4"),
             # Put the best candidate in the middle, to test sorting.
-            make_mock_candidate('2.0'),
-            make_mock_candidate('3.0', yanked_reason='bad metadata #3'),
-            make_mock_candidate('1.0'),
+            make_mock_candidate("2.0"),
+            make_mock_candidate("3.0", yanked_reason="bad metadata #3"),
+            make_mock_candidate("1.0"),
         ]
         expected_best = candidates[1]
-        evaluator = CandidateEvaluator.create('my-project')
+        evaluator = CandidateEvaluator.create("my-project")
         actual = evaluator.sort_best_candidate(candidates)
         assert actual is expected_best
-        assert str(actual.version) == '2.0'
+        assert str(actual.version) == "2.0"
 
         # Check the log messages.
         assert len(caplog.records) == 0
 
 
 class TestPackageFinder:
-
-    @pytest.mark.parametrize('allow_all_prereleases, prefer_binary', [
-        (False, False),
-        (False, True),
-        (True, False),
-        (True, True),
-    ])
+    @pytest.mark.parametrize(
+        "allow_all_prereleases, prefer_binary",
+        [
+            (False, False),
+            (False, True),
+            (True, False),
+            (True, True),
+        ],
+    )
     def test_create__candidate_prefs(
-        self, allow_all_prereleases, prefer_binary,
+        self,
+        allow_all_prereleases,
+        prefer_binary,
     ):
         """
         Test that the _candidate_prefs attribute is set correctly.
@@ -566,7 +618,7 @@ def test_create__target_python_none(self):
         assert actual_target_python._given_py_version_info is None
         assert actual_target_python.py_version_info == CURRENT_PY_VERSION_INFO
 
-    @pytest.mark.parametrize('allow_yanked', [False, True])
+    @pytest.mark.parametrize("allow_yanked", [False, True])
     def test_create__allow_yanked(self, allow_yanked):
         """
         Test that the _allow_yanked attribute is set correctly.
@@ -582,7 +634,7 @@ def test_create__allow_yanked(self, allow_yanked):
         )
         assert finder._allow_yanked == allow_yanked
 
-    @pytest.mark.parametrize('ignore_requires_python', [False, True])
+    @pytest.mark.parametrize("ignore_requires_python", [False, True])
     def test_create__ignore_requires_python(self, ignore_requires_python):
         """
         Test that the _ignore_requires_python attribute is set correctly.
@@ -609,7 +661,7 @@ def test_create__format_control(self):
             session=PipSession(),
             search_scope=SearchScope([], []),
         )
-        format_control = FormatControl(set(), {':all:'})
+        format_control = FormatControl(set(), {":all:"})
         selection_prefs = SelectionPreferences(
             allow_yanked=True,
             format_control=format_control,
@@ -621,22 +673,25 @@ def test_create__format_control(self):
         actual_format_control = finder.format_control
         assert actual_format_control is format_control
         # Check that the attributes weren't reset.
-        assert actual_format_control.only_binary == {':all:'}
+        assert actual_format_control.only_binary == {":all:"}
 
     @pytest.mark.parametrize(
-        'allow_yanked, ignore_requires_python, only_binary, expected_formats',
+        "allow_yanked, ignore_requires_python, only_binary, expected_formats",
         [
-            (False, False, {}, frozenset({'binary', 'source'})),
+            (False, False, {}, frozenset({"binary", "source"})),
             # Test allow_yanked=True.
-            (True, False, {}, frozenset({'binary', 'source'})),
+            (True, False, {}, frozenset({"binary", "source"})),
             # Test ignore_requires_python=True.
-            (False, True, {}, frozenset({'binary', 'source'})),
+            (False, True, {}, frozenset({"binary", "source"})),
             # Test a non-trivial only_binary.
-            (False, False, {'twine'}, frozenset({'binary'})),
-        ]
+            (False, False, {"twine"}, frozenset({"binary"})),
+        ],
     )
     def test_make_link_evaluator(
-        self, allow_yanked, ignore_requires_python, only_binary,
+        self,
+        allow_yanked,
+        ignore_requires_python,
+        only_binary,
         expected_formats,
     ):
         # Create a test TargetPython that we can check for.
@@ -657,10 +712,10 @@ def test_make_link_evaluator(
         )
 
         # Pass a project_name that will be different from canonical_name.
-        link_evaluator = finder.make_link_evaluator('Twine')
+        link_evaluator = finder.make_link_evaluator("Twine")
 
-        assert link_evaluator.project_name == 'Twine'
-        assert link_evaluator._canonical_name == 'twine'
+        assert link_evaluator.project_name == "Twine"
+        assert link_evaluator._canonical_name == "twine"
         assert link_evaluator._allow_yanked == allow_yanked
         assert link_evaluator._ignore_requires_python == ignore_requires_python
         assert link_evaluator._formats == expected_formats
@@ -673,17 +728,22 @@ def test_make_link_evaluator(
         assert actual_target_python._given_py_version_info == (3, 7)
         assert actual_target_python.py_version_info == (3, 7, 0)
 
-    @pytest.mark.parametrize('allow_all_prereleases, prefer_binary', [
-        (False, False),
-        (False, True),
-        (True, False),
-        (True, True),
-    ])
+    @pytest.mark.parametrize(
+        "allow_all_prereleases, prefer_binary",
+        [
+            (False, False),
+            (False, True),
+            (True, False),
+            (True, True),
+        ],
+    )
     def test_make_candidate_evaluator(
-        self, allow_all_prereleases, prefer_binary,
+        self,
+        allow_all_prereleases,
+        prefer_binary,
     ):
         target_python = TargetPython()
-        target_python._valid_tags = [('py36', 'none', 'any')]
+        target_python._valid_tags = [("py36", "none", "any")]
         candidate_prefs = CandidatePreferences(
             prefer_binary=prefer_binary,
             allow_all_prereleases=allow_all_prereleases,
@@ -701,18 +761,18 @@ def test_make_candidate_evaluator(
 
         specifier = SpecifierSet()
         # Pass hashes to check that _hashes is set.
-        hashes = Hashes({'sha256': [64 * 'a']})
+        hashes = Hashes({"sha256": [64 * "a"]})
         evaluator = finder.make_candidate_evaluator(
-            'my-project',
+            "my-project",
             specifier=specifier,
             hashes=hashes,
         )
         assert evaluator._allow_all_prereleases == allow_all_prereleases
         assert evaluator._hashes == hashes
         assert evaluator._prefer_binary == prefer_binary
-        assert evaluator._project_name == 'my-project'
+        assert evaluator._project_name == "my-project"
         assert evaluator._specifier is specifier
-        assert evaluator._supported_tags == [('py36', 'none', 'any')]
+        assert evaluator._supported_tags == [("py36", "none", "any")]
 
 
 @pytest.mark.parametrize(
@@ -721,26 +781,21 @@ def test_make_candidate_evaluator(
         # Trivial.
         ("pip-18.0", "pip", 3),
         ("zope-interface-4.5.0", "zope-interface", 14),
-
         # Canonicalized name match non-canonicalized egg info. (pypa/pip#5870)
         ("Jinja2-2.10", "jinja2", 6),
         ("zope.interface-4.5.0", "zope-interface", 14),
         ("zope_interface-4.5.0", "zope-interface", 14),
-
         # Should be smart enough to parse ambiguous names from the provided
         # package name.
         ("foo-2-2", "foo", 3),
         ("foo-2-2", "foo-2", 5),
-
         # Should be able to detect collapsed characters in the egg info.
         ("foo--bar-1.0", "foo-bar", 8),
         ("foo-_bar-1.0", "foo-bar", 8),
-
         # The package name must not ends with a dash (PEP 508), so the first
         # dash would be the separator, not the second.
         ("zope.interface--4.5.0", "zope-interface", 14),
         ("zope.interface--", "zope-interface", 14),
-
         # The version part is missing, but the split function does not care.
         ("zope.interface-", "zope-interface", 14),
     ],
@@ -773,23 +828,19 @@ def test_find_name_version_sep_failure(fragment, canonical_name):
         # Trivial.
         ("pip-18.0", "pip", "18.0"),
         ("zope-interface-4.5.0", "zope-interface", "4.5.0"),
-
         # Canonicalized name match non-canonicalized egg info. (pypa/pip#5870)
         ("Jinja2-2.10", "jinja2", "2.10"),
         ("zope.interface-4.5.0", "zope-interface", "4.5.0"),
         ("zope_interface-4.5.0", "zope-interface", "4.5.0"),
-
         # Should be smart enough to parse ambiguous names from the provided
         # package name.
         ("foo-2-2", "foo", "2-2"),
         ("foo-2-2", "foo-2", "2"),
         ("zope.interface--4.5.0", "zope-interface", "-4.5.0"),
         ("zope.interface--", "zope-interface", "-"),
-
         # Should be able to detect collapsed characters in the egg info.
         ("foo--bar-1.0", "foo-bar", "1.0"),
         ("foo-_bar-1.0", "foo-bar", "1.0"),
-
         # Invalid.
         ("the-package-name-8.19", "does-not-match", None),
         ("zope.interface.-4.5.0", "zope.interface", None),
diff --git a/tests/unit/test_link.py b/tests/unit/test_link.py
index a9e75e38bd3..ac7aa40590f 100644
--- a/tests/unit/test_link.py
+++ b/tests/unit/test_link.py
@@ -5,136 +5,151 @@
 
 
 class TestLink:
-
-    @pytest.mark.parametrize('url, expected', [
-        (
-            'https://user:password@example.com/path/page.html',
-            '<Link https://user:****@example.com/path/page.html>',
-        ),
-    ])
+    @pytest.mark.parametrize(
+        "url, expected",
+        [
+            (
+                "https://user:password@example.com/path/page.html",
+                "<Link https://user:****@example.com/path/page.html>",
+            ),
+        ],
+    )
     def test_repr(self, url, expected):
         link = Link(url)
         assert repr(link) == expected
 
-    @pytest.mark.parametrize('url, expected', [
-        ('http://yo/wheel.whl', 'wheel.whl'),
-        ('http://yo/wheel', 'wheel'),
-        ('https://example.com/path/page.html', 'page.html'),
-        # Test a quoted character.
-        ('https://example.com/path/page%231.html', 'page#1.html'),
-        (
-            'http://yo/myproject-1.0%2Bfoobar.0-py2.py3-none-any.whl',
-            'myproject-1.0+foobar.0-py2.py3-none-any.whl',
-        ),
-        # Test a path that ends in a slash.
-        ('https://example.com/path/', 'path'),
-        ('https://example.com/path//', 'path'),
-        # Test a url with no filename.
-        ('https://example.com/', 'example.com'),
-        # Test a url with no filename and with auth information.
-        (
-            'https://user:password@example.com/',
-            'example.com',
-        ),
-    ])
+    @pytest.mark.parametrize(
+        "url, expected",
+        [
+            ("http://yo/wheel.whl", "wheel.whl"),
+            ("http://yo/wheel", "wheel"),
+            ("https://example.com/path/page.html", "page.html"),
+            # Test a quoted character.
+            ("https://example.com/path/page%231.html", "page#1.html"),
+            (
+                "http://yo/myproject-1.0%2Bfoobar.0-py2.py3-none-any.whl",
+                "myproject-1.0+foobar.0-py2.py3-none-any.whl",
+            ),
+            # Test a path that ends in a slash.
+            ("https://example.com/path/", "path"),
+            ("https://example.com/path//", "path"),
+            # Test a url with no filename.
+            ("https://example.com/", "example.com"),
+            # Test a url with no filename and with auth information.
+            (
+                "https://user:password@example.com/",
+                "example.com",
+            ),
+        ],
+    )
     def test_filename(self, url, expected):
         link = Link(url)
         assert link.filename == expected
 
     def test_splitext(self):
-        assert ('wheel', '.whl') == Link('http://yo/wheel.whl').splitext()
+        assert ("wheel", ".whl") == Link("http://yo/wheel.whl").splitext()
 
     def test_no_ext(self):
-        assert '' == Link('http://yo/wheel').ext
+        assert "" == Link("http://yo/wheel").ext
 
     def test_ext(self):
-        assert '.whl' == Link('http://yo/wheel.whl').ext
+        assert ".whl" == Link("http://yo/wheel.whl").ext
 
     def test_ext_fragment(self):
-        assert '.whl' == Link('http://yo/wheel.whl#frag').ext
+        assert ".whl" == Link("http://yo/wheel.whl#frag").ext
 
     def test_ext_query(self):
-        assert '.whl' == Link('http://yo/wheel.whl?a=b').ext
+        assert ".whl" == Link("http://yo/wheel.whl?a=b").ext
 
     def test_is_wheel(self):
-        assert Link('http://yo/wheel.whl').is_wheel
+        assert Link("http://yo/wheel.whl").is_wheel
 
     def test_is_wheel_false(self):
-        assert not Link('http://yo/not_a_wheel').is_wheel
+        assert not Link("http://yo/not_a_wheel").is_wheel
 
     def test_fragments(self):
-        url = 'git+https://example.com/package#egg=eggname'
-        assert 'eggname' == Link(url).egg_fragment
+        url = "git+https://example.com/package#egg=eggname"
+        assert "eggname" == Link(url).egg_fragment
         assert None is Link(url).subdirectory_fragment
-        url = 'git+https://example.com/package#egg=eggname&subdirectory=subdir'
-        assert 'eggname' == Link(url).egg_fragment
-        assert 'subdir' == Link(url).subdirectory_fragment
-        url = 'git+https://example.com/package#subdirectory=subdir&egg=eggname'
-        assert 'eggname' == Link(url).egg_fragment
-        assert 'subdir' == Link(url).subdirectory_fragment
-
-    @pytest.mark.parametrize('yanked_reason, expected', [
-        (None, False),
-        ('', True),
-        ('there was a mistake', True),
-    ])
+        url = "git+https://example.com/package#egg=eggname&subdirectory=subdir"
+        assert "eggname" == Link(url).egg_fragment
+        assert "subdir" == Link(url).subdirectory_fragment
+        url = "git+https://example.com/package#subdirectory=subdir&egg=eggname"
+        assert "eggname" == Link(url).egg_fragment
+        assert "subdir" == Link(url).subdirectory_fragment
+
+    @pytest.mark.parametrize(
+        "yanked_reason, expected",
+        [
+            (None, False),
+            ("", True),
+            ("there was a mistake", True),
+        ],
+    )
     def test_is_yanked(self, yanked_reason, expected):
         link = Link(
-            'https://example.com/wheel.whl',
+            "https://example.com/wheel.whl",
             yanked_reason=yanked_reason,
         )
         assert link.is_yanked == expected
 
-    @pytest.mark.parametrize('hash_name, hex_digest, expected', [
-        # Test a value that matches but with the wrong hash_name.
-        ('sha384', 128 * 'a', False),
-        # Test matching values, including values other than the first.
-        ('sha512', 128 * 'a', True),
-        ('sha512', 128 * 'b', True),
-        # Test a matching hash_name with a value that doesn't match.
-        ('sha512', 128 * 'c', False),
-        # Test a link without a hash value.
-        ('sha512', '', False),
-    ])
+    @pytest.mark.parametrize(
+        "hash_name, hex_digest, expected",
+        [
+            # Test a value that matches but with the wrong hash_name.
+            ("sha384", 128 * "a", False),
+            # Test matching values, including values other than the first.
+            ("sha512", 128 * "a", True),
+            ("sha512", 128 * "b", True),
+            # Test a matching hash_name with a value that doesn't match.
+            ("sha512", 128 * "c", False),
+            # Test a link without a hash value.
+            ("sha512", "", False),
+        ],
+    )
     def test_is_hash_allowed(self, hash_name, hex_digest, expected):
-        url = (
-            'https://example.com/wheel.whl#{hash_name}={hex_digest}'.format(
-                hash_name=hash_name,
-                hex_digest=hex_digest,
-            )
+        url = "https://example.com/wheel.whl#{hash_name}={hex_digest}".format(
+            hash_name=hash_name,
+            hex_digest=hex_digest,
         )
         link = Link(url)
         hashes_data = {
-            'sha512': [128 * 'a', 128 * 'b'],
+            "sha512": [128 * "a", 128 * "b"],
         }
         hashes = Hashes(hashes_data)
         assert link.is_hash_allowed(hashes) == expected
 
     def test_is_hash_allowed__no_hash(self):
-        link = Link('https://example.com/wheel.whl')
+        link = Link("https://example.com/wheel.whl")
         hashes_data = {
-            'sha512': [128 * 'a'],
+            "sha512": [128 * "a"],
         }
         hashes = Hashes(hashes_data)
         assert not link.is_hash_allowed(hashes)
 
-    @pytest.mark.parametrize('hashes, expected', [
-        (None, False),
-        # Also test a success case to show the test is correct.
-        (Hashes({'sha512': [128 * 'a']}), True),
-    ])
+    @pytest.mark.parametrize(
+        "hashes, expected",
+        [
+            (None, False),
+            # Also test a success case to show the test is correct.
+            (Hashes({"sha512": [128 * "a"]}), True),
+        ],
+    )
     def test_is_hash_allowed__none_hashes(self, hashes, expected):
-        url = 'https://example.com/wheel.whl#sha512={}'.format(128 * 'a')
+        url = "https://example.com/wheel.whl#sha512={}".format(128 * "a")
         link = Link(url)
         assert link.is_hash_allowed(hashes) == expected
 
-    @pytest.mark.parametrize('url, expected', [
-        ('git+https://github.com/org/repo', True),
-        ('bzr+http://bzr.myproject.org/MyProject/trunk/#egg=MyProject', True),
-        ('hg+file://hg.company.com/repo', True),
-        ('https://example.com/some.whl', False),
-        ('file://home/foo/some.whl', False),
-    ])
+    @pytest.mark.parametrize(
+        "url, expected",
+        [
+            ("git+https://github.com/org/repo", True),
+            ("bzr+http://bzr.myproject.org/MyProject/trunk/#egg=MyProject", True),
+            ("hg+file://hg.company.com/repo", True),
+            ("https://example.com/some.whl", False),
+            ("file://home/foo/some.whl", False),
+        ],
+    )
     def test_is_vcs(self, url, expected):
         link = Link(url)
         assert link.is_vcs is expected
diff --git a/tests/unit/test_locations.py b/tests/unit/test_locations.py
index 2ede236f91f..bfa299917c5 100644
--- a/tests/unit/test_locations.py
+++ b/tests/unit/test_locations.py
@@ -13,7 +13,7 @@
 
 from pip._internal.locations import distutils_scheme
 
-if sys.platform == 'win32':
+if sys.platform == "win32":
     pwd = Mock()
 else:
     import pwd
@@ -34,7 +34,7 @@ def patch(self):
         """ first store and then patch python methods pythons """
         self.tempfile_gettempdir = tempfile.gettempdir
         self.old_os_fstat = os.fstat
-        if sys.platform != 'win32':
+        if sys.platform != "win32":
             # os.geteuid and pwd.getpwuid are not implemented on windows
             self.old_os_geteuid = os.geteuid
             self.old_pwd_getpwuid = pwd.getpwuid
@@ -46,30 +46,30 @@ def patch(self):
         os.geteuid = lambda: self.st_uid
         os.fstat = lambda fd: self.get_mock_fstat(fd)
 
-        if sys.platform != 'win32':
+        if sys.platform != "win32":
             pwd.getpwuid = lambda uid: self.get_mock_getpwuid(uid)
 
     def revert_patch(self):
         """ revert the patches to python methods """
         tempfile.gettempdir = self.tempfile_gettempdir
         getpass.getuser = self.old_getpass_getuser
-        if sys.platform != 'win32':
+        if sys.platform != "win32":
             # os.geteuid and pwd.getpwuid are not implemented on windows
             os.geteuid = self.old_os_geteuid
             pwd.getpwuid = self.old_pwd_getpwuid
         os.fstat = self.old_os_fstat
 
     def get_mock_fstat(self, fd):
-        """ returns a basic mock fstat call result.
-            Currently only the st_uid attribute has been set.
+        """returns a basic mock fstat call result.
+        Currently only the st_uid attribute has been set.
         """
         result = Mock()
         result.st_uid = self.st_uid
         return result
 
     def get_mock_getpwuid(self, uid):
-        """ returns a basic mock pwd.getpwuid call result.
-            Currently only the pw_name attribute has been set.
+        """returns a basic mock pwd.getpwuid call result.
+        Currently only the pw_name attribute has been set.
         """
         result = Mock()
         result.pw_name = self.username
@@ -77,12 +77,12 @@ def get_mock_getpwuid(self, uid):
 
 
 class TestDistutilsScheme:
-
     def test_root_modifies_appropriately(self, monkeypatch):
         # This deals with nt/posix path differences
         # root is c:\somewhere\else or /somewhere/else
-        root = os.path.normcase(os.path.abspath(
-            os.path.join(os.path.sep, 'somewhere', 'else')))
+        root = os.path.normcase(
+            os.path.abspath(os.path.join(os.path.sep, "somewhere", "else"))
+        )
         norm_scheme = distutils_scheme("example")
         root_scheme = distutils_scheme("example", root=root)
 
@@ -94,8 +94,9 @@ def test_root_modifies_appropriately(self, monkeypatch):
     @pytest.mark.incompatible_with_venv
     def test_distutils_config_file_read(self, tmpdir, monkeypatch):
         # This deals with nt/posix path differences
-        install_scripts = os.path.normcase(os.path.abspath(
-            os.path.join(os.path.sep, 'somewhere', 'else')))
+        install_scripts = os.path.normcase(
+            os.path.abspath(os.path.join(os.path.sep, "somewhere", "else"))
+        )
         f = tmpdir / "config" / "setup.cfg"
         f.parent.mkdir()
         f.write_text("[install]\ninstall-scripts=" + install_scripts)
@@ -104,11 +105,11 @@ def test_distutils_config_file_read(self, tmpdir, monkeypatch):
         # patch the function that returns what config files are present
         monkeypatch.setattr(
             Distribution,
-            'find_config_files',
+            "find_config_files",
             lambda self: [f],
         )
-        scheme = distutils_scheme('example')
-        assert scheme['scripts'] == install_scripts
+        scheme = distutils_scheme("example")
+        assert scheme["scripts"] == install_scripts
 
     @pytest.mark.incompatible_with_venv
     # when we request install-lib, we should install everything (.py &
@@ -116,8 +117,9 @@ def test_distutils_config_file_read(self, tmpdir, monkeypatch):
     # this path
     def test_install_lib_takes_precedence(self, tmpdir, monkeypatch):
         # This deals with nt/posix path differences
-        install_lib = os.path.normcase(os.path.abspath(
-            os.path.join(os.path.sep, 'somewhere', 'else')))
+        install_lib = os.path.normcase(
+            os.path.abspath(os.path.join(os.path.sep, "somewhere", "else"))
+        )
         f = tmpdir / "config" / "setup.cfg"
         f.parent.mkdir()
         f.write_text("[install]\ninstall-lib=" + install_lib)
@@ -126,15 +128,15 @@ def test_install_lib_takes_precedence(self, tmpdir, monkeypatch):
         # patch the function that returns what config files are present
         monkeypatch.setattr(
             Distribution,
-            'find_config_files',
+            "find_config_files",
             lambda self: [f],
         )
-        scheme = distutils_scheme('example')
-        assert scheme['platlib'] == install_lib + os.path.sep
-        assert scheme['purelib'] == install_lib + os.path.sep
+        scheme = distutils_scheme("example")
+        assert scheme["platlib"] == install_lib + os.path.sep
+        assert scheme["purelib"] == install_lib + os.path.sep
 
     def test_prefix_modifies_appropriately(self):
-        prefix = os.path.abspath(os.path.join('somewhere', 'else'))
+        prefix = os.path.abspath(os.path.join("somewhere", "else"))
 
         normal_scheme = distutils_scheme("example")
         prefix_scheme = distutils_scheme("example", prefix=prefix)
@@ -143,8 +145,5 @@ def _calculate_expected(value):
             path = os.path.join(prefix, os.path.relpath(value, sys.prefix))
             return os.path.normpath(path)
 
-        expected = {
-            k: _calculate_expected(v)
-            for k, v in normal_scheme.items()
-        }
+        expected = {k: _calculate_expected(v) for k, v in normal_scheme.items()}
         assert prefix_scheme == expected
diff --git a/tests/unit/test_logging.py b/tests/unit/test_logging.py
index 10d47eb6143..96e69927fa9 100644
--- a/tests/unit/test_logging.py
+++ b/tests/unit/test_logging.py
@@ -25,7 +25,7 @@ def _make_broken_pipe_error():
     if PY2:
         # This is one way a broken pipe error can show up in Python 2
         # (a non-Windows example in this case).
-        return IOError(errno.EPIPE, 'Broken pipe')
+        return IOError(errno.EPIPE, "Broken pipe")
 
     return BrokenPipeError()  # noqa: F821
 
@@ -46,54 +46,65 @@ def make_record(self, msg, level_name):
 
         return record
 
-    @pytest.mark.parametrize('level_name, expected', [
-        ('DEBUG', 'hello\nworld'),
-        ('INFO', 'hello\nworld'),
-        ('WARNING', 'WARNING: hello\nworld'),
-        ('ERROR', 'ERROR: hello\nworld'),
-        ('CRITICAL', 'ERROR: hello\nworld'),
-    ])
+    @pytest.mark.parametrize(
+        "level_name, expected",
+        [
+            ("DEBUG", "hello\nworld"),
+            ("INFO", "hello\nworld"),
+            ("WARNING", "WARNING: hello\nworld"),
+            ("ERROR", "ERROR: hello\nworld"),
+            ("CRITICAL", "ERROR: hello\nworld"),
+        ],
+    )
     def test_format(self, level_name, expected, utc):
         """
         Args:
           level_name: a logging level name (e.g. "WARNING").
         """
-        record = self.make_record('hello\nworld', level_name=level_name)
+        record = self.make_record("hello\nworld", level_name=level_name)
         f = IndentingFormatter(fmt="%(message)s")
         assert f.format(record) == expected
 
-    @pytest.mark.parametrize('level_name, expected', [
-        ('INFO',
-         '2019-01-17T06:00:37,040 hello\n'
-         '2019-01-17T06:00:37,040 world'),
-        ('WARNING',
-         '2019-01-17T06:00:37,040 WARNING: hello\n'
-         '2019-01-17T06:00:37,040 world'),
-    ])
+    @pytest.mark.parametrize(
+        "level_name, expected",
+        [
+            ("INFO", "2019-01-17T06:00:37,040 hello\n" "2019-01-17T06:00:37,040 world"),
+            (
+                "WARNING",
+                "2019-01-17T06:00:37,040 WARNING: hello\n"
+                "2019-01-17T06:00:37,040 world",
+            ),
+        ],
+    )
     def test_format_with_timestamp(self, level_name, expected, utc):
-        record = self.make_record('hello\nworld', level_name=level_name)
+        record = self.make_record("hello\nworld", level_name=level_name)
         f = IndentingFormatter(fmt="%(message)s", add_timestamp=True)
         assert f.format(record) == expected
 
-    @pytest.mark.parametrize('level_name, expected', [
-        ('WARNING', 'DEPRECATION: hello\nworld'),
-        ('ERROR', 'DEPRECATION: hello\nworld'),
-        ('CRITICAL', 'DEPRECATION: hello\nworld'),
-    ])
+    @pytest.mark.parametrize(
+        "level_name, expected",
+        [
+            ("WARNING", "DEPRECATION: hello\nworld"),
+            ("ERROR", "DEPRECATION: hello\nworld"),
+            ("CRITICAL", "DEPRECATION: hello\nworld"),
+        ],
+    )
     def test_format_deprecated(self, level_name, expected, utc):
         """
         Test that logged deprecation warnings coming from deprecated()
         don't get another prefix.
         """
         record = self.make_record(
-            'DEPRECATION: hello\nworld', level_name=level_name,
+            "DEPRECATION: hello\nworld",
+            level_name=level_name,
         )
         f = IndentingFormatter(fmt="%(message)s")
         assert f.format(record) == expected
 
     def test_thread_safety_base(self, utc):
         record = self.make_record(
-            'DEPRECATION: hello\nworld', level_name='WARNING',
+            "DEPRECATION: hello\nworld",
+            level_name="WARNING",
         )
         f = IndentingFormatter(fmt="%(message)s")
         results = []
@@ -109,7 +120,8 @@ def thread_function():
 
     def test_thread_safety_indent_log(self, utc):
         record = self.make_record(
-            'DEPRECATION: hello\nworld', level_name='WARNING',
+            "DEPRECATION: hello\nworld",
+            level_name="WARNING",
         )
         f = IndentingFormatter(fmt="%(message)s")
         results = []
@@ -126,10 +138,9 @@ def thread_function():
 
 
 class TestColorizedStreamHandler(object):
-
     def _make_log_record(self):
         attrs = {
-            'msg': 'my error',
+            "msg": "my error",
         }
         record = logging.makeLogRecord(attrs)
 
@@ -145,21 +156,21 @@ def test_broken_pipe_in_stderr_flush(self):
 
         with captured_stderr() as stderr:
             handler = ColorizedStreamHandler(stream=stderr)
-            with patch('sys.stderr.flush') as mock_flush:
+            with patch("sys.stderr.flush") as mock_flush:
                 mock_flush.side_effect = _make_broken_pipe_error()
                 # The emit() call raises no exception.
                 handler.emit(record)
 
             err_text = stderr.getvalue()
 
-        assert err_text.startswith('my error')
+        assert err_text.startswith("my error")
         # Check that the logging framework tried to log the exception.
         if PY2:
-            assert 'IOError: [Errno 32] Broken pipe' in err_text
-            assert 'Logged from file' in err_text
+            assert "IOError: [Errno 32] Broken pipe" in err_text
+            assert "Logged from file" in err_text
         else:
-            assert 'Logging error' in err_text
-            assert 'BrokenPipeError' in err_text
+            assert "Logging error" in err_text
+            assert "BrokenPipeError" in err_text
             assert "Message: 'my error'" in err_text
 
     def test_broken_pipe_in_stdout_write(self):
@@ -172,7 +183,7 @@ def test_broken_pipe_in_stdout_write(self):
 
         with captured_stdout() as stdout:
             handler = ColorizedStreamHandler(stream=stdout)
-            with patch('sys.stdout.write') as mock_write:
+            with patch("sys.stdout.write") as mock_write:
                 mock_write.side_effect = _make_broken_pipe_error()
                 with pytest.raises(BrokenStdoutLoggingError):
                     handler.emit(record)
@@ -187,7 +198,7 @@ def test_broken_pipe_in_stdout_flush(self):
 
         with captured_stdout() as stdout:
             handler = ColorizedStreamHandler(stream=stdout)
-            with patch('sys.stdout.flush') as mock_flush:
+            with patch("sys.stdout.flush") as mock_flush:
                 mock_flush.side_effect = _make_broken_pipe_error()
                 with pytest.raises(BrokenStdoutLoggingError):
                     handler.emit(record)
@@ -196,4 +207,4 @@ def test_broken_pipe_in_stdout_flush(self):
 
         # Sanity check that the log record was written, since flush() happens
         # after write().
-        assert output.startswith('my error')
+        assert output.startswith("my error")
diff --git a/tests/unit/test_models.py b/tests/unit/test_models.py
index f6363367755..8262908358c 100644
--- a/tests/unit/test_models.py
+++ b/tests/unit/test_models.py
@@ -7,8 +7,7 @@
 
 
 class TestPackageIndex(object):
-    """Tests for pip._internal.models.index.PackageIndex
-    """
+    """Tests for pip._internal.models.index.PackageIndex"""
 
     def test_gives_right_urls(self):
         url = "https://mypypi.internal/path/"
@@ -42,7 +41,6 @@ def test_TestPyPI_urls_are_correct(self):
 
 
 class TestInstallationCandidate(object):
-
     def test_sets_correct_variables(self):
         obj = candidate.InstallationCandidate(
             "A", "1.0.0", "https://somewhere.com/path/A-1.0.0.tar.gz"
diff --git a/tests/unit/test_models_wheel.py b/tests/unit/test_models_wheel.py
index f1fef6f09e8..a58c78e2510 100644
--- a/tests/unit/test_models_wheel.py
+++ b/tests/unit/test_models_wheel.py
@@ -7,80 +7,79 @@
 
 
 class TestWheelFile(object):
-
     def test_std_wheel_pattern(self):
-        w = Wheel('simple-1.1.1-py2-none-any.whl')
-        assert w.name == 'simple'
-        assert w.version == '1.1.1'
-        assert w.pyversions == ['py2']
-        assert w.abis == ['none']
-        assert w.plats == ['any']
+        w = Wheel("simple-1.1.1-py2-none-any.whl")
+        assert w.name == "simple"
+        assert w.version == "1.1.1"
+        assert w.pyversions == ["py2"]
+        assert w.abis == ["none"]
+        assert w.plats == ["any"]
 
     def test_wheel_pattern_multi_values(self):
-        w = Wheel('simple-1.1-py2.py3-abi1.abi2-any.whl')
-        assert w.name == 'simple'
-        assert w.version == '1.1'
-        assert w.pyversions == ['py2', 'py3']
-        assert w.abis == ['abi1', 'abi2']
-        assert w.plats == ['any']
+        w = Wheel("simple-1.1-py2.py3-abi1.abi2-any.whl")
+        assert w.name == "simple"
+        assert w.version == "1.1"
+        assert w.pyversions == ["py2", "py3"]
+        assert w.abis == ["abi1", "abi2"]
+        assert w.plats == ["any"]
 
     def test_wheel_with_build_tag(self):
         # pip doesn't do anything with build tags, but theoretically, we might
         # see one, in this case the build tag = '4'
-        w = Wheel('simple-1.1-4-py2-none-any.whl')
-        assert w.name == 'simple'
-        assert w.version == '1.1'
-        assert w.pyversions == ['py2']
-        assert w.abis == ['none']
-        assert w.plats == ['any']
+        w = Wheel("simple-1.1-4-py2-none-any.whl")
+        assert w.name == "simple"
+        assert w.version == "1.1"
+        assert w.pyversions == ["py2"]
+        assert w.abis == ["none"]
+        assert w.plats == ["any"]
 
     def test_single_digit_version(self):
-        w = Wheel('simple-1-py2-none-any.whl')
-        assert w.version == '1'
+        w = Wheel("simple-1-py2-none-any.whl")
+        assert w.version == "1"
 
     def test_non_pep440_version(self):
-        w = Wheel('simple-_invalid_-py2-none-any.whl')
-        assert w.version == '-invalid-'
+        w = Wheel("simple-_invalid_-py2-none-any.whl")
+        assert w.version == "-invalid-"
 
     def test_missing_version_raises(self):
         with pytest.raises(InvalidWheelFilename):
-            Wheel('Cython-cp27-none-linux_x86_64.whl')
+            Wheel("Cython-cp27-none-linux_x86_64.whl")
 
     def test_invalid_filename_raises(self):
         with pytest.raises(InvalidWheelFilename):
-            Wheel('invalid.whl')
+            Wheel("invalid.whl")
 
     def test_supported_single_version(self):
         """
         Test single-version wheel is known to be supported
         """
-        w = Wheel('simple-0.1-py2-none-any.whl')
-        assert w.supported(tags=[Tag('py2', 'none', 'any')])
+        w = Wheel("simple-0.1-py2-none-any.whl")
+        assert w.supported(tags=[Tag("py2", "none", "any")])
 
     def test_supported_multi_version(self):
         """
         Test multi-version wheel is known to be supported
         """
-        w = Wheel('simple-0.1-py2.py3-none-any.whl')
-        assert w.supported(tags=[Tag('py3', 'none', 'any')])
+        w = Wheel("simple-0.1-py2.py3-none-any.whl")
+        assert w.supported(tags=[Tag("py3", "none", "any")])
 
     def test_not_supported_version(self):
         """
         Test unsupported wheel is known to be unsupported
         """
-        w = Wheel('simple-0.1-py2-none-any.whl')
-        assert not w.supported(tags=[Tag('py1', 'none', 'any')])
+        w = Wheel("simple-0.1-py2-none-any.whl")
+        assert not w.supported(tags=[Tag("py1", "none", "any")])
 
     def test_supported_osx_version(self):
         """
         Wheels built for macOS 10.6 are supported on 10.9
         """
         tags = compatibility_tags.get_supported(
-            '27', platform='macosx_10_9_intel', impl='cp'
+            "27", platform="macosx_10_9_intel", impl="cp"
         )
-        w = Wheel('simple-0.1-cp27-none-macosx_10_6_intel.whl')
+        w = Wheel("simple-0.1-cp27-none-macosx_10_6_intel.whl")
         assert w.supported(tags=tags)
-        w = Wheel('simple-0.1-cp27-none-macosx_10_9_intel.whl')
+        w = Wheel("simple-0.1-cp27-none-macosx_10_9_intel.whl")
         assert w.supported(tags=tags)
 
     def test_not_supported_osx_version(self):
@@ -88,9 +87,9 @@ def test_not_supported_osx_version(self):
         Wheels built for macOS 10.9 are not supported on 10.6
         """
         tags = compatibility_tags.get_supported(
-            '27', platform='macosx_10_6_intel', impl='cp'
+            "27", platform="macosx_10_6_intel", impl="cp"
         )
-        w = Wheel('simple-0.1-cp27-none-macosx_10_9_intel.whl')
+        w = Wheel("simple-0.1-cp27-none-macosx_10_9_intel.whl")
         assert not w.supported(tags=tags)
 
     def test_supported_multiarch_darwin(self):
@@ -98,32 +97,32 @@ def test_supported_multiarch_darwin(self):
         Multi-arch wheels (intel) are supported on components (i386, x86_64)
         """
         universal = compatibility_tags.get_supported(
-            '27', platform='macosx_10_5_universal', impl='cp'
+            "27", platform="macosx_10_5_universal", impl="cp"
         )
         intel = compatibility_tags.get_supported(
-            '27', platform='macosx_10_5_intel', impl='cp'
+            "27", platform="macosx_10_5_intel", impl="cp"
         )
         x64 = compatibility_tags.get_supported(
-            '27', platform='macosx_10_5_x86_64', impl='cp'
+            "27", platform="macosx_10_5_x86_64", impl="cp"
         )
         i386 = compatibility_tags.get_supported(
-            '27', platform='macosx_10_5_i386', impl='cp'
+            "27", platform="macosx_10_5_i386", impl="cp"
         )
         ppc = compatibility_tags.get_supported(
-            '27', platform='macosx_10_5_ppc', impl='cp'
+            "27", platform="macosx_10_5_ppc", impl="cp"
         )
         ppc64 = compatibility_tags.get_supported(
-            '27', platform='macosx_10_5_ppc64', impl='cp'
+            "27", platform="macosx_10_5_ppc64", impl="cp"
         )
 
-        w = Wheel('simple-0.1-cp27-none-macosx_10_5_intel.whl')
+        w = Wheel("simple-0.1-cp27-none-macosx_10_5_intel.whl")
         assert w.supported(tags=intel)
         assert w.supported(tags=x64)
         assert w.supported(tags=i386)
         assert not w.supported(tags=universal)
         assert not w.supported(tags=ppc)
         assert not w.supported(tags=ppc64)
-        w = Wheel('simple-0.1-cp27-none-macosx_10_5_universal.whl')
+        w = Wheel("simple-0.1-cp27-none-macosx_10_5_universal.whl")
         assert w.supported(tags=universal)
         assert w.supported(tags=intel)
         assert w.supported(tags=x64)
@@ -136,16 +135,16 @@ def test_not_supported_multiarch_darwin(self):
         Single-arch wheels (x86_64) are not supported on multi-arch (intel)
         """
         universal = compatibility_tags.get_supported(
-            '27', platform='macosx_10_5_universal', impl='cp'
+            "27", platform="macosx_10_5_universal", impl="cp"
         )
         intel = compatibility_tags.get_supported(
-            '27', platform='macosx_10_5_intel', impl='cp'
+            "27", platform="macosx_10_5_intel", impl="cp"
         )
 
-        w = Wheel('simple-0.1-cp27-none-macosx_10_5_i386.whl')
+        w = Wheel("simple-0.1-cp27-none-macosx_10_5_i386.whl")
         assert not w.supported(tags=intel)
         assert not w.supported(tags=universal)
-        w = Wheel('simple-0.1-cp27-none-macosx_10_5_x86_64.whl')
+        w = Wheel("simple-0.1-cp27-none-macosx_10_5_x86_64.whl")
         assert not w.supported(tags=intel)
         assert not w.supported(tags=universal)
 
@@ -154,20 +153,20 @@ def test_support_index_min(self):
         Test results from `support_index_min`
         """
         tags = [
-            Tag('py2', 'none', 'TEST'),
-            Tag('py2', 'TEST', 'any'),
-            Tag('py2', 'none', 'any'),
+            Tag("py2", "none", "TEST"),
+            Tag("py2", "TEST", "any"),
+            Tag("py2", "none", "any"),
         ]
-        w = Wheel('simple-0.1-py2-none-any.whl')
+        w = Wheel("simple-0.1-py2-none-any.whl")
         assert w.support_index_min(tags=tags) == 2
-        w = Wheel('simple-0.1-py2-none-TEST.whl')
+        w = Wheel("simple-0.1-py2-none-TEST.whl")
         assert w.support_index_min(tags=tags) == 0
 
     def test_support_index_min__none_supported(self):
         """
         Test a wheel not supported by the given tags.
         """
-        w = Wheel('simple-0.1-py2-none-any.whl')
+        w = Wheel("simple-0.1-py2-none-any.whl")
         with pytest.raises(ValueError):
             w.support_index_min(tags=[])
 
@@ -176,5 +175,5 @@ def test_version_underscore_conversion(self):
         Test that we convert '_' to '-' for versions parsed out of wheel
         filenames
         """
-        w = Wheel('simple-0.1_1-py2-none-any.whl')
-        assert w.version == '0.1-1'
+        w = Wheel("simple-0.1_1-py2-none-any.whl")
+        assert w.version == "0.1-1"
diff --git a/tests/unit/test_network_auth.py b/tests/unit/test_network_auth.py
index 8116b627f79..a895ffa1169 100644
--- a/tests/unit/test_network_auth.py
+++ b/tests/unit/test_network_auth.py
@@ -7,32 +7,35 @@
 from tests.lib.requests_mocks import MockConnection, MockRequest, MockResponse
 
 
-@pytest.mark.parametrize(["input_url", "url", "username", "password"], [
-    (
-        "http://user%40email.com:password@example.com/path",
-        "http://example.com/path",
-        "user@email.com",
-        "password",
-    ),
-    (
-        "http://username:password@example.com/path",
-        "http://example.com/path",
-        "username",
-        "password",
-    ),
-    (
-        "http://token@example.com/path",
-        "http://example.com/path",
-        "token",
-        "",
-    ),
-    (
-        "http://example.com/path",
-        "http://example.com/path",
-        None,
-        None,
-    ),
-])
+@pytest.mark.parametrize(
+    ["input_url", "url", "username", "password"],
+    [
+        (
+            "http://user%40email.com:password@example.com/path",
+            "http://example.com/path",
+            "user@email.com",
+            "password",
+        ),
+        (
+            "http://username:password@example.com/path",
+            "http://example.com/path",
+            "username",
+            "password",
+        ),
+        (
+            "http://token@example.com/path",
+            "http://example.com/path",
+            "token",
+            "",
+        ),
+        (
+            "http://example.com/path",
+            "http://example.com/path",
+            None,
+            None,
+        ),
+    ],
+)
 def test_get_credentials_parses_correctly(input_url, url, username, password):
     auth = MultiDomainBasicAuth()
     get = auth._get_url_and_credentials
@@ -41,33 +44,30 @@ def test_get_credentials_parses_correctly(input_url, url, username, password):
     assert get(input_url) == (url, username, password)
     assert (
         # There are no credentials in the URL
-        (username is None and password is None) or
+        (username is None and password is None)
+        or
         # Credentials were found and "cached" appropriately
-        auth.passwords['example.com'] == (username, password)
+        auth.passwords["example.com"] == (username, password)
     )
 
 
 def test_get_credentials_uses_cached_credentials():
     auth = MultiDomainBasicAuth()
-    auth.passwords['example.com'] = ('user', 'pass')
+    auth.passwords["example.com"] = ("user", "pass")
 
     got = auth._get_url_and_credentials("http://foo:bar@example.com/path")
-    expected = ('http://example.com/path', 'user', 'pass')
+    expected = ("http://example.com/path", "user", "pass")
     assert got == expected
 
 
 def test_get_index_url_credentials():
-    auth = MultiDomainBasicAuth(index_urls=[
-        "http://foo:bar@example.com/path"
-    ])
+    auth = MultiDomainBasicAuth(index_urls=["http://foo:bar@example.com/path"])
     get = functools.partial(
-        auth._get_new_credentials,
-        allow_netrc=False,
-        allow_keyring=False
+        auth._get_new_credentials, allow_netrc=False, allow_keyring=False
     )
 
     # Check resolution of indexes
-    assert get("http://example.com/path/path2") == ('foo', 'bar')
+    assert get("http://example.com/path/path2") == ("foo", "bar")
     assert get("http://example.com/path3/path2") == (None, None)
 
 
@@ -90,42 +90,44 @@ def set_password(self, system, username, password):
         self.saved_passwords.append((system, username, password))
 
 
-@pytest.mark.parametrize('url, expect', (
-    ("http://example.com/path1", (None, None)),
-    # path1 URLs will be resolved by netloc
-    ("http://user@example.com/path1", ("user", "user!netloc")),
-    ("http://user2@example.com/path1", ("user2", "user2!netloc")),
-    # path2 URLs will be resolved by index URL
-    ("http://example.com/path2/path3", (None, None)),
-    ("http://foo@example.com/path2/path3", ("foo", "foo!url")),
-))
+@pytest.mark.parametrize(
+    "url, expect",
+    (
+        ("http://example.com/path1", (None, None)),
+        # path1 URLs will be resolved by netloc
+        ("http://user@example.com/path1", ("user", "user!netloc")),
+        ("http://user2@example.com/path1", ("user2", "user2!netloc")),
+        # path2 URLs will be resolved by index URL
+        ("http://example.com/path2/path3", (None, None)),
+        ("http://foo@example.com/path2/path3", ("foo", "foo!url")),
+    ),
+)
 def test_keyring_get_password(monkeypatch, url, expect):
     keyring = KeyringModuleV1()
-    monkeypatch.setattr('pip._internal.network.auth.keyring', keyring)
+    monkeypatch.setattr("pip._internal.network.auth.keyring", keyring)
     auth = MultiDomainBasicAuth(index_urls=["http://example.com/path2"])
 
-    actual = auth._get_new_credentials(url, allow_netrc=False,
-                                       allow_keyring=True)
+    actual = auth._get_new_credentials(url, allow_netrc=False, allow_keyring=True)
     assert actual == expect
 
 
 def test_keyring_get_password_after_prompt(monkeypatch):
     keyring = KeyringModuleV1()
-    monkeypatch.setattr('pip._internal.network.auth.keyring', keyring)
+    monkeypatch.setattr("pip._internal.network.auth.keyring", keyring)
     auth = MultiDomainBasicAuth()
 
     def ask_input(prompt):
         assert prompt == "User for example.com: "
         return "user"
 
-    monkeypatch.setattr('pip._internal.network.auth.ask_input', ask_input)
+    monkeypatch.setattr("pip._internal.network.auth.ask_input", ask_input)
     actual = auth._prompt_for_password("example.com")
     assert actual == ("user", "user!netloc", False)
 
 
 def test_keyring_get_password_after_prompt_when_none(monkeypatch):
     keyring = KeyringModuleV1()
-    monkeypatch.setattr('pip._internal.network.auth.keyring', keyring)
+    monkeypatch.setattr("pip._internal.network.auth.keyring", keyring)
     auth = MultiDomainBasicAuth()
 
     def ask_input(prompt):
@@ -136,52 +138,60 @@ def ask_password(prompt):
         assert prompt == "Password: "
         return "fake_password"
 
-    monkeypatch.setattr('pip._internal.network.auth.ask_input', ask_input)
-    monkeypatch.setattr(
-        'pip._internal.network.auth.ask_password', ask_password)
+    monkeypatch.setattr("pip._internal.network.auth.ask_input", ask_input)
+    monkeypatch.setattr("pip._internal.network.auth.ask_password", ask_password)
     actual = auth._prompt_for_password("unknown.com")
     assert actual == ("user", "fake_password", True)
 
 
 def test_keyring_get_password_username_in_index(monkeypatch):
     keyring = KeyringModuleV1()
-    monkeypatch.setattr('pip._internal.network.auth.keyring', keyring)
+    monkeypatch.setattr("pip._internal.network.auth.keyring", keyring)
     auth = MultiDomainBasicAuth(index_urls=["http://user@example.com/path2"])
     get = functools.partial(
-        auth._get_new_credentials,
-        allow_netrc=False,
-        allow_keyring=True
+        auth._get_new_credentials, allow_netrc=False, allow_keyring=True
     )
 
     assert get("http://example.com/path2/path3") == ("user", "user!url")
     assert get("http://example.com/path4/path1") == (None, None)
 
 
-@pytest.mark.parametrize("response_status, creds, expect_save", (
-    (403, ("user", "pass", True), False),
-    (200, ("user", "pass", True), True,),
-    (200, ("user", "pass", False), False,),
-))
-def test_keyring_set_password(monkeypatch, response_status, creds,
-                              expect_save):
+@pytest.mark.parametrize(
+    "response_status, creds, expect_save",
+    (
+        (403, ("user", "pass", True), False),
+        (
+            200,
+            ("user", "pass", True),
+            True,
+        ),
+        (
+            200,
+            ("user", "pass", False),
+            False,
+        ),
+    ),
+)
+def test_keyring_set_password(monkeypatch, response_status, creds, expect_save):
     keyring = KeyringModuleV1()
-    monkeypatch.setattr('pip._internal.network.auth.keyring', keyring)
+    monkeypatch.setattr("pip._internal.network.auth.keyring", keyring)
     auth = MultiDomainBasicAuth(prompting=True)
-    monkeypatch.setattr(auth, '_get_url_and_credentials',
-                        lambda u: (u, None, None))
-    monkeypatch.setattr(auth, '_prompt_for_password', lambda *a: creds)
+    monkeypatch.setattr(auth, "_get_url_and_credentials", lambda u: (u, None, None))
+    monkeypatch.setattr(auth, "_prompt_for_password", lambda *a: creds)
     if creds[2]:
         # when _prompt_for_password indicates to save, we should save
         def should_save_password_to_keyring(*a):
             return True
+
     else:
         # when _prompt_for_password indicates not to save, we should
         # never call this function
         def should_save_password_to_keyring(*a):
-            assert False, ("_should_save_password_to_keyring should not be " +
-                           "called")
-    monkeypatch.setattr(auth, '_should_save_password_to_keyring',
-                        should_save_password_to_keyring)
+            assert False, "_should_save_password_to_keyring should not be " + "called"
+
+    monkeypatch.setattr(
+        auth, "_should_save_password_to_keyring", should_save_password_to_keyring
+    )
 
     req = MockRequest("https://example.com")
     resp = MockResponse(b"")
@@ -228,20 +238,21 @@ def get_credential(self, system, username):
         return None
 
 
-@pytest.mark.parametrize('url, expect', (
-    ("http://example.com/path1", ("username", "netloc")),
-    ("http://example.com/path2/path3", ("username", "url")),
-    ("http://user2@example.com/path2/path3", ("username", "url")),
-))
+@pytest.mark.parametrize(
+    "url, expect",
+    (
+        ("http://example.com/path1", ("username", "netloc")),
+        ("http://example.com/path2/path3", ("username", "url")),
+        ("http://user2@example.com/path2/path3", ("username", "url")),
+    ),
+)
 def test_keyring_get_credential(monkeypatch, url, expect):
-    monkeypatch.setattr(
-        pip._internal.network.auth, 'keyring', KeyringModuleV2()
-    )
+    monkeypatch.setattr(pip._internal.network.auth, "keyring", KeyringModuleV2())
     auth = MultiDomainBasicAuth(index_urls=["http://example.com/path2"])
 
-    assert auth._get_new_credentials(
-        url, allow_netrc=False, allow_keyring=True
-    ) == expect
+    assert (
+        auth._get_new_credentials(url, allow_netrc=False, allow_keyring=True) == expect
+    )
 
 
 class KeyringModuleBroken(object):
@@ -257,7 +268,7 @@ def get_credential(self, system, username):
 
 def test_broken_keyring_disables_keyring(monkeypatch):
     keyring_broken = KeyringModuleBroken()
-    monkeypatch.setattr(pip._internal.network.auth, 'keyring', keyring_broken)
+    monkeypatch.setattr(pip._internal.network.auth, "keyring", keyring_broken)
 
     auth = MultiDomainBasicAuth(index_urls=["http://example.com/"])
 
diff --git a/tests/unit/test_network_cache.py b/tests/unit/test_network_cache.py
index 5f1d0a0975a..63515aac91f 100644
--- a/tests/unit/test_network_cache.py
+++ b/tests/unit/test_network_cache.py
@@ -56,7 +56,5 @@ def test_safe_delete_no_perms(self, cache_tmpdir):
     def test_cache_hashes_are_same(self, cache_tmpdir):
         cache = SafeFileCache(cache_tmpdir)
         key = "test key"
-        fake_cache = Mock(
-            FileCache, directory=cache.directory, encode=FileCache.encode
-        )
+        fake_cache = Mock(FileCache, directory=cache.directory, encode=FileCache.encode)
         assert cache._get_cache_path(key) == FileCache._fn(fake_cache, key)
diff --git a/tests/unit/test_network_download.py b/tests/unit/test_network_download.py
index 20f5513a2df..c1bc2ea1e1b 100644
--- a/tests/unit/test_network_download.py
+++ b/tests/unit/test_network_download.py
@@ -12,23 +12,45 @@
 from tests.lib.requests_mocks import MockResponse
 
 
-@pytest.mark.parametrize("url, headers, from_cache, expected", [
-    ('http://example.com/foo.tgz', {}, False,
-        "Downloading http://example.com/foo.tgz"),
-    ('http://example.com/foo.tgz', {'content-length': 2}, False,
-        "Downloading http://example.com/foo.tgz (2 bytes)"),
-    ('http://example.com/foo.tgz', {'content-length': 2}, True,
-        "Using cached http://example.com/foo.tgz (2 bytes)"),
-    ('https://files.pythonhosted.org/foo.tgz', {}, False,
-        "Downloading foo.tgz"),
-    ('https://files.pythonhosted.org/foo.tgz', {'content-length': 2}, False,
-        "Downloading foo.tgz (2 bytes)"),
-    ('https://files.pythonhosted.org/foo.tgz', {'content-length': 2}, True,
-        "Using cached foo.tgz"),
-])
+@pytest.mark.parametrize(
+    "url, headers, from_cache, expected",
+    [
+        (
+            "http://example.com/foo.tgz",
+            {},
+            False,
+            "Downloading http://example.com/foo.tgz",
+        ),
+        (
+            "http://example.com/foo.tgz",
+            {"content-length": 2},
+            False,
+            "Downloading http://example.com/foo.tgz (2 bytes)",
+        ),
+        (
+            "http://example.com/foo.tgz",
+            {"content-length": 2},
+            True,
+            "Using cached http://example.com/foo.tgz (2 bytes)",
+        ),
+        ("https://files.pythonhosted.org/foo.tgz", {}, False, "Downloading foo.tgz"),
+        (
+            "https://files.pythonhosted.org/foo.tgz",
+            {"content-length": 2},
+            False,
+            "Downloading foo.tgz (2 bytes)",
+        ),
+        (
+            "https://files.pythonhosted.org/foo.tgz",
+            {"content-length": 2},
+            True,
+            "Using cached foo.tgz",
+        ),
+    ],
+)
 def test_prepare_download__log(caplog, url, headers, from_cache, expected):
     caplog.set_level(logging.INFO)
-    resp = MockResponse(b'')
+    resp = MockResponse(b"")
     resp.url = url
     resp.headers = headers
     if from_cache:
@@ -38,18 +60,21 @@ def test_prepare_download__log(caplog, url, headers, from_cache, expected):
 
     assert len(caplog.records) == 1
     record = caplog.records[0]
-    assert record.levelname == 'INFO'
+    assert record.levelname == "INFO"
     assert expected in record.message
 
 
-@pytest.mark.parametrize("filename, expected", [
-    ('dir/file', 'file'),
-    ('../file', 'file'),
-    ('../../file', 'file'),
-    ('../', ''),
-    ('../..', '..'),
-    ('/', ''),
-])
+@pytest.mark.parametrize(
+    "filename, expected",
+    [
+        ("dir/file", "file"),
+        ("../file", "file"),
+        ("../../file", "file"),
+        ("../", ""),
+        ("../..", ".."),
+        ("/", ""),
+    ],
+)
 def test_sanitize_content_filename(filename, expected):
     """
     Test inputs where the result is the same for Windows and non-Windows.
@@ -57,36 +82,36 @@ def test_sanitize_content_filename(filename, expected):
     assert sanitize_content_filename(filename) == expected
 
 
-@pytest.mark.parametrize("filename, win_expected, non_win_expected", [
-    ('dir\\file', 'file', 'dir\\file'),
-    ('..\\file', 'file', '..\\file'),
-    ('..\\..\\file', 'file', '..\\..\\file'),
-    ('..\\', '', '..\\'),
-    ('..\\..', '..', '..\\..'),
-    ('\\', '', '\\'),
-])
+@pytest.mark.parametrize(
+    "filename, win_expected, non_win_expected",
+    [
+        ("dir\\file", "file", "dir\\file"),
+        ("..\\file", "file", "..\\file"),
+        ("..\\..\\file", "file", "..\\..\\file"),
+        ("..\\", "", "..\\"),
+        ("..\\..", "..", "..\\.."),
+        ("\\", "", "\\"),
+    ],
+)
 def test_sanitize_content_filename__platform_dependent(
-    filename,
-    win_expected,
-    non_win_expected
+    filename, win_expected, non_win_expected
 ):
     """
     Test inputs where the result is different for Windows and non-Windows.
     """
-    if sys.platform == 'win32':
+    if sys.platform == "win32":
         expected = win_expected
     else:
         expected = non_win_expected
     assert sanitize_content_filename(filename) == expected
 
 
-@pytest.mark.parametrize("content_disposition, default_filename, expected", [
-    ('attachment;filename="../file"', 'df', 'file'),
-])
-def test_parse_content_disposition(
-    content_disposition,
-    default_filename,
-    expected
-):
+@pytest.mark.parametrize(
+    "content_disposition, default_filename, expected",
+    [
+        ('attachment;filename="../file"', "df", "file"),
+    ],
+)
+def test_parse_content_disposition(content_disposition, default_filename, expected):
     actual = parse_content_disposition(content_disposition, default_filename)
     assert actual == expected
diff --git a/tests/unit/test_network_lazy_wheel.py b/tests/unit/test_network_lazy_wheel.py
index cf0e6213d3f..81fa502dfac 100644
--- a/tests/unit/test_network_lazy_wheel.py
+++ b/tests/unit/test_network_lazy_wheel.py
@@ -11,14 +11,14 @@
 from tests.lib.server import file_response
 
 MYPY_0_782_WHL = (
-    'https://files.pythonhosted.org/packages/9d/65/'
-    'b96e844150ce18b9892b155b780248955ded13a2581d31872e7daa90a503/'
-    'mypy-0.782-py3-none-any.whl'
+    "https://files.pythonhosted.org/packages/9d/65/"
+    "b96e844150ce18b9892b155b780248955ded13a2581d31872e7daa90a503/"
+    "mypy-0.782-py3-none-any.whl"
 )
 MYPY_0_782_REQS = {
-    Requirement('typed-ast (<1.5.0,>=1.4.0)'),
-    Requirement('typing-extensions (>=3.7.4)'),
-    Requirement('mypy-extensions (<0.5.0,>=0.4.3)'),
+    Requirement("typed-ast (<1.5.0,>=1.4.0)"),
+    Requirement("typing-extensions (>=3.7.4)"),
+    Requirement("mypy-extensions (<0.5.0,>=0.4.3)"),
     Requirement('psutil (>=4.0); extra == "dmypy"'),
 }
 
@@ -30,32 +30,32 @@ def session():
 
 @fixture
 def mypy_whl_no_range(mock_server, shared_data):
-    mypy_whl = shared_data.packages / 'mypy-0.782-py3-none-any.whl'
+    mypy_whl = shared_data.packages / "mypy-0.782-py3-none-any.whl"
     mock_server.set_responses([file_response(mypy_whl)])
     mock_server.start()
-    base_address = 'http://{}:{}'.format(mock_server.host, mock_server.port)
-    yield "{}/{}".format(base_address, 'mypy-0.782-py3-none-any.whl')
+    base_address = "http://{}:{}".format(mock_server.host, mock_server.port)
+    yield "{}/{}".format(base_address, "mypy-0.782-py3-none-any.whl")
     mock_server.stop()
 
 
 @mark.network
 def test_dist_from_wheel_url(session):
     """Test if the acquired distribution contain correct information."""
-    dist = dist_from_wheel_url('mypy', MYPY_0_782_WHL, session)
-    assert dist.key == 'mypy'
-    assert dist.version == '0.782'
-    assert dist.extras == ['dmypy']
+    dist = dist_from_wheel_url("mypy", MYPY_0_782_WHL, session)
+    assert dist.key == "mypy"
+    assert dist.version == "0.782"
+    assert dist.extras == ["dmypy"]
     assert set(dist.requires(dist.extras)) == MYPY_0_782_REQS
 
 
 def test_dist_from_wheel_url_no_range(session, mypy_whl_no_range):
     """Test handling when HTTP range requests are not supported."""
     with raises(HTTPRangeRequestUnsupported):
-        dist_from_wheel_url('mypy', mypy_whl_no_range, session)
+        dist_from_wheel_url("mypy", mypy_whl_no_range, session)
 
 
 @mark.network
 def test_dist_from_wheel_url_not_zip(session):
     """Test handling with the given URL does not point to a ZIP."""
     with raises(BadZipfile):
-        dist_from_wheel_url('python', 'https://www.python.org/', session)
+        dist_from_wheel_url("python", "https://www.python.org/", session)
diff --git a/tests/unit/test_network_session.py b/tests/unit/test_network_session.py
index a0d1463b2cf..351213a6490 100644
--- a/tests/unit/test_network_session.py
+++ b/tests/unit/test_network_session.py
@@ -16,14 +16,17 @@ def test_user_agent():
     assert user_agent.startswith("pip/{}".format(__version__))
 
 
-@pytest.mark.parametrize('name, expected_like_ci', [
-    ('BUILD_BUILDID', True),
-    ('BUILD_ID', True),
-    ('CI', True),
-    ('PIP_IS_CI', True),
-    # Test a prefix substring of one of the variable names we use.
-    ('BUILD', False),
-])
+@pytest.mark.parametrize(
+    "name, expected_like_ci",
+    [
+        ("BUILD_BUILDID", True),
+        ("BUILD_ID", True),
+        ("CI", True),
+        ("PIP_IS_CI", True),
+        # Test a prefix substring of one of the variable names we use.
+        ("BUILD", False),
+    ],
+)
 def test_user_agent__ci(monkeypatch, name, expected_like_ci):
     # Delete the variable names we use to check for CI to prevent the
     # detection from always returning True in case the tests are being run
@@ -38,7 +41,7 @@ def test_user_agent__ci(monkeypatch, name, expected_like_ci):
     assert '"ci":null' in user_agent
     assert '"ci":true' not in user_agent
 
-    monkeypatch.setenv(name, 'true')
+    monkeypatch.setenv(name, "true")
     user_agent = get_user_agent()
     assert ('"ci":true' in user_agent) == expected_like_ci
     assert ('"ci":null' in user_agent) == (not expected_like_ci)
@@ -50,7 +53,6 @@ def test_user_agent_user_data(monkeypatch):
 
 
 class TestPipSession:
-
     def test_cache_defaults_off(self):
         session = PipSession()
 
@@ -63,9 +65,7 @@ def test_cache_is_enabled(self, tmpdir):
 
         assert hasattr(session.adapters["https://"], "cache")
 
-        assert (
-            session.adapters["https://"].cache.directory == cache_directory
-        )
+        assert session.adapters["https://"].cache.directory == cache_directory
 
     def test_http_cache_is_not_enabled(self, tmpdir):
         session = PipSession(cache=tmpdir.joinpath("test-cache"))
@@ -86,42 +86,46 @@ def test_trusted_hosts_adapter(self, tmpdir):
 
     def test_add_trusted_host(self):
         # Leave a gap to test how the ordering is affected.
-        trusted_hosts = ['host1', 'host3']
+        trusted_hosts = ["host1", "host3"]
         session = PipSession(trusted_hosts=trusted_hosts)
         trusted_host_adapter = session._trusted_host_adapter
-        prefix2 = 'https://host2/'
-        prefix3 = 'https://host3/'
-        prefix3_wildcard = 'https://host3:'
+        prefix2 = "https://host2/"
+        prefix3 = "https://host3/"
+        prefix3_wildcard = "https://host3:"
 
         # Confirm some initial conditions as a baseline.
-        assert session.pip_trusted_origins == [
-            ('host1', None), ('host3', None)
-        ]
+        assert session.pip_trusted_origins == [("host1", None), ("host3", None)]
         assert session.adapters[prefix3] is trusted_host_adapter
         assert session.adapters[prefix3_wildcard] is trusted_host_adapter
 
         assert prefix2 not in session.adapters
 
         # Test adding a new host.
-        session.add_trusted_host('host2')
+        session.add_trusted_host("host2")
         assert session.pip_trusted_origins == [
-            ('host1', None), ('host3', None), ('host2', None)
+            ("host1", None),
+            ("host3", None),
+            ("host2", None),
         ]
         # Check that prefix3 is still present.
         assert session.adapters[prefix3] is trusted_host_adapter
         assert session.adapters[prefix2] is trusted_host_adapter
 
         # Test that adding the same host doesn't create a duplicate.
-        session.add_trusted_host('host3')
+        session.add_trusted_host("host3")
         assert session.pip_trusted_origins == [
-            ('host1', None), ('host3', None), ('host2', None)
-        ], 'actual: {}'.format(session.pip_trusted_origins)
+            ("host1", None),
+            ("host3", None),
+            ("host2", None),
+        ], "actual: {}".format(session.pip_trusted_origins)
 
-        session.add_trusted_host('host4:8080')
-        prefix4 = 'https://host4:8080/'
+        session.add_trusted_host("host4:8080")
+        prefix4 = "https://host4:8080/"
         assert session.pip_trusted_origins == [
-            ('host1', None), ('host3', None),
-            ('host2', None), ('host4', 8080)
+            ("host1", None),
+            ("host3", None),
+            ("host2", None),
+            ("host4", 8080),
         ]
         assert session.adapters[prefix4] is trusted_host_adapter
 
@@ -129,36 +133,36 @@ def test_add_trusted_host__logging(self, caplog):
         """
         Test logging when add_trusted_host() is called.
         """
-        trusted_hosts = ['host0', 'host1']
+        trusted_hosts = ["host0", "host1"]
         session = PipSession(trusted_hosts=trusted_hosts)
         with caplog.at_level(logging.INFO):
             # Test adding an existing host.
-            session.add_trusted_host('host1', source='somewhere')
-            session.add_trusted_host('host2')
+            session.add_trusted_host("host1", source="somewhere")
+            session.add_trusted_host("host2")
             # Test calling add_trusted_host() on the same host twice.
-            session.add_trusted_host('host2')
+            session.add_trusted_host("host2")
 
         actual = [(r.levelname, r.message) for r in caplog.records]
         # Observe that "host0" isn't included in the logs.
         expected = [
-            ('INFO', "adding trusted host: 'host1' (from somewhere)"),
-            ('INFO', "adding trusted host: 'host2'"),
-            ('INFO', "adding trusted host: 'host2'"),
+            ("INFO", "adding trusted host: 'host1' (from somewhere)"),
+            ("INFO", "adding trusted host: 'host2'"),
+            ("INFO", "adding trusted host: 'host2'"),
         ]
         assert actual == expected
 
     def test_iter_secure_origins(self):
-        trusted_hosts = ['host1', 'host2', 'host3:8080']
+        trusted_hosts = ["host1", "host2", "host3:8080"]
         session = PipSession(trusted_hosts=trusted_hosts)
 
         actual = list(session.iter_secure_origins())
         assert len(actual) == 9
         # Spot-check that SECURE_ORIGINS is included.
-        assert actual[0] == ('https', '*', '*')
+        assert actual[0] == ("https", "*", "*")
         assert actual[-3:] == [
-            ('*', 'host1', '*'),
-            ('*', 'host2', '*'),
-            ('*', 'host3', 8080)
+            ("*", "host1", "*"),
+            ("*", "host2", "*"),
+            ("*", "host3", 8080),
         ]
 
     def test_iter_secure_origins__trusted_hosts_empty(self):
@@ -170,10 +174,10 @@ def test_iter_secure_origins__trusted_hosts_empty(self):
         actual = list(session.iter_secure_origins())
         assert len(actual) == 6
         # Spot-check that SECURE_ORIGINS is included.
-        assert actual[0] == ('https', '*', '*')
+        assert actual[0] == ("https", "*", "*")
 
     @pytest.mark.parametrize(
-        'location, trusted, expected',
+        "location, trusted, expected",
         [
             ("http://pypi.org/something", [], False),
             ("https://pypi.org/something", [], True),
@@ -191,11 +195,7 @@ def test_iter_secure_origins__trusted_hosts_empty(self):
             # Test a trusted_host with a port.
             ("http://example.com:8080/something/", ["example.com:8080"], True),
             ("http://example.com/something/", ["example.com:8080"], False),
-            (
-                "http://example.com:8888/something/",
-                ["example.com:8080"],
-                False
-            ),
+            ("http://example.com:8888/something/", ["example.com:8080"], False),
         ],
     )
     def test_is_secure_origin(self, caplog, location, trusted, expected):
@@ -217,5 +217,5 @@ def warning(self, *args, **kwargs):
 
         assert len(log_records) == 1
         actual_level, actual_message = log_records[0]
-        assert actual_level == 'WARNING'
-        assert 'is not a trusted or secure host' in actual_message
+        assert actual_level == "WARNING"
+        assert "is not a trusted or secure host" in actual_message
diff --git a/tests/unit/test_network_utils.py b/tests/unit/test_network_utils.py
index 09f0684c5ee..8105e16006d 100644
--- a/tests/unit/test_network_utils.py
+++ b/tests/unit/test_network_utils.py
@@ -5,12 +5,15 @@
 from tests.lib.requests_mocks import MockResponse
 
 
-@pytest.mark.parametrize(("status_code", "error_type"), [
-    (401, "Client Error"),
-    (501, "Server Error"),
-])
+@pytest.mark.parametrize(
+    ("status_code", "error_type"),
+    [
+        (401, "Client Error"),
+        (501, "Server Error"),
+    ],
+)
 def test_raise_for_status_raises_exception(status_code, error_type):
-    contents = b'downloaded'
+    contents = b"downloaded"
     resp = MockResponse(contents)
     resp.status_code = status_code
     resp.url = "http://www.example.com/whatever.tgz"
@@ -19,13 +22,12 @@ def test_raise_for_status_raises_exception(status_code, error_type):
         raise_for_status(resp)
         assert str(exc.info) == (
             "{} {}: Network Error for url:"
-            " http://www.example.com/whatever.tgz".format(
-                status_code, error_type)
+            " http://www.example.com/whatever.tgz".format(status_code, error_type)
         )
 
 
 def test_raise_for_status_does_not_raises_exception():
-    contents = b'downloaded'
+    contents = b"downloaded"
     resp = MockResponse(contents)
     resp.status_code = 201
     resp.url = "http://www.example.com/whatever.tgz"
diff --git a/tests/unit/test_operations_prepare.py b/tests/unit/test_operations_prepare.py
index ab6aaf6aa93..b0d225ffff6 100644
--- a/tests/unit/test_operations_prepare.py
+++ b/tests/unit/test_operations_prepare.py
@@ -13,11 +13,7 @@
 from pip._internal.operations.prepare import _copy_source_tree, unpack_url
 from pip._internal.utils.hashes import Hashes
 from pip._internal.utils.urls import path_to_url
-from tests.lib.filesystem import (
-    get_filelist,
-    make_socket_file,
-    make_unreadable_file,
-)
+from tests.lib.filesystem import get_filelist, make_socket_file, make_unreadable_file
 from tests.lib.path import Path
 from tests.lib.requests_mocks import MockResponse
 
@@ -48,21 +44,24 @@ def _fake_session_get(*args, **kwargs):
             download_dir=None,
         )
         assert set(os.listdir(temp_dir)) == {
-            'PKG-INFO', 'setup.cfg', 'setup.py', 'simple', 'simple.egg-info'
+            "PKG-INFO",
+            "setup.cfg",
+            "setup.py",
+            "simple",
+            "simple.egg-info",
         }
     finally:
         rmtree(temp_dir)
 
 
 @patch("pip._internal.network.download.raise_for_status")
-def test_download_http_url__no_directory_traversal(mock_raise_for_status,
-                                                   tmpdir):
+def test_download_http_url__no_directory_traversal(mock_raise_for_status, tmpdir):
     """
     Test that directory traversal doesn't happen on download when the
     Content-Disposition header contains a filename with a ".." path part.
     """
-    mock_url = 'http://www.example.com/whatever.tgz'
-    contents = b'downloaded'
+    mock_url = "http://www.example.com/whatever.tgz"
+    contents = b"downloaded"
     link = Link(mock_url)
 
     session = Mock()
@@ -71,18 +70,18 @@ def test_download_http_url__no_directory_traversal(mock_raise_for_status,
     resp.headers = {
         # Set the content-type to a random value to prevent
         # mimetypes.guess_extension from guessing the extension.
-        'content-type': 'random',
-        'content-disposition': 'attachment;filename="../out_dir_file"'
+        "content-type": "random",
+        "content-disposition": 'attachment;filename="../out_dir_file"',
     }
     session.get.return_value = resp
     download = Downloader(session, progress_bar="on")
 
-    download_dir = tmpdir.joinpath('download')
+    download_dir = tmpdir.joinpath("download")
     os.mkdir(download_dir)
     file_path, content_type = download(link, download_dir)
     # The file should be downloaded to download_dir.
     actual = os.listdir(download_dir)
-    assert actual == ['out_dir_file']
+    assert actual == ["out_dir_file"]
     mock_raise_for_status.assert_called_once_with(resp)
 
 
@@ -121,14 +120,12 @@ def test_copy_source_tree_with_socket(clean_project, tmpdir, caplog):
     # Warning should have been logged.
     assert len(caplog.records) == 1
     record = caplog.records[0]
-    assert record.levelname == 'WARNING'
+    assert record.levelname == "WARNING"
     assert socket_path in record.message
 
 
 @pytest.mark.skipif("sys.platform == 'win32' or sys.version_info < (3,)")
-def test_copy_source_tree_with_socket_fails_with_no_socket_error(
-    clean_project, tmpdir
-):
+def test_copy_source_tree_with_socket_fails_with_no_socket_error(clean_project, tmpdir):
     target = tmpdir.joinpath("target")
     expected_files = get_filelist(clean_project)
     make_socket_file(clean_project.joinpath("aaa"))
@@ -166,10 +163,9 @@ def test_copy_source_tree_with_unreadable_dir_fails(clean_project, tmpdir):
 
 
 class Test_unpack_url(object):
-
     def prep(self, tmpdir, data):
-        self.build_dir = tmpdir.joinpath('build')
-        self.download_dir = tmpdir.joinpath('download')
+        self.build_dir = tmpdir.joinpath("build")
+        self.download_dir = tmpdir.joinpath("download")
         os.mkdir(self.build_dir)
         os.mkdir(self.download_dir)
         self.dist_file = "simple-1.0.tar.gz"
@@ -183,45 +179,45 @@ def prep(self, tmpdir, data):
     def test_unpack_url_no_download(self, tmpdir, data):
         self.prep(tmpdir, data)
         unpack_url(self.dist_url, self.build_dir, self.no_download)
-        assert os.path.isdir(os.path.join(self.build_dir, 'simple'))
-        assert not os.path.isfile(
-            os.path.join(self.download_dir, self.dist_file))
+        assert os.path.isdir(os.path.join(self.build_dir, "simple"))
+        assert not os.path.isfile(os.path.join(self.download_dir, self.dist_file))
 
-    def test_unpack_url_bad_hash(self, tmpdir, data,
-                                 monkeypatch):
+    def test_unpack_url_bad_hash(self, tmpdir, data, monkeypatch):
         """
         Test when the file url hash fragment is wrong
         """
         self.prep(tmpdir, data)
-        url = '{}#md5=bogus'.format(self.dist_url.url)
+        url = "{}#md5=bogus".format(self.dist_url.url)
         dist_url = Link(url)
         with pytest.raises(HashMismatch):
-            unpack_url(dist_url,
-                       self.build_dir,
-                       download=self.no_download,
-                       hashes=Hashes({'md5': ['bogus']}))
+            unpack_url(
+                dist_url,
+                self.build_dir,
+                download=self.no_download,
+                hashes=Hashes({"md5": ["bogus"]}),
+            )
 
     def test_unpack_url_thats_a_dir(self, tmpdir, data):
         self.prep(tmpdir, data)
         dist_path = data.packages.joinpath("FSPkg")
         dist_url = Link(path_to_url(dist_path))
-        unpack_url(dist_url, self.build_dir,
-                   download=self.no_download,
-                   download_dir=self.download_dir)
-        assert os.path.isdir(os.path.join(self.build_dir, 'fspkg'))
+        unpack_url(
+            dist_url,
+            self.build_dir,
+            download=self.no_download,
+            download_dir=self.download_dir,
+        )
+        assert os.path.isdir(os.path.join(self.build_dir, "fspkg"))
 
 
-@pytest.mark.parametrize('exclude_dir', [
-    '.nox',
-    '.tox'
-])
+@pytest.mark.parametrize("exclude_dir", [".nox", ".tox"])
 def test_unpack_url_excludes_expected_dirs(tmpdir, exclude_dir):
-    src_dir = tmpdir / 'src'
-    dst_dir = tmpdir / 'dst'
-    src_included_file = src_dir.joinpath('file.txt')
+    src_dir = tmpdir / "src"
+    dst_dir = tmpdir / "dst"
+    src_included_file = src_dir.joinpath("file.txt")
     src_excluded_dir = src_dir.joinpath(exclude_dir)
-    src_excluded_file = src_dir.joinpath(exclude_dir, 'file.txt')
-    src_included_dir = src_dir.joinpath('subdir', exclude_dir)
+    src_excluded_file = src_dir.joinpath(exclude_dir, "file.txt")
+    src_included_dir = src_dir.joinpath("subdir", exclude_dir)
 
     # set up source directory
     src_excluded_dir.mkdir(parents=True)
@@ -229,18 +225,13 @@ def test_unpack_url_excludes_expected_dirs(tmpdir, exclude_dir):
     src_included_file.touch()
     src_excluded_file.touch()
 
-    dst_included_file = dst_dir.joinpath('file.txt')
+    dst_included_file = dst_dir.joinpath("file.txt")
     dst_excluded_dir = dst_dir.joinpath(exclude_dir)
-    dst_excluded_file = dst_dir.joinpath(exclude_dir, 'file.txt')
-    dst_included_dir = dst_dir.joinpath('subdir', exclude_dir)
+    dst_excluded_file = dst_dir.joinpath(exclude_dir, "file.txt")
+    dst_included_dir = dst_dir.joinpath("subdir", exclude_dir)
 
     src_link = Link(path_to_url(src_dir))
-    unpack_url(
-        src_link,
-        dst_dir,
-        Mock(side_effect=AssertionError),
-        download_dir=None
-    )
+    unpack_url(src_link, dst_dir, Mock(side_effect=AssertionError), download_dir=None)
     assert not os.path.isdir(dst_excluded_dir)
     assert not os.path.isfile(dst_excluded_file)
     assert os.path.isfile(dst_included_file)
diff --git a/tests/unit/test_options.py b/tests/unit/test_options.py
index 533a4b8db3d..4f858b059cc 100644
--- a/tests/unit/test_options.py
+++ b/tests/unit/test_options.py
@@ -30,7 +30,7 @@ def assert_option_error(capsys, expected):
 def assert_is_default_cache_dir(value):
     # This path looks different on different platforms, but the path always
     # has the substring "pip".
-    assert 'pip' in value
+    assert "pip" in value
 
 
 class TestOptionPrecedence(AddFakeCommandMixin):
@@ -42,15 +42,15 @@ class TestOptionPrecedence(AddFakeCommandMixin):
 
     def get_config_section(self, section):
         config = {
-            'global': [('timeout', '-3')],
-            'fake': [('timeout', '-2')],
+            "global": [("timeout", "-3")],
+            "fake": [("timeout", "-2")],
         }
         return config[section]
 
     def get_config_section_global(self, section):
         config = {
-            'global': [('timeout', '-3')],
-            'fake': [],
+            "global": [("timeout", "-3")],
+            "fake": [],
         }
         return config[section]
 
@@ -58,106 +58,115 @@ def test_env_override_default_int(self, monkeypatch):
         """
         Test that environment variable overrides an int option default.
         """
-        monkeypatch.setenv('PIP_TIMEOUT', '-1')
-        options, args = main(['fake'])
+        monkeypatch.setenv("PIP_TIMEOUT", "-1")
+        options, args = main(["fake"])
         assert options.timeout == -1
 
-    @pytest.mark.parametrize('values', (['F1'], ['F1', 'F2']))
+    @pytest.mark.parametrize("values", (["F1"], ["F1", "F2"]))
     def test_env_override_default_append(self, values, monkeypatch):
         """
         Test that environment variable overrides an append option default.
         """
-        monkeypatch.setenv('PIP_FIND_LINKS', ' '.join(values))
-        options, args = main(['fake'])
+        monkeypatch.setenv("PIP_FIND_LINKS", " ".join(values))
+        options, args = main(["fake"])
         assert options.find_links == values
 
-    @pytest.mark.parametrize('choises', (['w'], ['s', 'w']))
+    @pytest.mark.parametrize("choises", (["w"], ["s", "w"]))
     def test_env_override_default_choice(self, choises, monkeypatch):
         """
         Test that environment variable overrides a choice option default.
         """
-        monkeypatch.setenv('PIP_EXISTS_ACTION', ' '.join(choises))
-        options, args = main(['fake'])
+        monkeypatch.setenv("PIP_EXISTS_ACTION", " ".join(choises))
+        options, args = main(["fake"])
         assert options.exists_action == choises
 
-    @pytest.mark.parametrize('name', ('PIP_LOG_FILE', 'PIP_LOCAL_LOG'))
+    @pytest.mark.parametrize("name", ("PIP_LOG_FILE", "PIP_LOCAL_LOG"))
     def test_env_alias_override_default(self, name, monkeypatch):
         """
         When an option has multiple long forms, test that the technique of
         using the env variable, "PIP_<long form>" works for all cases.
         (e.g. PIP_LOG_FILE and PIP_LOCAL_LOG should all work)
         """
-        monkeypatch.setenv(name, 'override.log')
-        options, args = main(['fake'])
-        assert options.log == 'override.log'
+        monkeypatch.setenv(name, "override.log")
+        options, args = main(["fake"])
+        assert options.log == "override.log"
 
     def test_cli_override_environment(self, monkeypatch):
         """
         Test the cli overrides and environment variable
         """
-        monkeypatch.setenv('PIP_TIMEOUT', '-1')
-        options, args = main(['fake', '--timeout', '-2'])
+        monkeypatch.setenv("PIP_TIMEOUT", "-1")
+        options, args = main(["fake", "--timeout", "-2"])
         assert options.timeout == -2
 
-    @pytest.mark.parametrize('pip_no_cache_dir', [
-        # Enabling --no-cache-dir means no cache directory.
-        '1',
-        'true',
-        'on',
-        'yes',
-        # For historical / backwards compatibility reasons, we also disable
-        # the cache directory if provided a value that translates to 0.
-        '0',
-        'false',
-        'off',
-        'no',
-    ])
+    @pytest.mark.parametrize(
+        "pip_no_cache_dir",
+        [
+            # Enabling --no-cache-dir means no cache directory.
+            "1",
+            "true",
+            "on",
+            "yes",
+            # For historical / backwards compatibility reasons, we also disable
+            # the cache directory if provided a value that translates to 0.
+            "0",
+            "false",
+            "off",
+            "no",
+        ],
+    )
     def test_cache_dir__PIP_NO_CACHE_DIR(self, pip_no_cache_dir, monkeypatch):
         """
         Test setting the PIP_NO_CACHE_DIR environment variable without
         passing any command-line flags.
         """
-        monkeypatch.setenv('PIP_NO_CACHE_DIR', pip_no_cache_dir)
-        options, args = main(['fake'])
+        monkeypatch.setenv("PIP_NO_CACHE_DIR", pip_no_cache_dir)
+        options, args = main(["fake"])
         assert options.cache_dir is False
 
-    @pytest.mark.parametrize('pip_no_cache_dir', ['yes', 'no'])
+    @pytest.mark.parametrize("pip_no_cache_dir", ["yes", "no"])
     def test_cache_dir__PIP_NO_CACHE_DIR__with_cache_dir(
-        self, pip_no_cache_dir, monkeypatch,
+        self,
+        pip_no_cache_dir,
+        monkeypatch,
     ):
         """
         Test setting PIP_NO_CACHE_DIR while also passing an explicit
         --cache-dir value.
         """
-        monkeypatch.setenv('PIP_NO_CACHE_DIR', pip_no_cache_dir)
-        options, args = main(['--cache-dir', '/cache/dir', 'fake'])
+        monkeypatch.setenv("PIP_NO_CACHE_DIR", pip_no_cache_dir)
+        options, args = main(["--cache-dir", "/cache/dir", "fake"])
         # The command-line flag takes precedence.
-        assert options.cache_dir == '/cache/dir'
+        assert options.cache_dir == "/cache/dir"
 
-    @pytest.mark.parametrize('pip_no_cache_dir', ['yes', 'no'])
+    @pytest.mark.parametrize("pip_no_cache_dir", ["yes", "no"])
     def test_cache_dir__PIP_NO_CACHE_DIR__with_no_cache_dir(
-        self, pip_no_cache_dir, monkeypatch,
+        self,
+        pip_no_cache_dir,
+        monkeypatch,
     ):
         """
         Test setting PIP_NO_CACHE_DIR while also passing --no-cache-dir.
         """
-        monkeypatch.setenv('PIP_NO_CACHE_DIR', pip_no_cache_dir)
-        options, args = main(['--no-cache-dir', 'fake'])
+        monkeypatch.setenv("PIP_NO_CACHE_DIR", pip_no_cache_dir)
+        options, args = main(["--no-cache-dir", "fake"])
         # The command-line flag should take precedence (which has the same
         # value in this case).
         assert options.cache_dir is False
 
     def test_cache_dir__PIP_NO_CACHE_DIR_invalid__with_no_cache_dir(
-            self, monkeypatch, capsys,
+        self,
+        monkeypatch,
+        capsys,
     ):
         """
         Test setting PIP_NO_CACHE_DIR to an invalid value while also passing
         --no-cache-dir.
         """
-        monkeypatch.setenv('PIP_NO_CACHE_DIR', 'maybe')
+        monkeypatch.setenv("PIP_NO_CACHE_DIR", "maybe")
         expected_err = "--no-cache-dir error: invalid truth value 'maybe'"
         with assert_option_error(capsys, expected=expected_err):
-            main(['--no-cache-dir', 'fake'])
+            main(["--no-cache-dir", "fake"])
 
 
 class TestUsePEP517Options(object):
@@ -169,7 +178,7 @@ class TestUsePEP517Options(object):
     def parse_args(self, args):
         # We use DownloadCommand since that is one of the few Command
         # classes with the use_pep517 options.
-        command = create_command('download')
+        command = create_command("download")
         options, args = command.parse_args(args)
 
         return options
@@ -185,21 +194,21 @@ def test_use_pep517(self):
         """
         Test passing --use-pep517.
         """
-        options = self.parse_args(['--use-pep517'])
+        options = self.parse_args(["--use-pep517"])
         assert options.use_pep517 is True
 
     def test_no_use_pep517(self):
         """
         Test passing --no-use-pep517.
         """
-        options = self.parse_args(['--no-use-pep517'])
+        options = self.parse_args(["--no-use-pep517"])
         assert options.use_pep517 is False
 
     def test_PIP_USE_PEP517_true(self, monkeypatch):
         """
         Test setting PIP_USE_PEP517 to "true".
         """
-        monkeypatch.setenv('PIP_USE_PEP517', 'true')
+        monkeypatch.setenv("PIP_USE_PEP517", "true")
         options = self.parse_args([])
         # This is an int rather than a boolean because strtobool() in pip's
         # configuration code returns an int.
@@ -209,7 +218,7 @@ def test_PIP_USE_PEP517_false(self, monkeypatch):
         """
         Test setting PIP_USE_PEP517 to "false".
         """
-        monkeypatch.setenv('PIP_USE_PEP517', 'false')
+        monkeypatch.setenv("PIP_USE_PEP517", "false")
         options = self.parse_args([])
         # This is an int rather than a boolean because strtobool() in pip's
         # configuration code returns an int.
@@ -219,50 +228,49 @@ def test_use_pep517_and_PIP_USE_PEP517_false(self, monkeypatch):
         """
         Test passing --use-pep517 and setting PIP_USE_PEP517 to "false".
         """
-        monkeypatch.setenv('PIP_USE_PEP517', 'false')
-        options = self.parse_args(['--use-pep517'])
+        monkeypatch.setenv("PIP_USE_PEP517", "false")
+        options = self.parse_args(["--use-pep517"])
         assert options.use_pep517 is True
 
     def test_no_use_pep517_and_PIP_USE_PEP517_true(self, monkeypatch):
         """
         Test passing --no-use-pep517 and setting PIP_USE_PEP517 to "true".
         """
-        monkeypatch.setenv('PIP_USE_PEP517', 'true')
-        options = self.parse_args(['--no-use-pep517'])
+        monkeypatch.setenv("PIP_USE_PEP517", "true")
+        options = self.parse_args(["--no-use-pep517"])
         assert options.use_pep517 is False
 
     def test_PIP_NO_USE_PEP517(self, monkeypatch, capsys):
         """
         Test setting PIP_NO_USE_PEP517, which isn't allowed.
         """
-        monkeypatch.setenv('PIP_NO_USE_PEP517', 'true')
-        with assert_option_error(capsys, expected='--no-use-pep517 error'):
+        monkeypatch.setenv("PIP_NO_USE_PEP517", "true")
+        with assert_option_error(capsys, expected="--no-use-pep517 error"):
             self.parse_args([])
 
 
 class TestOptionsInterspersed(AddFakeCommandMixin):
-
     def test_general_option_after_subcommand(self):
-        options, args = main(['fake', '--timeout', '-1'])
+        options, args = main(["fake", "--timeout", "-1"])
         assert options.timeout == -1
 
     def test_option_after_subcommand_arg(self):
-        options, args = main(['fake', 'arg', '--timeout', '-1'])
+        options, args = main(["fake", "arg", "--timeout", "-1"])
         assert options.timeout == -1
 
     def test_additive_before_after_subcommand(self):
-        options, args = main(['-v', 'fake', '-v'])
+        options, args = main(["-v", "fake", "-v"])
         assert options.verbose == 2
 
     def test_subcommand_option_before_subcommand_fails(self):
         with pytest.raises(SystemExit):
-            main(['--find-links', 'F1', 'fake'])
+            main(["--find-links", "F1", "fake"])
 
 
 @contextmanager
-def tmpconfig(option, value, section='global'):
-    with NamedTemporaryFile(mode='w', delete=False) as f:
-        f.write('[{}]\n{}={}\n'.format(section, option, value))
+def tmpconfig(option, value, section="global"):
+    with NamedTemporaryFile(mode="w", delete=False) as f:
+        f.write("[{}]\n{}={}\n".format(section, option, value))
         name = f.name
     try:
         yield name
@@ -271,93 +279,92 @@ def tmpconfig(option, value, section='global'):
 
 
 class TestCountOptions(AddFakeCommandMixin):
-
-    @pytest.mark.parametrize('option', ('verbose', 'quiet'))
-    @pytest.mark.parametrize('value', range(4))
+    @pytest.mark.parametrize("option", ("verbose", "quiet"))
+    @pytest.mark.parametrize("value", range(4))
     def test_cli_long(self, option, value):
-        flags = ['--{}'.format(option)] * value
-        opt1, args1 = main(flags+['fake'])
-        opt2, args2 = main(['fake']+flags)
+        flags = ["--{}".format(option)] * value
+        opt1, args1 = main(flags + ["fake"])
+        opt2, args2 = main(["fake"] + flags)
         assert getattr(opt1, option) == getattr(opt2, option) == value
 
-    @pytest.mark.parametrize('option', ('verbose', 'quiet'))
-    @pytest.mark.parametrize('value', range(1, 4))
+    @pytest.mark.parametrize("option", ("verbose", "quiet"))
+    @pytest.mark.parametrize("value", range(1, 4))
     def test_cli_short(self, option, value):
-        flag = '-' + option[0]*value
-        opt1, args1 = main([flag, 'fake'])
-        opt2, args2 = main(['fake', flag])
+        flag = "-" + option[0] * value
+        opt1, args1 = main([flag, "fake"])
+        opt2, args2 = main(["fake", flag])
         assert getattr(opt1, option) == getattr(opt2, option) == value
 
-    @pytest.mark.parametrize('option', ('verbose', 'quiet'))
-    @pytest.mark.parametrize('value', range(4))
+    @pytest.mark.parametrize("option", ("verbose", "quiet"))
+    @pytest.mark.parametrize("value", range(4))
     def test_env_var(self, option, value, monkeypatch):
-        monkeypatch.setenv('PIP_'+option.upper(), str(value))
-        assert getattr(main(['fake'])[0], option) == value
+        monkeypatch.setenv("PIP_" + option.upper(), str(value))
+        assert getattr(main(["fake"])[0], option) == value
 
-    @pytest.mark.parametrize('option', ('verbose', 'quiet'))
-    @pytest.mark.parametrize('value', range(3))
+    @pytest.mark.parametrize("option", ("verbose", "quiet"))
+    @pytest.mark.parametrize("value", range(3))
     def test_env_var_integrate_cli(self, option, value, monkeypatch):
-        monkeypatch.setenv('PIP_'+option.upper(), str(value))
-        assert getattr(main(['fake', '--'+option])[0], option) == value + 1
+        monkeypatch.setenv("PIP_" + option.upper(), str(value))
+        assert getattr(main(["fake", "--" + option])[0], option) == value + 1
 
-    @pytest.mark.parametrize('option', ('verbose', 'quiet'))
-    @pytest.mark.parametrize('value', (-1, 'foobar'))
+    @pytest.mark.parametrize("option", ("verbose", "quiet"))
+    @pytest.mark.parametrize("value", (-1, "foobar"))
     def test_env_var_invalid(self, option, value, monkeypatch, capsys):
-        monkeypatch.setenv('PIP_'+option.upper(), str(value))
-        with assert_option_error(capsys, expected='a non-negative integer'):
-            main(['fake'])
+        monkeypatch.setenv("PIP_" + option.upper(), str(value))
+        with assert_option_error(capsys, expected="a non-negative integer"):
+            main(["fake"])
 
     # Undocumented, support for backward compatibility
-    @pytest.mark.parametrize('option', ('verbose', 'quiet'))
-    @pytest.mark.parametrize('value', ('no', 'false'))
+    @pytest.mark.parametrize("option", ("verbose", "quiet"))
+    @pytest.mark.parametrize("value", ("no", "false"))
     def test_env_var_false(self, option, value, monkeypatch):
-        monkeypatch.setenv('PIP_'+option.upper(), str(value))
-        assert getattr(main(['fake'])[0], option) == 0
+        monkeypatch.setenv("PIP_" + option.upper(), str(value))
+        assert getattr(main(["fake"])[0], option) == 0
 
     # Undocumented, support for backward compatibility
-    @pytest.mark.parametrize('option', ('verbose', 'quiet'))
-    @pytest.mark.parametrize('value', ('yes', 'true'))
+    @pytest.mark.parametrize("option", ("verbose", "quiet"))
+    @pytest.mark.parametrize("value", ("yes", "true"))
     def test_env_var_true(self, option, value, monkeypatch):
-        monkeypatch.setenv('PIP_'+option.upper(), str(value))
-        assert getattr(main(['fake'])[0], option) == 1
+        monkeypatch.setenv("PIP_" + option.upper(), str(value))
+        assert getattr(main(["fake"])[0], option) == 1
 
-    @pytest.mark.parametrize('option', ('verbose', 'quiet'))
-    @pytest.mark.parametrize('value', range(4))
+    @pytest.mark.parametrize("option", ("verbose", "quiet"))
+    @pytest.mark.parametrize("value", range(4))
     def test_config_file(self, option, value, monkeypatch):
         with tmpconfig(option, value) as name:
-            monkeypatch.setenv('PIP_CONFIG_FILE', name)
-            assert getattr(main(['fake'])[0], option) == value
+            monkeypatch.setenv("PIP_CONFIG_FILE", name)
+            assert getattr(main(["fake"])[0], option) == value
 
-    @pytest.mark.parametrize('option', ('verbose', 'quiet'))
-    @pytest.mark.parametrize('value', range(3))
+    @pytest.mark.parametrize("option", ("verbose", "quiet"))
+    @pytest.mark.parametrize("value", range(3))
     def test_config_file_integrate_cli(self, option, value, monkeypatch):
         with tmpconfig(option, value) as name:
-            monkeypatch.setenv('PIP_CONFIG_FILE', name)
-            assert getattr(main(['fake', '--'+option])[0], option) == value + 1
+            monkeypatch.setenv("PIP_CONFIG_FILE", name)
+            assert getattr(main(["fake", "--" + option])[0], option) == value + 1
 
-    @pytest.mark.parametrize('option', ('verbose', 'quiet'))
-    @pytest.mark.parametrize('value', (-1, 'foobar'))
+    @pytest.mark.parametrize("option", ("verbose", "quiet"))
+    @pytest.mark.parametrize("value", (-1, "foobar"))
     def test_config_file_invalid(self, option, value, monkeypatch, capsys):
         with tmpconfig(option, value) as name:
-            monkeypatch.setenv('PIP_CONFIG_FILE', name)
-            with assert_option_error(capsys, expected='non-negative integer'):
-                main(['fake'])
+            monkeypatch.setenv("PIP_CONFIG_FILE", name)
+            with assert_option_error(capsys, expected="non-negative integer"):
+                main(["fake"])
 
     # Undocumented, support for backward compatibility
-    @pytest.mark.parametrize('option', ('verbose', 'quiet'))
-    @pytest.mark.parametrize('value', ('no', 'false'))
+    @pytest.mark.parametrize("option", ("verbose", "quiet"))
+    @pytest.mark.parametrize("value", ("no", "false"))
     def test_config_file_false(self, option, value, monkeypatch):
         with tmpconfig(option, value) as name:
-            monkeypatch.setenv('PIP_CONFIG_FILE', name)
-            assert getattr(main(['fake'])[0], option) == 0
+            monkeypatch.setenv("PIP_CONFIG_FILE", name)
+            assert getattr(main(["fake"])[0], option) == 0
 
     # Undocumented, support for backward compatibility
-    @pytest.mark.parametrize('option', ('verbose', 'quiet'))
-    @pytest.mark.parametrize('value', ('yes', 'true'))
+    @pytest.mark.parametrize("option", ("verbose", "quiet"))
+    @pytest.mark.parametrize("value", ("yes", "true"))
     def test_config_file_true(self, option, value, monkeypatch):
         with tmpconfig(option, value) as name:
-            monkeypatch.setenv('PIP_CONFIG_FILE', name)
-            assert getattr(main(['fake'])[0], option) == 1
+            monkeypatch.setenv("PIP_CONFIG_FILE", name)
+            assert getattr(main(["fake"])[0], option) == 1
 
 
 class TestGeneralOptions(AddFakeCommandMixin):
@@ -366,78 +373,76 @@ class TestGeneralOptions(AddFakeCommandMixin):
     # extra processing they receive, and the number of bugs we've had
 
     def test_cache_dir__default(self):
-        options, args = main(['fake'])
+        options, args = main(["fake"])
         # With no options the default cache dir should be used.
         assert_is_default_cache_dir(options.cache_dir)
 
     def test_cache_dir__provided(self):
-        options, args = main(['--cache-dir', '/cache/dir', 'fake'])
-        assert options.cache_dir == '/cache/dir'
+        options, args = main(["--cache-dir", "/cache/dir", "fake"])
+        assert options.cache_dir == "/cache/dir"
 
     def test_no_cache_dir__provided(self):
-        options, args = main(['--no-cache-dir', 'fake'])
+        options, args = main(["--no-cache-dir", "fake"])
         assert options.cache_dir is False
 
     def test_require_virtualenv(self):
-        options1, args1 = main(['--require-virtualenv', 'fake'])
-        options2, args2 = main(['fake', '--require-virtualenv'])
+        options1, args1 = main(["--require-virtualenv", "fake"])
+        options2, args2 = main(["fake", "--require-virtualenv"])
         assert options1.require_venv
         assert options2.require_venv
 
     def test_log(self):
-        options1, args1 = main(['--log', 'path', 'fake'])
-        options2, args2 = main(['fake', '--log', 'path'])
-        assert options1.log == options2.log == 'path'
+        options1, args1 = main(["--log", "path", "fake"])
+        options2, args2 = main(["fake", "--log", "path"])
+        assert options1.log == options2.log == "path"
 
     def test_local_log(self):
-        options1, args1 = main(['--local-log', 'path', 'fake'])
-        options2, args2 = main(['fake', '--local-log', 'path'])
-        assert options1.log == options2.log == 'path'
+        options1, args1 = main(["--local-log", "path", "fake"])
+        options2, args2 = main(["fake", "--local-log", "path"])
+        assert options1.log == options2.log == "path"
 
     def test_no_input(self):
-        options1, args1 = main(['--no-input', 'fake'])
-        options2, args2 = main(['fake', '--no-input'])
+        options1, args1 = main(["--no-input", "fake"])
+        options2, args2 = main(["fake", "--no-input"])
         assert options1.no_input
         assert options2.no_input
 
     def test_proxy(self):
-        options1, args1 = main(['--proxy', 'path', 'fake'])
-        options2, args2 = main(['fake', '--proxy', 'path'])
-        assert options1.proxy == options2.proxy == 'path'
+        options1, args1 = main(["--proxy", "path", "fake"])
+        options2, args2 = main(["fake", "--proxy", "path"])
+        assert options1.proxy == options2.proxy == "path"
 
     def test_retries(self):
-        options1, args1 = main(['--retries', '-1', 'fake'])
-        options2, args2 = main(['fake', '--retries', '-1'])
+        options1, args1 = main(["--retries", "-1", "fake"])
+        options2, args2 = main(["fake", "--retries", "-1"])
         assert options1.retries == options2.retries == -1
 
     def test_timeout(self):
-        options1, args1 = main(['--timeout', '-1', 'fake'])
-        options2, args2 = main(['fake', '--timeout', '-1'])
+        options1, args1 = main(["--timeout", "-1", "fake"])
+        options2, args2 = main(["fake", "--timeout", "-1"])
         assert options1.timeout == options2.timeout == -1
 
     def test_exists_action(self):
-        options1, args1 = main(['--exists-action', 'w', 'fake'])
-        options2, args2 = main(['fake', '--exists-action', 'w'])
-        assert options1.exists_action == options2.exists_action == ['w']
+        options1, args1 = main(["--exists-action", "w", "fake"])
+        options2, args2 = main(["fake", "--exists-action", "w"])
+        assert options1.exists_action == options2.exists_action == ["w"]
 
     def test_cert(self):
-        options1, args1 = main(['--cert', 'path', 'fake'])
-        options2, args2 = main(['fake', '--cert', 'path'])
-        assert options1.cert == options2.cert == 'path'
+        options1, args1 = main(["--cert", "path", "fake"])
+        options2, args2 = main(["fake", "--cert", "path"])
+        assert options1.cert == options2.cert == "path"
 
     def test_client_cert(self):
-        options1, args1 = main(['--client-cert', 'path', 'fake'])
-        options2, args2 = main(['fake', '--client-cert', 'path'])
-        assert options1.client_cert == options2.client_cert == 'path'
+        options1, args1 = main(["--client-cert", "path", "fake"])
+        options2, args2 = main(["fake", "--client-cert", "path"])
+        assert options1.client_cert == options2.client_cert == "path"
 
 
 class TestOptionsConfigFiles(object):
-
     def test_venv_config_file_found(self, monkeypatch):
         # strict limit on the global config files list
         monkeypatch.setattr(
-            pip._internal.utils.appdirs, 'site_config_dirs',
-            lambda _: ['/a/place']
+            pip._internal.utils.appdirs, "site_config_dirs", lambda _: ["/a/place"]
         )
 
         cp = pip._internal.configuration.Configuration(isolated=False)
@@ -458,10 +463,10 @@ def test_venv_config_file_found(self, monkeypatch):
             (["--global", "--user"], PipError),
             (["--global", "--site"], PipError),
             (["--global", "--site", "--user"], PipError),
-        )
+        ),
     )
     def test_config_file_options(self, monkeypatch, args, expect):
-        cmd = create_command('config')
+        cmd = create_command("config")
         # Replace a handler with a no-op to avoid side effects
         monkeypatch.setattr(cmd, "get_name", lambda *a: None)
 
@@ -475,21 +480,21 @@ def test_config_file_options(self, monkeypatch, args, expect):
 
 class TestOptionsExpandUser(AddFakeCommandMixin):
     def test_cache_dir(self):
-        options, args = main(['--cache-dir', '~/cache/dir', 'fake'])
-        assert options.cache_dir == os.path.expanduser('~/cache/dir')
+        options, args = main(["--cache-dir", "~/cache/dir", "fake"])
+        assert options.cache_dir == os.path.expanduser("~/cache/dir")
 
     def test_log(self):
-        options, args = main(['--log', '~/path', 'fake'])
-        assert options.log == os.path.expanduser('~/path')
+        options, args = main(["--log", "~/path", "fake"])
+        assert options.log == os.path.expanduser("~/path")
 
     def test_local_log(self):
-        options, args = main(['--local-log', '~/path', 'fake'])
-        assert options.log == os.path.expanduser('~/path')
+        options, args = main(["--local-log", "~/path", "fake"])
+        assert options.log == os.path.expanduser("~/path")
 
     def test_cert(self):
-        options, args = main(['--cert', '~/path', 'fake'])
-        assert options.cert == os.path.expanduser('~/path')
+        options, args = main(["--cert", "~/path", "fake"])
+        assert options.cert == os.path.expanduser("~/path")
 
     def test_client_cert(self):
-        options, args = main(['--client-cert', '~/path', 'fake'])
-        assert options.client_cert == os.path.expanduser('~/path')
+        options, args = main(["--client-cert", "~/path", "fake"])
+        assert options.client_cert == os.path.expanduser("~/path")
diff --git a/tests/unit/test_packaging.py b/tests/unit/test_packaging.py
index 448e3806300..2386083dbd1 100644
--- a/tests/unit/test_packaging.py
+++ b/tests/unit/test_packaging.py
@@ -4,11 +4,14 @@
 from pip._internal.utils.packaging import check_requires_python
 
 
-@pytest.mark.parametrize('version_info, requires_python, expected', [
-    ((3, 6, 5), '== 3.6.4', False),
-    ((3, 6, 5), '== 3.6.5', True),
-    ((3, 6, 5), None, True),
-])
+@pytest.mark.parametrize(
+    "version_info, requires_python, expected",
+    [
+        ((3, 6, 5), "== 3.6.4", False),
+        ((3, 6, 5), "== 3.6.5", True),
+        ((3, 6, 5), None, True),
+    ],
+)
 def test_check_requires_python(version_info, requires_python, expected):
     actual = check_requires_python(requires_python, version_info)
     assert actual == expected
@@ -19,4 +22,4 @@ def test_check_requires_python__invalid():
     Test an invalid Requires-Python value.
     """
     with pytest.raises(specifiers.InvalidSpecifier):
-        check_requires_python('invalid', (3, 6, 5))
+        check_requires_python("invalid", (3, 6, 5))
diff --git a/tests/unit/test_pep517.py b/tests/unit/test_pep517.py
index 18cb178bba7..2242cf92d71 100644
--- a/tests/unit/test_pep517.py
+++ b/tests/unit/test_pep517.py
@@ -6,11 +6,14 @@
 from pip._internal.req import InstallRequirement
 
 
-@pytest.mark.parametrize(('source', 'expected'), [
-    ("pep517_setup_and_pyproject", True),
-    ("pep517_setup_only", False),
-    ("pep517_pyproject_only", True),
-])
+@pytest.mark.parametrize(
+    ("source", "expected"),
+    [
+        ("pep517_setup_and_pyproject", True),
+        ("pep517_setup_only", False),
+        ("pep517_pyproject_only", True),
+    ],
+)
 def test_use_pep517(shared_data, source, expected):
     """
     Test that we choose correctly between PEP 517 and legacy code paths
@@ -22,10 +25,13 @@ def test_use_pep517(shared_data, source, expected):
     assert req.use_pep517 is expected
 
 
-@pytest.mark.parametrize(('source', 'msg'), [
-    ("pep517_setup_and_pyproject", "specifies a build backend"),
-    ("pep517_pyproject_only", "does not have a setup.py"),
-])
+@pytest.mark.parametrize(
+    ("source", "msg"),
+    [
+        ("pep517_setup_and_pyproject", "specifies a build backend"),
+        ("pep517_pyproject_only", "does not have a setup.py"),
+    ],
+)
 def test_disabling_pep517_invalid(shared_data, source, msg):
     """
     Test that we fail if we try to disable PEP 517 when it's not acceptable
@@ -49,13 +55,17 @@ def test_disabling_pep517_invalid(shared_data, source, msg):
     ("spec",), [("./foo",), ("git+https://example.com/pkg@dev#egg=myproj",)]
 )
 def test_pep517_parsing_checks_requirements(tmpdir, spec):
-    tmpdir.joinpath("pyproject.toml").write_text(dedent(
-        """
+    tmpdir.joinpath("pyproject.toml").write_text(
+        dedent(
+            """
         [build-system]
         requires = [{!r}]
         build-backend = "foo"
-        """.format(spec)
-    ))
+        """.format(
+                spec
+            )
+        )
+    )
     req = InstallRequirement(None, None)
     req.source_dir = tmpdir  # make req believe it has been unpacked
 
diff --git a/tests/unit/test_req.py b/tests/unit/test_req.py
index 730a26a88d5..e7e060ed904 100644
--- a/tests/unit/test_req.py
+++ b/tests/unit/test_req.py
@@ -41,7 +41,7 @@
 from tests.lib import assert_raises_regexp, make_test_finder, requirements_file
 
 
-def get_processed_req_from_line(line, fname='file', lineno=1):
+def get_processed_req_from_line(line, fname="file", lineno=1):
     line_parser = get_line_parser(None)
     args_str, opts = line_parser(line)
     parsed_line = ParsedLine(
@@ -79,14 +79,14 @@ def _basic_resolver(self, finder, require_hashes=False):
 
         with get_requirement_tracker() as tracker:
             preparer = RequirementPreparer(
-                build_dir=os.path.join(self.tempdir, 'build'),
-                src_dir=os.path.join(self.tempdir, 'src'),
+                build_dir=os.path.join(self.tempdir, "build"),
+                src_dir=os.path.join(self.tempdir, "src"),
                 download_dir=None,
                 wheel_download_dir=None,
                 build_isolation=True,
                 req_tracker=tracker,
                 session=session,
-                progress_bar='on',
+                progress_bar="on",
                 finder=finder,
                 require_hashes=require_hashes,
                 use_user_site=False,
@@ -97,29 +97,32 @@ def _basic_resolver(self, finder, require_hashes=False):
                 make_install_req=make_install_req,
                 finder=finder,
                 wheel_cache=None,
-                use_user_site=False, upgrade_strategy="to-satisfy-only",
-                ignore_dependencies=False, ignore_installed=False,
-                ignore_requires_python=False, force_reinstall=False,
+                use_user_site=False,
+                upgrade_strategy="to-satisfy-only",
+                ignore_dependencies=False,
+                ignore_installed=False,
+                ignore_requires_python=False,
+                force_reinstall=False,
             )
 
     def test_no_reuse_existing_build_dir(self, data):
         """Test prepare_files raise exception with previous build dir"""
 
-        build_dir = os.path.join(self.tempdir, 'build', 'simple')
+        build_dir = os.path.join(self.tempdir, "build", "simple")
         os.makedirs(build_dir)
-        with open(os.path.join(build_dir, "setup.py"), 'w'):
+        with open(os.path.join(build_dir, "setup.py"), "w"):
             pass
         reqset = RequirementSet()
-        req = install_req_from_line('simple')
+        req = install_req_from_line("simple")
         req.user_supplied = True
         reqset.add_requirement(req)
         finder = make_test_finder(find_links=[data.find_links])
         with self._basic_resolver(finder) as resolver:
             assert_raises_regexp(
                 PreviousBuildDirError,
-                r"pip can't proceed with [\s\S]*{req}[\s\S]*{build_dir_esc}"
-                .format(
-                    build_dir_esc=build_dir.replace('\\', '\\\\'), req=req),
+                r"pip can't proceed with [\s\S]*{req}[\s\S]*{build_dir_esc}".format(
+                    build_dir_esc=build_dir.replace("\\", "\\\\"), req=req
+                ),
                 resolver.resolve,
                 reqset.all_requirements,
                 True,
@@ -132,9 +135,7 @@ def test_environment_marker_extras(self, data):
         non-wheel installs.
         """
         reqset = RequirementSet()
-        req = install_req_from_editable(
-            data.packages.joinpath("LocalEnvironMarker")
-        )
+        req = install_req_from_editable(data.packages.joinpath("LocalEnvironMarker"))
         req.user_supplied = True
         reqset.add_requirement(req)
         finder = make_test_finder(find_links=[data.find_links])
@@ -142,28 +143,26 @@ def test_environment_marker_extras(self, data):
             reqset = resolver.resolve(reqset.all_requirements, True)
         # This is hacky but does test both case in py2 and py3
         if sys.version_info[:2] == (2, 7):
-            assert reqset.has_requirement('simple')
+            assert reqset.has_requirement("simple")
         else:
-            assert not reqset.has_requirement('simple')
+            assert not reqset.has_requirement("simple")
 
     def test_missing_hash_with_require_hashes(self, data):
         """Setting --require-hashes explicitly should raise errors if hashes
         are missing.
         """
         reqset = RequirementSet()
-        reqset.add_requirement(get_processed_req_from_line(
-            'simple==1.0', lineno=1
-        ))
+        reqset.add_requirement(get_processed_req_from_line("simple==1.0", lineno=1))
 
         finder = make_test_finder(find_links=[data.find_links])
 
         with self._basic_resolver(finder, require_hashes=True) as resolver:
             assert_raises_regexp(
                 HashErrors,
-                r'Hashes are required in --require-hashes mode, but they are '
-                r'missing .*\n'
-                r'    simple==1.0 --hash=sha256:393043e672415891885c9a2a0929b1'
-                r'af95fb866d6ca016b42d2e6ce53619b653$',
+                r"Hashes are required in --require-hashes mode, but they are "
+                r"missing .*\n"
+                r"    simple==1.0 --hash=sha256:393043e672415891885c9a2a0929b1"
+                r"af95fb866d6ca016b42d2e6ce53619b653$",
                 resolver.resolve,
                 reqset.all_requirements,
                 True,
@@ -175,9 +174,9 @@ def test_missing_hash_with_require_hashes_in_reqs_file(self, data, tmpdir):
         """
         finder = make_test_finder(find_links=[data.find_links])
         session = finder._link_collector.session
-        command = create_command('install')
-        with requirements_file('--require-hashes', tmpdir) as reqs_file:
-            options, args = command.parse_args(['-r', reqs_file])
+        command = create_command("install")
+        with requirements_file("--require-hashes", tmpdir) as reqs_file:
+            options, args = command.parse_args(["-r", reqs_file])
             command.get_requirements(args, options, finder, session)
         assert options.require_hashes
 
@@ -190,20 +189,24 @@ def test_unsupported_hashes(self, data):
 
         """
         reqset = RequirementSet()
-        reqset.add_requirement(get_processed_req_from_line(
-            'git+git://github.com/pypa/pip-test-package --hash=sha256:123',
-            lineno=1,
-        ))
-        dir_path = data.packages.joinpath('FSPkg')
-        reqset.add_requirement(get_processed_req_from_line(
-            'file://{dir_path}'.format(**locals()),
-            lineno=2,
-        ))
+        reqset.add_requirement(
+            get_processed_req_from_line(
+                "git+git://github.com/pypa/pip-test-package --hash=sha256:123",
+                lineno=1,
+            )
+        )
+        dir_path = data.packages.joinpath("FSPkg")
+        reqset.add_requirement(
+            get_processed_req_from_line(
+                "file://{dir_path}".format(**locals()),
+                lineno=2,
+            )
+        )
         finder = make_test_finder(find_links=[data.find_links])
 
         sep = os.path.sep
-        if sep == '\\':
-            sep = '\\\\'  # This needs to be escaped for the regex
+        if sep == "\\":
+            sep = "\\\\"  # This needs to be escaped for the regex
 
         with self._basic_resolver(finder, require_hashes=True) as resolver:
             assert_raises_regexp(
@@ -227,24 +230,29 @@ def test_unpinned_hash_checking(self, data):
         """
         reqset = RequirementSet()
         # Test that there must be exactly 1 specifier:
-        reqset.add_requirement(get_processed_req_from_line(
-            'simple --hash=sha256:a90427ae31f5d1d0d7ec06ee97d9fcf2d0fc9a786985'
-            '250c1c83fd68df5911dd', lineno=1,
-        ))
+        reqset.add_requirement(
+            get_processed_req_from_line(
+                "simple --hash=sha256:a90427ae31f5d1d0d7ec06ee97d9fcf2d0fc9a786985"
+                "250c1c83fd68df5911dd",
+                lineno=1,
+            )
+        )
         # Test that the operator must be ==:
-        reqset.add_requirement(get_processed_req_from_line(
-            'simple2>1.0 --hash=sha256:3ad45e1e9aa48b4462af0'
-            '123f6a7e44a9115db1ef945d4d92c123dfe21815a06',
-            lineno=2,
-        ))
+        reqset.add_requirement(
+            get_processed_req_from_line(
+                "simple2>1.0 --hash=sha256:3ad45e1e9aa48b4462af0"
+                "123f6a7e44a9115db1ef945d4d92c123dfe21815a06",
+                lineno=2,
+            )
+        )
         finder = make_test_finder(find_links=[data.find_links])
         with self._basic_resolver(finder, require_hashes=True) as resolver:
             assert_raises_regexp(
                 HashErrors,
                 # Make sure all failing requirements are listed:
-                r'versions pinned with ==. These do not:\n'
-                r'    simple .* \(from -r file \(line 1\)\)\n'
-                r'    simple2>1.0 .* \(from -r file \(line 2\)\)',
+                r"versions pinned with ==. These do not:\n"
+                r"    simple .* \(from -r file \(line 1\)\)\n"
+                r"    simple2>1.0 .* \(from -r file \(line 2\)\)",
                 resolver.resolve,
                 reqset.all_requirements,
                 True,
@@ -252,21 +260,23 @@ def test_unpinned_hash_checking(self, data):
 
     def test_hash_mismatch(self, data):
         """A hash mismatch should raise an error."""
-        file_url = path_to_url(
-            (data.packages / 'simple-1.0.tar.gz').resolve())
+        file_url = path_to_url((data.packages / "simple-1.0.tar.gz").resolve())
         reqset = RequirementSet()
-        reqset.add_requirement(get_processed_req_from_line(
-            '{file_url} --hash=sha256:badbad'.format(**locals()), lineno=1,
-        ))
+        reqset.add_requirement(
+            get_processed_req_from_line(
+                "{file_url} --hash=sha256:badbad".format(**locals()),
+                lineno=1,
+            )
+        )
         finder = make_test_finder(find_links=[data.find_links])
         with self._basic_resolver(finder, require_hashes=True) as resolver:
             assert_raises_regexp(
                 HashErrors,
-                r'THESE PACKAGES DO NOT MATCH THE HASHES.*\n'
-                r'    file:///.*/data/packages/simple-1\.0\.tar\.gz .*:\n'
-                r'        Expected sha256 badbad\n'
-                r'             Got        393043e672415891885c9a2a0929b1af95fb'
-                r'866d6ca016b42d2e6ce53619b653$',
+                r"THESE PACKAGES DO NOT MATCH THE HASHES.*\n"
+                r"    file:///.*/data/packages/simple-1\.0\.tar\.gz .*:\n"
+                r"        Expected sha256 badbad\n"
+                r"             Got        393043e672415891885c9a2a0929b1af95fb"
+                r"866d6ca016b42d2e6ce53619b653$",
                 resolver.resolve,
                 reqset.all_requirements,
                 True,
@@ -277,19 +287,21 @@ def test_unhashed_deps_on_require_hashes(self, data):
         dependencies get complained about when --require-hashes is on."""
         reqset = RequirementSet()
         finder = make_test_finder(find_links=[data.find_links])
-        reqset.add_requirement(get_processed_req_from_line(
-            'TopoRequires2==0.0.1 '  # requires TopoRequires
-            '--hash=sha256:eaf9a01242c9f2f42cf2bd82a6a848cd'
-            'e3591d14f7896bdbefcf48543720c970',
-            lineno=1
-        ))
+        reqset.add_requirement(
+            get_processed_req_from_line(
+                "TopoRequires2==0.0.1 "  # requires TopoRequires
+                "--hash=sha256:eaf9a01242c9f2f42cf2bd82a6a848cd"
+                "e3591d14f7896bdbefcf48543720c970",
+                lineno=1,
+            )
+        )
 
         with self._basic_resolver(finder, require_hashes=True) as resolver:
             assert_raises_regexp(
                 HashErrors,
-                r'In --require-hashes mode, all requirements must have their '
-                r'versions pinned.*\n'
-                r'    TopoRequires from .*$',
+                r"In --require-hashes mode, all requirements must have their "
+                r"versions pinned.*\n"
+                r"    TopoRequires from .*$",
                 resolver.resolve,
                 reqset.all_requirements,
                 True,
@@ -305,18 +317,22 @@ def test_hashed_deps_on_require_hashes(self):
 
         """
         reqset = RequirementSet()
-        reqset.add_requirement(get_processed_req_from_line(
-            'TopoRequires2==0.0.1 '  # requires TopoRequires
-            '--hash=sha256:eaf9a01242c9f2f42cf2bd82a6a848cd'
-            'e3591d14f7896bdbefcf48543720c970',
-            lineno=1
-        ))
-        reqset.add_requirement(get_processed_req_from_line(
-            'TopoRequires==0.0.1 '
-            '--hash=sha256:d6dd1e22e60df512fdcf3640ced3039b3b02a56ab2cee81ebcb'
-            '3d0a6d4e8bfa6',
-            lineno=2
-        ))
+        reqset.add_requirement(
+            get_processed_req_from_line(
+                "TopoRequires2==0.0.1 "  # requires TopoRequires
+                "--hash=sha256:eaf9a01242c9f2f42cf2bd82a6a848cd"
+                "e3591d14f7896bdbefcf48543720c970",
+                lineno=1,
+            )
+        )
+        reqset.add_requirement(
+            get_processed_req_from_line(
+                "TopoRequires==0.0.1 "
+                "--hash=sha256:d6dd1e22e60df512fdcf3640ced3039b3b02a56ab2cee81ebcb"
+                "3d0a6d4e8bfa6",
+                lineno=2,
+            )
+        )
 
 
 class TestInstallRequirement(object):
@@ -328,32 +344,32 @@ def teardown(self):
 
     def test_url_with_query(self):
         """InstallRequirement should strip the fragment, but not the query."""
-        url = 'http://foo.com/?p=bar.git;a=snapshot;h=v0.1;sf=tgz'
-        fragment = '#egg=bar'
+        url = "http://foo.com/?p=bar.git;a=snapshot;h=v0.1;sf=tgz"
+        fragment = "#egg=bar"
         req = install_req_from_line(url + fragment)
         assert req.link.url == url + fragment, req.link
 
     def test_pep440_wheel_link_requirement(self):
-        url = 'https://whatever.com/test-0.4-py2.py3-bogus-any.whl'
-        line = 'test @ https://whatever.com/test-0.4-py2.py3-bogus-any.whl'
+        url = "https://whatever.com/test-0.4-py2.py3-bogus-any.whl"
+        line = "test @ https://whatever.com/test-0.4-py2.py3-bogus-any.whl"
         req = install_req_from_line(line)
-        parts = str(req.req).split('@', 1)
+        parts = str(req.req).split("@", 1)
         assert len(parts) == 2
-        assert parts[0].strip() == 'test'
+        assert parts[0].strip() == "test"
         assert parts[1].strip() == url
 
     def test_pep440_url_link_requirement(self):
-        url = 'git+http://foo.com@ref#egg=foo'
-        line = 'foo @ git+http://foo.com@ref#egg=foo'
+        url = "git+http://foo.com@ref#egg=foo"
+        line = "foo @ git+http://foo.com@ref#egg=foo"
         req = install_req_from_line(line)
-        parts = str(req.req).split('@', 1)
+        parts = str(req.req).split("@", 1)
         assert len(parts) == 2
-        assert parts[0].strip() == 'foo'
+        assert parts[0].strip() == "foo"
         assert parts[1].strip() == url
 
     def test_url_with_authentication_link_requirement(self):
-        url = 'https://what@whatever.com/test-0.4-py2.py3-bogus-any.whl'
-        line = 'https://what@whatever.com/test-0.4-py2.py3-bogus-any.whl'
+        url = "https://what@whatever.com/test-0.4-py2.py3-bogus-any.whl"
+        line = "https://what@whatever.com/test-0.4-py2.py3-bogus-any.whl"
         req = install_req_from_line(line)
         assert req.link is not None
         assert req.link.is_wheel
@@ -363,7 +379,7 @@ def test_url_with_authentication_link_requirement(self):
     def test_unsupported_wheel_link_requirement_raises(self):
         reqset = RequirementSet()
         req = install_req_from_line(
-            'https://whatever.com/peppercorn-0.4-py2.py3-bogus-any.whl',
+            "https://whatever.com/peppercorn-0.4-py2.py3-bogus-any.whl",
         )
         assert req.link is not None
         assert req.link.is_wheel
@@ -375,7 +391,7 @@ def test_unsupported_wheel_link_requirement_raises(self):
     def test_unsupported_wheel_local_file_requirement_raises(self, data):
         reqset = RequirementSet()
         req = install_req_from_line(
-            data.packages.joinpath('simple.dist-0.1-py1-none-invalid.whl'),
+            data.packages.joinpath("simple.dist-0.1-py1-none-invalid.whl"),
         )
         assert req.link is not None
         assert req.link.is_wheel
@@ -385,52 +401,53 @@ def test_unsupported_wheel_local_file_requirement_raises(self, data):
             reqset.add_requirement(req)
 
     def test_installed_version_not_installed(self):
-        req = install_req_from_line('simple-0.1-py2.py3-none-any.whl')
+        req = install_req_from_line("simple-0.1-py2.py3-none-any.whl")
         assert req.installed_version is None
 
     def test_str(self):
-        req = install_req_from_line('simple==0.1')
-        assert str(req) == 'simple==0.1'
+        req = install_req_from_line("simple==0.1")
+        assert str(req) == "simple==0.1"
 
     def test_repr(self):
-        req = install_req_from_line('simple==0.1')
-        assert repr(req) == (
-            '<InstallRequirement object: simple==0.1 editable=False>'
-        )
+        req = install_req_from_line("simple==0.1")
+        assert repr(req) == ("<InstallRequirement object: simple==0.1 editable=False>")
 
     def test_invalid_wheel_requirement_raises(self):
         with pytest.raises(InvalidWheelFilename):
-            install_req_from_line('invalid.whl')
+            install_req_from_line("invalid.whl")
 
     def test_wheel_requirement_sets_req_attribute(self):
-        req = install_req_from_line('simple-0.1-py2.py3-none-any.whl')
+        req = install_req_from_line("simple-0.1-py2.py3-none-any.whl")
         assert isinstance(req.req, Requirement)
-        assert str(req.req) == 'simple==0.1'
+        assert str(req.req) == "simple==0.1"
 
     def test_url_preserved_line_req(self):
         """Confirm the url is preserved in a non-editable requirement"""
-        url = 'git+http://foo.com@ref#egg=foo'
+        url = "git+http://foo.com@ref#egg=foo"
         req = install_req_from_line(url)
         assert req.link.url == url
 
     def test_url_preserved_editable_req(self):
         """Confirm the url is preserved in a editable requirement"""
-        url = 'git+http://foo.com@ref#egg=foo'
+        url = "git+http://foo.com@ref#egg=foo"
         req = install_req_from_editable(url)
         assert req.link.url == url
 
-    @pytest.mark.parametrize('path', (
-        '/path/to/foo.egg-info'.replace('/', os.path.sep),
-        # Tests issue fixed by https://github.com/pypa/pip/pull/2530
-        '/path/to/foo.egg-info/'.replace('/', os.path.sep),
-    ))
+    @pytest.mark.parametrize(
+        "path",
+        (
+            "/path/to/foo.egg-info".replace("/", os.path.sep),
+            # Tests issue fixed by https://github.com/pypa/pip/pull/2530
+            "/path/to/foo.egg-info/".replace("/", os.path.sep),
+        ),
+    )
     def test_get_dist(self, path):
-        req = install_req_from_line('foo')
+        req = install_req_from_line("foo")
         req.metadata_directory = path
         dist = req.get_dist()
         assert isinstance(dist, pkg_resources.Distribution)
-        assert dist.project_name == 'foo'
-        assert dist.location == '/path/to'.replace('/', os.path.sep)
+        assert dist.project_name == "foo"
+        assert dist.location == "/path/to".replace("/", os.path.sep)
 
     def test_markers(self):
         for line in (
@@ -442,27 +459,27 @@ def test_markers(self):
             'mock3;python_version >= "3"',
         ):
             req = install_req_from_line(line)
-            assert req.req.name == 'mock3'
-            assert str(req.req.specifier) == ''
+            assert req.req.name == "mock3"
+            assert str(req.req.specifier) == ""
             assert str(req.markers) == 'python_version >= "3"'
 
     def test_markers_semicolon(self):
         # check that the markers can contain a semicolon
         req = install_req_from_line('semicolon; os_name == "a; b"')
-        assert req.req.name == 'semicolon'
-        assert str(req.req.specifier) == ''
+        assert req.req.name == "semicolon"
+        assert str(req.req.specifier) == ""
         assert str(req.markers) == 'os_name == "a; b"'
 
     def test_markers_url(self):
         # test "URL; markers" syntax
-        url = 'http://foo.com/?p=bar.git;a=snapshot;h=v0.1;sf=tgz'
+        url = "http://foo.com/?p=bar.git;a=snapshot;h=v0.1;sf=tgz"
         line = '{}; python_version >= "3"'.format(url)
         req = install_req_from_line(line)
         assert req.link.url == url, req.url
         assert str(req.markers) == 'python_version >= "3"'
 
         # without space, markers are part of the URL
-        url = 'http://foo.com/?p=bar.git;a=snapshot;h=v0.1;sf=tgz'
+        url = "http://foo.com/?p=bar.git;a=snapshot;h=v0.1;sf=tgz"
         line = '{};python_version >= "3"'.format(url)
         req = install_req_from_line(line)
         assert req.link.url == line, req.url
@@ -472,9 +489,9 @@ def test_markers_match_from_line(self):
         # match
         for markers in (
             'python_version >= "1.0"',
-            'sys_platform == {sys.platform!r}'.format(**globals()),
+            "sys_platform == {sys.platform!r}".format(**globals()),
         ):
-            line = 'name; ' + markers
+            line = "name; " + markers
             req = install_req_from_line(line)
             assert str(req.markers) == str(Marker(markers))
             assert req.match_markers()
@@ -482,9 +499,9 @@ def test_markers_match_from_line(self):
         # don't match
         for markers in (
             'python_version >= "5.0"',
-            'sys_platform != {sys.platform!r}'.format(**globals()),
+            "sys_platform != {sys.platform!r}".format(**globals()),
         ):
-            line = 'name; ' + markers
+            line = "name; " + markers
             req = install_req_from_line(line)
             assert str(req.markers) == str(Marker(markers))
             assert not req.match_markers()
@@ -493,81 +510,80 @@ def test_markers_match(self):
         # match
         for markers in (
             'python_version >= "1.0"',
-            'sys_platform == {sys.platform!r}'.format(**globals()),
+            "sys_platform == {sys.platform!r}".format(**globals()),
         ):
-            line = 'name; ' + markers
-            req = install_req_from_line(line, comes_from='')
+            line = "name; " + markers
+            req = install_req_from_line(line, comes_from="")
             assert str(req.markers) == str(Marker(markers))
             assert req.match_markers()
 
         # don't match
         for markers in (
             'python_version >= "5.0"',
-            'sys_platform != {sys.platform!r}'.format(**globals()),
+            "sys_platform != {sys.platform!r}".format(**globals()),
         ):
-            line = 'name; ' + markers
-            req = install_req_from_line(line, comes_from='')
+            line = "name; " + markers
+            req = install_req_from_line(line, comes_from="")
             assert str(req.markers) == str(Marker(markers))
             assert not req.match_markers()
 
     def test_extras_for_line_path_requirement(self):
-        line = 'SomeProject[ex1,ex2]'
-        filename = 'filename'
-        comes_from = '-r {} (line {})'.format(filename, 1)
+        line = "SomeProject[ex1,ex2]"
+        filename = "filename"
+        comes_from = "-r {} (line {})".format(filename, 1)
         req = install_req_from_line(line, comes_from=comes_from)
         assert len(req.extras) == 2
-        assert req.extras == {'ex1', 'ex2'}
+        assert req.extras == {"ex1", "ex2"}
 
     def test_extras_for_line_url_requirement(self):
-        line = 'git+https://url#egg=SomeProject[ex1,ex2]'
-        filename = 'filename'
-        comes_from = '-r {} (line {})'.format(filename, 1)
+        line = "git+https://url#egg=SomeProject[ex1,ex2]"
+        filename = "filename"
+        comes_from = "-r {} (line {})".format(filename, 1)
         req = install_req_from_line(line, comes_from=comes_from)
         assert len(req.extras) == 2
-        assert req.extras == {'ex1', 'ex2'}
+        assert req.extras == {"ex1", "ex2"}
 
     def test_extras_for_editable_path_requirement(self):
-        url = '.[ex1,ex2]'
-        filename = 'filename'
-        comes_from = '-r {} (line {})'.format(filename, 1)
+        url = ".[ex1,ex2]"
+        filename = "filename"
+        comes_from = "-r {} (line {})".format(filename, 1)
         req = install_req_from_editable(url, comes_from=comes_from)
         assert len(req.extras) == 2
-        assert req.extras == {'ex1', 'ex2'}
+        assert req.extras == {"ex1", "ex2"}
 
     def test_extras_for_editable_url_requirement(self):
-        url = 'git+https://url#egg=SomeProject[ex1,ex2]'
-        filename = 'filename'
-        comes_from = '-r {} (line {})'.format(filename, 1)
+        url = "git+https://url#egg=SomeProject[ex1,ex2]"
+        filename = "filename"
+        comes_from = "-r {} (line {})".format(filename, 1)
         req = install_req_from_editable(url, comes_from=comes_from)
         assert len(req.extras) == 2
-        assert req.extras == {'ex1', 'ex2'}
+        assert req.extras == {"ex1", "ex2"}
 
     def test_unexisting_path(self):
         with pytest.raises(InstallationError) as e:
-            install_req_from_line(
-                os.path.join('this', 'path', 'does', 'not', 'exist'))
+            install_req_from_line(os.path.join("this", "path", "does", "not", "exist"))
         err_msg = e.value.args[0]
         assert "Invalid requirement" in err_msg
         assert "It looks like a path." in err_msg
 
     def test_single_equal_sign(self):
         with pytest.raises(InstallationError) as e:
-            install_req_from_line('toto=42')
+            install_req_from_line("toto=42")
         err_msg = e.value.args[0]
         assert "Invalid requirement" in err_msg
         assert "= is not a valid operator. Did you mean == ?" in err_msg
 
     def test_unidentifiable_name(self):
-        test_name = '-'
+        test_name = "-"
         with pytest.raises(InstallationError) as e:
             install_req_from_line(test_name)
         err_msg = e.value.args[0]
         assert "Invalid requirement: '{}'".format(test_name) == err_msg
 
     def test_requirement_file(self):
-        req_file_path = os.path.join(self.tempdir, 'test.txt')
-        with open(req_file_path, 'w') as req_file:
-            req_file.write('pip\nsetuptools')
+        req_file_path = os.path.join(self.tempdir, "test.txt")
+        with open(req_file_path, "w") as req_file:
+            req_file.write("pip\nsetuptools")
         with pytest.raises(InstallationError) as e:
             install_req_from_line(req_file_path)
         err_msg = e.value.args[0]
@@ -577,71 +593,73 @@ def test_requirement_file(self):
         assert "If that is the case, use the '-r' flag to install" in err_msg
 
 
-@patch('pip._internal.req.req_install.os.path.abspath')
-@patch('pip._internal.req.req_install.os.path.exists')
-@patch('pip._internal.req.req_install.os.path.isdir')
-def test_parse_editable_local(
-        isdir_mock, exists_mock, abspath_mock):
+@patch("pip._internal.req.req_install.os.path.abspath")
+@patch("pip._internal.req.req_install.os.path.exists")
+@patch("pip._internal.req.req_install.os.path.isdir")
+def test_parse_editable_local(isdir_mock, exists_mock, abspath_mock):
     exists_mock.return_value = isdir_mock.return_value = True
     # mocks needed to support path operations on windows tests
     abspath_mock.return_value = "/some/path"
-    assert parse_editable('.') == (None, 'file:///some/path', set())
+    assert parse_editable(".") == (None, "file:///some/path", set())
     abspath_mock.return_value = "/some/path/foo"
-    assert parse_editable('foo') == (
-        None, 'file:///some/path/foo', set(),
+    assert parse_editable("foo") == (
+        None,
+        "file:///some/path/foo",
+        set(),
     )
 
 
 def test_parse_editable_explicit_vcs():
-    assert parse_editable('svn+https://foo#egg=foo') == (
-        'foo',
-        'svn+https://foo#egg=foo',
+    assert parse_editable("svn+https://foo#egg=foo") == (
+        "foo",
+        "svn+https://foo#egg=foo",
         set(),
     )
 
 
 def test_parse_editable_vcs_extras():
-    assert parse_editable('svn+https://foo#egg=foo[extras]') == (
-        'foo[extras]',
-        'svn+https://foo#egg=foo[extras]',
+    assert parse_editable("svn+https://foo#egg=foo[extras]") == (
+        "foo[extras]",
+        "svn+https://foo#egg=foo[extras]",
         set(),
     )
 
 
-@patch('pip._internal.req.req_install.os.path.abspath')
-@patch('pip._internal.req.req_install.os.path.exists')
-@patch('pip._internal.req.req_install.os.path.isdir')
-def test_parse_editable_local_extras(
-        isdir_mock, exists_mock, abspath_mock):
+@patch("pip._internal.req.req_install.os.path.abspath")
+@patch("pip._internal.req.req_install.os.path.exists")
+@patch("pip._internal.req.req_install.os.path.isdir")
+def test_parse_editable_local_extras(isdir_mock, exists_mock, abspath_mock):
     exists_mock.return_value = isdir_mock.return_value = True
     abspath_mock.return_value = "/some/path"
-    assert parse_editable('.[extras]') == (
-        None, 'file://' + "/some/path", {'extras'},
+    assert parse_editable(".[extras]") == (
+        None,
+        "file://" + "/some/path",
+        {"extras"},
     )
     abspath_mock.return_value = "/some/path/foo"
-    assert parse_editable('foo[bar,baz]') == (
-        None, 'file:///some/path/foo', {'bar', 'baz'},
+    assert parse_editable("foo[bar,baz]") == (
+        None,
+        "file:///some/path/foo",
+        {"bar", "baz"},
     )
 
 
 def test_exclusive_environment_markers():
     """Make sure RequirementSet accepts several excluding env markers"""
-    eq36 = install_req_from_line(
-        "Django>=1.6.10,<1.7 ; python_version == '3.6'")
+    eq36 = install_req_from_line("Django>=1.6.10,<1.7 ; python_version == '3.6'")
     eq36.user_supplied = True
-    ne36 = install_req_from_line(
-        "Django>=1.6.10,<1.8 ; python_version != '3.6'")
+    ne36 = install_req_from_line("Django>=1.6.10,<1.8 ; python_version != '3.6'")
     ne36.user_supplied = True
 
     req_set = RequirementSet()
     req_set.add_requirement(eq36)
     req_set.add_requirement(ne36)
-    assert req_set.has_requirement('Django')
+    assert req_set.has_requirement("Django")
 
 
 def test_mismatched_versions(caplog):
     req = InstallRequirement(
-        req=Requirement('simplewheel==2.0'),
+        req=Requirement("simplewheel==2.0"),
         comes_from=None,
     )
     req.source_dir = "/tmp/somewhere"  # make req believe it has been unpacked
@@ -649,96 +667,117 @@ def test_mismatched_versions(caplog):
     req._metadata = {"name": "simplewheel", "version": "1.0"}
     req.assert_source_matches_version()
     assert caplog.records[-1].message == (
-        'Requested simplewheel==2.0, but installing version 1.0'
+        "Requested simplewheel==2.0, but installing version 1.0"
     )
 
 
-@pytest.mark.parametrize('args, expected', [
-    # Test UNIX-like paths
-    (('/path/to/installable'), True),
-    # Test relative paths
-    (('./path/to/installable'), True),
-    # Test current path
-    (('.'), True),
-    # Test url paths
-    (('https://whatever.com/test-0.4-py2.py3-bogus-any.whl'), True),
-    # Test pep440 paths
-    (('test @ https://whatever.com/test-0.4-py2.py3-bogus-any.whl'), True),
-    # Test wheel
-    (('simple-0.1-py2.py3-none-any.whl'), False),
-])
+@pytest.mark.parametrize(
+    "args, expected",
+    [
+        # Test UNIX-like paths
+        (("/path/to/installable"), True),
+        # Test relative paths
+        (("./path/to/installable"), True),
+        # Test current path
+        (("."), True),
+        # Test url paths
+        (("https://whatever.com/test-0.4-py2.py3-bogus-any.whl"), True),
+        # Test pep440 paths
+        (("test @ https://whatever.com/test-0.4-py2.py3-bogus-any.whl"), True),
+        # Test wheel
+        (("simple-0.1-py2.py3-none-any.whl"), False),
+    ],
+)
 def test_looks_like_path(args, expected):
     assert _looks_like_path(args) == expected
 
 
 @pytest.mark.skipif(
-    not sys.platform.startswith("win"),
-    reason='Test only available on Windows'
+    not sys.platform.startswith("win"), reason="Test only available on Windows"
+)
+@pytest.mark.parametrize(
+    "args, expected",
+    [
+        # Test relative paths
+        ((".\\path\\to\\installable"), True),
+        (("relative\\path"), True),
+        # Test absolute paths
+        (("C:\\absolute\\path"), True),
+    ],
 )
-@pytest.mark.parametrize('args, expected', [
-    # Test relative paths
-    (('.\\path\\to\\installable'), True),
-    (('relative\\path'), True),
-    # Test absolute paths
-    (('C:\\absolute\\path'), True),
-])
 def test_looks_like_path_win(args, expected):
     assert _looks_like_path(args) == expected
 
 
-@pytest.mark.parametrize('args, mock_returns, expected', [
-    # Test pep440 urls
-    (('/path/to/foo @ git+http://foo.com@ref#egg=foo',
-     'foo @ git+http://foo.com@ref#egg=foo'), (False, False), None),
-    # Test pep440 urls without spaces
-    (('/path/to/foo@git+http://foo.com@ref#egg=foo',
-     'foo @ git+http://foo.com@ref#egg=foo'), (False, False), None),
-    # Test pep440 wheel
-    (('/path/to/test @ https://whatever.com/test-0.4-py2.py3-bogus-any.whl',
-     'test @ https://whatever.com/test-0.4-py2.py3-bogus-any.whl'),
-     (False, False), None),
-    # Test name is not a file
-    (('/path/to/simple==0.1',
-     'simple==0.1'),
-     (False, False), None),
-])
-@patch('pip._internal.req.req_install.os.path.isdir')
-@patch('pip._internal.req.req_install.os.path.isfile')
-def test_get_url_from_path(
-    isdir_mock, isfile_mock, args, mock_returns, expected
-):
+@pytest.mark.parametrize(
+    "args, mock_returns, expected",
+    [
+        # Test pep440 urls
+        (
+            (
+                "/path/to/foo @ git+http://foo.com@ref#egg=foo",
+                "foo @ git+http://foo.com@ref#egg=foo",
+            ),
+            (False, False),
+            None,
+        ),
+        # Test pep440 urls without spaces
+        (
+            (
+                "/path/to/foo@git+http://foo.com@ref#egg=foo",
+                "foo @ git+http://foo.com@ref#egg=foo",
+            ),
+            (False, False),
+            None,
+        ),
+        # Test pep440 wheel
+        (
+            (
+                "/path/to/test @ https://whatever.com/test-0.4-py2.py3-bogus-any.whl",
+                "test @ https://whatever.com/test-0.4-py2.py3-bogus-any.whl",
+            ),
+            (False, False),
+            None,
+        ),
+        # Test name is not a file
+        (("/path/to/simple==0.1", "simple==0.1"), (False, False), None),
+    ],
+)
+@patch("pip._internal.req.req_install.os.path.isdir")
+@patch("pip._internal.req.req_install.os.path.isfile")
+def test_get_url_from_path(isdir_mock, isfile_mock, args, mock_returns, expected):
     isdir_mock.return_value = mock_returns[0]
     isfile_mock.return_value = mock_returns[1]
     assert _get_url_from_path(*args) is expected
 
 
-@patch('pip._internal.req.req_install.os.path.isdir')
-@patch('pip._internal.req.req_install.os.path.isfile')
+@patch("pip._internal.req.req_install.os.path.isdir")
+@patch("pip._internal.req.req_install.os.path.isfile")
 def test_get_url_from_path__archive_file(isdir_mock, isfile_mock):
     isdir_mock.return_value = False
     isfile_mock.return_value = True
-    name = 'simple-0.1-py2.py3-none-any.whl'
-    path = os.path.join('/path/to/' + name)
+    name = "simple-0.1-py2.py3-none-any.whl"
+    path = os.path.join("/path/to/" + name)
     url = path_to_url(path)
     assert _get_url_from_path(path, name) == url
 
 
-@patch('pip._internal.req.req_install.os.path.isdir')
-@patch('pip._internal.req.req_install.os.path.isfile')
+@patch("pip._internal.req.req_install.os.path.isdir")
+@patch("pip._internal.req.req_install.os.path.isfile")
 def test_get_url_from_path__installable_dir(isdir_mock, isfile_mock):
     isdir_mock.return_value = True
     isfile_mock.return_value = True
-    name = 'some/setuptools/project'
-    path = os.path.join('/path/to/' + name)
+    name = "some/setuptools/project"
+    path = os.path.join("/path/to/" + name)
     url = path_to_url(path)
     assert _get_url_from_path(path, name) == url
 
 
-@patch('pip._internal.req.req_install.os.path.isdir')
+@patch("pip._internal.req.req_install.os.path.isdir")
 def test_get_url_from_path__installable_error(isdir_mock):
     isdir_mock.return_value = True
-    name = 'some/setuptools/project'
-    path = os.path.join('/path/to/' + name)
+    name = "some/setuptools/project"
+    path = os.path.join("/path/to/" + name)
     with pytest.raises(InstallationError) as e:
         _get_url_from_path(path, name)
     err_msg = e.value.args[0]
diff --git a/tests/unit/test_req_file.py b/tests/unit/test_req_file.py
index 69d93a0cdc2..3624a62dc19 100644
--- a/tests/unit/test_req_file.py
+++ b/tests/unit/test_req_file.py
@@ -10,10 +10,7 @@
 from pretend import stub
 
 import pip._internal.req.req_file  # this will be monkeypatched
-from pip._internal.exceptions import (
-    InstallationError,
-    RequirementsFileParseError,
-)
+from pip._internal.exceptions import InstallationError, RequirementsFileParseError
 from pip._internal.models.format_control import FormatControl
 from pip._internal.network.session import PipSession
 from pip._internal.req.constructors import (
@@ -45,7 +42,7 @@ def finder(session):
 def options(session):
     return stub(
         isolated_mode=False,
-        index_url='default_url',
+        index_url="default_url",
         format_control=FormatControl(set(), set()),
         features_enabled=[],
     )
@@ -62,93 +59,105 @@ def parse_reqfile(
     # Wrap parse_requirements/install_req_from_parsed_requirement to
     # avoid having to write the same chunk of code in lots of tests.
     for parsed_req in parse_requirements(
-        filename, session, finder=finder,
-        options=options, constraint=constraint,
+        filename,
+        session,
+        finder=finder,
+        options=options,
+        constraint=constraint,
     ):
-        yield install_req_from_parsed_requirement(
-            parsed_req,
-            isolated=isolated
-        )
+        yield install_req_from_parsed_requirement(parsed_req, isolated=isolated)
 
 
 class TestPreprocess(object):
     """tests for `preprocess`"""
 
     def test_comments_and_joins_case1(self):
-        content = textwrap.dedent("""\
+        content = textwrap.dedent(
+            """\
           req1 \\
           # comment \\
           req2
-        """)
+        """
+        )
         result = preprocess(content)
-        assert list(result) == [(1, 'req1'), (3, 'req2')]
+        assert list(result) == [(1, "req1"), (3, "req2")]
 
     def test_comments_and_joins_case2(self):
-        content = textwrap.dedent("""\
+        content = textwrap.dedent(
+            """\
           req1\\
           # comment
-        """)
+        """
+        )
         result = preprocess(content)
-        assert list(result) == [(1, 'req1')]
+        assert list(result) == [(1, "req1")]
 
     def test_comments_and_joins_case3(self):
-        content = textwrap.dedent("""\
+        content = textwrap.dedent(
+            """\
           req1 \\
           # comment
           req2
-        """)
+        """
+        )
         result = preprocess(content)
-        assert list(result) == [(1, 'req1'), (3, 'req2')]
+        assert list(result) == [(1, "req1"), (3, "req2")]
 
 
 class TestIgnoreComments(object):
     """tests for `ignore_comment`"""
 
     def test_ignore_line(self):
-        lines = [(1, ''), (2, 'req1'), (3, 'req2')]
+        lines = [(1, ""), (2, "req1"), (3, "req2")]
         result = ignore_comments(lines)
-        assert list(result) == [(2, 'req1'), (3, 'req2')]
+        assert list(result) == [(2, "req1"), (3, "req2")]
 
     def test_ignore_comment(self):
-        lines = [(1, 'req1'), (2, '# comment'), (3, 'req2')]
+        lines = [(1, "req1"), (2, "# comment"), (3, "req2")]
         result = ignore_comments(lines)
-        assert list(result) == [(1, 'req1'), (3, 'req2')]
+        assert list(result) == [(1, "req1"), (3, "req2")]
 
     def test_strip_comment(self):
-        lines = [(1, 'req1'), (2, 'req # comment'), (3, 'req2')]
+        lines = [(1, "req1"), (2, "req # comment"), (3, "req2")]
         result = ignore_comments(lines)
-        assert list(result) == [(1, 'req1'), (2, 'req'), (3, 'req2')]
+        assert list(result) == [(1, "req1"), (2, "req"), (3, "req2")]
 
 
 class TestJoinLines(object):
     """tests for `join_lines`"""
 
     def test_join_lines(self):
-        lines = enumerate([
-            'line 1',
-            'line 2:1 \\',
-            'line 2:2',
-            'line 3:1 \\',
-            'line 3:2 \\',
-            'line 3:3',
-            'line 4'
-        ], start=1)
+        lines = enumerate(
+            [
+                "line 1",
+                "line 2:1 \\",
+                "line 2:2",
+                "line 3:1 \\",
+                "line 3:2 \\",
+                "line 3:3",
+                "line 4",
+            ],
+            start=1,
+        )
         expect = [
-            (1, 'line 1'),
-            (2, 'line 2:1 line 2:2'),
-            (4, 'line 3:1 line 3:2 line 3:3'),
-            (7, 'line 4'),
+            (1, "line 1"),
+            (2, "line 2:1 line 2:2"),
+            (4, "line 3:1 line 3:2 line 3:3"),
+            (7, "line 4"),
         ]
         assert expect == list(join_lines(lines))
 
     def test_last_line_with_escape(self):
-        lines = enumerate([
-            'line 1',
-            'line 2 \\',
-        ], start=1)
+        lines = enumerate(
+            [
+                "line 1",
+                "line 2 \\",
+            ],
+            start=1,
+        )
         expect = [
-            (1, 'line 1'),
-            (2, 'line 2 '),
+            (1, "line 1"),
+            (2, "line 2 "),
         ]
         assert expect == list(join_lines(lines))
 
@@ -170,19 +179,21 @@ def process_line(
         if session is None:
             session = PipSession()
 
-        prefix = '\n' * (line_number - 1)
+        prefix = "\n" * (line_number - 1)
         path = tmpdir.joinpath(filename)
         path.parent.mkdir(exist_ok=True)
         path.write_text(prefix + line)
         monkeypatch.chdir(str(tmpdir))
-        return list(parse_reqfile(
-            filename,
-            finder=finder,
-            options=options,
-            session=session,
-            constraint=constraint,
-            isolated=options.isolated_mode if options else False
-        ))
+        return list(
+            parse_reqfile(
+                filename,
+                finder=finder,
+                options=options,
+                session=session,
+                constraint=constraint,
+                isolated=options.isolated_mode if options else False,
+            )
+        )
 
     return process_line
 
@@ -195,16 +206,16 @@ def test_parser_error(self, line_processor):
             line_processor("--bogus", "file", 1)
 
     def test_parser_offending_line(self, line_processor):
-        line = 'pkg==1.0.0 --hash=somehash'
+        line = "pkg==1.0.0 --hash=somehash"
         with pytest.raises(RequirementsFileParseError) as err:
-            line_processor(line, 'file', 1)
+            line_processor(line, "file", 1)
         assert line in str(err.value)
 
     def test_parser_non_offending_line(self, line_processor):
         try:
-            line_processor('pkg==1.0.0 --hash=sha256:somehash', 'file', 1)
+            line_processor("pkg==1.0.0 --hash=sha256:somehash", "file", 1)
         except RequirementsFileParseError:
-            pytest.fail('Reported offending line where it should not.')
+            pytest.fail("Reported offending line where it should not.")
 
     def test_only_one_req_per_line(self, line_processor):
         # pkg_resources raises the ValueError
@@ -218,95 +229,89 @@ def test_error_message(self, line_processor):
         """
         with pytest.raises(InstallationError) as exc:
             line_processor(
-                'my-package=1.0',
-                filename='path/requirements.txt',
-                line_number=3
+                "my-package=1.0", filename="path/requirements.txt", line_number=3
             )
 
         package_name = "u'my-package=1.0'" if PY2 else "'my-package=1.0'"
         expected = (
             "Invalid requirement: {} "
-            '(from line 3 of path/requirements.txt)\n'
-            'Hint: = is not a valid operator. Did you mean == ?'
+            "(from line 3 of path/requirements.txt)\n"
+            "Hint: = is not a valid operator. Did you mean == ?"
         ).format(package_name)
         assert str(exc.value) == expected
 
     def test_yield_line_requirement(self, line_processor):
-        line = 'SomeProject'
-        filename = 'filename'
-        comes_from = '-r {} (line {})'.format(filename, 1)
+        line = "SomeProject"
+        filename = "filename"
+        comes_from = "-r {} (line {})".format(filename, 1)
         req = install_req_from_line(line, comes_from=comes_from)
         assert repr(line_processor(line, filename, 1)[0]) == repr(req)
 
     def test_yield_pep440_line_requirement(self, line_processor):
-        line = 'SomeProject @ https://url/SomeProject-py2-py3-none-any.whl'
-        filename = 'filename'
-        comes_from = '-r {} (line {})'.format(filename, 1)
+        line = "SomeProject @ https://url/SomeProject-py2-py3-none-any.whl"
+        filename = "filename"
+        comes_from = "-r {} (line {})".format(filename, 1)
         req = install_req_from_line(line, comes_from=comes_from)
         assert repr(line_processor(line, filename, 1)[0]) == repr(req)
 
     def test_yield_line_constraint(self, line_processor):
-        line = 'SomeProject'
-        filename = 'filename'
-        comes_from = '-c {} (line {})'.format(filename, 1)
-        req = install_req_from_line(
-            line, comes_from=comes_from, constraint=True)
+        line = "SomeProject"
+        filename = "filename"
+        comes_from = "-c {} (line {})".format(filename, 1)
+        req = install_req_from_line(line, comes_from=comes_from, constraint=True)
         found_req = line_processor(line, filename, 1, constraint=True)[0]
         assert repr(found_req) == repr(req)
         assert found_req.constraint is True
 
-    def test_yield_line_requirement_with_spaces_in_specifier(
-        self, line_processor
-    ):
-        line = 'SomeProject >= 2'
-        filename = 'filename'
-        comes_from = '-r {} (line {})'.format(filename, 1)
+    def test_yield_line_requirement_with_spaces_in_specifier(self, line_processor):
+        line = "SomeProject >= 2"
+        filename = "filename"
+        comes_from = "-r {} (line {})".format(filename, 1)
         req = install_req_from_line(line, comes_from=comes_from)
         assert repr(line_processor(line, filename, 1)[0]) == repr(req)
-        assert str(req.req.specifier) == '>=2'
+        assert str(req.req.specifier) == ">=2"
 
     def test_yield_editable_requirement(self, line_processor):
-        url = 'git+https://url#egg=SomeProject'
-        line = '-e {url}'.format(**locals())
-        filename = 'filename'
-        comes_from = '-r {} (line {})'.format(filename, 1)
+        url = "git+https://url#egg=SomeProject"
+        line = "-e {url}".format(**locals())
+        filename = "filename"
+        comes_from = "-r {} (line {})".format(filename, 1)
         req = install_req_from_editable(url, comes_from=comes_from)
         assert repr(line_processor(line, filename, 1)[0]) == repr(req)
 
     def test_yield_editable_constraint(self, line_processor):
-        url = 'git+https://url#egg=SomeProject'
-        line = '-e {}'.format(url)
-        filename = 'filename'
-        comes_from = '-c {} (line {})'.format(filename, 1)
-        req = install_req_from_editable(
-            url, comes_from=comes_from, constraint=True)
+        url = "git+https://url#egg=SomeProject"
+        line = "-e {}".format(url)
+        filename = "filename"
+        comes_from = "-c {} (line {})".format(filename, 1)
+        req = install_req_from_editable(url, comes_from=comes_from, constraint=True)
         found_req = line_processor(line, filename, 1, constraint=True)[0]
         assert repr(found_req) == repr(req)
         assert found_req.constraint is True
 
     def test_nested_constraints_file(self, monkeypatch, tmpdir):
-        req_name = 'hello'
-        req_file = tmpdir / 'parent' / 'req_file.txt'
+        req_name = "hello"
+        req_file = tmpdir / "parent" / "req_file.txt"
         req_file.parent.mkdir()
-        req_file.write_text('-c reqs.txt')
-        req_file.parent.joinpath('reqs.txt').write_text(req_name)
+        req_file.write_text("-c reqs.txt")
+        req_file.parent.joinpath("reqs.txt").write_text(req_name)
 
         monkeypatch.chdir(str(tmpdir))
 
-        reqs = list(
-            parse_reqfile('./parent/req_file.txt', session=session)
-        )
+        reqs = list(parse_reqfile("./parent/req_file.txt", session=session))
         assert len(reqs) == 1
         assert reqs[0].name == req_name
         assert reqs[0].constraint
 
     def test_options_on_a_requirement_line(self, line_processor):
-        line = 'SomeProject --install-option=yo1 --install-option yo2 '\
-               '--global-option="yo3" --global-option "yo4"'
-        filename = 'filename'
+        line = (
+            "SomeProject --install-option=yo1 --install-option yo2 "
+            '--global-option="yo3" --global-option "yo4"'
+        )
+        filename = "filename"
         req = line_processor(line, filename, 1)[0]
-        assert req.global_options == ['yo3', 'yo4']
-        assert req.install_options == ['yo1', 'yo2']
+        assert req.global_options == ["yo3", "yo4"]
+        assert req.install_options == ["yo1", "yo2"]
 
     def test_hash_options(self, line_processor):
         """Test the --hash option: mostly its value storage.
@@ -314,25 +319,30 @@ def test_hash_options(self, line_processor):
         Make sure it reads and preserve multiple hashes.
 
         """
-        line = ('SomeProject --hash=sha256:2cf24dba5fb0a30e26e83b2ac5b9e29e1b1'
-                '61e5c1fa7425e73043362938b9824 '
-                '--hash=sha384:59e1748777448c69de6b800d7a33bbfb9ff1b463e44354c'
-                '3553bcdb9c666fa90125a3c79f90397bdf5f6a13de828684f '
-                '--hash=sha256:486ea46224d1bb4fb680f34f7c9ad96a8f24ec88be73ea8'
-                'e5a6c65260e9cb8a7')
-        filename = 'filename'
+        line = (
+            "SomeProject --hash=sha256:2cf24dba5fb0a30e26e83b2ac5b9e29e1b1"
+            "61e5c1fa7425e73043362938b9824 "
+            "--hash=sha384:59e1748777448c69de6b800d7a33bbfb9ff1b463e44354c"
+            "3553bcdb9c666fa90125a3c79f90397bdf5f6a13de828684f "
+            "--hash=sha256:486ea46224d1bb4fb680f34f7c9ad96a8f24ec88be73ea8"
+            "e5a6c65260e9cb8a7"
+        )
+        filename = "filename"
         req = line_processor(line, filename, 1)[0]
         assert req.hash_options == {
-            'sha256': ['2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e730433'
-                       '62938b9824',
-                       '486ea46224d1bb4fb680f34f7c9ad96a8f24ec88be73ea8e5a6c65'
-                       '260e9cb8a7'],
-            'sha384': ['59e1748777448c69de6b800d7a33bbfb9ff1b463e44354c3553bcd'
-                       'b9c666fa90125a3c79f90397bdf5f6a13de828684f']}
+            "sha256": [
+                "2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e730433" "62938b9824",
+                "486ea46224d1bb4fb680f34f7c9ad96a8f24ec88be73ea8e5a6c65" "260e9cb8a7",
+            ],
+            "sha384": [
+                "59e1748777448c69de6b800d7a33bbfb9ff1b463e44354c3553bcd"
+                "b9c666fa90125a3c79f90397bdf5f6a13de828684f"
+            ],
+        }
 
     def test_set_isolated(self, line_processor, options):
-        line = 'SomeProject'
-        filename = 'filename'
+        line = "SomeProject"
+        filename = "filename"
         options.isolated_mode = True
         result = line_processor(line, filename, 1, options=options)
         assert result[0].isolated
@@ -342,46 +352,38 @@ def test_set_finder_no_index(self, line_processor, finder):
         assert finder.index_urls == []
 
     def test_set_finder_index_url(self, line_processor, finder, session):
-        line_processor(
-            "--index-url=url", "file", 1, finder=finder, session=session)
-        assert finder.index_urls == ['url']
-        assert session.auth.index_urls == ['url']
+        line_processor("--index-url=url", "file", 1, finder=finder, session=session)
+        assert finder.index_urls == ["url"]
+        assert session.auth.index_urls == ["url"]
 
     def test_set_finder_find_links(self, line_processor, finder):
         line_processor("--find-links=url", "file", 1, finder=finder)
-        assert finder.find_links == ['url']
+        assert finder.find_links == ["url"]
 
-    def test_set_finder_extra_index_urls(
-            self, line_processor, finder, session):
+    def test_set_finder_extra_index_urls(self, line_processor, finder, session):
         line_processor(
-            "--extra-index-url=url", "file", 1, finder=finder, session=session)
-        assert finder.index_urls == ['url']
-        assert session.auth.index_urls == ['url']
+            "--extra-index-url=url", "file", 1, finder=finder, session=session
+        )
+        assert finder.index_urls == ["url"]
+        assert session.auth.index_urls == ["url"]
 
-    def test_set_finder_trusted_host(
-        self, line_processor, caplog, session, finder
-    ):
+    def test_set_finder_trusted_host(self, line_processor, caplog, session, finder):
         with caplog.at_level(logging.INFO):
             line_processor(
                 "--trusted-host=host1 --trusted-host=host2:8080",
-                "file.txt", 1, finder=finder, session=session,
+                "file.txt",
+                1,
+                finder=finder,
+                session=session,
             )
-        assert list(finder.trusted_hosts) == ['host1', 'host2:8080']
+        assert list(finder.trusted_hosts) == ["host1", "host2:8080"]
         session = finder._link_collector.session
-        assert (
-            session.adapters['https://host1/']
-            is session._trusted_host_adapter
-        )
-        assert (
-            session.adapters['https://host2:8080/']
-            is session._trusted_host_adapter
-        )
+        assert session.adapters["https://host1/"] is session._trusted_host_adapter
+        assert session.adapters["https://host2:8080/"] is session._trusted_host_adapter
 
         # Test the log message.
         actual = [(r.levelname, r.message) for r in caplog.records]
-        expected = (
-            'INFO', "adding trusted host: 'host1' (from line 1 of file.txt)"
-        )
+        expected = ("INFO", "adding trusted host: 'host1' (from line 1 of file.txt)")
         assert expected in actual
 
     def test_set_finder_allow_all_prereleases(self, line_processor, finder):
@@ -390,9 +392,7 @@ def test_set_finder_allow_all_prereleases(self, line_processor, finder):
 
     def test_use_feature(self, line_processor, options):
         """--use-feature can be set in requirements files."""
-        line_processor(
-            "--use-feature=2020-resolver", "filename", 1, options=options
-        )
+        line_processor("--use-feature=2020-resolver", "filename", 1, options=options)
         assert "2020-resolver" in options.features_enabled
 
     def test_relative_local_find_links(
@@ -401,16 +401,14 @@ def test_relative_local_find_links(
         """
         Test a relative find_links path is joined with the req file directory
         """
-        base_path = tmpdir / 'path'
+        base_path = tmpdir / "path"
 
         def normalize(path):
-            return os.path.normcase(
-                os.path.abspath(os.path.normpath(str(path)))
-            )
+            return os.path.normcase(os.path.abspath(os.path.normpath(str(path))))
 
         # Make sure the test also passes on windows
-        req_file = normalize(base_path / 'req_file.txt')
-        nested_link = normalize(base_path / 'rel_path')
+        req_file = normalize(base_path / "req_file.txt")
+        nested_link = normalize(base_path / "rel_path")
         exists_ = os.path.exists
 
         def exists(path):
@@ -419,28 +417,26 @@ def exists(path):
             else:
                 exists_(path)
 
-        monkeypatch.setattr(os.path, 'exists', exists)
+        monkeypatch.setattr(os.path, "exists", exists)
         line_processor("--find-links=rel_path", req_file, 1, finder=finder)
         assert finder.find_links == [nested_link]
 
-    def test_relative_http_nested_req_files(
-        self, finder, session, monkeypatch
-    ):
+    def test_relative_http_nested_req_files(self, finder, session, monkeypatch):
         """
         Test a relative nested req file path is joined with the req file url
         """
-        req_name = 'hello'
-        req_file = 'http://me.com/me/req_file.txt'
+        req_name = "hello"
+        req_file = "http://me.com/me/req_file.txt"
 
         def get_file_content(filename, *args, **kwargs):
             if filename == req_file:
-                return None, '-r reqs.txt'
-            elif filename == 'http://me.com/me/reqs.txt':
+                return None, "-r reqs.txt"
+            elif filename == "http://me.com/me/reqs.txt":
                 return None, req_name
-            assert False, 'Unexpected file requested {}'.format(filename)
+            assert False, "Unexpected file requested {}".format(filename)
 
         monkeypatch.setattr(
-            pip._internal.req.req_file, 'get_file_content', get_file_content
+            pip._internal.req.req_file, "get_file_content", get_file_content
         )
 
         result = list(parse_reqfile(req_file, session=session))
@@ -448,42 +444,36 @@ def get_file_content(filename, *args, **kwargs):
         assert result[0].name == req_name
         assert not result[0].constraint
 
-    def test_relative_local_nested_req_files(
-        self, session, monkeypatch, tmpdir
-    ):
+    def test_relative_local_nested_req_files(self, session, monkeypatch, tmpdir):
         """
         Test a relative nested req file path is joined with the req file dir
         """
-        req_name = 'hello'
-        req_file = tmpdir / 'parent' / 'req_file.txt'
+        req_name = "hello"
+        req_file = tmpdir / "parent" / "req_file.txt"
         req_file.parent.mkdir()
-        req_file.write_text('-r reqs.txt')
-        req_file.parent.joinpath('reqs.txt').write_text(req_name)
+        req_file.write_text("-r reqs.txt")
+        req_file.parent.joinpath("reqs.txt").write_text(req_name)
 
         monkeypatch.chdir(str(tmpdir))
 
-        reqs = list(
-            parse_reqfile('./parent/req_file.txt', session=session)
-        )
+        reqs = list(parse_reqfile("./parent/req_file.txt", session=session))
         assert len(reqs) == 1
         assert reqs[0].name == req_name
         assert not reqs[0].constraint
 
-    def test_absolute_local_nested_req_files(
-        self, session, monkeypatch, tmpdir
-    ):
+    def test_absolute_local_nested_req_files(self, session, monkeypatch, tmpdir):
         """
         Test an absolute nested req file path
         """
-        req_name = 'hello'
-        req_file = tmpdir / 'parent' / 'req_file.txt'
+        req_name = "hello"
+        req_file = tmpdir / "parent" / "req_file.txt"
         req_file.parent.mkdir()
-        other_req_file = tmpdir / 'other' / 'reqs.txt'
+        other_req_file = tmpdir / "other" / "reqs.txt"
         other_req_file.parent.mkdir()
         # POSIX-ify the path, since Windows backslashes aren't supported.
-        other_req_file_str = str(other_req_file).replace('\\', '/')
+        other_req_file_str = str(other_req_file).replace("\\", "/")
 
-        req_file.write_text('-r {}'.format(other_req_file_str))
+        req_file.write_text("-r {}".format(other_req_file_str))
         other_req_file.write_text(req_name)
 
         reqs = list(parse_reqfile(str(req_file), session=session))
@@ -491,25 +481,23 @@ def test_absolute_local_nested_req_files(
         assert reqs[0].name == req_name
         assert not reqs[0].constraint
 
-    def test_absolute_http_nested_req_file_in_local(
-        self, session, monkeypatch, tmpdir
-    ):
+    def test_absolute_http_nested_req_file_in_local(self, session, monkeypatch, tmpdir):
         """
         Test a nested req file url in a local req file
         """
-        req_name = 'hello'
-        req_file = tmpdir / 'req_file.txt'
-        nested_req_file = 'http://me.com/me/req_file.txt'
+        req_name = "hello"
+        req_file = tmpdir / "req_file.txt"
+        nested_req_file = "http://me.com/me/req_file.txt"
 
         def get_file_content(filename, *args, **kwargs):
             if filename == str(req_file):
-                return None, '-r {}'.format(nested_req_file)
+                return None, "-r {}".format(nested_req_file)
             elif filename == nested_req_file:
                 return None, req_name
-            assert False, 'Unexpected file requested {}'.format(filename)
+            assert False, "Unexpected file requested {}".format(filename)
 
         monkeypatch.setattr(
-            pip._internal.req.req_file, 'get_file_content', get_file_content
+            pip._internal.req.req_file, "get_file_content", get_file_content
         )
 
         result = list(parse_reqfile(req_file, session=session))
@@ -519,20 +507,19 @@ def get_file_content(filename, *args, **kwargs):
 
 
 class TestBreakOptionsArgs(object):
-
     def test_no_args(self):
-        assert ('', '--option') == break_args_options('--option')
+        assert ("", "--option") == break_args_options("--option")
 
     def test_no_options(self):
-        assert ('arg arg', '') == break_args_options('arg arg')
+        assert ("arg arg", "") == break_args_options("arg arg")
 
     def test_args_short_options(self):
-        result = break_args_options('arg arg -s')
-        assert ('arg arg', '-s') == result
+        result = break_args_options("arg arg -s")
+        assert ("arg arg", "-s") == result
 
     def test_args_long_options(self):
-        result = break_args_options('arg arg --long')
-        assert ('arg arg', '--long') == result
+        result = break_args_options("arg arg --long")
+        assert ("arg arg", "--long") == result
 
 
 class TestOptionVariants(object):
@@ -541,23 +528,23 @@ class TestOptionVariants(object):
 
     def test_variant1(self, line_processor, finder):
         line_processor("-i url", "file", 1, finder=finder)
-        assert finder.index_urls == ['url']
+        assert finder.index_urls == ["url"]
 
     def test_variant2(self, line_processor, finder):
         line_processor("-i 'url'", "file", 1, finder=finder)
-        assert finder.index_urls == ['url']
+        assert finder.index_urls == ["url"]
 
     def test_variant3(self, line_processor, finder):
         line_processor("--index-url=url", "file", 1, finder=finder)
-        assert finder.index_urls == ['url']
+        assert finder.index_urls == ["url"]
 
     def test_variant4(self, line_processor, finder):
         line_processor("--index-url url", "file", 1, finder=finder)
-        assert finder.index_urls == ['url']
+        assert finder.index_urls == ["url"]
 
     def test_variant5(self, line_processor, finder):
         line_processor("--index-url='url'", "file", 1, finder=finder)
-        assert finder.index_urls == ['url']
+        assert finder.index_urls == ["url"]
 
 
 class TestParseRequirements(object):
@@ -571,9 +558,11 @@ def test_remote_reqs_parse(self):
         # this requirements file just contains a comment previously this has
         # failed in py3: https://github.com/pypa/pip/issues/760
         for _ in parse_reqfile(
-                'https://raw.githubusercontent.com/pypa/'
-                'pip-test-package/master/'
-                'tests/req_just_comment.txt', session=PipSession()):
+            "https://raw.githubusercontent.com/pypa/"
+            "pip-test-package/master/"
+            "tests/req_just_comment.txt",
+            session=PipSession(),
+        ):
             pass
 
     def test_multiple_appending_options(self, tmpdir, finder, options):
@@ -581,82 +570,91 @@ def test_multiple_appending_options(self, tmpdir, finder, options):
             fp.write("--extra-index-url url1 \n")
             fp.write("--extra-index-url url2 ")
 
-        list(parse_reqfile(tmpdir.joinpath("req1.txt"), finder=finder,
-                           session=PipSession(), options=options))
+        list(
+            parse_reqfile(
+                tmpdir.joinpath("req1.txt"),
+                finder=finder,
+                session=PipSession(),
+                options=options,
+            )
+        )
 
-        assert finder.index_urls == ['url1', 'url2']
+        assert finder.index_urls == ["url1", "url2"]
 
     def test_expand_existing_env_variables(self, tmpdir, finder):
-        template = (
-            'https://{}:x-oauth-basic@github.com/'
-            'user/{}/archive/master.zip'
-        )
+        template = "https://{}:x-oauth-basic@github.com/" "user/{}/archive/master.zip"
 
         def make_var(name):
-            return '${{{name}}}'.format(**locals())
+            return "${{{name}}}".format(**locals())
 
-        env_vars = collections.OrderedDict([
-            ('GITHUB_TOKEN', 'notarealtoken'),
-            ('DO_12_FACTOR', 'awwyeah'),
-        ])
+        env_vars = collections.OrderedDict(
+            [
+                ("GITHUB_TOKEN", "notarealtoken"),
+                ("DO_12_FACTOR", "awwyeah"),
+            ]
+        )
 
-        with open(tmpdir.joinpath('req1.txt'), 'w') as fp:
+        with open(tmpdir.joinpath("req1.txt"), "w") as fp:
             fp.write(template.format(*map(make_var, env_vars)))
 
-        with patch('pip._internal.req.req_file.os.getenv') as getenv:
+        with patch("pip._internal.req.req_file.os.getenv") as getenv:
             getenv.side_effect = lambda n: env_vars[n]
 
-            reqs = list(parse_reqfile(
-                tmpdir.joinpath('req1.txt'),
-                finder=finder,
-                session=PipSession()
-            ))
+            reqs = list(
+                parse_reqfile(
+                    tmpdir.joinpath("req1.txt"), finder=finder, session=PipSession()
+                )
+            )
 
-        assert len(reqs) == 1, \
-            'parsing requirement file with env variable failed'
+        assert len(reqs) == 1, "parsing requirement file with env variable failed"
 
         expected_url = template.format(*env_vars.values())
-        assert reqs[0].link.url == expected_url, \
-            'variable expansion in req file failed'
+        assert reqs[0].link.url == expected_url, "variable expansion in req file failed"
 
     def test_expand_missing_env_variables(self, tmpdir, finder):
         req_url = (
-            'https://${NON_EXISTENT_VARIABLE}:$WRONG_FORMAT@'
-            '%WINDOWS_FORMAT%github.com/user/repo/archive/master.zip'
+            "https://${NON_EXISTENT_VARIABLE}:$WRONG_FORMAT@"
+            "%WINDOWS_FORMAT%github.com/user/repo/archive/master.zip"
         )
 
-        with open(tmpdir.joinpath('req1.txt'), 'w') as fp:
+        with open(tmpdir.joinpath("req1.txt"), "w") as fp:
             fp.write(req_url)
 
-        with patch('pip._internal.req.req_file.os.getenv') as getenv:
-            getenv.return_value = ''
+        with patch("pip._internal.req.req_file.os.getenv") as getenv:
+            getenv.return_value = ""
 
-            reqs = list(parse_reqfile(
-                tmpdir.joinpath('req1.txt'),
-                finder=finder,
-                session=PipSession()
-            ))
+            reqs = list(
+                parse_reqfile(
+                    tmpdir.joinpath("req1.txt"), finder=finder, session=PipSession()
+                )
+            )
 
-            assert len(reqs) == 1, \
-                'parsing requirement file with env variable failed'
-            assert reqs[0].link.url == req_url, \
-                'ignoring invalid env variable in req file failed'
+            assert len(reqs) == 1, "parsing requirement file with env variable failed"
+            assert (
+                reqs[0].link.url == req_url
+            ), "ignoring invalid env variable in req file failed"
 
     def test_join_lines(self, tmpdir, finder):
         with open(tmpdir.joinpath("req1.txt"), "w") as fp:
             fp.write("--extra-index-url url1 \\\n--extra-index-url url2")
 
-        list(parse_reqfile(tmpdir.joinpath("req1.txt"), finder=finder,
-                           session=PipSession()))
+        list(
+            parse_reqfile(
+                tmpdir.joinpath("req1.txt"), finder=finder, session=PipSession()
+            )
+        )
 
-        assert finder.index_urls == ['url1', 'url2']
+        assert finder.index_urls == ["url1", "url2"]
 
     def test_req_file_parse_no_only_binary(self, data, finder):
-        list(parse_reqfile(
-            data.reqfiles.joinpath("supported_options2.txt"),
-            finder=finder,
-            session=PipSession()))
-        expected = FormatControl({'fred'}, {'wilma'})
+        list(
+            parse_reqfile(
+                data.reqfiles.joinpath("supported_options2.txt"),
+                finder=finder,
+                session=PipSession(),
+            )
+        )
+        expected = FormatControl({"fred"}, {"wilma"})
         assert finder.format_control == expected
 
     def test_req_file_parse_comment_start_of_line(self, tmpdir, finder):
@@ -666,9 +664,11 @@ def test_req_file_parse_comment_start_of_line(self, tmpdir, finder):
         with open(tmpdir.joinpath("req1.txt"), "w") as fp:
             fp.write("# Comment ")
 
-        reqs = list(parse_reqfile(tmpdir.joinpath("req1.txt"),
-                    finder=finder,
-                    session=PipSession()))
+        reqs = list(
+            parse_reqfile(
+                tmpdir.joinpath("req1.txt"), finder=finder, session=PipSession()
+            )
+        )
 
         assert not reqs
 
@@ -679,9 +679,11 @@ def test_req_file_parse_comment_end_of_line_with_url(self, tmpdir, finder):
         with open(tmpdir.joinpath("req1.txt"), "w") as fp:
             fp.write("https://example.com/foo.tar.gz # Comment ")
 
-        reqs = list(parse_reqfile(tmpdir.joinpath("req1.txt"),
-                    finder=finder,
-                    session=PipSession()))
+        reqs = list(
+            parse_reqfile(
+                tmpdir.joinpath("req1.txt"), finder=finder, session=PipSession()
+            )
+        )
 
         assert len(reqs) == 1
         assert reqs[0].link.url == "https://example.com/foo.tar.gz"
@@ -693,9 +695,11 @@ def test_req_file_parse_egginfo_end_of_line_with_url(self, tmpdir, finder):
         with open(tmpdir.joinpath("req1.txt"), "w") as fp:
             fp.write("https://example.com/foo.tar.gz#egg=wat")
 
-        reqs = list(parse_reqfile(tmpdir.joinpath("req1.txt"),
-                    finder=finder,
-                    session=PipSession()))
+        reqs = list(
+            parse_reqfile(
+                tmpdir.joinpath("req1.txt"), finder=finder, session=PipSession()
+            )
+        )
 
         assert len(reqs) == 1
         assert reqs[0].name == "wat"
@@ -705,35 +709,39 @@ def test_req_file_no_finder(self, tmpdir):
         Test parsing a requirements file without a finder
         """
         with open(tmpdir.joinpath("req.txt"), "w") as fp:
-            fp.write("""
+            fp.write(
+                """
     --find-links https://example.com/
     --index-url https://example.com/
     --extra-index-url https://two.example.com/
     --no-use-wheel
     --no-index
-            """)
+            """
+            )
 
         parse_reqfile(tmpdir.joinpath("req.txt"), session=PipSession())
 
-    def test_install_requirements_with_options(self, tmpdir, finder, session,
-                                               options):
-        global_option = '--dry-run'
-        install_option = '--prefix=/opt'
+    def test_install_requirements_with_options(self, tmpdir, finder, session, options):
+        global_option = "--dry-run"
+        install_option = "--prefix=/opt"
 
-        content = '''
+        content = """
         --only-binary :all:
         INITools==2.0 --global-option="{global_option}" \
                         --install-option "{install_option}"
-        '''.format(global_option=global_option, install_option=install_option)
+        """.format(
+            global_option=global_option, install_option=install_option
+        )
 
         with requirements_file(content, tmpdir) as reqs_file:
-            req = next(parse_reqfile(reqs_file.resolve(),
-                                     finder=finder,
-                                     options=options,
-                                     session=session))
+            req = next(
+                parse_reqfile(
+                    reqs_file.resolve(), finder=finder, options=options, session=session
+                )
+            )
 
         req.source_dir = os.curdir
-        with patch.object(subprocess, 'Popen') as popen:
+        with patch.object(subprocess, "Popen") as popen:
             popen.return_value.stdout.readline.return_value = b""
             try:
                 req.install([])
@@ -743,8 +751,10 @@ def test_install_requirements_with_options(self, tmpdir, finder, session,
             last_call = popen.call_args_list[-1]
             args = last_call[0][0]
             assert (
-                0 < args.index(global_option) < args.index('install') <
-                args.index(install_option)
+                0
+                < args.index(global_option)
+                < args.index("install")
+                < args.index(install_option)
             )
-        assert options.format_control.no_binary == {':all:'}
+        assert options.format_control.no_binary == {":all:"}
         assert options.format_control.only_binary == set()
diff --git a/tests/unit/test_req_install.py b/tests/unit/test_req_install.py
index d0d80035299..f31ec9f58e6 100644
--- a/tests/unit/test_req_install.py
+++ b/tests/unit/test_req_install.py
@@ -19,13 +19,14 @@ def test_tmp_build_directory(self):
         # when req is None, we can produce a temporary directory
         # Make sure we're handling it correctly with real path.
         requirement = InstallRequirement(None, None)
-        tmp_dir = tempfile.mkdtemp('-build', 'pip-')
+        tmp_dir = tempfile.mkdtemp("-build", "pip-")
         tmp_build_dir = requirement.ensure_build_location(
-            tmp_dir, autodelete=False, parallel_builds=False,
+            tmp_dir,
+            autodelete=False,
+            parallel_builds=False,
         )
-        assert (
-            os.path.dirname(tmp_build_dir) ==
-            os.path.realpath(os.path.dirname(tmp_dir))
+        assert os.path.dirname(tmp_build_dir) == os.path.realpath(
+            os.path.dirname(tmp_dir)
         )
         # are we on a system where /tmp is a symlink
         if os.path.realpath(tmp_dir) != os.path.abspath(tmp_dir):
@@ -41,8 +42,8 @@ def test_forward_slash_results_in_a_link(self, tmpdir):
         # Just create a file for letting the logic work
         setup_py_path = install_dir / "setup.py"
         os.makedirs(str(install_dir))
-        with open(setup_py_path, 'w') as f:
-            f.write('')
+        with open(setup_py_path, "w") as f:
+            f.write("")
 
         requirement = install_req_from_line(
             str(install_dir).replace(os.sep, os.altsep or os.sep)
@@ -52,7 +53,6 @@ def test_forward_slash_results_in_a_link(self, tmpdir):
 
 
 class TestInstallRequirementFrom(object):
-
     def test_install_req_from_string_invalid_requirement(self):
         """
         Requirement strings that cannot be parsed by
@@ -61,9 +61,7 @@ def test_install_req_from_string_invalid_requirement(self):
         with pytest.raises(InstallationError) as excinfo:
             install_req_from_req_string("http:/this/is/invalid")
 
-        assert str(excinfo.value) == (
-            "Invalid requirement: 'http:/this/is/invalid'"
-        )
+        assert str(excinfo.value) == ("Invalid requirement: 'http:/this/is/invalid'")
 
     def test_install_req_from_string_without_comes_from(self):
         """
@@ -71,8 +69,10 @@ def test_install_req_from_string_without_comes_from(self):
         when called with URL (PEP 508) but without comes_from.
         """
         # Test with a PEP 508 url install string:
-        wheel_url = ("https://download.pytorch.org/whl/cu90/"
-                     "torch-1.0.0-cp36-cp36m-win_amd64.whl")
+        wheel_url = (
+            "https://download.pytorch.org/whl/cu90/"
+            "torch-1.0.0-cp36-cp36m-win_amd64.whl"
+        )
         install_str = "torch@ " + wheel_url
         install_req = install_req_from_req_string(install_str)
 
@@ -89,19 +89,17 @@ def test_install_req_from_string_with_comes_from_without_link(self):
         does not have a link.
         """
         # Test with a PEP 508 url install string:
-        wheel_url = ("https://download.pytorch.org/whl/cu90/"
-                     "torch-1.0.0-cp36-cp36m-win_amd64.whl")
+        wheel_url = (
+            "https://download.pytorch.org/whl/cu90/"
+            "torch-1.0.0-cp36-cp36m-win_amd64.whl"
+        )
         install_str = "torch@ " + wheel_url
 
         # Dummy numpy "comes_from" requirement without link:
-        comes_from = InstallRequirement(
-            Requirement("numpy>=1.15.0"), comes_from=None
-        )
+        comes_from = InstallRequirement(Requirement("numpy>=1.15.0"), comes_from=None)
 
         # Attempt install from install string comes:
-        install_req = install_req_from_req_string(
-            install_str, comes_from=comes_from
-        )
+        install_req = install_req_from_req_string(install_str, comes_from=comes_from)
 
         assert isinstance(install_req, InstallRequirement)
         assert install_req.comes_from.link is None
diff --git a/tests/unit/test_req_uninstall.py b/tests/unit/test_req_uninstall.py
index d4d707e6042..608709fb642 100644
--- a/tests/unit/test_req_uninstall.py
+++ b/tests/unit/test_req_uninstall.py
@@ -26,23 +26,23 @@ def mock_is_local(path):
 def test_uninstallation_paths():
     class dist(object):
         def get_metadata_lines(self, record):
-            return ['file.py,,',
-                    'file.pyc,,',
-                    'file.so,,',
-                    'nopyc.py']
-        location = ''
+            return ["file.py,,", "file.pyc,,", "file.so,,", "nopyc.py"]
+
+        location = ""
 
     d = dist()
 
     paths = list(uninstallation_paths(d))
 
-    expected = ['file.py',
-                'file.pyc',
-                'file.pyo',
-                'file.so',
-                'nopyc.py',
-                'nopyc.pyc',
-                'nopyc.pyo']
+    expected = [
+        "file.py",
+        "file.pyc",
+        "file.pyo",
+        "file.so",
+        "nopyc.py",
+        "nopyc.pyc",
+        "nopyc.pyo",
+    ]
 
     assert paths == expected
 
@@ -56,26 +56,26 @@ def test_compressed_listing(tmpdir):
     def in_tmpdir(paths):
         li = []
         for path in paths:
-            li.append(
-                str(os.path.join(tmpdir, path.replace("/", os.path.sep)))
-            )
+            li.append(str(os.path.join(tmpdir, path.replace("/", os.path.sep))))
         return li
 
-    sample = in_tmpdir([
-        "lib/mypkg.dist-info/METADATA",
-        "lib/mypkg.dist-info/PKG-INFO",
-        "lib/mypkg/would_be_removed.txt",
-        "lib/mypkg/would_be_skipped.skip.txt",
-        "lib/mypkg/__init__.py",
-        "lib/mypkg/my_awesome_code.py",
-        "lib/mypkg/__pycache__/my_awesome_code-magic.pyc",
-        "lib/mypkg/support/support_file.py",
-        "lib/mypkg/support/more_support.py",
-        "lib/mypkg/support/would_be_skipped.skip.py",
-        "lib/mypkg/support/__pycache__/support_file-magic.pyc",
-        "lib/random_other_place/file_without_a_dot_pyc",
-        "bin/mybin",
-    ])
+    sample = in_tmpdir(
+        [
+            "lib/mypkg.dist-info/METADATA",
+            "lib/mypkg.dist-info/PKG-INFO",
+            "lib/mypkg/would_be_removed.txt",
+            "lib/mypkg/would_be_skipped.skip.txt",
+            "lib/mypkg/__init__.py",
+            "lib/mypkg/my_awesome_code.py",
+            "lib/mypkg/__pycache__/my_awesome_code-magic.pyc",
+            "lib/mypkg/support/support_file.py",
+            "lib/mypkg/support/more_support.py",
+            "lib/mypkg/support/would_be_skipped.skip.py",
+            "lib/mypkg/support/__pycache__/support_file-magic.pyc",
+            "lib/random_other_place/file_without_a_dot_pyc",
+            "bin/mybin",
+        ]
+    )
 
     # Create the required files
     for fname in sample:
@@ -84,30 +84,36 @@ def in_tmpdir(paths):
     # Remove the files to be skipped from the paths
     sample = [path for path in sample if ".skip." not in path]
 
-    expected_remove = in_tmpdir([
-        "bin/mybin",
-        "lib/mypkg.dist-info/*",
-        "lib/mypkg/*",
-        "lib/random_other_place/file_without_a_dot_pyc",
-    ])
-
-    expected_skip = in_tmpdir([
-        "lib/mypkg/would_be_skipped.skip.txt",
-        "lib/mypkg/support/would_be_skipped.skip.py",
-    ])
-
-    expected_rename = in_tmpdir([
-        "bin/",
-        "lib/mypkg.dist-info/",
-        "lib/mypkg/would_be_removed.txt",
-        "lib/mypkg/__init__.py",
-        "lib/mypkg/my_awesome_code.py",
-        "lib/mypkg/__pycache__/",
-        "lib/mypkg/support/support_file.py",
-        "lib/mypkg/support/more_support.py",
-        "lib/mypkg/support/__pycache__/",
-        "lib/random_other_place/",
-    ])
+    expected_remove = in_tmpdir(
+        [
+            "bin/mybin",
+            "lib/mypkg.dist-info/*",
+            "lib/mypkg/*",
+            "lib/random_other_place/file_without_a_dot_pyc",
+        ]
+    )
+
+    expected_skip = in_tmpdir(
+        [
+            "lib/mypkg/would_be_skipped.skip.txt",
+            "lib/mypkg/support/would_be_skipped.skip.py",
+        ]
+    )
+
+    expected_rename = in_tmpdir(
+        [
+            "bin/",
+            "lib/mypkg.dist-info/",
+            "lib/mypkg/would_be_removed.txt",
+            "lib/mypkg/__init__.py",
+            "lib/mypkg/my_awesome_code.py",
+            "lib/mypkg/__pycache__/",
+            "lib/mypkg/support/support_file.py",
+            "lib/mypkg/support/more_support.py",
+            "lib/mypkg/support/__pycache__/",
+            "lib/random_other_place/",
+        ]
+    )
 
     will_remove, will_skip = compress_for_output_listing(sample)
     will_rename = compress_for_rename(sample)
@@ -118,13 +124,11 @@ def in_tmpdir(paths):
 
 class TestUninstallPathSet(object):
     def test_add(self, tmpdir, monkeypatch):
-        monkeypatch.setattr(pip._internal.req.req_uninstall, 'is_local',
-                            mock_is_local)
+        monkeypatch.setattr(pip._internal.req.req_uninstall, "is_local", mock_is_local)
         # Fix case for windows tests
-        file_extant = os.path.normcase(os.path.join(tmpdir, 'foo'))
-        file_nonexistent = os.path.normcase(
-            os.path.join(tmpdir, 'nonexistent'))
-        with open(file_extant, 'w'):
+        file_extant = os.path.normcase(os.path.join(tmpdir, "foo"))
+        file_nonexistent = os.path.normcase(os.path.join(tmpdir, "nonexistent"))
+        with open(file_extant, "w"):
             pass
 
         ups = UninstallPathSet(dist=Mock())
@@ -136,23 +140,20 @@ def test_add(self, tmpdir, monkeypatch):
         assert ups.paths == {file_extant}
 
     def test_add_pth(self, tmpdir, monkeypatch):
-        monkeypatch.setattr(pip._internal.req.req_uninstall, 'is_local',
-                            mock_is_local)
+        monkeypatch.setattr(pip._internal.req.req_uninstall, "is_local", mock_is_local)
         # Fix case for windows tests
         tmpdir = os.path.normcase(tmpdir)
-        on_windows = sys.platform == 'win32'
-        pth_file = os.path.join(tmpdir, 'foo.pth')
-        relative = '../../example'
+        on_windows = sys.platform == "win32"
+        pth_file = os.path.join(tmpdir, "foo.pth")
+        relative = "../../example"
         if on_windows:
-            share = '\\\\example\\share\\'
-            share_com = '\\\\example.com\\share\\'
+            share = "\\\\example\\share\\"
+            share_com = "\\\\example.com\\share\\"
         # Create a .pth file for testing
-        with open(pth_file, 'w') as f:
-            f.writelines([tmpdir, '\n',
-                          relative, '\n'])
+        with open(pth_file, "w") as f:
+            f.writelines([tmpdir, "\n", relative, "\n"])
             if on_windows:
-                f.writelines([share, '\n',
-                              share_com, '\n'])
+                f.writelines([share, "\n", share_com, "\n"])
         # Add paths to be removed
         pth = UninstallPthEntries(pth_file)
         pth.add(tmpdir)
@@ -169,12 +170,11 @@ def test_add_pth(self, tmpdir, monkeypatch):
 
     @pytest.mark.skipif("sys.platform == 'win32'")
     def test_add_symlink(self, tmpdir, monkeypatch):
-        monkeypatch.setattr(pip._internal.req.req_uninstall, 'is_local',
-                            mock_is_local)
-        f = os.path.join(tmpdir, 'foo')
-        with open(f, 'w'):
+        monkeypatch.setattr(pip._internal.req.req_uninstall, "is_local", mock_is_local)
+        f = os.path.join(tmpdir, "foo")
+        with open(f, "w"):
             pass
-        foo_link = os.path.join(tmpdir, 'foo_link')
+        foo_link = os.path.join(tmpdir, "foo_link")
         os.symlink(f, foo_link)
 
         ups = UninstallPathSet(dist=Mock())
@@ -182,32 +182,31 @@ def test_add_symlink(self, tmpdir, monkeypatch):
         assert ups.paths == {foo_link}
 
     def test_compact_shorter_path(self, monkeypatch):
-        monkeypatch.setattr(pip._internal.req.req_uninstall, 'is_local',
-                            mock_is_local)
-        monkeypatch.setattr('os.path.exists', lambda p: True)
+        monkeypatch.setattr(pip._internal.req.req_uninstall, "is_local", mock_is_local)
+        monkeypatch.setattr("os.path.exists", lambda p: True)
         # This deals with nt/posix path differences
-        short_path = os.path.normcase(os.path.abspath(
-            os.path.join(os.path.sep, 'path')))
+        short_path = os.path.normcase(
+            os.path.abspath(os.path.join(os.path.sep, "path"))
+        )
         ups = UninstallPathSet(dist=Mock())
         ups.add(short_path)
-        ups.add(os.path.join(short_path, 'longer'))
+        ups.add(os.path.join(short_path, "longer"))
         assert compact(ups.paths) == {short_path}
 
     @pytest.mark.skipif("sys.platform == 'win32'")
     def test_detect_symlink_dirs(self, monkeypatch, tmpdir):
-        monkeypatch.setattr(pip._internal.req.req_uninstall, 'is_local',
-                            mock_is_local)
+        monkeypatch.setattr(pip._internal.req.req_uninstall, "is_local", mock_is_local)
 
         # construct 2 paths:
         #  tmpdir/dir/file
         #  tmpdir/dirlink/file (where dirlink is a link to dir)
-        d = tmpdir.joinpath('dir')
+        d = tmpdir.joinpath("dir")
         d.mkdir()
-        dlink = tmpdir.joinpath('dirlink')
+        dlink = tmpdir.joinpath("dirlink")
         os.symlink(d, dlink)
-        d.joinpath('file').touch()
-        path1 = str(d.joinpath('file'))
-        path2 = str(dlink.joinpath('file'))
+        d.joinpath("file").touch()
+        path1 = str(d.joinpath("file"))
+        path2 = str(dlink.joinpath("file"))
 
         ups = UninstallPathSet(dist=Mock())
         ups.add(path1)
@@ -232,25 +231,31 @@ def mock_walk(cls, root):
         for dirname, subdirs, files in cls.WALK_RESULT:
             dirname = os.path.sep.join(dirname.split("/"))
             if dirname.startswith(root):
-                yield dirname[len(root) + 1:], subdirs, files
+                yield dirname[len(root) + 1 :], subdirs, files
 
     def test_compress_for_rename(self, monkeypatch):
-        paths = [os.path.sep.join(p.split("/")) for p in [
-            "A/B/b.py",
-            "A/B/D/c.py",
-            "A/C/d.py",
-            "A/E/f.py",
-            "A/G/g.py",
-        ]]
-
-        expected_paths = [os.path.sep.join(p.split("/")) for p in [
-            "A/B/",         # selected everything below A/B
-            "A/C/d.py",     # did not select everything below A/C
-            "A/E/",         # only empty folders remain under A/E
-            "A/G/g.py",     # non-empty folder remains under A/G
-        ]]
-
-        monkeypatch.setattr('os.walk', self.mock_walk)
+        paths = [
+            os.path.sep.join(p.split("/"))
+            for p in [
+                "A/B/b.py",
+                "A/B/D/c.py",
+                "A/C/d.py",
+                "A/E/f.py",
+                "A/G/g.py",
+            ]
+        ]
+
+        expected_paths = [
+            os.path.sep.join(p.split("/"))
+            for p in [
+                "A/B/",  # selected everything below A/B
+                "A/C/d.py",  # did not select everything below A/C
+                "A/E/",  # only empty folders remain under A/E
+                "A/G/g.py",  # non-empty folder remains under A/G
+            ]
+        ]
+
+        monkeypatch.setattr("os.walk", self.mock_walk)
 
         actual_paths = compress_for_rename(paths)
         assert set(expected_paths) == set(actual_paths)
@@ -269,15 +274,21 @@ def make_stash(cls, tmpdir, paths):
 
         pathset = StashedUninstallPathSet()
 
-        paths = [os.path.join(tmpdir, *p.split('/')) for p in paths]
+        paths = [os.path.join(tmpdir, *p.split("/")) for p in paths]
         stashed_paths = [(p, pathset.stash(p)) for p in paths]
 
         return pathset, stashed_paths
 
     def test_stash(self, tmpdir):
-        pathset, stashed_paths = self.make_stash(tmpdir, [
-            "A/B/", "A/C/d.py", "A/E/", "A/G/g.py",
-        ])
+        pathset, stashed_paths = self.make_stash(
+            tmpdir,
+            [
+                "A/B/",
+                "A/C/d.py",
+                "A/E/",
+                "A/G/g.py",
+            ],
+        )
 
         for old_path, new_path in stashed_paths:
             assert not os.path.exists(old_path)
@@ -286,9 +297,15 @@ def test_stash(self, tmpdir):
         assert stashed_paths == pathset._moves
 
     def test_commit(self, tmpdir):
-        pathset, stashed_paths = self.make_stash(tmpdir, [
-            "A/B/", "A/C/d.py", "A/E/", "A/G/g.py",
-        ])
+        pathset, stashed_paths = self.make_stash(
+            tmpdir,
+            [
+                "A/B/",
+                "A/C/d.py",
+                "A/E/",
+                "A/G/g.py",
+            ],
+        )
 
         pathset.commit()
 
@@ -297,9 +314,15 @@ def test_commit(self, tmpdir):
             assert not os.path.exists(new_path)
 
     def test_rollback(self, tmpdir):
-        pathset, stashed_paths = self.make_stash(tmpdir, [
-            "A/B/", "A/C/d.py", "A/E/", "A/G/g.py",
-        ])
+        pathset, stashed_paths = self.make_stash(
+            tmpdir,
+            [
+                "A/B/",
+                "A/C/d.py",
+                "A/E/",
+                "A/G/g.py",
+            ],
+        )
 
         pathset.rollback()
 
diff --git a/tests/unit/test_resolution_legacy_resolver.py b/tests/unit/test_resolution_legacy_resolver.py
index 561313c002b..df4321513d0 100644
--- a/tests/unit/test_resolution_legacy_resolver.py
+++ b/tests/unit/test_resolution_legacy_resolver.py
@@ -4,10 +4,7 @@
 import pytest
 from pip._vendor import pkg_resources
 
-from pip._internal.exceptions import (
-    NoneMetadataError,
-    UnsupportedPythonVersion,
-)
+from pip._internal.exceptions import NoneMetadataError, UnsupportedPythonVersion
 from pip._internal.req.constructors import install_req_from_line
 from pip._internal.resolution.legacy.resolver import (
     Resolver,
@@ -21,7 +18,6 @@
 # We need to inherit from DistInfoDistribution for the `isinstance()`
 # check inside `packaging.get_metadata()` to work.
 class FakeDist(pkg_resources.DistInfoDistribution):
-
     def __init__(self, metadata, metadata_name=None):
         """
         :param metadata: The value that dist.get_metadata() should return
@@ -30,17 +26,17 @@ def __init__(self, metadata, metadata_name=None):
             (can be "METADATA" or "PKG-INFO").  Defaults to "METADATA".
         """
         if metadata_name is None:
-            metadata_name = 'METADATA'
+            metadata_name = "METADATA"
 
-        self.project_name = 'my-project'
+        self.project_name = "my-project"
         self.metadata_name = metadata_name
         self.metadata = metadata
 
     def __str__(self):
-        return '<distribution {!r}>'.format(self.project_name)
+        return "<distribution {!r}>".format(self.project_name)
 
     def has_metadata(self, name):
-        return (name == self.metadata_name)
+        return name == self.metadata_name
 
     def get_metadata(self, name):
         assert name == self.metadata_name
@@ -48,9 +44,9 @@ def get_metadata(self, name):
 
 
 def make_fake_dist(requires_python=None, metadata_name=None):
-    metadata = 'Name: test\n'
+    metadata = "Name: test\n"
     if requires_python is not None:
-        metadata += 'Requires-Python:{}'.format(requires_python)
+        metadata += "Requires-Python:{}".format(requires_python)
 
     return FakeDist(metadata, metadata_name=metadata_name)
 
@@ -66,7 +62,7 @@ def test_compatible(self, caplog):
         Test a Python version compatible with the dist's Requires-Python.
         """
         caplog.set_level(logging.DEBUG)
-        dist = make_fake_dist('== 3.6.5')
+        dist = make_fake_dist("== 3.6.5")
 
         _check_dist_requires_python(
             dist,
@@ -79,7 +75,7 @@ def test_incompatible(self):
         """
         Test a Python version incompatible with the dist's Requires-Python.
         """
-        dist = make_fake_dist('== 3.6.4')
+        dist = make_fake_dist("== 3.6.4")
         with pytest.raises(UnsupportedPythonVersion) as exc:
             _check_dist_requires_python(
                 dist,
@@ -97,7 +93,7 @@ def test_incompatible_with_ignore_requires(self, caplog):
         while passing ignore_requires_python=True.
         """
         caplog.set_level(logging.DEBUG)
-        dist = make_fake_dist('== 3.6.4')
+        dist = make_fake_dist("== 3.6.4")
         _check_dist_requires_python(
             dist,
             version_info=(3, 6, 5),
@@ -105,7 +101,7 @@ def test_incompatible_with_ignore_requires(self, caplog):
         )
         assert len(caplog.records) == 1
         record = caplog.records[0]
-        assert record.levelname == 'DEBUG'
+        assert record.levelname == "DEBUG"
         assert record.message == (
             "Ignoring failed Requires-Python check for package 'my-project': "
             "3.6.5 not in '== 3.6.4'"
@@ -134,7 +130,7 @@ def test_invalid_requires_python(self, caplog):
         Test a dist with an invalid Requires-Python.
         """
         caplog.set_level(logging.DEBUG)
-        dist = make_fake_dist('invalid')
+        dist = make_fake_dist("invalid")
         _check_dist_requires_python(
             dist,
             version_info=(3, 6, 5),
@@ -142,16 +138,19 @@ def test_invalid_requires_python(self, caplog):
         )
         assert len(caplog.records) == 1
         record = caplog.records[0]
-        assert record.levelname == 'WARNING'
+        assert record.levelname == "WARNING"
         assert record.message == (
             "Package 'my-project' has an invalid Requires-Python: "
             "Invalid specifier: 'invalid'"
         )
 
-    @pytest.mark.parametrize('metadata_name', [
-        'METADATA',
-        'PKG-INFO',
-    ])
+    @pytest.mark.parametrize(
+        "metadata_name",
+        [
+            "METADATA",
+            "PKG-INFO",
+        ],
+    )
     def test_empty_metadata_error(self, caplog, metadata_name):
         """
         Test dist.has_metadata() returning True and dist.get_metadata()
@@ -180,6 +179,7 @@ class TestYankedWarning(object):
     """
     Test _populate_link() emits warning if one or more candidates are yanked.
     """
+
     def _make_test_resolver(self, monkeypatch, mock_candidates):
         def _find_candidates(project_name):
             return mock_candidates
@@ -205,8 +205,8 @@ def test_sort_best_candidate__has_non_yanked(self, caplog, monkeypatch):
         Test unyanked candidate preferred over yanked.
         """
         candidates = [
-            make_mock_candidate('1.0'),
-            make_mock_candidate('2.0', yanked_reason='bad metadata #2'),
+            make_mock_candidate("1.0"),
+            make_mock_candidate("2.0", yanked_reason="bad metadata #2"),
         ]
         ireq = install_req_from_line("pkg")
 
@@ -221,10 +221,10 @@ def test_sort_best_candidate__all_yanked(self, caplog, monkeypatch):
         Test all candidates yanked.
         """
         candidates = [
-            make_mock_candidate('1.0', yanked_reason='bad metadata #1'),
+            make_mock_candidate("1.0", yanked_reason="bad metadata #1"),
             # Put the best candidate in the middle, to test sorting.
-            make_mock_candidate('3.0', yanked_reason='bad metadata #3'),
-            make_mock_candidate('2.0', yanked_reason='bad metadata #2'),
+            make_mock_candidate("3.0", yanked_reason="bad metadata #3"),
+            make_mock_candidate("2.0", yanked_reason="bad metadata #2"),
         ]
         ireq = install_req_from_line("pkg")
 
@@ -236,28 +236,35 @@ def test_sort_best_candidate__all_yanked(self, caplog, monkeypatch):
         # Check the log messages.
         assert len(caplog.records) == 1
         record = caplog.records[0]
-        assert record.levelname == 'WARNING'
+        assert record.levelname == "WARNING"
         assert record.message == (
-            'The candidate selected for download or install is a yanked '
+            "The candidate selected for download or install is a yanked "
             "version: 'mypackage' candidate "
-            '(version 3.0 at https://example.com/pkg-3.0.tar.gz)\n'
-            'Reason for being yanked: bad metadata #3'
+            "(version 3.0 at https://example.com/pkg-3.0.tar.gz)\n"
+            "Reason for being yanked: bad metadata #3"
         )
 
-    @pytest.mark.parametrize('yanked_reason, expected_reason', [
-        # Test no reason given.
-        ('', '<none given>'),
-        # Test a unicode string with a non-ascii character.
-        (u'curly quote: \u2018', u'curly quote: \u2018'),
-    ])
+    @pytest.mark.parametrize(
+        "yanked_reason, expected_reason",
+        [
+            # Test no reason given.
+            ("", "<none given>"),
+            # Test a unicode string with a non-ascii character.
+            (u"curly quote: \u2018", u"curly quote: \u2018"),
+        ],
+    )
     def test_sort_best_candidate__yanked_reason(
-        self, caplog, monkeypatch, yanked_reason, expected_reason,
+        self,
+        caplog,
+        monkeypatch,
+        yanked_reason,
+        expected_reason,
     ):
         """
         Test the log message with various reason strings.
         """
         candidates = [
-            make_mock_candidate('1.0', yanked_reason=yanked_reason),
+            make_mock_candidate("1.0", yanked_reason=yanked_reason),
         ]
         ireq = install_req_from_line("pkg")
 
@@ -268,11 +275,11 @@ def test_sort_best_candidate__yanked_reason(
 
         assert len(caplog.records) == 1
         record = caplog.records[0]
-        assert record.levelname == 'WARNING'
+        assert record.levelname == "WARNING"
         expected_message = (
-            'The candidate selected for download or install is a yanked '
+            "The candidate selected for download or install is a yanked "
             "version: 'mypackage' candidate "
-            '(version 1.0 at https://example.com/pkg-1.0.tar.gz)\n'
-            'Reason for being yanked: '
+            "(version 1.0 at https://example.com/pkg-1.0.tar.gz)\n"
+            "Reason for being yanked: "
         ) + expected_reason
         assert record.message == expected_message
diff --git a/tests/unit/test_search_scope.py b/tests/unit/test_search_scope.py
index e7f4e3f16b5..b7c86b020e6 100644
--- a/tests/unit/test_search_scope.py
+++ b/tests/unit/test_search_scope.py
@@ -3,39 +3,37 @@
 
 
 class TestSearchScope:
-
     def test_get_formatted_locations_basic_auth(self):
         """
         Test that basic authentication credentials defined in URL
         is not included in formatted output.
         """
         index_urls = [
-            'https://pypi.org/simple',
-            'https://repo-user:repo-pass@repo.domain.com',
-        ]
-        find_links = [
-            'https://links-user:links-pass@page.domain.com'
+            "https://pypi.org/simple",
+            "https://repo-user:repo-pass@repo.domain.com",
         ]
+        find_links = ["https://links-user:links-pass@page.domain.com"]
         search_scope = SearchScope(
-            find_links=find_links, index_urls=index_urls,
+            find_links=find_links,
+            index_urls=index_urls,
         )
 
         result = search_scope.get_formatted_locations()
-        assert 'repo-user:****@repo.domain.com' in result
-        assert 'repo-pass' not in result
-        assert 'links-user:****@page.domain.com' in result
-        assert 'links-pass' not in result
+        assert "repo-user:****@repo.domain.com" in result
+        assert "repo-pass" not in result
+        assert "links-user:****@page.domain.com" in result
+        assert "links-pass" not in result
 
     def test_get_index_urls_locations(self):
         """Check that the canonical name is on all indexes"""
         search_scope = SearchScope(
             find_links=[],
-            index_urls=['file://index1/', 'file://index2'],
+            index_urls=["file://index1/", "file://index2"],
         )
         actual = search_scope.get_index_urls_locations(
-            install_req_from_line('Complex_Name').name
+            install_req_from_line("Complex_Name").name
         )
         assert actual == [
-            'file://index1/complex-name/',
-            'file://index2/complex-name/',
+            "file://index1/complex-name/",
+            "file://index2/complex-name/",
         ]
diff --git a/tests/unit/test_self_check_outdated.py b/tests/unit/test_self_check_outdated.py
index c5e60d92fc4..074425e3073 100644
--- a/tests/unit/test_self_check_outdated.py
+++ b/tests/unit/test_self_check_outdated.py
@@ -24,15 +24,12 @@ def __init__(self, best):
 
 class MockPackageFinder(object):
 
-    BASE_URL = 'https://pypi.org/simple/pip-{0}.tar.gz'
-    PIP_PROJECT_NAME = 'pip'
+    BASE_URL = "https://pypi.org/simple/pip-{0}.tar.gz"
+    PIP_PROJECT_NAME = "pip"
     INSTALLATION_CANDIDATES = [
-        InstallationCandidate(PIP_PROJECT_NAME, '6.9.0',
-                              BASE_URL.format('6.9.0')),
-        InstallationCandidate(PIP_PROJECT_NAME, '3.3.1',
-                              BASE_URL.format('3.3.1')),
-        InstallationCandidate(PIP_PROJECT_NAME, '1.0',
-                              BASE_URL.format('1.0')),
+        InstallationCandidate(PIP_PROJECT_NAME, "6.9.0", BASE_URL.format("6.9.0")),
+        InstallationCandidate(PIP_PROJECT_NAME, "3.3.1", BASE_URL.format("3.3.1")),
+        InstallationCandidate(PIP_PROJECT_NAME, "1.0", BASE_URL.format("1.0")),
     ]
 
     @classmethod
@@ -48,65 +45,76 @@ def __init__(self, installer):
         self.installer = installer
 
     def has_metadata(self, name):
-        return name == 'INSTALLER'
+        return name == "INSTALLER"
 
     def get_metadata_lines(self, name):
         if self.has_metadata(name):
             yield self.installer
         else:
-            raise NotImplementedError('nope')
+            raise NotImplementedError("nope")
 
 
 def _options():
-    ''' Some default options that we pass to
-    self_outdated_check.pip_self_version_check '''
+    """Some default options that we pass to
+    self_outdated_check.pip_self_version_check"""
     return pretend.stub(
-        find_links=[], index_url='default_url', extra_index_urls=[],
-        no_index=False, pre=False, cache_dir='',
+        find_links=[],
+        index_url="default_url",
+        extra_index_urls=[],
+        no_index=False,
+        pre=False,
+        cache_dir="",
     )
 
 
 @pytest.mark.parametrize(
     [
-        'stored_time',
-        'installed_ver',
-        'new_ver',
-        'installer',
-        'check_if_upgrade_required',
-        'check_warn_logs',
+        "stored_time",
+        "installed_ver",
+        "new_ver",
+        "installer",
+        "check_if_upgrade_required",
+        "check_warn_logs",
     ],
     [
         # Test we return None when installed version is None
-        ('1970-01-01T10:00:00Z', None, '1.0', 'pip', False, False),
+        ("1970-01-01T10:00:00Z", None, "1.0", "pip", False, False),
         # Need an upgrade - upgrade warning should print
-        ('1970-01-01T10:00:00Z', '1.0', '6.9.0', 'pip', True, True),
+        ("1970-01-01T10:00:00Z", "1.0", "6.9.0", "pip", True, True),
         # Upgrade available, pip installed via rpm - warning should not print
-        ('1970-01-01T10:00:00Z', '1.0', '6.9.0', 'rpm', True, False),
+        ("1970-01-01T10:00:00Z", "1.0", "6.9.0", "rpm", True, False),
         # No upgrade - upgrade warning should not print
-        ('1970-01-9T10:00:00Z', '6.9.0', '6.9.0', 'pip', False, False),
-    ]
+        ("1970-01-9T10:00:00Z", "6.9.0", "6.9.0", "pip", False, False),
+    ],
 )
-def test_pip_self_version_check(monkeypatch, stored_time, installed_ver,
-                                new_ver, installer,
-                                check_if_upgrade_required, check_warn_logs):
-    monkeypatch.setattr(self_outdated_check, 'get_installed_version',
-                        lambda name: installed_ver)
-    monkeypatch.setattr(self_outdated_check, 'PackageFinder',
-                        MockPackageFinder)
-    monkeypatch.setattr(logger, 'warning',
-                        pretend.call_recorder(lambda *a, **kw: None))
-    monkeypatch.setattr(logger, 'debug',
-                        pretend.call_recorder(lambda s, exc_info=None: None))
-    monkeypatch.setattr(self_outdated_check, 'get_distribution',
-                        lambda name: MockDistribution(installer))
+def test_pip_self_version_check(
+    monkeypatch,
+    stored_time,
+    installed_ver,
+    new_ver,
+    installer,
+    check_if_upgrade_required,
+    check_warn_logs,
+):
+    monkeypatch.setattr(
+        self_outdated_check, "get_installed_version", lambda name: installed_ver
+    )
+    monkeypatch.setattr(self_outdated_check, "PackageFinder", MockPackageFinder)
+    monkeypatch.setattr(logger, "warning", pretend.call_recorder(lambda *a, **kw: None))
+    monkeypatch.setattr(
+        logger, "debug", pretend.call_recorder(lambda s, exc_info=None: None)
+    )
+    monkeypatch.setattr(
+        self_outdated_check,
+        "get_distribution",
+        lambda name: MockDistribution(installer),
+    )
 
     fake_state = pretend.stub(
-        state={"last_check": stored_time, 'pypi_version': installed_ver},
+        state={"last_check": stored_time, "pypi_version": installed_ver},
         save=pretend.call_recorder(lambda v, t: None),
     )
-    monkeypatch.setattr(
-        self_outdated_check, 'SelfCheckState', lambda **kw: fake_state
-    )
+    monkeypatch.setattr(self_outdated_check, "SelfCheckState", lambda **kw: fake_state)
 
     with freezegun.freeze_time(
         "1970-01-09 10:00:00",
@@ -114,7 +122,7 @@ def test_pip_self_version_check(monkeypatch, stored_time, installed_ver,
             "six.moves",
             "pip._vendor.six.moves",
             "pip._vendor.requests.packages.urllib3.packages.six.moves",
-        ]
+        ],
     ):
         latest_pypi_version = pip_self_version_check(None, _options())
 
@@ -139,19 +147,18 @@ def test_pip_self_version_check(monkeypatch, stored_time, installed_ver,
         assert len(logger.warning.calls) == 0
 
 
-statefile_name_case_1 = (
-    "fcd2d5175dd33d5df759ee7b045264230205ef837bf9f582f7c3ada7"
-)
+statefile_name_case_1 = "fcd2d5175dd33d5df759ee7b045264230205ef837bf9f582f7c3ada7"
 
-statefile_name_case_2 = (
-    "902cecc0745b8ecf2509ba473f3556f0ba222fedc6df433acda24aa5"
-)
+statefile_name_case_2 = "902cecc0745b8ecf2509ba473f3556f0ba222fedc6df433acda24aa5"
 
 
-@pytest.mark.parametrize("key,expected", [
-    ("/hello/world/venv", statefile_name_case_1),
-    ("C:\\Users\\User\\Desktop\\venv", statefile_name_case_2),
-])
+@pytest.mark.parametrize(
+    "key,expected",
+    [
+        ("/hello/world/venv", statefile_name_case_1),
+        ("C:\\Users\\User\\Desktop\\venv", statefile_name_case_2),
+    ],
+)
 def test_get_statefile_name_known_values(key, expected):
     assert expected == self_outdated_check._get_statefile_name(key)
 
@@ -223,8 +230,7 @@ def test_self_check_state_writes_expected_statefile(monkeypatch, tmpdir):
 
     expected = {
         "key": key,
-        "last_check": last_check.strftime(
-            self_outdated_check.SELFCHECK_DATE_FMT),
+        "last_check": last_check.strftime(self_outdated_check.SELFCHECK_DATE_FMT),
         "pypi_version": pypi_version,
     }
     assert expected == saved
diff --git a/tests/unit/test_target_python.py b/tests/unit/test_target_python.py
index 0dc2af22bd0..8897df4c8b4 100644
--- a/tests/unit/test_target_python.py
+++ b/tests/unit/test_target_python.py
@@ -6,16 +6,18 @@
 
 
 class TestTargetPython:
-
-    @pytest.mark.parametrize('py_version_info, expected', [
-        ((), ((0, 0, 0), '0.0')),
-        ((2, ), ((2, 0, 0), '2.0')),
-        ((3, ), ((3, 0, 0), '3.0')),
-        ((3, 7), ((3, 7, 0), '3.7')),
-        ((3, 7, 3), ((3, 7, 3), '3.7')),
-        # Check a minor version with two digits.
-        ((3, 10, 1), ((3, 10, 1), '3.10')),
-    ])
+    @pytest.mark.parametrize(
+        "py_version_info, expected",
+        [
+            ((), ((0, 0, 0), "0.0")),
+            ((2,), ((2, 0, 0), "2.0")),
+            ((3,), ((3, 0, 0), "3.0")),
+            ((3, 7), ((3, 7, 0), "3.7")),
+            ((3, 7, 3), ((3, 7, 3), "3.7")),
+            # Check a minor version with two digits.
+            ((3, 10, 1), ((3, 10, 1), "3.10")),
+        ],
+    )
     def test_init__py_version_info(self, py_version_info, expected):
         """
         Test passing the py_version_info argument.
@@ -41,61 +43,72 @@ def test_init__py_version_info_none(self):
         assert target_python.py_version_info == CURRENT_PY_VERSION_INFO
         assert target_python.py_version == pyversion
 
-    @pytest.mark.parametrize('kwargs, expected', [
-        ({}, ''),
-        (dict(py_version_info=(3, 6)), "version_info='3.6'"),
-        (
-            dict(platform='darwin', py_version_info=(3, 6)),
-            "platform='darwin' version_info='3.6'",
-        ),
-        (
-            dict(
-                platform='darwin', py_version_info=(3, 6), abi='cp36m',
-                implementation='cp'
+    @pytest.mark.parametrize(
+        "kwargs, expected",
+        [
+            ({}, ""),
+            (dict(py_version_info=(3, 6)), "version_info='3.6'"),
+            (
+                dict(platform="darwin", py_version_info=(3, 6)),
+                "platform='darwin' version_info='3.6'",
             ),
             (
-                "platform='darwin' version_info='3.6' abi='cp36m' "
-                "implementation='cp'"
+                dict(
+                    platform="darwin",
+                    py_version_info=(3, 6),
+                    abi="cp36m",
+                    implementation="cp",
+                ),
+                (
+                    "platform='darwin' version_info='3.6' abi='cp36m' "
+                    "implementation='cp'"
+                ),
             ),
-        ),
-    ])
+        ],
+    )
     def test_format_given(self, kwargs, expected):
         target_python = TargetPython(**kwargs)
         actual = target_python.format_given()
         assert actual == expected
 
-    @pytest.mark.parametrize('py_version_info, expected_version', [
-        ((), ''),
-        ((2, ), '2'),
-        ((3, ), '3'),
-        ((3, 7), '37'),
-        ((3, 7, 3), '37'),
-        # Check a minor version with two digits.
-        ((3, 10, 1), '310'),
-        # Check that versions=None is passed to get_tags().
-        (None, None),
-    ])
-    @patch('pip._internal.models.target_python.get_supported')
+    @pytest.mark.parametrize(
+        "py_version_info, expected_version",
+        [
+            ((), ""),
+            ((2,), "2"),
+            ((3,), "3"),
+            ((3, 7), "37"),
+            ((3, 7, 3), "37"),
+            # Check a minor version with two digits.
+            ((3, 10, 1), "310"),
+            # Check that versions=None is passed to get_tags().
+            (None, None),
+        ],
+    )
+    @patch("pip._internal.models.target_python.get_supported")
     def test_get_tags(
-        self, mock_get_supported, py_version_info, expected_version,
+        self,
+        mock_get_supported,
+        py_version_info,
+        expected_version,
     ):
-        mock_get_supported.return_value = ['tag-1', 'tag-2']
+        mock_get_supported.return_value = ["tag-1", "tag-2"]
 
         target_python = TargetPython(py_version_info=py_version_info)
         actual = target_python.get_tags()
-        assert actual == ['tag-1', 'tag-2']
+        assert actual == ["tag-1", "tag-2"]
 
-        actual = mock_get_supported.call_args[1]['version']
+        actual = mock_get_supported.call_args[1]["version"]
         assert actual == expected_version
 
         # Check that the value was cached.
-        assert target_python._valid_tags == ['tag-1', 'tag-2']
+        assert target_python._valid_tags == ["tag-1", "tag-2"]
 
     def test_get_tags__uses_cached_value(self):
         """
         Test that get_tags() uses the cached value.
         """
         target_python = TargetPython(py_version_info=None)
-        target_python._valid_tags = ['tag-1', 'tag-2']
+        target_python._valid_tags = ["tag-1", "tag-2"]
         actual = target_python.get_tags()
-        assert actual == ['tag-1', 'tag-2']
+        assert actual == ["tag-1", "tag-2"]
diff --git a/tests/unit/test_urls.py b/tests/unit/test_urls.py
index 7428cef9ebc..026e54cafd6 100644
--- a/tests/unit/test_urls.py
+++ b/tests/unit/test_urls.py
@@ -7,44 +7,50 @@
 from pip._internal.utils.urls import get_url_scheme, path_to_url, url_to_path
 
 
-@pytest.mark.parametrize("url,expected", [
-    ('http://localhost:8080/', 'http'),
-    ('file:c:/path/to/file', 'file'),
-    ('file:/dev/null', 'file'),
-    ('', None),
-])
+@pytest.mark.parametrize(
+    "url,expected",
+    [
+        ("http://localhost:8080/", "http"),
+        ("file:c:/path/to/file", "file"),
+        ("file:/dev/null", "file"),
+        ("", None),
+    ],
+)
 def test_get_url_scheme(url, expected):
     assert get_url_scheme(url) == expected
 
 
 @pytest.mark.skipif("sys.platform == 'win32'")
 def test_path_to_url_unix():
-    assert path_to_url('/tmp/file') == 'file:///tmp/file'
-    path = os.path.join(os.getcwd(), 'file')
-    assert path_to_url('file') == 'file://' + urllib_request.pathname2url(path)
+    assert path_to_url("/tmp/file") == "file:///tmp/file"
+    path = os.path.join(os.getcwd(), "file")
+    assert path_to_url("file") == "file://" + urllib_request.pathname2url(path)
 
 
 @pytest.mark.skipif("sys.platform != 'win32'")
 def test_path_to_url_win():
-    assert path_to_url('c:/tmp/file') == 'file:///C:/tmp/file'
-    assert path_to_url('c:\\tmp\\file') == 'file:///C:/tmp/file'
-    assert path_to_url(r'\\unc\as\path') == 'file://unc/as/path'
-    path = os.path.join(os.getcwd(), 'file')
-    assert path_to_url('file') == 'file:' + urllib_request.pathname2url(path)
+    assert path_to_url("c:/tmp/file") == "file:///C:/tmp/file"
+    assert path_to_url("c:\\tmp\\file") == "file:///C:/tmp/file"
+    assert path_to_url(r"\\unc\as\path") == "file://unc/as/path"
+    path = os.path.join(os.getcwd(), "file")
+    assert path_to_url("file") == "file:" + urllib_request.pathname2url(path)
 
 
-@pytest.mark.parametrize("url,win_expected,non_win_expected", [
-    ('file:tmp', 'tmp', 'tmp'),
-    ('file:c:/path/to/file', r'C:\path\to\file', 'c:/path/to/file'),
-    ('file:/path/to/file', r'\path\to\file', '/path/to/file'),
-    ('file://localhost/tmp/file', r'\tmp\file', '/tmp/file'),
-    ('file://localhost/c:/tmp/file', r'C:\tmp\file', '/c:/tmp/file'),
-    ('file://somehost/tmp/file', r'\\somehost\tmp\file', None),
-    ('file:///tmp/file', r'\tmp\file', '/tmp/file'),
-    ('file:///c:/tmp/file', r'C:\tmp\file', '/c:/tmp/file'),
-])
+@pytest.mark.parametrize(
+    "url,win_expected,non_win_expected",
+    [
+        ("file:tmp", "tmp", "tmp"),
+        ("file:c:/path/to/file", r"C:\path\to\file", "c:/path/to/file"),
+        ("file:/path/to/file", r"\path\to\file", "/path/to/file"),
+        ("file://localhost/tmp/file", r"\tmp\file", "/tmp/file"),
+        ("file://localhost/c:/tmp/file", r"C:\tmp\file", "/c:/tmp/file"),
+        ("file://somehost/tmp/file", r"\\somehost\tmp\file", None),
+        ("file:///tmp/file", r"\tmp\file", "/tmp/file"),
+        ("file:///c:/tmp/file", r"C:\tmp\file", "/c:/tmp/file"),
+    ],
+)
 def test_url_to_path(url, win_expected, non_win_expected):
-    if sys.platform == 'win32':
+    if sys.platform == "win32":
         expected_path = win_expected
     else:
         expected_path = non_win_expected
@@ -58,8 +64,8 @@ def test_url_to_path(url, win_expected, non_win_expected):
 
 @pytest.mark.skipif("sys.platform != 'win32'")
 def test_url_to_path_path_to_url_symmetry_win():
-    path = r'C:\tmp\file'
+    path = r"C:\tmp\file"
     assert url_to_path(path_to_url(path)) == path
 
-    unc_path = r'\\unc\share\path'
+    unc_path = r"\\unc\share\path"
     assert url_to_path(path_to_url(unc_path)) == unc_path
diff --git a/tests/unit/test_utils.py b/tests/unit/test_utils.py
index 0a1c47cd7ae..60c304d7ab5 100644
--- a/tests/unit/test_utils.py
+++ b/tests/unit/test_utils.py
@@ -16,11 +16,7 @@
 import pytest
 from mock import Mock, patch
 
-from pip._internal.exceptions import (
-    HashMismatch,
-    HashMissing,
-    InstallationError,
-)
+from pip._internal.exceptions import HashMismatch, HashMissing, InstallationError
 from pip._internal.utils.deprecation import PipDeprecationWarning, deprecated
 from pip._internal.utils.encoding import BOMS, auto_decode
 from pip._internal.utils.glibc import (
@@ -62,42 +58,44 @@ class Tests_EgglinkPath:
 
     def setup(self):
 
-        project = 'foo'
+        project = "foo"
 
         self.mock_dist = Mock(project_name=project)
-        self.site_packages = 'SITE_PACKAGES'
-        self.user_site = 'USER_SITE'
+        self.site_packages = "SITE_PACKAGES"
+        self.user_site = "USER_SITE"
         self.user_site_egglink = os.path.join(
-            self.user_site,
-            '{}.egg-link'.format(project)
+            self.user_site, "{}.egg-link".format(project)
         )
         self.site_packages_egglink = os.path.join(
             self.site_packages,
-            '{}.egg-link'.format(project),
+            "{}.egg-link".format(project),
         )
 
         # patches
         from pip._internal.utils import misc as utils
+
         self.old_site_packages = utils.site_packages
-        self.mock_site_packages = utils.site_packages = 'SITE_PACKAGES'
+        self.mock_site_packages = utils.site_packages = "SITE_PACKAGES"
         self.old_running_under_virtualenv = utils.running_under_virtualenv
-        self.mock_running_under_virtualenv = utils.running_under_virtualenv = \
-            Mock()
+        self.mock_running_under_virtualenv = utils.running_under_virtualenv = Mock()
         self.old_virtualenv_no_global = utils.virtualenv_no_global
         self.mock_virtualenv_no_global = utils.virtualenv_no_global = Mock()
         self.old_user_site = utils.user_site
         self.mock_user_site = utils.user_site = self.user_site
         from os import path
+
         self.old_isfile = path.isfile
         self.mock_isfile = path.isfile = Mock()
 
     def teardown(self):
         from pip._internal.utils import misc as utils
+
         utils.site_packages = self.old_site_packages
         utils.running_under_virtualenv = self.old_running_under_virtualenv
         utils.virtualenv_no_global = self.old_virtualenv_no_global
         utils.user_site = self.old_user_site
         from os import path
+
         path.isfile = self.old_isfile
 
     def eggLinkInUserSite(self, egglink):
@@ -191,47 +189,53 @@ def test_noegglink_in_sitepkgs_venv_global(self):
         assert egg_link_path(self.mock_dist) is None
 
 
-@patch('pip._internal.utils.misc.dist_in_usersite')
-@patch('pip._internal.utils.misc.dist_is_local')
-@patch('pip._internal.utils.misc.dist_is_editable')
+@patch("pip._internal.utils.misc.dist_in_usersite")
+@patch("pip._internal.utils.misc.dist_is_local")
+@patch("pip._internal.utils.misc.dist_is_editable")
 class TestsGetDistributions(object):
-    """Test get_installed_distributions() and get_distribution().
-    """
+    """Test get_installed_distributions() and get_distribution()."""
+
     class MockWorkingSet(list):
         def require(self, name):
             pass
 
-    workingset = MockWorkingSet((
-        Mock(test_name="global", key="global"),
-        Mock(test_name="editable", key="editable"),
-        Mock(test_name="normal", key="normal"),
-        Mock(test_name="user", key="user"),
-    ))
+    workingset = MockWorkingSet(
+        (
+            Mock(test_name="global", key="global"),
+            Mock(test_name="editable", key="editable"),
+            Mock(test_name="normal", key="normal"),
+            Mock(test_name="user", key="user"),
+        )
+    )
 
-    workingset_stdlib = MockWorkingSet((
-        Mock(test_name='normal', key='argparse'),
-        Mock(test_name='normal', key='wsgiref')
-    ))
+    workingset_stdlib = MockWorkingSet(
+        (
+            Mock(test_name="normal", key="argparse"),
+            Mock(test_name="normal", key="wsgiref"),
+        )
+    )
 
-    workingset_freeze = MockWorkingSet((
-        Mock(test_name='normal', key='pip'),
-        Mock(test_name='normal', key='setuptools'),
-        Mock(test_name='normal', key='distribute')
-    ))
+    workingset_freeze = MockWorkingSet(
+        (
+            Mock(test_name="normal", key="pip"),
+            Mock(test_name="normal", key="setuptools"),
+            Mock(test_name="normal", key="distribute"),
+        )
+    )
 
     def dist_is_editable(self, dist):
         return dist.test_name == "editable"
 
     def dist_is_local(self, dist):
-        return dist.test_name != "global" and dist.test_name != 'user'
+        return dist.test_name != "global" and dist.test_name != "user"
 
     def dist_in_usersite(self, dist):
         return dist.test_name == "user"
 
-    @patch('pip._vendor.pkg_resources.working_set', workingset)
-    def test_editables_only(self, mock_dist_is_editable,
-                            mock_dist_is_local,
-                            mock_dist_in_usersite):
+    @patch("pip._vendor.pkg_resources.working_set", workingset)
+    def test_editables_only(
+        self, mock_dist_is_editable, mock_dist_is_local, mock_dist_in_usersite
+    ):
         mock_dist_is_editable.side_effect = self.dist_is_editable
         mock_dist_is_local.side_effect = self.dist_is_local
         mock_dist_in_usersite.side_effect = self.dist_in_usersite
@@ -239,10 +243,10 @@ def test_editables_only(self, mock_dist_is_editable,
         assert len(dists) == 1, dists
         assert dists[0].test_name == "editable"
 
-    @patch('pip._vendor.pkg_resources.working_set', workingset)
-    def test_exclude_editables(self, mock_dist_is_editable,
-                               mock_dist_is_local,
-                               mock_dist_in_usersite):
+    @patch("pip._vendor.pkg_resources.working_set", workingset)
+    def test_exclude_editables(
+        self, mock_dist_is_editable, mock_dist_is_local, mock_dist_in_usersite
+    ):
         mock_dist_is_editable.side_effect = self.dist_is_editable
         mock_dist_is_local.side_effect = self.dist_is_local
         mock_dist_in_usersite.side_effect = self.dist_in_usersite
@@ -250,47 +254,45 @@ def test_exclude_editables(self, mock_dist_is_editable,
         assert len(dists) == 1
         assert dists[0].test_name == "normal"
 
-    @patch('pip._vendor.pkg_resources.working_set', workingset)
-    def test_include_globals(self, mock_dist_is_editable,
-                             mock_dist_is_local,
-                             mock_dist_in_usersite):
+    @patch("pip._vendor.pkg_resources.working_set", workingset)
+    def test_include_globals(
+        self, mock_dist_is_editable, mock_dist_is_local, mock_dist_in_usersite
+    ):
         mock_dist_is_editable.side_effect = self.dist_is_editable
         mock_dist_is_local.side_effect = self.dist_is_local
         mock_dist_in_usersite.side_effect = self.dist_in_usersite
         dists = get_installed_distributions(local_only=False)
         assert len(dists) == 4
 
-    @patch('pip._vendor.pkg_resources.working_set', workingset)
-    def test_user_only(self, mock_dist_is_editable,
-                       mock_dist_is_local,
-                       mock_dist_in_usersite):
+    @patch("pip._vendor.pkg_resources.working_set", workingset)
+    def test_user_only(
+        self, mock_dist_is_editable, mock_dist_is_local, mock_dist_in_usersite
+    ):
         mock_dist_is_editable.side_effect = self.dist_is_editable
         mock_dist_is_local.side_effect = self.dist_is_local
         mock_dist_in_usersite.side_effect = self.dist_in_usersite
-        dists = get_installed_distributions(local_only=False,
-                                            user_only=True)
+        dists = get_installed_distributions(local_only=False, user_only=True)
         assert len(dists) == 1
         assert dists[0].test_name == "user"
 
-    @patch('pip._vendor.pkg_resources.working_set', workingset_stdlib)
-    def test_gte_py27_excludes(self, mock_dist_is_editable,
-                               mock_dist_is_local,
-                               mock_dist_in_usersite):
+    @patch("pip._vendor.pkg_resources.working_set", workingset_stdlib)
+    def test_gte_py27_excludes(
+        self, mock_dist_is_editable, mock_dist_is_local, mock_dist_in_usersite
+    ):
         mock_dist_is_editable.side_effect = self.dist_is_editable
         mock_dist_is_local.side_effect = self.dist_is_local
         mock_dist_in_usersite.side_effect = self.dist_in_usersite
         dists = get_installed_distributions()
         assert len(dists) == 0
 
-    @patch('pip._vendor.pkg_resources.working_set', workingset_freeze)
-    def test_freeze_excludes(self, mock_dist_is_editable,
-                             mock_dist_is_local,
-                             mock_dist_in_usersite):
+    @patch("pip._vendor.pkg_resources.working_set", workingset_freeze)
+    def test_freeze_excludes(
+        self, mock_dist_is_editable, mock_dist_is_local, mock_dist_in_usersite
+    ):
         mock_dist_is_editable.side_effect = self.dist_is_editable
         mock_dist_is_local.side_effect = self.dist_is_local
         mock_dist_in_usersite.side_effect = self.dist_in_usersite
-        dists = get_installed_distributions(
-            skip=('setuptools', 'pip', 'distribute'))
+        dists = get_installed_distributions(skip=("setuptools", "pip", "distribute"))
         assert len(dists) == 0
 
     @pytest.mark.parametrize(
@@ -298,7 +300,8 @@ def test_freeze_excludes(self, mock_dist_is_editable,
         itertools.chain(
             itertools.product([workingset], (d.key for d in workingset)),
             itertools.product(
-                [workingset_stdlib], (d.key for d in workingset_stdlib),
+                [workingset_stdlib],
+                (d.key for d in workingset_stdlib),
             ),
         ),
     )
@@ -310,8 +313,7 @@ def test_get_distribution(
         working_set,
         req_name,
     ):
-        """Ensure get_distribution() finds all kinds of distributions.
-        """
+        """Ensure get_distribution() finds all kinds of distributions."""
         mock_dist_is_editable.side_effect = self.dist_is_editable
         mock_dist_is_local.side_effect = self.dist_is_local
         mock_dist_in_usersite.side_effect = self.dist_in_usersite
@@ -320,7 +322,7 @@ def test_get_distribution(
         assert dist is not None
         assert dist.key == req_name
 
-    @patch('pip._vendor.pkg_resources.working_set', workingset)
+    @patch("pip._vendor.pkg_resources.working_set", workingset)
     def test_get_distribution_nonexist(
         self,
         mock_dist_is_editable,
@@ -338,7 +340,7 @@ def test_rmtree_errorhandler_nonexistent_directory(tmpdir):
     """
     Test rmtree_errorhandler ignores the given non-existing directory.
     """
-    nonexistent_path = str(tmpdir / 'foo')
+    nonexistent_path = str(tmpdir / "foo")
     mock_func = Mock()
     rmtree_errorhandler(mock_func, nonexistent_path, None)
     mock_func.assert_not_called()
@@ -349,7 +351,7 @@ def test_rmtree_errorhandler_readonly_directory(tmpdir):
     Test rmtree_errorhandler makes the given read-only directory writable.
     """
     # Create read only directory
-    subdir_path = tmpdir / 'subdir'
+    subdir_path = tmpdir / "subdir"
     subdir_path.mkdir()
     path = str(subdir_path)
     os.chmod(path, stat.S_IREAD)
@@ -369,7 +371,7 @@ def test_rmtree_errorhandler_reraises_error(tmpdir):
     by the given unreadable directory.
     """
     # Create directory without read permission
-    subdir_path = tmpdir / 'subdir'
+    subdir_path = tmpdir / "subdir"
     subdir_path.mkdir()
     path = str(subdir_path)
     os.chmod(path, stat.S_IWRITE)
@@ -377,10 +379,10 @@ def test_rmtree_errorhandler_reraises_error(tmpdir):
     mock_func = Mock()
 
     try:
-        raise RuntimeError('test message')
+        raise RuntimeError("test message")
     except RuntimeError:
         # Make sure the handler reraises an exception
-        with pytest.raises(RuntimeError, match='test message'):
+        with pytest.raises(RuntimeError, match="test message"):
             rmtree_errorhandler(mock_func, path, None)
 
     mock_func.assert_not_called()
@@ -391,7 +393,7 @@ def test_rmtree_skips_nonexistent_directory():
     Test wrapped rmtree doesn't raise an error
     by the given nonexistent directory.
     """
-    rmtree.__wrapped__('nonexistent-subdir')
+    rmtree.__wrapped__("nonexistent-subdir")
 
 
 class Failer:
@@ -408,45 +410,46 @@ def test_rmtree_retries(tmpdir, monkeypatch):
     """
     Test pip._internal.utils.rmtree will retry failures
     """
-    monkeypatch.setattr(shutil, 'rmtree', Failer(duration=1).call)
-    rmtree('foo')
+    monkeypatch.setattr(shutil, "rmtree", Failer(duration=1).call)
+    rmtree("foo")
 
 
 def test_rmtree_retries_for_3sec(tmpdir, monkeypatch):
     """
     Test pip._internal.utils.rmtree will retry failures for no more than 3 sec
     """
-    monkeypatch.setattr(shutil, 'rmtree', Failer(duration=5).call)
+    monkeypatch.setattr(shutil, "rmtree", Failer(duration=5).call)
     with pytest.raises(OSError):
-        rmtree('foo')
+        rmtree("foo")
 
 
 if sys.byteorder == "little":
     expected_byte_string = (
-        u"b'\\xff\\xfe/\\x00p\\x00a\\x00t\\x00h\\x00/"
-        "\\x00d\\x00\\xe9\\x00f\\x00'"
+        u"b'\\xff\\xfe/\\x00p\\x00a\\x00t\\x00h\\x00/" "\\x00d\\x00\\xe9\\x00f\\x00'"
     )
 elif sys.byteorder == "big":
     expected_byte_string = (
-        u"b'\\xfe\\xff\\x00/\\x00p\\x00a\\x00t\\x00h\\"
-        "x00/\\x00d\\x00\\xe9\\x00f'"
+        u"b'\\xfe\\xff\\x00/\\x00p\\x00a\\x00t\\x00h\\" "x00/\\x00d\\x00\\xe9\\x00f'"
     )
 
 
-@pytest.mark.parametrize('path, fs_encoding, expected', [
-    (None, None, None),
-    # Test passing a text (unicode) string.
-    (u'/path/déf', None, u'/path/déf'),
-    # Test a bytes object with a non-ascii character.
-    (u'/path/déf'.encode('utf-8'), 'utf-8', u'/path/déf'),
-    # Test a bytes object with a character that can't be decoded.
-    (u'/path/déf'.encode('utf-8'), 'ascii', u"b'/path/d\\xc3\\xa9f'"),
-    (u'/path/déf'.encode('utf-16'), 'utf-8', expected_byte_string),
-])
+@pytest.mark.parametrize(
+    "path, fs_encoding, expected",
+    [
+        (None, None, None),
+        # Test passing a text (unicode) string.
+        (u"/path/déf", None, u"/path/déf"),
+        # Test a bytes object with a non-ascii character.
+        (u"/path/déf".encode("utf-8"), "utf-8", u"/path/déf"),
+        # Test a bytes object with a character that can't be decoded.
+        (u"/path/déf".encode("utf-8"), "ascii", u"b'/path/d\\xc3\\xa9f'"),
+        (u"/path/déf".encode("utf-16"), "utf-8", expected_byte_string),
+    ],
+)
 def test_path_to_display(monkeypatch, path, fs_encoding, expected):
-    monkeypatch.setattr(sys, 'getfilesystemencoding', lambda: fs_encoding)
+    monkeypatch.setattr(sys, "getfilesystemencoding", lambda: fs_encoding)
     actual = path_to_display(path)
-    assert actual == expected, 'actual: {!r}'.format(actual)
+    assert actual == expected, "actual: {!r}".format(actual)
 
 
 class Test_normalize_path(object):
@@ -460,28 +463,28 @@ def test_resolve_symlinks(self, tmpdir):
         orig_working_dir = os.getcwd()
         os.chdir(tmpdir)
         try:
-            d = os.path.join('foo', 'bar')
-            f = os.path.join(d, 'file1')
+            d = os.path.join("foo", "bar")
+            f = os.path.join(d, "file1")
             os.makedirs(d)
-            with open(f, 'w'):  # Create the file
+            with open(f, "w"):  # Create the file
                 pass
 
-            os.symlink(d, 'dir_link')
-            os.symlink(f, 'file_link')
-
-            assert normalize_path(
-                'dir_link/file1', resolve_symlinks=True
-            ) == os.path.join(tmpdir, f)
-            assert normalize_path(
-                'dir_link/file1', resolve_symlinks=False
-            ) == os.path.join(tmpdir, 'dir_link', 'file1')
+            os.symlink(d, "dir_link")
+            os.symlink(f, "file_link")
 
             assert normalize_path(
-                'file_link', resolve_symlinks=True
+                "dir_link/file1", resolve_symlinks=True
             ) == os.path.join(tmpdir, f)
             assert normalize_path(
-                'file_link', resolve_symlinks=False
-            ) == os.path.join(tmpdir, 'file_link')
+                "dir_link/file1", resolve_symlinks=False
+            ) == os.path.join(tmpdir, "dir_link", "file1")
+
+            assert normalize_path("file_link", resolve_symlinks=True) == os.path.join(
+                tmpdir, f
+            )
+            assert normalize_path("file_link", resolve_symlinks=False) == os.path.join(
+                tmpdir, "file_link"
+            )
         finally:
             os.chdir(orig_working_dir)
 
@@ -489,18 +492,21 @@ def test_resolve_symlinks(self, tmpdir):
 class TestHashes(object):
     """Tests for pip._internal.utils.hashes"""
 
-    @pytest.mark.parametrize('hash_name, hex_digest, expected', [
-        # Test a value that matches but with the wrong hash_name.
-        ('sha384', 128 * 'a', False),
-        # Test matching values, including values other than the first.
-        ('sha512', 128 * 'a', True),
-        ('sha512', 128 * 'b', True),
-        # Test a matching hash_name with a value that doesn't match.
-        ('sha512', 128 * 'c', False),
-    ])
+    @pytest.mark.parametrize(
+        "hash_name, hex_digest, expected",
+        [
+            # Test a value that matches but with the wrong hash_name.
+            ("sha384", 128 * "a", False),
+            # Test matching values, including values other than the first.
+            ("sha512", 128 * "a", True),
+            ("sha512", 128 * "b", True),
+            # Test a matching hash_name with a value that doesn't match.
+            ("sha512", 128 * "c", False),
+        ],
+    )
     def test_is_hash_allowed(self, hash_name, hex_digest, expected):
         hashes_data = {
-            'sha512': [128 * 'a', 128 * 'b'],
+            "sha512": [128 * "a", 128 * "b"],
         }
         hashes = Hashes(hashes_data)
         assert hashes.is_hash_allowed(hash_name, hex_digest) == expected
@@ -511,37 +517,42 @@ def test_success(self, tmpdir):
         Test check_against_path because it calls everything else.
 
         """
-        file = tmpdir / 'to_hash'
-        file.write_text('hello')
-        hashes = Hashes({
-            'sha256': ['2cf24dba5fb0a30e26e83b2ac5b9e29e'
-                       '1b161e5c1fa7425e73043362938b9824'],
-            'sha224': ['wrongwrong'],
-            'md5': ['5d41402abc4b2a76b9719d911017c592']})
+        file = tmpdir / "to_hash"
+        file.write_text("hello")
+        hashes = Hashes(
+            {
+                "sha256": [
+                    "2cf24dba5fb0a30e26e83b2ac5b9e29e"
+                    "1b161e5c1fa7425e73043362938b9824"
+                ],
+                "sha224": ["wrongwrong"],
+                "md5": ["5d41402abc4b2a76b9719d911017c592"],
+            }
+        )
         hashes.check_against_path(file)
 
     def test_failure(self):
         """Hashes should raise HashMismatch when no hashes match."""
-        hashes = Hashes({'sha256': ['wrongwrong']})
+        hashes = Hashes({"sha256": ["wrongwrong"]})
         with pytest.raises(HashMismatch):
-            hashes.check_against_file(BytesIO(b'hello'))
+            hashes.check_against_file(BytesIO(b"hello"))
 
     def test_missing_hashes(self):
         """MissingHashes should raise HashMissing when any check is done."""
         with pytest.raises(HashMissing):
-            MissingHashes().check_against_file(BytesIO(b'hello'))
+            MissingHashes().check_against_file(BytesIO(b"hello"))
 
     def test_unknown_hash(self):
         """Hashes should raise InstallationError when it encounters an unknown
         hash."""
-        hashes = Hashes({'badbad': ['dummy']})
+        hashes = Hashes({"badbad": ["dummy"]})
         with pytest.raises(InstallationError):
-            hashes.check_against_file(BytesIO(b'hello'))
+            hashes.check_against_file(BytesIO(b"hello"))
 
     def test_non_zero(self):
         """Test that truthiness tests tell whether any known-good hashes
         exist."""
-        assert Hashes({'sha256': 'dummy'})
+        assert Hashes({"sha256": "dummy"})
         assert not Hashes()
         assert not Hashes({})
 
@@ -551,41 +562,41 @@ class TestEncoding(object):
 
     def test_auto_decode_utf_16_le(self):
         data = (
-            b'\xff\xfeD\x00j\x00a\x00n\x00g\x00o\x00=\x00'
-            b'=\x001\x00.\x004\x00.\x002\x00'
+            b"\xff\xfeD\x00j\x00a\x00n\x00g\x00o\x00=\x00"
+            b"=\x001\x00.\x004\x00.\x002\x00"
         )
         assert data.startswith(codecs.BOM_UTF16_LE)
         assert auto_decode(data) == "Django==1.4.2"
 
     def test_auto_decode_utf_16_be(self):
         data = (
-            b'\xfe\xff\x00D\x00j\x00a\x00n\x00g\x00o\x00='
-            b'\x00=\x001\x00.\x004\x00.\x002'
+            b"\xfe\xff\x00D\x00j\x00a\x00n\x00g\x00o\x00="
+            b"\x00=\x001\x00.\x004\x00.\x002"
         )
         assert data.startswith(codecs.BOM_UTF16_BE)
         assert auto_decode(data) == "Django==1.4.2"
 
     def test_auto_decode_no_bom(self):
-        assert auto_decode(b'foobar') == u'foobar'
+        assert auto_decode(b"foobar") == u"foobar"
 
     def test_auto_decode_pep263_headers(self):
-        latin1_req = u'# coding=latin1\n# Pas trop de café'
-        assert auto_decode(latin1_req.encode('latin1')) == latin1_req
+        latin1_req = u"# coding=latin1\n# Pas trop de café"
+        assert auto_decode(latin1_req.encode("latin1")) == latin1_req
 
     def test_auto_decode_no_preferred_encoding(self):
         om, em = Mock(), Mock()
-        om.return_value = 'ascii'
+        om.return_value = "ascii"
         em.return_value = None
-        data = u'data'
-        with patch('sys.getdefaultencoding', om):
-            with patch('locale.getpreferredencoding', em):
+        data = u"data"
+        with patch("sys.getdefaultencoding", om):
+            with patch("locale.getpreferredencoding", em):
                 ret = auto_decode(data.encode(sys.getdefaultencoding()))
         assert ret == data
 
-    @pytest.mark.parametrize('encoding', [encoding for bom, encoding in BOMS])
+    @pytest.mark.parametrize("encoding", [encoding for bom, encoding in BOMS])
     def test_all_encodings_are_valid(self, encoding):
         # we really only care that there is no LookupError
-        assert ''.encode(encoding).decode(encoding) == ''
+        assert "".encode(encoding).decode(encoding) == ""
 
 
 def raises(error):
@@ -596,22 +607,31 @@ class TestGlibc(object):
     @pytest.mark.skipif("sys.platform == 'win32'")
     def test_glibc_version_string(self, monkeypatch):
         monkeypatch.setattr(
-            os, "confstr", lambda x: "glibc 2.20", raising=False,
+            os,
+            "confstr",
+            lambda x: "glibc 2.20",
+            raising=False,
         )
         assert glibc_version_string() == "2.20"
 
     @pytest.mark.skipif("sys.platform == 'win32'")
     def test_glibc_version_string_confstr(self, monkeypatch):
         monkeypatch.setattr(
-            os, "confstr", lambda x: "glibc 2.20", raising=False,
+            os,
+            "confstr",
+            lambda x: "glibc 2.20",
+            raising=False,
         )
         assert glibc_version_string_confstr() == "2.20"
 
-    @pytest.mark.parametrize("failure", [
-        lambda x: raises(ValueError),
-        lambda x: raises(OSError),
-        lambda x: "XXX",
-    ])
+    @pytest.mark.parametrize(
+        "failure",
+        [
+            lambda x: raises(ValueError),
+            lambda x: raises(OSError),
+            lambda x: "XXX",
+        ],
+    )
     def test_glibc_version_string_confstr_fail(self, monkeypatch, failure):
         monkeypatch.setattr(os, "confstr", failure, raising=False)
         assert glibc_version_string_confstr() is None
@@ -625,206 +645,243 @@ def test_glibc_version_string_ctypes_missing(self, monkeypatch):
         assert glibc_version_string_ctypes() is None
 
 
-@pytest.mark.parametrize('version_info, expected', [
-    ((), (0, 0, 0)),
-    ((3, ), (3, 0, 0)),
-    ((3, 6), (3, 6, 0)),
-    ((3, 6, 2), (3, 6, 2)),
-    ((3, 6, 2, 4), (3, 6, 2)),
-])
+@pytest.mark.parametrize(
+    "version_info, expected",
+    [
+        ((), (0, 0, 0)),
+        ((3,), (3, 0, 0)),
+        ((3, 6), (3, 6, 0)),
+        ((3, 6, 2), (3, 6, 2)),
+        ((3, 6, 2, 4), (3, 6, 2)),
+    ],
+)
 def test_normalize_version_info(version_info, expected):
     actual = normalize_version_info(version_info)
     assert actual == expected
 
 
 class TestGetProg(object):
-
     @pytest.mark.parametrize(
         ("argv", "executable", "expected"),
         [
-            ('/usr/bin/pip', '', 'pip'),
-            ('-c', '/usr/bin/python', '/usr/bin/python -m pip'),
-            ('__main__.py', '/usr/bin/python', '/usr/bin/python -m pip'),
-            ('/usr/bin/pip3', '', 'pip3'),
-        ]
+            ("/usr/bin/pip", "", "pip"),
+            ("-c", "/usr/bin/python", "/usr/bin/python -m pip"),
+            ("__main__.py", "/usr/bin/python", "/usr/bin/python -m pip"),
+            ("/usr/bin/pip3", "", "pip3"),
+        ],
     )
     def test_get_prog(self, monkeypatch, argv, executable, expected):
-        monkeypatch.setattr('pip._internal.utils.misc.sys.argv', [argv])
-        monkeypatch.setattr(
-            'pip._internal.utils.misc.sys.executable',
-            executable
-        )
+        monkeypatch.setattr("pip._internal.utils.misc.sys.argv", [argv])
+        monkeypatch.setattr("pip._internal.utils.misc.sys.executable", executable)
         assert get_prog() == expected
 
 
-@pytest.mark.parametrize('host_port, expected_netloc', [
-    # Test domain name.
-    (('example.com', None), 'example.com'),
-    (('example.com', 5000), 'example.com:5000'),
-    # Test IPv4 address.
-    (('127.0.0.1', None), '127.0.0.1'),
-    (('127.0.0.1', 5000), '127.0.0.1:5000'),
-    # Test bare IPv6 address.
-    (('2001:db6::1', None), '2001:db6::1'),
-    # Test IPv6 with port.
-    (('2001:db6::1', 5000), '[2001:db6::1]:5000'),
-])
+@pytest.mark.parametrize(
+    "host_port, expected_netloc",
+    [
+        # Test domain name.
+        (("example.com", None), "example.com"),
+        (("example.com", 5000), "example.com:5000"),
+        # Test IPv4 address.
+        (("127.0.0.1", None), "127.0.0.1"),
+        (("127.0.0.1", 5000), "127.0.0.1:5000"),
+        # Test bare IPv6 address.
+        (("2001:db6::1", None), "2001:db6::1"),
+        # Test IPv6 with port.
+        (("2001:db6::1", 5000), "[2001:db6::1]:5000"),
+    ],
+)
 def test_build_netloc(host_port, expected_netloc):
     assert build_netloc(*host_port) == expected_netloc
 
 
-@pytest.mark.parametrize('netloc, expected_url, expected_host_port', [
-    # Test domain name.
-    ('example.com', 'https://example.com', ('example.com', None)),
-    ('example.com:5000', 'https://example.com:5000', ('example.com', 5000)),
-    # Test IPv4 address.
-    ('127.0.0.1', 'https://127.0.0.1', ('127.0.0.1', None)),
-    ('127.0.0.1:5000', 'https://127.0.0.1:5000', ('127.0.0.1', 5000)),
-    # Test bare IPv6 address.
-    ('2001:db6::1', 'https://[2001:db6::1]', ('2001:db6::1', None)),
-    # Test IPv6 with port.
-    (
-        '[2001:db6::1]:5000',
-        'https://[2001:db6::1]:5000',
-        ('2001:db6::1', 5000)
-    ),
-    # Test netloc with auth.
-    (
-        'user:password@localhost:5000',
-        'https://user:password@localhost:5000',
-        ('localhost', 5000)
-    )
-])
+@pytest.mark.parametrize(
+    "netloc, expected_url, expected_host_port",
+    [
+        # Test domain name.
+        ("example.com", "https://example.com", ("example.com", None)),
+        ("example.com:5000", "https://example.com:5000", ("example.com", 5000)),
+        # Test IPv4 address.
+        ("127.0.0.1", "https://127.0.0.1", ("127.0.0.1", None)),
+        ("127.0.0.1:5000", "https://127.0.0.1:5000", ("127.0.0.1", 5000)),
+        # Test bare IPv6 address.
+        ("2001:db6::1", "https://[2001:db6::1]", ("2001:db6::1", None)),
+        # Test IPv6 with port.
+        ("[2001:db6::1]:5000", "https://[2001:db6::1]:5000", ("2001:db6::1", 5000)),
+        # Test netloc with auth.
+        (
+            "user:password@localhost:5000",
+            "https://user:password@localhost:5000",
+            ("localhost", 5000),
+        ),
+    ],
+)
 def test_build_url_from_netloc_and_parse_netloc(
-    netloc, expected_url, expected_host_port,
+    netloc,
+    expected_url,
+    expected_host_port,
 ):
     assert build_url_from_netloc(netloc) == expected_url
     assert parse_netloc(netloc) == expected_host_port
 
 
-@pytest.mark.parametrize('netloc, expected', [
-    # Test a basic case.
-    ('example.com', ('example.com', (None, None))),
-    # Test with username and no password.
-    ('user@example.com', ('example.com', ('user', None))),
-    # Test with username and password.
-    ('user:pass@example.com', ('example.com', ('user', 'pass'))),
-    # Test with username and empty password.
-    ('user:@example.com', ('example.com', ('user', ''))),
-    # Test the password containing an @ symbol.
-    ('user:pass@word@example.com', ('example.com', ('user', 'pass@word'))),
-    # Test the password containing a : symbol.
-    ('user:pass:word@example.com', ('example.com', ('user', 'pass:word'))),
-    # Test URL-encoded reserved characters.
-    ('user%3Aname:%23%40%5E@example.com',
-     ('example.com', ('user:name', '#@^'))),
-])
+@pytest.mark.parametrize(
+    "netloc, expected",
+    [
+        # Test a basic case.
+        ("example.com", ("example.com", (None, None))),
+        # Test with username and no password.
+        ("user@example.com", ("example.com", ("user", None))),
+        # Test with username and password.
+        ("user:pass@example.com", ("example.com", ("user", "pass"))),
+        # Test with username and empty password.
+        ("user:@example.com", ("example.com", ("user", ""))),
+        # Test the password containing an @ symbol.
+        ("user:pass@word@example.com", ("example.com", ("user", "pass@word"))),
+        # Test the password containing a : symbol.
+        ("user:pass:word@example.com", ("example.com", ("user", "pass:word"))),
+        # Test URL-encoded reserved characters.
+        ("user%3Aname:%23%40%5E@example.com", ("example.com", ("user:name", "#@^"))),
+    ],
+)
 def test_split_auth_from_netloc(netloc, expected):
     actual = split_auth_from_netloc(netloc)
     assert actual == expected
 
 
-@pytest.mark.parametrize('url, expected', [
-    # Test a basic case.
-    ('http://example.com/path#anchor',
-     ('http://example.com/path#anchor', 'example.com', (None, None))),
-    # Test with username and no password.
-    ('http://user@example.com/path#anchor',
-     ('http://example.com/path#anchor', 'example.com', ('user', None))),
-    # Test with username and password.
-    ('http://user:pass@example.com/path#anchor',
-     ('http://example.com/path#anchor', 'example.com', ('user', 'pass'))),
-    # Test with username and empty password.
-    ('http://user:@example.com/path#anchor',
-     ('http://example.com/path#anchor', 'example.com', ('user', ''))),
-    # Test the password containing an @ symbol.
-    ('http://user:pass@word@example.com/path#anchor',
-     ('http://example.com/path#anchor', 'example.com', ('user', 'pass@word'))),
-    # Test the password containing a : symbol.
-    ('http://user:pass:word@example.com/path#anchor',
-     ('http://example.com/path#anchor', 'example.com', ('user', 'pass:word'))),
-    # Test URL-encoded reserved characters.
-    ('http://user%3Aname:%23%40%5E@example.com/path#anchor',
-     ('http://example.com/path#anchor', 'example.com', ('user:name', '#@^'))),
-])
+@pytest.mark.parametrize(
+    "url, expected",
+    [
+        # Test a basic case.
+        (
+            "http://example.com/path#anchor",
+            ("http://example.com/path#anchor", "example.com", (None, None)),
+        ),
+        # Test with username and no password.
+        (
+            "http://user@example.com/path#anchor",
+            ("http://example.com/path#anchor", "example.com", ("user", None)),
+        ),
+        # Test with username and password.
+        (
+            "http://user:pass@example.com/path#anchor",
+            ("http://example.com/path#anchor", "example.com", ("user", "pass")),
+        ),
+        # Test with username and empty password.
+        (
+            "http://user:@example.com/path#anchor",
+            ("http://example.com/path#anchor", "example.com", ("user", "")),
+        ),
+        # Test the password containing an @ symbol.
+        (
+            "http://user:pass@word@example.com/path#anchor",
+            ("http://example.com/path#anchor", "example.com", ("user", "pass@word")),
+        ),
+        # Test the password containing a : symbol.
+        (
+            "http://user:pass:word@example.com/path#anchor",
+            ("http://example.com/path#anchor", "example.com", ("user", "pass:word")),
+        ),
+        # Test URL-encoded reserved characters.
+        (
+            "http://user%3Aname:%23%40%5E@example.com/path#anchor",
+            ("http://example.com/path#anchor", "example.com", ("user:name", "#@^")),
+        ),
+    ],
+)
 def test_split_auth_netloc_from_url(url, expected):
     actual = split_auth_netloc_from_url(url)
     assert actual == expected
 
 
-@pytest.mark.parametrize('netloc, expected', [
-    # Test a basic case.
-    ('example.com', 'example.com'),
-    # Test with username and no password.
-    ('accesstoken@example.com', '****@example.com'),
-    # Test with username and password.
-    ('user:pass@example.com', 'user:****@example.com'),
-    # Test with username and empty password.
-    ('user:@example.com', 'user:****@example.com'),
-    # Test the password containing an @ symbol.
-    ('user:pass@word@example.com', 'user:****@example.com'),
-    # Test the password containing a : symbol.
-    ('user:pass:word@example.com', 'user:****@example.com'),
-    # Test URL-encoded reserved characters.
-    ('user%3Aname:%23%40%5E@example.com', 'user%3Aname:****@example.com'),
-])
+@pytest.mark.parametrize(
+    "netloc, expected",
+    [
+        # Test a basic case.
+        ("example.com", "example.com"),
+        # Test with username and no password.
+        ("accesstoken@example.com", "****@example.com"),
+        # Test with username and password.
+        ("user:pass@example.com", "user:****@example.com"),
+        # Test with username and empty password.
+        ("user:@example.com", "user:****@example.com"),
+        # Test the password containing an @ symbol.
+        ("user:pass@word@example.com", "user:****@example.com"),
+        # Test the password containing a : symbol.
+        ("user:pass:word@example.com", "user:****@example.com"),
+        # Test URL-encoded reserved characters.
+        ("user%3Aname:%23%40%5E@example.com", "user%3Aname:****@example.com"),
+    ],
+)
 def test_redact_netloc(netloc, expected):
     actual = redact_netloc(netloc)
     assert actual == expected
 
 
-@pytest.mark.parametrize('auth_url, expected_url', [
-    ('https://user:pass@domain.tld/project/tags/v0.2',
-     'https://domain.tld/project/tags/v0.2'),
-    ('https://domain.tld/project/tags/v0.2',
-     'https://domain.tld/project/tags/v0.2',),
-    ('https://user:pass@domain.tld/svn/project/trunk@8181',
-     'https://domain.tld/svn/project/trunk@8181'),
-    ('https://domain.tld/project/trunk@8181',
-     'https://domain.tld/project/trunk@8181',),
-    ('git+https://pypi.org/something',
-     'git+https://pypi.org/something'),
-    ('git+https://user:pass@pypi.org/something',
-     'git+https://pypi.org/something'),
-    ('git+ssh://git@pypi.org/something',
-     'git+ssh://pypi.org/something'),
-])
+@pytest.mark.parametrize(
+    "auth_url, expected_url",
+    [
+        (
+            "https://user:pass@domain.tld/project/tags/v0.2",
+            "https://domain.tld/project/tags/v0.2",
+        ),
+        (
+            "https://domain.tld/project/tags/v0.2",
+            "https://domain.tld/project/tags/v0.2",
+        ),
+        (
+            "https://user:pass@domain.tld/svn/project/trunk@8181",
+            "https://domain.tld/svn/project/trunk@8181",
+        ),
+        (
+            "https://domain.tld/project/trunk@8181",
+            "https://domain.tld/project/trunk@8181",
+        ),
+        ("git+https://pypi.org/something", "git+https://pypi.org/something"),
+        ("git+https://user:pass@pypi.org/something", "git+https://pypi.org/something"),
+        ("git+ssh://git@pypi.org/something", "git+ssh://pypi.org/something"),
+    ],
+)
 def test_remove_auth_from_url(auth_url, expected_url):
     url = remove_auth_from_url(auth_url)
     assert url == expected_url
 
 
-@pytest.mark.parametrize('auth_url, expected_url', [
-    ('https://accesstoken@example.com/abc', 'https://****@example.com/abc'),
-    ('https://user:password@example.com', 'https://user:****@example.com'),
-    ('https://user:@example.com', 'https://user:****@example.com'),
-    ('https://example.com', 'https://example.com'),
-    # Test URL-encoded reserved characters.
-    ('https://user%3Aname:%23%40%5E@example.com',
-     'https://user%3Aname:****@example.com'),
-])
+@pytest.mark.parametrize(
+    "auth_url, expected_url",
+    [
+        ("https://accesstoken@example.com/abc", "https://****@example.com/abc"),
+        ("https://user:password@example.com", "https://user:****@example.com"),
+        ("https://user:@example.com", "https://user:****@example.com"),
+        ("https://example.com", "https://example.com"),
+        # Test URL-encoded reserved characters.
+        (
+            "https://user%3Aname:%23%40%5E@example.com",
+            "https://user%3Aname:****@example.com",
+        ),
+    ],
+)
 def test_redact_auth_from_url(auth_url, expected_url):
     url = redact_auth_from_url(auth_url)
     assert url == expected_url
 
 
 class TestHiddenText:
-
     def test_basic(self):
         """
         Test str(), repr(), and attribute access.
         """
-        hidden = HiddenText('my-secret', redacted='######')
+        hidden = HiddenText("my-secret", redacted="######")
         assert repr(hidden) == "<HiddenText '######'>"
-        assert str(hidden) == '######'
-        assert hidden.redacted == '######'
-        assert hidden.secret == 'my-secret'
+        assert str(hidden) == "######"
+        assert hidden.redacted == "######"
+        assert hidden.secret == "my-secret"
 
     def test_equality_with_str(self):
         """
         Test equality (and inequality) with str objects.
         """
-        hidden = HiddenText('secret', redacted='****')
+        hidden = HiddenText("secret", redacted="****")
 
         # Test that the object doesn't compare equal to either its original
         # or redacted forms.
@@ -839,8 +896,8 @@ def test_equality_same_secret(self):
         Test equality with an object having the same secret.
         """
         # Choose different redactions for the two objects.
-        hidden1 = HiddenText('secret', redacted='****')
-        hidden2 = HiddenText('secret', redacted='####')
+        hidden1 = HiddenText("secret", redacted="****")
+        hidden2 = HiddenText("secret", redacted="####")
 
         assert hidden1 == hidden2
         # Also test __ne__.  This assertion fails in Python 2 without
@@ -851,8 +908,8 @@ def test_equality_different_secret(self):
         """
         Test equality with an object having a different secret.
         """
-        hidden1 = HiddenText('secret-1', redacted='****')
-        hidden2 = HiddenText('secret-2', redacted='****')
+        hidden1 = HiddenText("secret-1", redacted="****")
+        hidden2 = HiddenText("secret-2", redacted="****")
 
         assert hidden1 != hidden2
         # Also test __eq__.
@@ -860,25 +917,26 @@ def test_equality_different_secret(self):
 
 
 def test_hide_value():
-    hidden = hide_value('my-secret')
+    hidden = hide_value("my-secret")
     assert repr(hidden) == "<HiddenText '****'>"
-    assert str(hidden) == '****'
-    assert hidden.redacted == '****'
-    assert hidden.secret == 'my-secret'
+    assert str(hidden) == "****"
+    assert hidden.redacted == "****"
+    assert hidden.secret == "my-secret"
 
 
 def test_hide_url():
-    hidden_url = hide_url('https://user:password@example.com')
+    hidden_url = hide_url("https://user:password@example.com")
     assert repr(hidden_url) == "<HiddenText 'https://user:****@example.com'>"
-    assert str(hidden_url) == 'https://user:****@example.com'
-    assert hidden_url.redacted == 'https://user:****@example.com'
-    assert hidden_url.secret == 'https://user:password@example.com'
+    assert str(hidden_url) == "https://user:****@example.com"
+    assert hidden_url.redacted == "https://user:****@example.com"
+    assert hidden_url.secret == "https://user:password@example.com"
 
 
 @pytest.fixture()
 def patch_deprecation_check_version():
     # We do this, so that the deprecation tests are easier to write.
     import pip._internal.utils.deprecation as d
+
     old_version = d.current_version
     d.current_version = "1.0"
     yield
@@ -954,27 +1012,23 @@ def test_deprecated_message_reads_well():
 def test_make_setuptools_shim_args():
     # Test all arguments at once, including the overall ordering.
     args = make_setuptools_shim_args(
-        '/dir/path/setup.py',
-        global_options=['--some', '--option'],
+        "/dir/path/setup.py",
+        global_options=["--some", "--option"],
         no_user_config=True,
         unbuffered_output=True,
     )
 
-    assert args[1:3] == ['-u', '-c']
+    assert args[1:3] == ["-u", "-c"]
     # Spot-check key aspects of the command string.
     assert "sys.argv[0] = '/dir/path/setup.py'" in args[3]
     assert "__file__='/dir/path/setup.py'" in args[3]
-    assert args[4:] == ['--some', '--option', '--no-user-cfg']
+    assert args[4:] == ["--some", "--option", "--no-user-cfg"]
 
 
-@pytest.mark.parametrize('global_options', [
-    None,
-    [],
-    ['--some', '--option']
-])
+@pytest.mark.parametrize("global_options", [None, [], ["--some", "--option"]])
 def test_make_setuptools_shim_args__global_options(global_options):
     args = make_setuptools_shim_args(
-        '/dir/path/setup.py',
+        "/dir/path/setup.py",
         global_options=global_options,
     )
 
@@ -986,61 +1040,77 @@ def test_make_setuptools_shim_args__global_options(global_options):
         assert len(args) == 3
 
 
-@pytest.mark.parametrize('no_user_config', [False, True])
+@pytest.mark.parametrize("no_user_config", [False, True])
 def test_make_setuptools_shim_args__no_user_config(no_user_config):
     args = make_setuptools_shim_args(
-        '/dir/path/setup.py',
+        "/dir/path/setup.py",
         no_user_config=no_user_config,
     )
-    assert ('--no-user-cfg' in args) == no_user_config
+    assert ("--no-user-cfg" in args) == no_user_config
 
 
-@pytest.mark.parametrize('unbuffered_output', [False, True])
+@pytest.mark.parametrize("unbuffered_output", [False, True])
 def test_make_setuptools_shim_args__unbuffered_output(unbuffered_output):
     args = make_setuptools_shim_args(
-        '/dir/path/setup.py',
-        unbuffered_output=unbuffered_output
+        "/dir/path/setup.py", unbuffered_output=unbuffered_output
     )
-    assert ('-u' in args) == unbuffered_output
+    assert ("-u" in args) == unbuffered_output
 
 
-@pytest.mark.parametrize('isatty,no_stdin,expected', [
-    (True, False, True),
-    (False, False, False),
-    (True, True, False),
-    (False, True, False),
-])
+@pytest.mark.parametrize(
+    "isatty,no_stdin,expected",
+    [
+        (True, False, True),
+        (False, False, False),
+        (True, True, False),
+        (False, True, False),
+    ],
+)
 def test_is_console_interactive(monkeypatch, isatty, no_stdin, expected):
-    monkeypatch.setattr(sys.stdin, 'isatty', Mock(return_value=isatty))
+    monkeypatch.setattr(sys.stdin, "isatty", Mock(return_value=isatty))
 
     if no_stdin:
-        monkeypatch.setattr(sys, 'stdin', None)
+        monkeypatch.setattr(sys, "stdin", None)
 
     assert is_console_interactive() is expected
 
 
-@pytest.mark.parametrize('size,expected', [
-    (123, "123 bytes"),
-    (1234, "1.2 kB"),
-    (123456, "123 kB"),
-    (1234567890, "1234.6 MB"),
-])
+@pytest.mark.parametrize(
+    "size,expected",
+    [
+        (123, "123 bytes"),
+        (1234, "1.2 kB"),
+        (123456, "123 kB"),
+        (1234567890, "1234.6 MB"),
+    ],
+)
 def test_format_size(size, expected):
     assert format_size(size) == expected
 
 
 @pytest.mark.parametrize(
-    ('rows', 'table', 'sizes'),
-    [([], [], []),
-     ([('I?', 'version', 'sdist', 'wheel'),
-       ('', '1.18.2', 'zip', 'cp38-cp38m-win_amd64'),
-       ('v', 1.18, 'zip')],
-      ['I? version sdist wheel',
-       '   1.18.2  zip   cp38-cp38m-win_amd64',
-       'v  1.18    zip'],
-      [2, 7, 5, 20]),
-     ([('I?', 'version', 'sdist', 'wheel'), (), ('v', '1.18.1', 'zip')],
-      ['I? version sdist wheel', '', 'v  1.18.1  zip'],
-      [2, 7, 5, 5])])
+    ("rows", "table", "sizes"),
+    [
+        ([], [], []),
+        (
+            [
+                ("I?", "version", "sdist", "wheel"),
+                ("", "1.18.2", "zip", "cp38-cp38m-win_amd64"),
+                ("v", 1.18, "zip"),
+            ],
+            [
+                "I? version sdist wheel",
+                "   1.18.2  zip   cp38-cp38m-win_amd64",
+                "v  1.18    zip",
+            ],
+            [2, 7, 5, 20],
+        ),
+        (
+            [("I?", "version", "sdist", "wheel"), (), ("v", "1.18.1", "zip")],
+            ["I? version sdist wheel", "", "v  1.18.1  zip"],
+            [2, 7, 5, 5],
+        ),
+    ],
+)
 def test_tabulate(rows, table, sizes):
     assert tabulate(rows) == (table, sizes)
diff --git a/tests/unit/test_utils_compatibility_tags.py b/tests/unit/test_utils_compatibility_tags.py
index 12c8da453d9..ecc8d6f857b 100644
--- a/tests/unit/test_utils_compatibility_tags.py
+++ b/tests/unit/test_utils_compatibility_tags.py
@@ -6,23 +6,25 @@
 from pip._internal.utils import compatibility_tags
 
 
-@pytest.mark.parametrize('version_info, expected', [
-    ((2,), '2'),
-    ((2, 8), '28'),
-    ((3,), '3'),
-    ((3, 6), '36'),
-    # Test a tuple of length 3.
-    ((3, 6, 5), '36'),
-    # Test a 2-digit minor version.
-    ((3, 10), '310'),
-])
+@pytest.mark.parametrize(
+    "version_info, expected",
+    [
+        ((2,), "2"),
+        ((2, 8), "28"),
+        ((3,), "3"),
+        ((3, 6), "36"),
+        # Test a tuple of length 3.
+        ((3, 6, 5), "36"),
+        # Test a 2-digit minor version.
+        ((3, 10), "310"),
+    ],
+)
 def test_version_info_to_nodot(version_info, expected):
     actual = compatibility_tags.version_info_to_nodot(version_info)
     assert actual == expected
 
 
 class Testcompatibility_tags(object):
-
     def mock_get_config_var(self, **kwd):
         """
         Patch sysconfig.get_config_var for arbitrary keys.
@@ -33,6 +35,7 @@ def _mock_get_config_var(var):
             if var in kwd:
                 return kwd[var]
             return get_config_var(var)
+
         return _mock_get_config_var
 
     def test_no_hyphen_tag(self):
@@ -41,23 +44,25 @@ def test_no_hyphen_tag(self):
         """
         import pip._internal.utils.compatibility_tags
 
-        mock_gcf = self.mock_get_config_var(SOABI='cpython-35m-darwin')
+        mock_gcf = self.mock_get_config_var(SOABI="cpython-35m-darwin")
 
-        with patch('sysconfig.get_config_var', mock_gcf):
+        with patch("sysconfig.get_config_var", mock_gcf):
             supported = pip._internal.utils.compatibility_tags.get_supported()
 
         for tag in supported:
-            assert '-' not in tag.interpreter
-            assert '-' not in tag.abi
-            assert '-' not in tag.platform
+            assert "-" not in tag.interpreter
+            assert "-" not in tag.abi
+            assert "-" not in tag.platform
 
 
 class TestManylinux2010Tags(object):
-
-    @pytest.mark.parametrize("manylinux2010,manylinux1", [
-        ("manylinux2010_x86_64", "manylinux1_x86_64"),
-        ("manylinux2010_i686", "manylinux1_i686"),
-    ])
+    @pytest.mark.parametrize(
+        "manylinux2010,manylinux1",
+        [
+            ("manylinux2010_x86_64", "manylinux1_x86_64"),
+            ("manylinux2010_i686", "manylinux1_i686"),
+        ],
+    )
     def test_manylinux2010_implies_manylinux1(self, manylinux2010, manylinux1):
         """
         Specifying manylinux2010 implies manylinux1.
@@ -65,23 +70,22 @@ def test_manylinux2010_implies_manylinux1(self, manylinux2010, manylinux1):
         groups = {}
         supported = compatibility_tags.get_supported(platform=manylinux2010)
         for tag in supported:
-            groups.setdefault(
-                (tag.interpreter, tag.abi), []
-            ).append(tag.platform)
+            groups.setdefault((tag.interpreter, tag.abi), []).append(tag.platform)
 
         for arches in groups.values():
-            if arches == ['any']:
+            if arches == ["any"]:
                 continue
             assert arches[:2] == [manylinux2010, manylinux1]
 
 
 class TestManylinux2014Tags(object):
-
-    @pytest.mark.parametrize("manylinuxA,manylinuxB", [
-        ("manylinux2014_x86_64", ["manylinux2010_x86_64",
-                                  "manylinux1_x86_64"]),
-        ("manylinux2014_i686", ["manylinux2010_i686", "manylinux1_i686"]),
-    ])
+    @pytest.mark.parametrize(
+        "manylinuxA,manylinuxB",
+        [
+            ("manylinux2014_x86_64", ["manylinux2010_x86_64", "manylinux1_x86_64"]),
+            ("manylinux2014_i686", ["manylinux2010_i686", "manylinux1_i686"]),
+        ],
+    )
     def test_manylinuxA_implies_manylinuxB(self, manylinuxA, manylinuxB):
         """
         Specifying manylinux2014 implies manylinux2010/manylinux1.
@@ -89,13 +93,11 @@ def test_manylinuxA_implies_manylinuxB(self, manylinuxA, manylinuxB):
         groups = {}
         supported = compatibility_tags.get_supported(platform=manylinuxA)
         for tag in supported:
-            groups.setdefault(
-                (tag.interpreter, tag.abi), []
-            ).append(tag.platform)
+            groups.setdefault((tag.interpreter, tag.abi), []).append(tag.platform)
 
         expected_arches = [manylinuxA]
         expected_arches.extend(manylinuxB)
         for arches in groups.values():
-            if arches == ['any']:
+            if arches == ["any"]:
                 continue
             assert arches[:3] == expected_arches
diff --git a/tests/unit/test_utils_distutils_args.py b/tests/unit/test_utils_distutils_args.py
index 5bca65018ec..57e80a9c8ca 100644
--- a/tests/unit/test_utils_distutils_args.py
+++ b/tests/unit/test_utils_distutils_args.py
@@ -36,19 +36,22 @@ def test_multiple_invocations_do_not_keep_options():
     assert result["root"] == "world1"
 
 
-@pytest.mark.parametrize("name,value", [
-    ("exec-prefix", "1"),
-    ("home", "2"),
-    ("install-base", "3"),
-    ("install-data", "4"),
-    ("install-headers", "5"),
-    ("install-lib", "6"),
-    ("install-platlib", "7"),
-    ("install-purelib", "8"),
-    ("install-scripts", "9"),
-    ("prefix", "10"),
-    ("root", "11"),
-])
+@pytest.mark.parametrize(
+    "name,value",
+    [
+        ("exec-prefix", "1"),
+        ("home", "2"),
+        ("install-base", "3"),
+        ("install-data", "4"),
+        ("install-headers", "5"),
+        ("install-lib", "6"),
+        ("install-platlib", "7"),
+        ("install-purelib", "8"),
+        ("install-scripts", "9"),
+        ("prefix", "10"),
+        ("root", "11"),
+    ],
+)
 def test_all_value_options_work(name, value):
     result = parse_distutils_args(["--{}={}".format(name, value)])
     key_name = name.replace("-", "_")
diff --git a/tests/unit/test_utils_filesystem.py b/tests/unit/test_utils_filesystem.py
index 3ef814dce4b..c7b3b90d4e8 100644
--- a/tests/unit/test_utils_filesystem.py
+++ b/tests/unit/test_utils_filesystem.py
@@ -30,13 +30,16 @@ def make_dir(path):
 
 
 @skip_on_windows
-@pytest.mark.parametrize("create,result", [
-    (make_socket_file, True),
-    (make_file, False),
-    (make_valid_symlink, False),
-    (make_broken_symlink, False),
-    (make_dir, False),
-])
+@pytest.mark.parametrize(
+    "create,result",
+    [
+        (make_socket_file, True),
+        (make_file, False),
+        (make_valid_symlink, False),
+        (make_broken_symlink, False),
+        (make_dir, False),
+    ],
+)
 def test_is_socket(create, result, tmpdir):
     target = tmpdir.joinpath("target")
     create(target)
@@ -44,12 +47,13 @@ def test_is_socket(create, result, tmpdir):
     assert is_socket(target) == result
 
 
-@pytest.mark.parametrize("create,error_type", [
-    pytest.param(
-        make_socket_file, shutil.SpecialFileError, marks=skip_on_windows
-    ),
-    (make_unreadable_file, OSError),
-])
+@pytest.mark.parametrize(
+    "create,error_type",
+    [
+        pytest.param(make_socket_file, shutil.SpecialFileError, marks=skip_on_windows),
+        (make_unreadable_file, OSError),
+    ],
+)
 def test_copy2_fixed_raises_appropriate_errors(create, error_type, tmpdir):
     src = tmpdir.joinpath("src")
     create(src)
diff --git a/tests/unit/test_utils_parallel.py b/tests/unit/test_utils_parallel.py
index 6086dcaa08b..1d3f561e86c 100644
--- a/tests/unit/test_utils_parallel.py
+++ b/tests/unit/test_utils_parallel.py
@@ -9,15 +9,15 @@
 from pip._vendor.six.moves import map
 from pytest import mark
 
-DUNDER_IMPORT = '__builtin__.__import__' if PY2 else 'builtins.__import__'
+DUNDER_IMPORT = "__builtin__.__import__" if PY2 else "builtins.__import__"
 FUNC, ITERABLE = factorial, range(42)
-MAPS = 'map_multiprocess', 'map_multithread'
+MAPS = "map_multiprocess", "map_multithread"
 _import = __import__
 
 
 def unload_parallel():
     try:
-        del modules['pip._internal.utils.parallel']
+        del modules["pip._internal.utils.parallel"]
     except KeyError:
         pass
 
@@ -26,14 +26,14 @@ def unload_parallel():
 def tmp_import_parallel():
     unload_parallel()
     try:
-        yield import_module('pip._internal.utils.parallel')
+        yield import_module("pip._internal.utils.parallel")
     finally:
         unload_parallel()
 
 
 def lack_sem_open(name, *args, **kwargs):
     """Raise ImportError on import of multiprocessing.synchronize."""
-    if name.endswith('synchronize'):
+    if name.endswith("synchronize"):
         raise ImportError
     return _import(name, *args, **kwargs)
 
@@ -42,12 +42,12 @@ def have_sem_open(name, *args, **kwargs):
     """Make sure multiprocessing.synchronize import is successful."""
     # We don't care about the return value
     # since we don't use the pool with this import.
-    if name.endswith('synchronize'):
+    if name.endswith("synchronize"):
         return
     return _import(name, *args, **kwargs)
 
 
-@mark.parametrize('name', MAPS)
+@mark.parametrize("name", MAPS)
 def test_lack_sem_open(name, monkeypatch):
     """Test fallback when sem_open is not available.
 
@@ -59,17 +59,17 @@ def test_lack_sem_open(name, monkeypatch):
         assert getattr(parallel, name) is parallel._map_fallback
 
 
-@mark.parametrize('name', MAPS)
+@mark.parametrize("name", MAPS)
 def test_have_sem_open(name, monkeypatch):
     """Test fallback when sem_open is available."""
     monkeypatch.setattr(DUNDER_IMPORT, have_sem_open)
-    impl = '_map_fallback' if PY2 else '_{}'.format(name)
+    impl = "_map_fallback" if PY2 else "_{}".format(name)
     with tmp_import_parallel() as parallel:
         assert getattr(parallel, name) is getattr(parallel, impl)
 
 
-@mark.parametrize('name', MAPS)
+@mark.parametrize("name", MAPS)
 def test_map(name):
     """Test correctness of result of asynchronous maps."""
-    map_async = getattr(import_module('pip._internal.utils.parallel'), name)
+    map_async = getattr(import_module("pip._internal.utils.parallel"), name)
     assert set(map_async(FUNC, ITERABLE)) == set(map(FUNC, ITERABLE))
diff --git a/tests/unit/test_utils_pkg_resources.py b/tests/unit/test_utils_pkg_resources.py
index d113d6df124..e4d67e513fc 100644
--- a/tests/unit/test_utils_pkg_resources.py
+++ b/tests/unit/test_utils_pkg_resources.py
@@ -27,9 +27,7 @@ def test_dict_metadata_works():
         metadata["Provides-Extra"] = extra
     metadata["Requires-Python"] = requires_python
 
-    inner_metadata = DictMetadata({
-        "METADATA": ensure_binary(metadata.as_string())
-    })
+    inner_metadata = DictMetadata({"METADATA": ensure_binary(metadata.as_string())})
     dist = DistInfoDistribution(
         location="<in-memory>", metadata=inner_metadata, project_name=name
     )
@@ -39,7 +37,8 @@ def test_dict_metadata_works():
     assert set(extras) == set(dist.extras)
     assert [Requirement.parse(require_a)] == dist.requires([])
     assert [
-        Requirement.parse(require_a), Requirement.parse(require_b)
+        Requirement.parse(require_a),
+        Requirement.parse(require_b),
     ] == dist.requires(["also_b"])
     assert metadata.as_string() == get_metadata(dist).as_string()
     assert requires_python == get_requires_python(dist)
@@ -48,9 +47,7 @@ def test_dict_metadata_works():
 # Metadata is not decoded on Python 2, so no chance for error.
 @skip_if_python2
 def test_dict_metadata_throws_on_bad_unicode():
-    metadata = DictMetadata({
-        "METADATA": b"\xff"
-    })
+    metadata = DictMetadata({"METADATA": b"\xff"})
 
     with pytest.raises(UnicodeDecodeError) as e:
         metadata.get_metadata("METADATA")
diff --git a/tests/unit/test_utils_subprocess.py b/tests/unit/test_utils_subprocess.py
index b0de2bf578d..94244863bb4 100644
--- a/tests/unit/test_utils_subprocess.py
+++ b/tests/unit/test_utils_subprocess.py
@@ -17,30 +17,38 @@
 )
 
 
-@pytest.mark.parametrize('args, expected', [
-    (['pip', 'list'], 'pip list'),
-    (['foo', 'space space', 'new\nline', 'double"quote', "single'quote"],
-     """foo 'space space' 'new\nline' 'double"quote' 'single'"'"'quote'"""),
-    # Test HiddenText arguments.
-    (make_command(hide_value('secret1'), 'foo', hide_value('secret2')),
-        "'****' foo '****'"),
-])
+@pytest.mark.parametrize(
+    "args, expected",
+    [
+        (["pip", "list"], "pip list"),
+        (
+            ["foo", "space space", "new\nline", 'double"quote', "single'quote"],
+            """foo 'space space' 'new\nline' 'double"quote' 'single'"'"'quote'""",
+        ),
+        # Test HiddenText arguments.
+        (
+            make_command(hide_value("secret1"), "foo", hide_value("secret2")),
+            "'****' foo '****'",
+        ),
+    ],
+)
 def test_format_command_args(args, expected):
     actual = format_command_args(args)
     assert actual == expected
 
 
 def test_make_subprocess_output_error():
-    cmd_args = ['test', 'has space']
-    cwd = '/path/to/cwd'
-    lines = ['line1\n', 'line2\n', 'line3\n']
+    cmd_args = ["test", "has space"]
+    cwd = "/path/to/cwd"
+    lines = ["line1\n", "line2\n", "line3\n"]
     actual = make_subprocess_output_error(
         cmd_args=cmd_args,
         cwd=cwd,
         lines=lines,
         exit_status=3,
     )
-    expected = dedent("""\
+    expected = dedent(
+        """\
     Command errored out with exit status 3:
      command: test 'has space'
          cwd: /path/to/cwd
@@ -48,36 +56,39 @@ def test_make_subprocess_output_error():
     line1
     line2
     line3
-    ----------------------------------------""")
-    assert actual == expected, 'actual: {}'.format(actual)
+    ----------------------------------------"""
+    )
+    assert actual == expected, "actual: {}".format(actual)
 
 
 def test_make_subprocess_output_error__non_ascii_command_arg(monkeypatch):
     """
     Test a command argument with a non-ascii character.
     """
-    cmd_args = ['foo', 'déf']
+    cmd_args = ["foo", "déf"]
     if sys.version_info[0] == 2:
         # Check in Python 2 that the str (bytes object) with the non-ascii
         # character has the encoding we expect. (This comes from the source
         # code encoding at the top of the file.)
-        assert cmd_args[1].decode('utf-8') == u'déf'
+        assert cmd_args[1].decode("utf-8") == u"déf"
 
     # We need to monkeypatch so the encoding will be correct on Windows.
-    monkeypatch.setattr(locale, 'getpreferredencoding', lambda: 'utf-8')
+    monkeypatch.setattr(locale, "getpreferredencoding", lambda: "utf-8")
     actual = make_subprocess_output_error(
         cmd_args=cmd_args,
-        cwd='/path/to/cwd',
+        cwd="/path/to/cwd",
         lines=[],
         exit_status=1,
     )
-    expected = dedent(u"""\
+    expected = dedent(
+        u"""\
     Command errored out with exit status 1:
      command: foo 'déf'
          cwd: /path/to/cwd
     Complete output (0 lines):
-    ----------------------------------------""")
-    assert actual == expected, u'actual: {}'.format(actual)
+    ----------------------------------------"""
+    )
+    assert actual == expected, u"actual: {}".format(actual)
 
 
 @pytest.mark.skipif("sys.version_info < (3,)")
@@ -85,51 +96,59 @@ def test_make_subprocess_output_error__non_ascii_cwd_python_3(monkeypatch):
     """
     Test a str (text) cwd with a non-ascii character in Python 3.
     """
-    cmd_args = ['test']
-    cwd = '/path/to/cwd/déf'
+    cmd_args = ["test"]
+    cwd = "/path/to/cwd/déf"
     actual = make_subprocess_output_error(
         cmd_args=cmd_args,
         cwd=cwd,
         lines=[],
         exit_status=1,
     )
-    expected = dedent("""\
+    expected = dedent(
+        """\
     Command errored out with exit status 1:
      command: test
          cwd: /path/to/cwd/déf
     Complete output (0 lines):
-    ----------------------------------------""")
-    assert actual == expected, 'actual: {}'.format(actual)
+    ----------------------------------------"""
+    )
+    assert actual == expected, "actual: {}".format(actual)
 
 
-@pytest.mark.parametrize('encoding', [
-    'utf-8',
-    # Test a Windows encoding.
-    'cp1252',
-])
+@pytest.mark.parametrize(
+    "encoding",
+    [
+        "utf-8",
+        # Test a Windows encoding.
+        "cp1252",
+    ],
+)
 @pytest.mark.skipif("sys.version_info >= (3,)")
 def test_make_subprocess_output_error__non_ascii_cwd_python_2(
-    monkeypatch, encoding,
+    monkeypatch,
+    encoding,
 ):
     """
     Test a str (bytes object) cwd with a non-ascii character in Python 2.
     """
-    cmd_args = ['test']
-    cwd = u'/path/to/cwd/déf'.encode(encoding)
-    monkeypatch.setattr(sys, 'getfilesystemencoding', lambda: encoding)
+    cmd_args = ["test"]
+    cwd = u"/path/to/cwd/déf".encode(encoding)
+    monkeypatch.setattr(sys, "getfilesystemencoding", lambda: encoding)
     actual = make_subprocess_output_error(
         cmd_args=cmd_args,
         cwd=cwd,
         lines=[],
         exit_status=1,
     )
-    expected = dedent(u"""\
+    expected = dedent(
+        u"""\
     Command errored out with exit status 1:
      command: test
          cwd: /path/to/cwd/déf
     Complete output (0 lines):
-    ----------------------------------------""")
-    assert actual == expected, u'actual: {}'.format(actual)
+    ----------------------------------------"""
+    )
+    assert actual == expected, u"actual: {}".format(actual)
 
 
 # This test is mainly important for checking unicode in Python 2.
@@ -137,25 +156,26 @@ def test_make_subprocess_output_error__non_ascii_line():
     """
     Test a line with a non-ascii character.
     """
-    lines = [u'curly-quote: \u2018\n']
+    lines = [u"curly-quote: \u2018\n"]
     actual = make_subprocess_output_error(
-        cmd_args=['test'],
-        cwd='/path/to/cwd',
+        cmd_args=["test"],
+        cwd="/path/to/cwd",
         lines=lines,
         exit_status=1,
     )
-    expected = dedent(u"""\
+    expected = dedent(
+        u"""\
     Command errored out with exit status 1:
      command: test
          cwd: /path/to/cwd
     Complete output (1 lines):
     curly-quote: \u2018
-    ----------------------------------------""")
-    assert actual == expected, u'actual: {}'.format(actual)
+    ----------------------------------------"""
+    )
+    assert actual == expected, u"actual: {}".format(actual)
 
 
 class FakeSpinner(SpinnerInterface):
-
     def __init__(self):
         self.spin_count = 0
         self.final_status = None
@@ -174,7 +194,13 @@ class TestCallSubprocess(object):
     """
 
     def check_result(
-        self, capfd, caplog, log_level, spinner, result, expected,
+        self,
+        capfd,
+        caplog,
+        log_level,
+        spinner,
+        result,
+        expected,
         expected_spinner,
     ):
         """
@@ -202,11 +228,11 @@ def check_result(
 
         # Confirm that stdout and stderr haven't been written to.
         captured = capfd.readouterr()
-        assert (captured.out, captured.err) == ('', '')
+        assert (captured.out, captured.err) == ("", "")
 
         records = caplog.record_tuples
         if len(records) != len(expected_records):
-            raise RuntimeError('{} != {}'.format(records, expected_records))
+            raise RuntimeError("{} != {}".format(records, expected_records))
 
         for record, expected_record in zip(records, expected_records):
             # Check the logger_name and log level parts exactly.
@@ -227,7 +253,7 @@ def prepare_call(self, caplog, log_level, command=None):
 
         caplog.set_level(log_level)
         spinner = FakeSpinner()
-        args = [sys.executable, '-c', command]
+        args = [sys.executable, "-c", command]
 
         return (args, spinner)
 
@@ -239,15 +265,23 @@ def test_debug_logging(self, capfd, caplog):
         args, spinner = self.prepare_call(caplog, log_level)
         result = call_subprocess(args, spinner=spinner)
 
-        expected = (['Hello', 'world'], [
-            ('pip.subprocessor', DEBUG, 'Running command '),
-            ('pip.subprocessor', DEBUG, 'Hello'),
-            ('pip.subprocessor', DEBUG, 'world'),
-        ])
+        expected = (
+            ["Hello", "world"],
+            [
+                ("pip.subprocessor", DEBUG, "Running command "),
+                ("pip.subprocessor", DEBUG, "Hello"),
+                ("pip.subprocessor", DEBUG, "world"),
+            ],
+        )
         # The spinner shouldn't spin in this case since the subprocess
         # output is already being logged to the console.
         self.check_result(
-            capfd, caplog, log_level, spinner, result, expected,
+            capfd,
+            caplog,
+            log_level,
+            spinner,
+            result,
+            expected,
             expected_spinner=(0, None),
         )
 
@@ -259,12 +293,17 @@ def test_info_logging(self, capfd, caplog):
         args, spinner = self.prepare_call(caplog, log_level)
         result = call_subprocess(args, spinner=spinner)
 
-        expected = (['Hello', 'world'], [])
+        expected = (["Hello", "world"], [])
         # The spinner should spin twice in this case since the subprocess
         # output isn't being written to the console.
         self.check_result(
-            capfd, caplog, log_level, spinner, result, expected,
-            expected_spinner=(2, 'done'),
+            capfd,
+            caplog,
+            log_level,
+            spinner,
+            result,
+            expected,
+            expected_spinner=(2, "done"),
         )
 
     def test_info_logging__subprocess_error(self, capfd, caplog):
@@ -280,19 +319,25 @@ def test_info_logging__subprocess_error(self, capfd, caplog):
             call_subprocess(args, spinner=spinner)
         result = None
         exc_message = str(exc.value)
-        assert exc_message.startswith(
-            'Command errored out with exit status 1: '
+        assert exc_message.startswith("Command errored out with exit status 1: ")
+        assert exc_message.endswith("Check the logs for full command output.")
+
+        expected = (
+            None,
+            [
+                ("pip.subprocessor", ERROR, "Complete output (3 lines):\n"),
+            ],
         )
-        assert exc_message.endswith('Check the logs for full command output.')
-
-        expected = (None, [
-            ('pip.subprocessor', ERROR, 'Complete output (3 lines):\n'),
-        ])
         # The spinner should spin three times in this case since the
         # subprocess output isn't being written to the console.
         self.check_result(
-            capfd, caplog, log_level, spinner, result, expected,
-            expected_spinner=(3, 'error'),
+            capfd,
+            caplog,
+            log_level,
+            spinner,
+            result,
+            expected,
+            expected_spinner=(3, "error"),
         )
 
         # Do some further checking on the captured log records to confirm
@@ -310,16 +355,18 @@ def test_info_logging__subprocess_error(self, capfd, caplog):
         # exact match.
         command_line = actual.pop(1)
         assert actual == [
-            '     cwd: None',
-            '----------------------------------------',
-            'Command errored out with exit status 1:',
-            'Complete output (3 lines):',
-            'Hello',
-            'fail',
-            'world',
-        ], 'lines: {}'.format(actual)  # Show the full output on failure.
-
-        assert command_line.startswith(' command: ')
+            "     cwd: None",
+            "----------------------------------------",
+            "Command errored out with exit status 1:",
+            "Complete output (3 lines):",
+            "Hello",
+            "fail",
+            "world",
+        ], "lines: {}".format(
+            actual
+        )  # Show the full output on failure.
+
+        assert command_line.startswith(" command: ")
         assert command_line.endswith('print("world"); exit("fail")\'')
 
     def test_info_logging_with_show_stdout_true(self, capfd, caplog):
@@ -330,26 +377,33 @@ def test_info_logging_with_show_stdout_true(self, capfd, caplog):
         args, spinner = self.prepare_call(caplog, log_level)
         result = call_subprocess(args, spinner=spinner, show_stdout=True)
 
-        expected = (['Hello', 'world'], [
-            ('pip.subprocessor', INFO, 'Running command '),
-            ('pip.subprocessor', INFO, 'Hello'),
-            ('pip.subprocessor', INFO, 'world'),
-        ])
+        expected = (
+            ["Hello", "world"],
+            [
+                ("pip.subprocessor", INFO, "Running command "),
+                ("pip.subprocessor", INFO, "Hello"),
+                ("pip.subprocessor", INFO, "world"),
+            ],
+        )
         # The spinner shouldn't spin in this case since the subprocess
         # output is already being written to the console.
         self.check_result(
-            capfd, caplog, log_level, spinner, result, expected,
+            capfd,
+            caplog,
+            log_level,
+            spinner,
+            result,
+            expected,
             expected_spinner=(0, None),
         )
 
-    @pytest.mark.parametrize((
-        'exit_status', 'show_stdout', 'extra_ok_returncodes', 'log_level',
-        'expected'),
+    @pytest.mark.parametrize(
+        ("exit_status", "show_stdout", "extra_ok_returncodes", "log_level", "expected"),
         [
             # The spinner should show here because show_stdout=False means
             # the subprocess should get logged at DEBUG level, but the passed
             # log level is only INFO.
-            (0, False, None, INFO, (None, 'done', 2)),
+            (0, False, None, INFO, (None, "done", 2)),
             # Test some cases where the spinner should not be shown.
             (0, False, None, DEBUG, (None, None, 0)),
             # Test show_stdout=True.
@@ -358,15 +412,21 @@ def test_info_logging_with_show_stdout_true(self, capfd, caplog):
             # The spinner should show here because show_stdout=True means
             # the subprocess should get logged at INFO level, but the passed
             # log level is only WARNING.
-            (0, True, None, WARNING, (None, 'done', 2)),
+            (0, True, None, WARNING, (None, "done", 2)),
             # Test a non-zero exit status.
-            (3, False, None, INFO, (InstallationError, 'error', 2)),
+            (3, False, None, INFO, (InstallationError, "error", 2)),
             # Test a non-zero exit status also in extra_ok_returncodes.
-            (3, False, (3, ), INFO, (None, 'done', 2)),
-    ])
+            (3, False, (3,), INFO, (None, "done", 2)),
+        ],
+    )
     def test_spinner_finish(
-        self, exit_status, show_stdout, extra_ok_returncodes, log_level,
-        caplog, expected,
+        self,
+        exit_status,
+        show_stdout,
+        extra_ok_returncodes,
+        log_level,
+        caplog,
+        expected,
     ):
         """
         Test that the spinner finishes correctly.
@@ -375,9 +435,7 @@ def test_spinner_finish(
         expected_final_status = expected[1]
         expected_spin_count = expected[2]
 
-        command = (
-            'print("Hello"); print("world"); exit({})'.format(exit_status)
-        )
+        command = 'print("Hello"); print("world"); exit({})'.format(exit_status)
         args, spinner = self.prepare_call(caplog, log_level, command=command)
         try:
             call_subprocess(
@@ -398,6 +456,6 @@ def test_spinner_finish(
     def test_closes_stdin(self):
         with pytest.raises(InstallationError):
             call_subprocess(
-                [sys.executable, '-c', 'input()'],
+                [sys.executable, "-c", "input()"],
                 show_stdout=True,
             )
diff --git a/tests/unit/test_utils_temp_dir.py b/tests/unit/test_utils_temp_dir.py
index 0d1b0a5ea20..187d449a2b0 100644
--- a/tests/unit/test_utils_temp_dir.py
+++ b/tests/unit/test_utils_temp_dir.py
@@ -23,21 +23,14 @@ def test_symlinked_path():
         assert os.path.exists(tmp_dir.path)
 
         alt_tmp_dir = tempfile.mkdtemp(prefix="pip-test-")
-        assert (
-            os.path.dirname(tmp_dir.path) ==
-            os.path.dirname(os.path.realpath(alt_tmp_dir))
+        assert os.path.dirname(tmp_dir.path) == os.path.dirname(
+            os.path.realpath(alt_tmp_dir)
         )
         # are we on a system where /tmp is a symlink
         if os.path.realpath(alt_tmp_dir) != os.path.abspath(alt_tmp_dir):
-            assert (
-                os.path.dirname(tmp_dir.path) !=
-                os.path.dirname(alt_tmp_dir)
-            )
+            assert os.path.dirname(tmp_dir.path) != os.path.dirname(alt_tmp_dir)
         else:
-            assert (
-                os.path.dirname(tmp_dir.path) ==
-                os.path.dirname(alt_tmp_dir)
-            )
+            assert os.path.dirname(tmp_dir.path) == os.path.dirname(alt_tmp_dir)
         os.rmdir(tmp_dir.path)
         assert not os.path.exists(tmp_dir.path)
 
@@ -95,16 +88,19 @@ def test_create_and_cleanup_work():
     assert not os.path.exists(created_path)
 
 
-@pytest.mark.parametrize("name", [
-    "ABC",
-    "ABC.dist-info",
-    "_+-",
-    "_package",
-    "A......B",
-    "AB",
-    "A",
-    "2",
-])
+@pytest.mark.parametrize(
+    "name",
+    [
+        "ABC",
+        "ABC.dist-info",
+        "_+-",
+        "_package",
+        "A......B",
+        "AB",
+        "A",
+        "2",
+    ],
+)
 def test_adjacent_directory_names(name):
     def names():
         return AdjacentTempDirectory._generate_names(name)
@@ -132,15 +128,12 @@ def names():
         assert len(some_names) > 0.9 * len(set(some_names))
 
         # Ensure the first few names are the same length as the original
-        same_len = list(itertools.takewhile(
-            lambda x: len(x) == len(name),
-            some_names
-        ))
+        same_len = list(itertools.takewhile(lambda x: len(x) == len(name), some_names))
         assert len(same_len) > 10
 
         # Check the first group are correct
-        expected_names = ['~' + name[1:]]
-        expected_names.extend('~' + c + name[2:] for c in chars)
+        expected_names = ["~" + name[1:]]
+        expected_names.extend("~" + c + name[2:] for c in chars)
         for x, y in zip(some_names, expected_names):
             assert x == y
 
@@ -159,16 +152,20 @@ def names():
             assert all(x.endswith(name) for x in some_names)
 
 
-@pytest.mark.parametrize("name", [
-    "A",
-    "ABC",
-    "ABC.dist-info",
-    "_+-",
-    "_package",
-])
+@pytest.mark.parametrize(
+    "name",
+    [
+        "A",
+        "ABC",
+        "ABC.dist-info",
+        "_+-",
+        "_package",
+    ],
+)
 def test_adjacent_directory_exists(name, tmpdir):
     block_name, expect_name = itertools.islice(
-        AdjacentTempDirectory._generate_names(name), 2)
+        AdjacentTempDirectory._generate_names(name), 2
+    )
 
     original = os.path.join(tmpdir, name)
     blocker = os.path.join(tmpdir, block_name)
@@ -215,20 +212,23 @@ def test_tempdirectory_asserts_global_tempdir(monkeypatch):
 not_deleted_kind = "not-deleted"
 
 
-@pytest.mark.parametrize("delete,kind,exists", [
-    (None, deleted_kind, False),
-    (_default, deleted_kind, False),
-    (True, deleted_kind, False),
-    (False, deleted_kind, True),
-    (None, not_deleted_kind, True),
-    (_default, not_deleted_kind, True),
-    (True, not_deleted_kind, False),
-    (False, not_deleted_kind, True),
-    (None, "unspecified", False),
-    (_default, "unspecified", False),
-    (True, "unspecified", False),
-    (False, "unspecified", True),
-])
+@pytest.mark.parametrize(
+    "delete,kind,exists",
+    [
+        (None, deleted_kind, False),
+        (_default, deleted_kind, False),
+        (True, deleted_kind, False),
+        (False, deleted_kind, True),
+        (None, not_deleted_kind, True),
+        (_default, not_deleted_kind, True),
+        (True, not_deleted_kind, False),
+        (False, not_deleted_kind, True),
+        (None, "unspecified", False),
+        (_default, "unspecified", False),
+        (True, "unspecified", False),
+        (False, "unspecified", True),
+    ],
+)
 def test_tempdir_registry(kind, delete, exists):
     with tempdir_registry() as registry:
         registry.set_delete(deleted_kind, True)
@@ -240,12 +240,8 @@ def test_tempdir_registry(kind, delete, exists):
         assert os.path.exists(path) == exists
 
 
-@pytest.mark.parametrize("delete,exists", [
-    (_default, True), (None, False)
-])
-def test_temp_dir_does_not_delete_explicit_paths_by_default(
-    tmpdir, delete, exists
-):
+@pytest.mark.parametrize("delete,exists", [(_default, True), (None, False)])
+def test_temp_dir_does_not_delete_explicit_paths_by_default(tmpdir, delete, exists):
     path = tmpdir / "example"
     path.mkdir()
 
diff --git a/tests/unit/test_utils_unpacking.py b/tests/unit/test_utils_unpacking.py
index d01ffb9cd0b..f11087f9cb7 100644
--- a/tests/unit/test_utils_unpacking.py
+++ b/tests/unit/test_utils_unpacking.py
@@ -10,11 +10,7 @@
 import pytest
 
 from pip._internal.exceptions import InstallationError
-from pip._internal.utils.unpacking import (
-    is_within_directory,
-    untar_file,
-    unzip_file,
-)
+from pip._internal.utils.unpacking import is_within_directory, untar_file, unzip_file
 
 
 class TestUnpackArchives(object):
@@ -53,31 +49,31 @@ def confirm_files(self):
         # expectations based on 022 umask set above and the unpack logic that
         # sets execute permissions, not preservation
         for fname, expected_mode, test, expected_contents in [
-            ('file.txt', 0o644, os.path.isfile, b'file\n'),
+            ("file.txt", 0o644, os.path.isfile, b"file\n"),
             # We don't test the "symlink.txt" contents for now.
-            ('symlink.txt', 0o644, os.path.isfile, None),
-            ('script_owner.sh', 0o755, os.path.isfile, b'file\n'),
-            ('script_group.sh', 0o755, os.path.isfile, b'file\n'),
-            ('script_world.sh', 0o755, os.path.isfile, b'file\n'),
-            ('dir', 0o755, os.path.isdir, None),
-            (os.path.join('dir', 'dirfile'), 0o644, os.path.isfile, b''),
+            ("symlink.txt", 0o644, os.path.isfile, None),
+            ("script_owner.sh", 0o755, os.path.isfile, b"file\n"),
+            ("script_group.sh", 0o755, os.path.isfile, b"file\n"),
+            ("script_world.sh", 0o755, os.path.isfile, b"file\n"),
+            ("dir", 0o755, os.path.isdir, None),
+            (os.path.join("dir", "dirfile"), 0o644, os.path.isfile, b""),
         ]:
             path = os.path.join(self.tempdir, fname)
-            if path.endswith('symlink.txt') and sys.platform == 'win32':
+            if path.endswith("symlink.txt") and sys.platform == "win32":
                 # no symlinks created on windows
                 continue
             assert test(path), path
             if expected_contents is not None:
-                with open(path, mode='rb') as f:
+                with open(path, mode="rb") as f:
                     contents = f.read()
-                assert contents == expected_contents, 'fname: {}'.format(fname)
-            if sys.platform == 'win32':
+                assert contents == expected_contents, "fname: {}".format(fname)
+            if sys.platform == "win32":
                 # the permissions tests below don't apply in windows
                 # due to os.chmod being a noop
                 continue
             mode = self.mode(path)
-            assert mode == expected_mode, (
-                "mode: {}, expected mode: {}".format(mode, expected_mode)
+            assert mode == expected_mode, "mode: {}, expected mode: {}".format(
+                mode, expected_mode
             )
 
     def make_zip_file(self, filename, file_list):
@@ -85,9 +81,9 @@ def make_zip_file(self, filename, file_list):
         Create a zip file for test case
         """
         test_zip = os.path.join(self.tempdir, filename)
-        with zipfile.ZipFile(test_zip, 'w') as myzip:
+        with zipfile.ZipFile(test_zip, "w") as myzip:
             for item in file_list:
-                myzip.writestr(item, 'file content')
+                myzip.writestr(item, "file content")
         return test_zip
 
     def make_tar_file(self, filename, file_list):
@@ -95,10 +91,10 @@ def make_tar_file(self, filename, file_list):
         Create a tar file for test case
         """
         test_tar = os.path.join(self.tempdir, filename)
-        with tarfile.open(test_tar, 'w') as mytar:
+        with tarfile.open(test_tar, "w") as mytar:
             for item in file_list:
                 file_tarinfo = tarfile.TarInfo(item)
-                mytar.addfile(file_tarinfo, 'file content')
+                mytar.addfile(file_tarinfo, "file content")
         return test_tar
 
     def test_unpack_tgz(self, data):
@@ -109,7 +105,7 @@ def test_unpack_tgz(self, data):
         untar_file(test_file, self.tempdir)
         self.confirm_files()
         # Check the timestamp of an extracted file
-        file_txt_path = os.path.join(self.tempdir, 'file.txt')
+        file_txt_path = os.path.join(self.tempdir, "file.txt")
         mtime = time.gmtime(os.stat(file_txt_path).st_mtime)
         assert mtime[0:6] == (2013, 8, 16, 5, 13, 37), mtime
 
@@ -126,11 +122,11 @@ def test_unpack_zip_failure(self):
         Test unpacking a *.zip with file containing .. path
         and expect exception
         """
-        files = ['regular_file.txt', os.path.join('..', 'outside_file.txt')]
-        test_zip = self.make_zip_file('test_zip.zip', files)
+        files = ["regular_file.txt", os.path.join("..", "outside_file.txt")]
+        test_zip = self.make_zip_file("test_zip.zip", files)
         with pytest.raises(InstallationError) as e:
             unzip_file(test_zip, self.tempdir)
-        assert 'trying to install outside target directory' in str(e.value)
+        assert "trying to install outside target directory" in str(e.value)
 
     def test_unpack_zip_success(self):
         """
@@ -139,11 +135,11 @@ def test_unpack_zip_success(self):
         so no exception raised
         """
         files = [
-            'regular_file1.txt',
-            os.path.join('dir', 'dir_file1.txt'),
-            os.path.join('dir', '..', 'dir_file2.txt'),
+            "regular_file1.txt",
+            os.path.join("dir", "dir_file1.txt"),
+            os.path.join("dir", "..", "dir_file2.txt"),
         ]
-        test_zip = self.make_zip_file('test_zip.zip', files)
+        test_zip = self.make_zip_file("test_zip.zip", files)
         unzip_file(test_zip, self.tempdir)
 
     def test_unpack_tar_failure(self):
@@ -151,11 +147,11 @@ def test_unpack_tar_failure(self):
         Test unpacking a *.tar with file containing .. path
         and expect exception
         """
-        files = ['regular_file.txt', os.path.join('..', 'outside_file.txt')]
-        test_tar = self.make_tar_file('test_tar.tar', files)
+        files = ["regular_file.txt", os.path.join("..", "outside_file.txt")]
+        test_tar = self.make_tar_file("test_tar.tar", files)
         with pytest.raises(InstallationError) as e:
             untar_file(test_tar, self.tempdir)
-        assert 'trying to install outside target directory' in str(e.value)
+        assert "trying to install outside target directory" in str(e.value)
 
     def test_unpack_tar_success(self):
         """
@@ -164,26 +160,29 @@ def test_unpack_tar_success(self):
         so no exception raised
         """
         files = [
-            'regular_file1.txt',
-            os.path.join('dir', 'dir_file1.txt'),
-            os.path.join('dir', '..', 'dir_file2.txt'),
+            "regular_file1.txt",
+            os.path.join("dir", "dir_file1.txt"),
+            os.path.join("dir", "..", "dir_file2.txt"),
         ]
-        test_tar = self.make_tar_file('test_tar.tar', files)
+        test_tar = self.make_tar_file("test_tar.tar", files)
         untar_file(test_tar, self.tempdir)
 
 
-@pytest.mark.parametrize('args, expected', [
-    # Test the second containing the first.
-    (('parent/sub', 'parent/'), False),
-    # Test the first not ending in a trailing slash.
-    (('parent', 'parent/foo'), True),
-    # Test target containing `..` but still inside the parent.
-    (('parent/', 'parent/foo/../bar'), True),
-    # Test target within the parent
-    (('parent/', 'parent/sub'), True),
-    # Test target outside parent
-    (('parent/', 'parent/../sub'), False),
-])
+@pytest.mark.parametrize(
+    "args, expected",
+    [
+        # Test the second containing the first.
+        (("parent/sub", "parent/"), False),
+        # Test the first not ending in a trailing slash.
+        (("parent", "parent/foo"), True),
+        # Test target containing `..` but still inside the parent.
+        (("parent/", "parent/foo/../bar"), True),
+        # Test target within the parent
+        (("parent/", "parent/sub"), True),
+        # Test target outside parent
+        (("parent/", "parent/../sub"), False),
+    ],
+)
 def test_is_within_directory(args, expected):
     result = is_within_directory(*args)
     assert result == expected
diff --git a/tests/unit/test_utils_virtualenv.py b/tests/unit/test_utils_virtualenv.py
index 625539d7617..207c087a823 100644
--- a/tests/unit/test_utils_virtualenv.py
+++ b/tests/unit/test_utils_virtualenv.py
@@ -7,19 +7,21 @@
 from pip._internal.utils import virtualenv
 
 
-@pytest.mark.parametrize("real_prefix, base_prefix, expected", [
-    (None, None, False),  # Python 2 base interpreter
-    (None, sys.prefix, False),  # Python 3 base interpreter
-    (None, "not_sys_prefix", True),  # PEP405 venv
-    (sys.prefix, None, True),  # Unknown case
-    (sys.prefix, sys.prefix, True),  # Unknown case
-    (sys.prefix, "not_sys_prefix", True),  # Unknown case
-    ("not_sys_prefix", None, True),  # Python 2 virtualenv
-    ("not_sys_prefix", sys.prefix, True),  # Python 3 virtualenv
-    ("not_sys_prefix", "not_sys_prefix", True),  # Unknown case
-])
-def test_running_under_virtualenv(
-        monkeypatch, real_prefix, base_prefix, expected):
+@pytest.mark.parametrize(
+    "real_prefix, base_prefix, expected",
+    [
+        (None, None, False),  # Python 2 base interpreter
+        (None, sys.prefix, False),  # Python 3 base interpreter
+        (None, "not_sys_prefix", True),  # PEP405 venv
+        (sys.prefix, None, True),  # Unknown case
+        (sys.prefix, sys.prefix, True),  # Unknown case
+        (sys.prefix, "not_sys_prefix", True),  # Unknown case
+        ("not_sys_prefix", None, True),  # Python 2 virtualenv
+        ("not_sys_prefix", sys.prefix, True),  # Python 3 virtualenv
+        ("not_sys_prefix", "not_sys_prefix", True),  # Unknown case
+    ],
+)
+def test_running_under_virtualenv(monkeypatch, real_prefix, base_prefix, expected):
     # Use raising=False to prevent AttributeError on missing attribute
     if real_prefix is None:
         monkeypatch.delattr(sys, "real_prefix", raising=False)
@@ -33,7 +35,8 @@ def test_running_under_virtualenv(
 
 
 @pytest.mark.parametrize(
-    "under_virtualenv, no_global_file, expected", [
+    "under_virtualenv, no_global_file, expected",
+    [
         (False, False, False),
         (False, True, False),
         (True, False, False),
@@ -47,21 +50,23 @@ def test_virtualenv_no_global_with_regular_virtualenv(
     no_global_file,
     expected,
 ):
-    monkeypatch.setattr(virtualenv, '_running_under_venv', lambda: False)
+    monkeypatch.setattr(virtualenv, "_running_under_venv", lambda: False)
 
-    monkeypatch.setattr(site, '__file__', tmpdir / 'site.py')
+    monkeypatch.setattr(site, "__file__", tmpdir / "site.py")
     monkeypatch.setattr(
-        virtualenv, '_running_under_regular_virtualenv',
+        virtualenv,
+        "_running_under_regular_virtualenv",
         lambda: under_virtualenv,
     )
     if no_global_file:
-        (tmpdir / 'no-global-site-packages.txt').touch()
+        (tmpdir / "no-global-site-packages.txt").touch()
 
     assert virtualenv.virtualenv_no_global() == expected
 
 
 @pytest.mark.parametrize(
-    "pyvenv_cfg_lines, under_venv, expected, expect_warning", [
+    "pyvenv_cfg_lines, under_venv, expected, expect_warning",
+    [
         (None, False, False, False),
         (None, True, True, True),  # this has a warning.
         (
@@ -94,13 +99,9 @@ def test_virtualenv_no_global_with_pep_405_virtual_environment(
     expected,
     expect_warning,
 ):
-    monkeypatch.setattr(
-        virtualenv, '_running_under_regular_virtualenv', lambda: False
-    )
-    monkeypatch.setattr(
-        virtualenv, '_get_pyvenv_cfg_lines', lambda: pyvenv_cfg_lines
-    )
-    monkeypatch.setattr(virtualenv, '_running_under_venv', lambda: under_venv)
+    monkeypatch.setattr(virtualenv, "_running_under_regular_virtualenv", lambda: False)
+    monkeypatch.setattr(virtualenv, "_get_pyvenv_cfg_lines", lambda: pyvenv_cfg_lines)
+    monkeypatch.setattr(virtualenv, "_running_under_venv", lambda: under_venv)
 
     with caplog.at_level(logging.WARNING):
         assert virtualenv.virtualenv_no_global() == expected
@@ -115,12 +116,13 @@ def test_virtualenv_no_global_with_pep_405_virtual_environment(
 
 
 @pytest.mark.parametrize(
-    "contents, expected", [
+    "contents, expected",
+    [
         (None, None),
         ("", []),
         ("a = b\nc = d\n", ["a = b", "c = d"]),
         ("a = b\nc = d", ["a = b", "c = d"]),  # no trailing newlines
-    ]
+    ],
 )
 def test_get_pyvenv_cfg_lines_for_pep_405_virtual_environment(
     monkeypatch,
@@ -128,8 +130,8 @@ def test_get_pyvenv_cfg_lines_for_pep_405_virtual_environment(
     contents,
     expected,
 ):
-    monkeypatch.setattr(sys, 'prefix', str(tmpdir))
+    monkeypatch.setattr(sys, "prefix", str(tmpdir))
     if contents is not None:
-        tmpdir.joinpath('pyvenv.cfg').write_text(contents)
+        tmpdir.joinpath("pyvenv.cfg").write_text(contents)
 
     assert virtualenv._get_pyvenv_cfg_lines() == expected
diff --git a/tests/unit/test_utils_wheel.py b/tests/unit/test_utils_wheel.py
index cf8bd6dc3ed..e71b6edbf8e 100644
--- a/tests/unit/test_utils_wheel.py
+++ b/tests/unit/test_utils_wheel.py
@@ -73,9 +73,7 @@ def test_wheel_dist_info_dir_wrong_name(tmpdir, zip_dir):
 
 
 def test_wheel_version_ok(tmpdir, data):
-    assert wheel.wheel_version(
-        message_from_string("Wheel-Version: 1.9")
-    ) == (1, 9)
+    assert wheel.wheel_version(message_from_string("Wheel-Version: 1.9")) == (1, 9)
 
 
 def test_wheel_metadata_fails_missing_wheel(tmpdir, zip_dir):
@@ -106,21 +104,22 @@ def test_wheel_version_fails_on_no_wheel_version():
     assert "missing Wheel-Version" in str(e.value)
 
 
-@pytest.mark.parametrize("version", [
-    ("",),
-    ("1.b",),
-    ("1.",),
-])
+@pytest.mark.parametrize(
+    "version",
+    [
+        ("",),
+        ("1.b",),
+        ("1.",),
+    ],
+)
 def test_wheel_version_fails_on_bad_wheel_version(version):
     with pytest.raises(UnsupportedWheel) as e:
-        wheel.wheel_version(
-            message_from_string("Wheel-Version: {}".format(version))
-        )
+        wheel.wheel_version(message_from_string("Wheel-Version: {}".format(version)))
     assert "invalid Wheel-Version" in str(e.value)
 
 
 def test_check_compatibility():
-    name = 'test'
+    name = "test"
     vc = wheel.VERSION_COMPATIBLE
 
     # Major version is higher - should be incompatible
@@ -129,7 +128,7 @@ def test_check_compatibility():
     # test raises with correct error
     with pytest.raises(UnsupportedWheel) as e:
         wheel.check_compatibility(higher_v, name)
-    assert 'is not compatible' in str(e)
+    assert "is not compatible" in str(e)
 
     # Should only log.warning - minor version is greater
     higher_v = (vc[0], vc[1] + 1)
diff --git a/tests/unit/test_vcs.py b/tests/unit/test_vcs.py
index b6ed86b6296..f98a5f25c25 100644
--- a/tests/unit/test_vcs.py
+++ b/tests/unit/test_vcs.py
@@ -15,60 +15,78 @@
 from pip._internal.vcs.versioncontrol import RevOptions, VersionControl
 from tests.lib import is_svn_installed, need_svn, pyversion
 
-if pyversion >= '3':
+if pyversion >= "3":
     VERBOSE_FALSE = False
 else:
     VERBOSE_FALSE = 0
 
 
 @pytest.mark.skipif(
-    'TRAVIS' not in os.environ,
-    reason='Subversion is only required under Travis')
+    "TRAVIS" not in os.environ, reason="Subversion is only required under Travis"
+)
 def test_ensure_svn_available():
     """Make sure that svn is available when running in Travis."""
     assert is_svn_installed()
 
 
-@pytest.mark.parametrize('args, expected', [
-    # Test without subdir.
-    (('git+https://example.com/pkg', 'dev', 'myproj'),
-     'git+https://example.com/pkg@dev#egg=myproj'),
-    # Test with subdir.
-    (('git+https://example.com/pkg', 'dev', 'myproj', 'sub/dir'),
-     'git+https://example.com/pkg@dev#egg=myproj&subdirectory=sub/dir'),
-    # Test with None subdir.
-    (('git+https://example.com/pkg', 'dev', 'myproj', None),
-     'git+https://example.com/pkg@dev#egg=myproj'),
-    # Test an unescaped project name.
-    (('git+https://example.com/pkg', 'dev', 'zope-interface'),
-     'git+https://example.com/pkg@dev#egg=zope_interface'),
-])
+@pytest.mark.parametrize(
+    "args, expected",
+    [
+        # Test without subdir.
+        (
+            ("git+https://example.com/pkg", "dev", "myproj"),
+            "git+https://example.com/pkg@dev#egg=myproj",
+        ),
+        # Test with subdir.
+        (
+            ("git+https://example.com/pkg", "dev", "myproj", "sub/dir"),
+            "git+https://example.com/pkg@dev#egg=myproj&subdirectory=sub/dir",
+        ),
+        # Test with None subdir.
+        (
+            ("git+https://example.com/pkg", "dev", "myproj", None),
+            "git+https://example.com/pkg@dev#egg=myproj",
+        ),
+        # Test an unescaped project name.
+        (
+            ("git+https://example.com/pkg", "dev", "zope-interface"),
+            "git+https://example.com/pkg@dev#egg=zope_interface",
+        ),
+    ],
+)
 def test_make_vcs_requirement_url(args, expected):
     actual = make_vcs_requirement_url(*args)
     assert actual == expected
 
 
 def test_rev_options_repr():
-    rev_options = RevOptions(Git, 'develop')
+    rev_options = RevOptions(Git, "develop")
     assert repr(rev_options) == "<RevOptions git: rev='develop'>"
 
 
-@pytest.mark.parametrize(('vc_class', 'expected1', 'expected2', 'kwargs'), [
-    # First check VCS-specific RevOptions behavior.
-    (Bazaar, [], ['-r', '123'], {}),
-    (Git, ['HEAD'], ['123'], {}),
-    (Mercurial, [], ['123'], {}),
-    (Subversion, [], ['-r', '123'], {}),
-    # Test extra_args.  For this, test using a single VersionControl class.
-    (Git, ['HEAD', 'opt1', 'opt2'], ['123', 'opt1', 'opt2'],
-        dict(extra_args=['opt1', 'opt2'])),
-])
+@pytest.mark.parametrize(
+    ("vc_class", "expected1", "expected2", "kwargs"),
+    [
+        # First check VCS-specific RevOptions behavior.
+        (Bazaar, [], ["-r", "123"], {}),
+        (Git, ["HEAD"], ["123"], {}),
+        (Mercurial, [], ["123"], {}),
+        (Subversion, [], ["-r", "123"], {}),
+        # Test extra_args.  For this, test using a single VersionControl class.
+        (
+            Git,
+            ["HEAD", "opt1", "opt2"],
+            ["123", "opt1", "opt2"],
+            dict(extra_args=["opt1", "opt2"]),
+        ),
+    ],
+)
 def test_rev_options_to_args(vc_class, expected1, expected2, kwargs):
     """
     Test RevOptions.to_args().
     """
     assert RevOptions(vc_class, **kwargs).to_args() == expected1
-    assert RevOptions(vc_class, '123', **kwargs).to_args() == expected2
+    assert RevOptions(vc_class, "123", **kwargs).to_args() == expected2
 
 
 def test_rev_options_to_display():
@@ -78,10 +96,10 @@ def test_rev_options_to_display():
     # The choice of VersionControl class doesn't matter here since
     # the implementation is the same for all of them.
     rev_options = RevOptions(Git)
-    assert rev_options.to_display() == ''
+    assert rev_options.to_display() == ""
 
-    rev_options = RevOptions(Git, 'master')
-    assert rev_options.to_display() == ' (to revision master)'
+    rev_options = RevOptions(Git, "master")
+    assert rev_options.to_display() == " (to revision master)"
 
 
 def test_rev_options_make_new():
@@ -90,87 +108,93 @@ def test_rev_options_make_new():
     """
     # The choice of VersionControl class doesn't matter here since
     # the implementation is the same for all of them.
-    rev_options = RevOptions(Git, 'master', extra_args=['foo', 'bar'])
-    new_options = rev_options.make_new('develop')
+    rev_options = RevOptions(Git, "master", extra_args=["foo", "bar"])
+    new_options = rev_options.make_new("develop")
 
     assert new_options is not rev_options
-    assert new_options.extra_args == ['foo', 'bar']
-    assert new_options.rev == 'develop'
+    assert new_options.extra_args == ["foo", "bar"]
+    assert new_options.rev == "develop"
     assert new_options.vc_class is Git
 
 
-@pytest.mark.parametrize('sha, expected', [
-    ((40 * 'a'), True),
-    ((40 * 'A'), True),
-    # Test a string containing all valid characters.
-    ((18 * 'a' + '0123456789abcdefABCDEF'), True),
-    ((40 * 'g'), False),
-    ((39 * 'a'), False),
-    ((41 * 'a'), False)
-])
+@pytest.mark.parametrize(
+    "sha, expected",
+    [
+        ((40 * "a"), True),
+        ((40 * "A"), True),
+        # Test a string containing all valid characters.
+        ((18 * "a" + "0123456789abcdefABCDEF"), True),
+        ((40 * "g"), False),
+        ((39 * "a"), False),
+        ((41 * "a"), False),
+    ],
+)
 def test_looks_like_hash(sha, expected):
     assert looks_like_hash(sha) == expected
 
 
-@pytest.mark.parametrize('vcs_cls, remote_url, expected', [
-    # Git is one of the subclasses using the base class implementation.
-    (Git, 'git://example.com/MyProject', False),
-    (Git, 'http://example.com/MyProject', True),
-    # Subversion is the only subclass overriding the base class implementation.
-    (Subversion, 'svn://example.com/MyProject', True),
-])
+@pytest.mark.parametrize(
+    "vcs_cls, remote_url, expected",
+    [
+        # Git is one of the subclasses using the base class implementation.
+        (Git, "git://example.com/MyProject", False),
+        (Git, "http://example.com/MyProject", True),
+        # Subversion is the only subclass overriding the base class implementation.
+        (Subversion, "svn://example.com/MyProject", True),
+    ],
+)
 def test_should_add_vcs_url_prefix(vcs_cls, remote_url, expected):
     actual = vcs_cls.should_add_vcs_url_prefix(remote_url)
     assert actual == expected
 
 
-@patch('pip._internal.vcs.git.Git.get_remote_url')
-@patch('pip._internal.vcs.git.Git.get_revision')
-@patch('pip._internal.vcs.git.Git.get_subdirectory')
+@patch("pip._internal.vcs.git.Git.get_remote_url")
+@patch("pip._internal.vcs.git.Git.get_revision")
+@patch("pip._internal.vcs.git.Git.get_subdirectory")
 @pytest.mark.network
 def test_git_get_src_requirements(
     mock_get_subdirectory, mock_get_revision, mock_get_remote_url
 ):
-    git_url = 'https://github.com/pypa/pip-test-package'
-    sha = '5547fa909e83df8bd743d3978d6667497983a4b7'
+    git_url = "https://github.com/pypa/pip-test-package"
+    sha = "5547fa909e83df8bd743d3978d6667497983a4b7"
 
     mock_get_remote_url.return_value = git_url
     mock_get_revision.return_value = sha
     mock_get_subdirectory.return_value = None
 
-    ret = Git.get_src_requirement('.', 'pip-test-package')
+    ret = Git.get_src_requirement(".", "pip-test-package")
 
     assert ret == (
-        'git+https://github.com/pypa/pip-test-package'
-        '@5547fa909e83df8bd743d3978d6667497983a4b7#egg=pip_test_package'
+        "git+https://github.com/pypa/pip-test-package"
+        "@5547fa909e83df8bd743d3978d6667497983a4b7#egg=pip_test_package"
     )
 
 
-@patch('pip._internal.vcs.git.Git.get_revision_sha')
+@patch("pip._internal.vcs.git.Git.get_revision_sha")
 def test_git_resolve_revision_rev_exists(get_sha_mock):
-    get_sha_mock.return_value = ('123456', False)
-    url = 'git+https://git.example.com'
-    rev_options = Git.make_rev_options('develop')
+    get_sha_mock.return_value = ("123456", False)
+    url = "git+https://git.example.com"
+    rev_options = Git.make_rev_options("develop")
 
-    new_options = Git.resolve_revision('.', url, rev_options)
-    assert new_options.rev == '123456'
+    new_options = Git.resolve_revision(".", url, rev_options)
+    assert new_options.rev == "123456"
 
 
-@patch('pip._internal.vcs.git.Git.get_revision_sha')
+@patch("pip._internal.vcs.git.Git.get_revision_sha")
 def test_git_resolve_revision_rev_not_found(get_sha_mock):
     get_sha_mock.return_value = (None, False)
-    url = 'git+https://git.example.com'
-    rev_options = Git.make_rev_options('develop')
+    url = "git+https://git.example.com"
+    rev_options = Git.make_rev_options("develop")
 
-    new_options = Git.resolve_revision('.', url, rev_options)
-    assert new_options.rev == 'develop'
+    new_options = Git.resolve_revision(".", url, rev_options)
+    assert new_options.rev == "develop"
 
 
-@patch('pip._internal.vcs.git.Git.get_revision_sha')
+@patch("pip._internal.vcs.git.Git.get_revision_sha")
 def test_git_resolve_revision_not_found_warning(get_sha_mock, caplog):
     get_sha_mock.return_value = (None, False)
-    url = 'git+https://git.example.com'
-    sha = 40 * 'a'
+    url = "git+https://git.example.com"
+    sha = 40 * "a"
     rev_options = Git.make_rev_options(sha)
 
     # resolve_revision with a full sha would fail here because
@@ -178,43 +202,48 @@ def test_git_resolve_revision_not_found_warning(get_sha_mock, caplog):
     # test_resolve_commit_not_on_branch.
 
     rev_options = Git.make_rev_options(sha[:6])
-    new_options = Git.resolve_revision('.', url, rev_options)
-    assert new_options.rev == 'aaaaaa'
+    new_options = Git.resolve_revision(".", url, rev_options)
+    assert new_options.rev == "aaaaaa"
 
     # Check that a warning got logged only for the abbreviated hash.
     messages = [r.getMessage() for r in caplog.records]
-    messages = [msg for msg in messages if msg.startswith('Did not find ')]
+    messages = [msg for msg in messages if msg.startswith("Did not find ")]
     assert messages == [
         "Did not find branch or tag 'aaaaaa', assuming revision or ref."
     ]
 
 
-@pytest.mark.parametrize('rev_name,result', (
-    ('5547fa909e83df8bd743d3978d6667497983a4b7', True),
-    ('5547fa909', False),
-    ('5678', False),
-    ('abc123', False),
-    ('foo', False),
-    (None, False),
-))
-@patch('pip._internal.vcs.git.Git.get_revision')
+@pytest.mark.parametrize(
+    "rev_name,result",
+    (
+        ("5547fa909e83df8bd743d3978d6667497983a4b7", True),
+        ("5547fa909", False),
+        ("5678", False),
+        ("abc123", False),
+        ("foo", False),
+        (None, False),
+    ),
+)
+@patch("pip._internal.vcs.git.Git.get_revision")
 def test_git_is_commit_id_equal(mock_get_revision, rev_name, result):
     """
     Test Git.is_commit_id_equal().
     """
-    mock_get_revision.return_value = '5547fa909e83df8bd743d3978d6667497983a4b7'
-    assert Git.is_commit_id_equal('/path', rev_name) is result
+    mock_get_revision.return_value = "5547fa909e83df8bd743d3978d6667497983a4b7"
+    assert Git.is_commit_id_equal("/path", rev_name) is result
 
 
 # The non-SVN backends all use the same get_netloc_and_auth(), so only test
 # Git as a representative.
-@pytest.mark.parametrize('args, expected', [
-    # Test a basic case.
-    (('example.com', 'https'), ('example.com', (None, None))),
-    # Test with username and password.
-    (('user:pass@example.com', 'https'),
-     ('user:pass@example.com', (None, None))),
-])
+@pytest.mark.parametrize(
+    "args, expected",
+    [
+        # Test a basic case.
+        (("example.com", "https"), ("example.com", (None, None))),
+        # Test with username and password.
+        (("user:pass@example.com", "https"), ("user:pass@example.com", (None, None))),
+    ],
+)
 def test_git__get_netloc_and_auth(args, expected):
     """
     Test VersionControl.get_netloc_and_auth().
@@ -224,20 +253,24 @@ def test_git__get_netloc_and_auth(args, expected):
     assert actual == expected
 
 
-@pytest.mark.parametrize('args, expected', [
-    # Test https.
-    (('example.com', 'https'), ('example.com', (None, None))),
-    # Test https with username and no password.
-    (('user@example.com', 'https'), ('example.com', ('user', None))),
-    # Test https with username and password.
-    (('user:pass@example.com', 'https'), ('example.com', ('user', 'pass'))),
-    # Test https with URL-encoded reserved characters.
-    (('user%3Aname:%23%40%5E@example.com', 'https'),
-     ('example.com', ('user:name', '#@^'))),
-    # Test ssh with username and password.
-    (('user:pass@example.com', 'ssh'),
-     ('user:pass@example.com', (None, None))),
-])
+@pytest.mark.parametrize(
+    "args, expected",
+    [
+        # Test https.
+        (("example.com", "https"), ("example.com", (None, None))),
+        # Test https with username and no password.
+        (("user@example.com", "https"), ("example.com", ("user", None))),
+        # Test https with username and password.
+        (("user:pass@example.com", "https"), ("example.com", ("user", "pass"))),
+        # Test https with URL-encoded reserved characters.
+        (
+            ("user%3Aname:%23%40%5E@example.com", "https"),
+            ("example.com", ("user:name", "#@^")),
+        ),
+        # Test ssh with username and password.
+        (("user:pass@example.com", "ssh"), ("user:pass@example.com", (None, None))),
+    ],
+)
 def test_subversion__get_netloc_and_auth(args, expected):
     """
     Test Subversion.get_netloc_and_auth().
@@ -254,21 +287,28 @@ def test_git__get_url_rev__idempotent():
 
     Also check that it doesn't change self.url.
     """
-    url = 'git+git@git.example.com:MyProject#egg=MyProject'
+    url = "git+git@git.example.com:MyProject#egg=MyProject"
     result1 = Git.get_url_rev_and_auth(url)
     result2 = Git.get_url_rev_and_auth(url)
-    expected = ('git@git.example.com:MyProject', None, (None, None))
+    expected = ("git@git.example.com:MyProject", None, (None, None))
     assert result1 == expected
     assert result2 == expected
 
 
-@pytest.mark.parametrize('url, expected', [
-    ('svn+https://svn.example.com/MyProject',
-     ('https://svn.example.com/MyProject', None, (None, None))),
-    # Test a "+" in the path portion.
-    ('svn+https://svn.example.com/My+Project',
-     ('https://svn.example.com/My+Project', None, (None, None))),
-])
+@pytest.mark.parametrize(
+    "url, expected",
+    [
+        (
+            "svn+https://svn.example.com/MyProject",
+            ("https://svn.example.com/MyProject", None, (None, None)),
+        ),
+        # Test a "+" in the path portion.
+        (
+            "svn+https://svn.example.com/My+Project",
+            ("https://svn.example.com/My+Project", None, (None, None)),
+        ),
+    ],
+)
 def test_version_control__get_url_rev_and_auth(url, expected):
     """
     Test the basic case of VersionControl.get_url_rev_and_auth().
@@ -277,11 +317,14 @@ def test_version_control__get_url_rev_and_auth(url, expected):
     assert actual == expected
 
 
-@pytest.mark.parametrize('url', [
-    'https://svn.example.com/MyProject',
-    # Test a URL containing a "+" (but not in the scheme).
-    'https://svn.example.com/My+Project',
-])
+@pytest.mark.parametrize(
+    "url",
+    [
+        "https://svn.example.com/MyProject",
+        # Test a URL containing a "+" (but not in the scheme).
+        "https://svn.example.com/My+Project",
+    ],
+)
 def test_version_control__get_url_rev_and_auth__missing_plus(url):
     """
     Test passing a URL to VersionControl.get_url_rev_and_auth() with a "+"
@@ -290,13 +333,16 @@ def test_version_control__get_url_rev_and_auth__missing_plus(url):
     with pytest.raises(ValueError) as excinfo:
         VersionControl.get_url_rev_and_auth(url)
 
-    assert 'malformed VCS url' in str(excinfo.value)
+    assert "malformed VCS url" in str(excinfo.value)
 
 
-@pytest.mark.parametrize('url', [
-    # Test a URL with revision part as empty.
-    'git+https://github.com/MyUser/myProject.git@#egg=py_pkg',
-])
+@pytest.mark.parametrize(
+    "url",
+    [
+        # Test a URL with revision part as empty.
+        "git+https://github.com/MyUser/myProject.git@#egg=py_pkg",
+    ],
+)
 def test_version_control__get_url_rev_and_auth__no_revision(url):
     """
     Test passing a URL to VersionControl.get_url_rev_and_auth() with
@@ -305,29 +351,41 @@ def test_version_control__get_url_rev_and_auth__no_revision(url):
     with pytest.raises(InstallationError) as excinfo:
         VersionControl.get_url_rev_and_auth(url)
 
-    assert 'an empty revision (after @)' in str(excinfo.value)
-
-
-@pytest.mark.parametrize('url, expected', [
-    # Test http.
-    ('bzr+http://bzr.myproject.org/MyProject/trunk/#egg=MyProject',
-     'http://bzr.myproject.org/MyProject/trunk/'),
-    # Test https.
-    ('bzr+https://bzr.myproject.org/MyProject/trunk/#egg=MyProject',
-     'https://bzr.myproject.org/MyProject/trunk/'),
-    # Test ftp.
-    ('bzr+ftp://bzr.myproject.org/MyProject/trunk/#egg=MyProject',
-     'ftp://bzr.myproject.org/MyProject/trunk/'),
-    # Test sftp.
-    ('bzr+sftp://bzr.myproject.org/MyProject/trunk/#egg=MyProject',
-     'sftp://bzr.myproject.org/MyProject/trunk/'),
-    # Test launchpad.
-    ('bzr+lp:MyLaunchpadProject#egg=MyLaunchpadProject',
-     'lp:MyLaunchpadProject'),
-    # Test ssh (special handling).
-    ('bzr+ssh://bzr.myproject.org/MyProject/trunk/#egg=MyProject',
-     'bzr+ssh://bzr.myproject.org/MyProject/trunk/'),
-])
+    assert "an empty revision (after @)" in str(excinfo.value)
+
+
+@pytest.mark.parametrize(
+    "url, expected",
+    [
+        # Test http.
+        (
+            "bzr+http://bzr.myproject.org/MyProject/trunk/#egg=MyProject",
+            "http://bzr.myproject.org/MyProject/trunk/",
+        ),
+        # Test https.
+        (
+            "bzr+https://bzr.myproject.org/MyProject/trunk/#egg=MyProject",
+            "https://bzr.myproject.org/MyProject/trunk/",
+        ),
+        # Test ftp.
+        (
+            "bzr+ftp://bzr.myproject.org/MyProject/trunk/#egg=MyProject",
+            "ftp://bzr.myproject.org/MyProject/trunk/",
+        ),
+        # Test sftp.
+        (
+            "bzr+sftp://bzr.myproject.org/MyProject/trunk/#egg=MyProject",
+            "sftp://bzr.myproject.org/MyProject/trunk/",
+        ),
+        # Test launchpad.
+        ("bzr+lp:MyLaunchpadProject#egg=MyLaunchpadProject", "lp:MyLaunchpadProject"),
+        # Test ssh (special handling).
+        (
+            "bzr+ssh://bzr.myproject.org/MyProject/trunk/#egg=MyProject",
+            "bzr+ssh://bzr.myproject.org/MyProject/trunk/",
+        ),
+    ],
+)
 def test_bazaar__get_url_rev_and_auth(url, expected):
     """
     Test Bazaar.get_url_rev_and_auth().
@@ -336,20 +394,31 @@ def test_bazaar__get_url_rev_and_auth(url, expected):
     assert actual == (expected, None, (None, None))
 
 
-@pytest.mark.parametrize('url, expected', [
-    # Test an https URL.
-    ('svn+https://svn.example.com/MyProject#egg=MyProject',
-     ('https://svn.example.com/MyProject', None, (None, None))),
-    # Test an https URL with a username and password.
-    ('svn+https://user:pass@svn.example.com/MyProject#egg=MyProject',
-     ('https://svn.example.com/MyProject', None, ('user', 'pass'))),
-    # Test an ssh URL.
-    ('svn+ssh://svn.example.com/MyProject#egg=MyProject',
-     ('svn+ssh://svn.example.com/MyProject', None, (None, None))),
-    # Test an ssh URL with a username.
-    ('svn+ssh://user@svn.example.com/MyProject#egg=MyProject',
-     ('svn+ssh://user@svn.example.com/MyProject', None, (None, None))),
-])
+@pytest.mark.parametrize(
+    "url, expected",
+    [
+        # Test an https URL.
+        (
+            "svn+https://svn.example.com/MyProject#egg=MyProject",
+            ("https://svn.example.com/MyProject", None, (None, None)),
+        ),
+        # Test an https URL with a username and password.
+        (
+            "svn+https://user:pass@svn.example.com/MyProject#egg=MyProject",
+            ("https://svn.example.com/MyProject", None, ("user", "pass")),
+        ),
+        # Test an ssh URL.
+        (
+            "svn+ssh://svn.example.com/MyProject#egg=MyProject",
+            ("svn+ssh://svn.example.com/MyProject", None, (None, None)),
+        ),
+        # Test an ssh URL with a username.
+        (
+            "svn+ssh://user@svn.example.com/MyProject#egg=MyProject",
+            ("svn+ssh://user@svn.example.com/MyProject", None, (None, None)),
+        ),
+    ],
+)
 def test_subversion__get_url_rev_and_auth(url, expected):
     """
     Test Subversion.get_url_rev_and_auth().
@@ -360,11 +429,14 @@ def test_subversion__get_url_rev_and_auth(url, expected):
 
 # The non-SVN backends all use the same make_rev_args(), so only test
 # Git as a representative.
-@pytest.mark.parametrize('username, password, expected', [
-    (None, None, []),
-    ('user', None, []),
-    ('user', hide_value('pass'), []),
-])
+@pytest.mark.parametrize(
+    "username, password, expected",
+    [
+        (None, None, []),
+        ("user", None, []),
+        ("user", hide_value("pass"), []),
+    ],
+)
 def test_git__make_rev_args(username, password, expected):
     """
     Test VersionControl.make_rev_args().
@@ -373,12 +445,18 @@ def test_git__make_rev_args(username, password, expected):
     assert actual == expected
 
 
-@pytest.mark.parametrize('username, password, expected', [
-    (None, None, []),
-    ('user', None, ['--username', 'user']),
-    ('user', hide_value('pass'),
-     ['--username', 'user', '--password', hide_value('pass')]),
-])
+@pytest.mark.parametrize(
+    "username, password, expected",
+    [
+        (None, None, []),
+        ("user", None, ["--username", "user"]),
+        (
+            "user",
+            hide_value("pass"),
+            ["--username", "user", "--password", hide_value("pass")],
+        ),
+    ],
+)
 def test_subversion__make_rev_args(username, password, expected):
     """
     Test Subversion.make_rev_args().
@@ -391,34 +469,36 @@ def test_subversion__get_url_rev_options():
     """
     Test Subversion.get_url_rev_options().
     """
-    secret_url = (
-        'svn+https://user:pass@svn.example.com/MyProject@v1.0#egg=MyProject'
-    )
+    secret_url = "svn+https://user:pass@svn.example.com/MyProject@v1.0#egg=MyProject"
     hidden_url = hide_url(secret_url)
     url, rev_options = Subversion().get_url_rev_options(hidden_url)
-    assert url == hide_url('https://svn.example.com/MyProject')
-    assert rev_options.rev == 'v1.0'
+    assert url == hide_url("https://svn.example.com/MyProject")
+    assert rev_options.rev == "v1.0"
     assert rev_options.extra_args == (
-        ['--username', 'user', '--password', hide_value('pass')]
+        ["--username", "user", "--password", hide_value("pass")]
     )
 
 
 def test_get_git_version():
     git_version = Git().get_git_version()
-    assert git_version >= parse_version('1.0.0')
-
-
-@pytest.mark.parametrize('use_interactive,is_atty,expected', [
-    (None, False, False),
-    (None, True, True),
-    (False, False, False),
-    (False, True, False),
-    (True, False, True),
-    (True, True, True),
-])
-@patch('sys.stdin.isatty')
+    assert git_version >= parse_version("1.0.0")
+
+
+@pytest.mark.parametrize(
+    "use_interactive,is_atty,expected",
+    [
+        (None, False, False),
+        (None, True, True),
+        (False, False, False),
+        (False, True, False),
+        (True, False, True),
+        (True, True, True),
+    ],
+)
+@patch("sys.stdin.isatty")
 def test_subversion__init_use_interactive(
-        mock_isatty, use_interactive, is_atty, expected):
+    mock_isatty, use_interactive, is_atty, expected
+):
     """
     Test Subversion.__init__() with mocked sys.stdin.isatty() output.
     """
@@ -440,25 +520,33 @@ def test_subversion__call_vcs_version():
     assert version[0] >= 1
 
 
-@pytest.mark.parametrize('svn_output, expected_version', [
-    ('svn, version 1.10.3 (r1842928)\n'
-     '   compiled Feb 25 2019, 14:20:39 on x86_64-apple-darwin17.0.0',
-     (1, 10, 3)),
-    ('svn, version 1.12.0-SlikSvn (SlikSvn/1.12.0)\n'
-     '   compiled May 28 2019, 13:44:56 on x86_64-microsoft-windows6.2',
-     (1, 12, 0)),
-    ('svn, version 1.9.7 (r1800392)', (1, 9, 7)),
-    ('svn, version 1.9.7a1 (r1800392)', ()),
-    ('svn, version 1.9 (r1800392)', (1, 9)),
-    ('svn, version .9.7 (r1800392)', ()),
-    ('svn version 1.9.7 (r1800392)', ()),
-    ('svn 1.9.7', ()),
-    ('svn, version . .', ()),
-    ('', ()),
-])
-@patch('pip._internal.vcs.subversion.Subversion.run_command')
+@pytest.mark.parametrize(
+    "svn_output, expected_version",
+    [
+        (
+            "svn, version 1.10.3 (r1842928)\n"
+            "   compiled Feb 25 2019, 14:20:39 on x86_64-apple-darwin17.0.0",
+            (1, 10, 3),
+        ),
+        (
+            "svn, version 1.12.0-SlikSvn (SlikSvn/1.12.0)\n"
+            "   compiled May 28 2019, 13:44:56 on x86_64-microsoft-windows6.2",
+            (1, 12, 0),
+        ),
+        ("svn, version 1.9.7 (r1800392)", (1, 9, 7)),
+        ("svn, version 1.9.7a1 (r1800392)", ()),
+        ("svn, version 1.9 (r1800392)", (1, 9)),
+        ("svn, version .9.7 (r1800392)", ()),
+        ("svn version 1.9.7 (r1800392)", ()),
+        ("svn 1.9.7", ()),
+        ("svn, version . .", ()),
+        ("", ()),
+    ],
+)
+@patch("pip._internal.vcs.subversion.Subversion.run_command")
 def test_subversion__call_vcs_version_patched(
-        mock_run_command, svn_output, expected_version):
+    mock_run_command, svn_output, expected_version
+):
     """
     Test Subversion.call_vcs_version() against patched output.
     """
@@ -467,7 +555,7 @@ def test_subversion__call_vcs_version_patched(
     assert version == expected_version
 
 
-@patch('pip._internal.vcs.subversion.Subversion.run_command')
+@patch("pip._internal.vcs.subversion.Subversion.run_command")
 def test_subversion__call_vcs_version_svn_not_installed(mock_run_command):
     """
     Test Subversion.call_vcs_version() when svn is not installed.
@@ -477,12 +565,15 @@ def test_subversion__call_vcs_version_svn_not_installed(mock_run_command):
         Subversion().call_vcs_version()
 
 
-@pytest.mark.parametrize('version', [
-    (),
-    (1,),
-    (1, 8),
-    (1, 8, 0),
-])
+@pytest.mark.parametrize(
+    "version",
+    [
+        (),
+        (1,),
+        (1, 8),
+        (1, 8, 0),
+    ],
+)
 def test_subversion__get_vcs_version_cached(version):
     """
     Test Subversion.get_vcs_version() with previously cached result.
@@ -492,12 +583,15 @@ def test_subversion__get_vcs_version_cached(version):
     assert svn.get_vcs_version() == version
 
 
-@pytest.mark.parametrize('vcs_version', [
-    (),
-    (1, 7),
-    (1, 8, 0),
-])
-@patch('pip._internal.vcs.subversion.Subversion.call_vcs_version')
+@pytest.mark.parametrize(
+    "vcs_version",
+    [
+        (),
+        (1, 7),
+        (1, 8, 0),
+    ],
+)
+@patch("pip._internal.vcs.subversion.Subversion.call_vcs_version")
 def test_subversion__get_vcs_version_call_vcs(mock_call_vcs, vcs_version):
     """
     Test Subversion.get_vcs_version() with mocked output from
@@ -511,16 +605,20 @@ def test_subversion__get_vcs_version_call_vcs(mock_call_vcs, vcs_version):
     assert svn._vcs_version == vcs_version
 
 
-@pytest.mark.parametrize('use_interactive,vcs_version,expected_options', [
-    (False, (), ['--non-interactive']),
-    (False, (1, 7, 0), ['--non-interactive']),
-    (False, (1, 8, 0), ['--non-interactive']),
-    (True, (), []),
-    (True, (1, 7, 0), []),
-    (True, (1, 8, 0), ['--force-interactive']),
-])
+@pytest.mark.parametrize(
+    "use_interactive,vcs_version,expected_options",
+    [
+        (False, (), ["--non-interactive"]),
+        (False, (1, 7, 0), ["--non-interactive"]),
+        (False, (1, 8, 0), ["--non-interactive"]),
+        (True, (), []),
+        (True, (1, 7, 0), []),
+        (True, (1, 8, 0), ["--force-interactive"]),
+    ],
+)
 def test_subversion__get_remote_call_options(
-        use_interactive, vcs_version, expected_options):
+    use_interactive, vcs_version, expected_options
+):
     """
     Test Subversion.get_remote_call_options().
     """
@@ -531,64 +629,102 @@ def test_subversion__get_remote_call_options(
 
 class TestSubversionArgs(TestCase):
     def setUp(self):
-        patcher = patch('pip._internal.vcs.versioncontrol.call_subprocess')
+        patcher = patch("pip._internal.vcs.versioncontrol.call_subprocess")
         self.addCleanup(patcher.stop)
         self.call_subprocess_mock = patcher.start()
 
         # Test Data.
-        self.url = 'svn+http://username:password@svn.example.com/'
+        self.url = "svn+http://username:password@svn.example.com/"
         # use_interactive is set to False to test that remote call options are
         # properly added.
         self.svn = Subversion(use_interactive=False)
         self.rev_options = RevOptions(Subversion)
-        self.dest = '/tmp/test'
+        self.dest = "/tmp/test"
 
     def assert_call_args(self, args):
         assert self.call_subprocess_mock.call_args[0][0] == args
 
     def test_obtain(self):
         self.svn.obtain(self.dest, hide_url(self.url))
-        self.assert_call_args([
-            'svn', 'checkout', '-q', '--non-interactive', '--username',
-            'username', '--password', hide_value('password'),
-            hide_url('http://svn.example.com/'), '/tmp/test',
-        ])
+        self.assert_call_args(
+            [
+                "svn",
+                "checkout",
+                "-q",
+                "--non-interactive",
+                "--username",
+                "username",
+                "--password",
+                hide_value("password"),
+                hide_url("http://svn.example.com/"),
+                "/tmp/test",
+            ]
+        )
 
     def test_export(self):
         self.svn.export(self.dest, hide_url(self.url))
-        self.assert_call_args([
-            'svn', 'export', '--non-interactive', '--username', 'username',
-            '--password', hide_value('password'),
-            hide_url('http://svn.example.com/'), '/tmp/test',
-        ])
+        self.assert_call_args(
+            [
+                "svn",
+                "export",
+                "--non-interactive",
+                "--username",
+                "username",
+                "--password",
+                hide_value("password"),
+                hide_url("http://svn.example.com/"),
+                "/tmp/test",
+            ]
+        )
 
     def test_fetch_new(self):
         self.svn.fetch_new(self.dest, hide_url(self.url), self.rev_options)
-        self.assert_call_args([
-            'svn', 'checkout', '-q', '--non-interactive',
-            hide_url('svn+http://username:password@svn.example.com/'),
-            '/tmp/test',
-        ])
+        self.assert_call_args(
+            [
+                "svn",
+                "checkout",
+                "-q",
+                "--non-interactive",
+                hide_url("svn+http://username:password@svn.example.com/"),
+                "/tmp/test",
+            ]
+        )
 
     def test_fetch_new_revision(self):
-        rev_options = RevOptions(Subversion, '123')
+        rev_options = RevOptions(Subversion, "123")
         self.svn.fetch_new(self.dest, hide_url(self.url), rev_options)
-        self.assert_call_args([
-            'svn', 'checkout', '-q', '--non-interactive', '-r', '123',
-            hide_url('svn+http://username:password@svn.example.com/'),
-            '/tmp/test',
-        ])
+        self.assert_call_args(
+            [
+                "svn",
+                "checkout",
+                "-q",
+                "--non-interactive",
+                "-r",
+                "123",
+                hide_url("svn+http://username:password@svn.example.com/"),
+                "/tmp/test",
+            ]
+        )
 
     def test_switch(self):
         self.svn.switch(self.dest, hide_url(self.url), self.rev_options)
-        self.assert_call_args([
-            'svn', 'switch', '--non-interactive',
-            hide_url('svn+http://username:password@svn.example.com/'),
-            '/tmp/test',
-        ])
+        self.assert_call_args(
+            [
+                "svn",
+                "switch",
+                "--non-interactive",
+                hide_url("svn+http://username:password@svn.example.com/"),
+                "/tmp/test",
+            ]
+        )
 
     def test_update(self):
         self.svn.update(self.dest, hide_url(self.url), self.rev_options)
-        self.assert_call_args([
-            'svn', 'update', '--non-interactive', '/tmp/test',
-        ])
+        self.assert_call_args(
+            [
+                "svn",
+                "update",
+                "--non-interactive",
+                "/tmp/test",
+            ]
+        )
diff --git a/tests/unit/test_vcs_mercurial.py b/tests/unit/test_vcs_mercurial.py
index 630619b8236..6554d8fc701 100644
--- a/tests/unit/test_vcs_mercurial.py
+++ b/tests/unit/test_vcs_mercurial.py
@@ -15,19 +15,19 @@
 def test_mercurial_switch_updates_config_file_when_found(tmpdir):
     hg = Mercurial()
     options = hg.make_rev_options()
-    hg_dir = os.path.join(tmpdir, '.hg')
+    hg_dir = os.path.join(tmpdir, ".hg")
     os.mkdir(hg_dir)
 
     config = configparser.RawConfigParser()
-    config.add_section('paths')
-    config.set('paths', 'default', 'old_url')
+    config.add_section("paths")
+    config.set("paths", "default", "old_url")
 
-    hgrc_path = os.path.join(hg_dir, 'hgrc')
-    with open(hgrc_path, 'w') as f:
+    hgrc_path = os.path.join(hg_dir, "hgrc")
+    with open(hgrc_path, "w") as f:
         config.write(f)
-    hg.switch(tmpdir, hide_url('new_url'), options)
+    hg.switch(tmpdir, hide_url("new_url"), options)
 
     config.read(hgrc_path)
 
-    default_path = config.get('paths', 'default')
-    assert default_path == 'new_url'
+    default_path = config.get("paths", "default")
+    assert default_path == "new_url"
diff --git a/tests/unit/test_wheel.py b/tests/unit/test_wheel.py
index 6c9fe02b32e..463aebdd7be 100644
--- a/tests/unit/test_wheel.py
+++ b/tests/unit/test_wheel.py
@@ -19,9 +19,7 @@
     DirectUrl,
 )
 from pip._internal.models.scheme import Scheme
-from pip._internal.operations.build.wheel_legacy import (
-    get_legacy_build_wheel_path,
-)
+from pip._internal.operations.build.wheel_legacy import get_legacy_build_wheel_path
 from pip._internal.operations.install import wheel
 from pip._internal.utils.compat import WINDOWS
 from pip._internal.utils.misc import hash_file
@@ -34,17 +32,17 @@
 def call_get_legacy_build_wheel_path(caplog, names):
     wheel_path = get_legacy_build_wheel_path(
         names=names,
-        temp_dir='/tmp/abcd',
-        name='pendulum',
-        command_args=['arg1', 'arg2'],
-        command_output='output line 1\noutput line 2\n',
+        temp_dir="/tmp/abcd",
+        name="pendulum",
+        command_args=["arg1", "arg2"],
+        command_output="output line 1\noutput line 2\n",
     )
     return wheel_path
 
 
 def test_get_legacy_build_wheel_path(caplog):
-    actual = call_get_legacy_build_wheel_path(caplog, names=['name'])
-    assert_paths_equal(actual, '/tmp/abcd/name')
+    actual = call_get_legacy_build_wheel_path(caplog, names=["name"])
+    assert_paths_equal(actual, "/tmp/abcd/name")
     assert not caplog.records
 
 
@@ -54,11 +52,11 @@ def test_get_legacy_build_wheel_path__no_names(caplog):
     assert actual is None
     assert len(caplog.records) == 1
     record = caplog.records[0]
-    assert record.levelname == 'WARNING'
+    assert record.levelname == "WARNING"
     assert record.message.splitlines() == [
         "Legacy build of wheel for 'pendulum' created no files.",
         "Command arguments: arg1 arg2",
-        'Command output: [use --verbose to show]',
+        "Command output: [use --verbose to show]",
     ]
 
 
@@ -66,17 +64,18 @@ def test_get_legacy_build_wheel_path__multiple_names(caplog):
     caplog.set_level(logging.INFO)
     # Deliberately pass the names in non-sorted order.
     actual = call_get_legacy_build_wheel_path(
-        caplog, names=['name2', 'name1'],
+        caplog,
+        names=["name2", "name1"],
     )
-    assert_paths_equal(actual, '/tmp/abcd/name1')
+    assert_paths_equal(actual, "/tmp/abcd/name1")
     assert len(caplog.records) == 1
     record = caplog.records[0]
-    assert record.levelname == 'WARNING'
+    assert record.levelname == "WARNING"
     assert record.message.splitlines() == [
         "Legacy build of wheel for 'pendulum' created more than one file.",
         "Filenames (choosing first): ['name1', 'name2']",
         "Command arguments: arg1 arg2",
-        'Command output: [use --verbose to show]',
+        "Command output: [use --verbose to show]",
     ]
 
 
@@ -95,7 +94,9 @@ def test_get_entrypoints(console_scripts):
         [section]
         common:one = module:func
         common:two = module:other_func
-    """.format(console_scripts)
+    """.format(
+        console_scripts
+    )
 
     wheel_zip = make_wheel(
         "simple",
@@ -109,7 +110,7 @@ def test_get_entrypoints(console_scripts):
     )
 
     assert wheel.get_entrypoints(distribution) == (
-        dict([console_scripts.split(' = ')]),
+        dict([console_scripts.split(" = ")]),
         {},
     )
 
@@ -125,67 +126,84 @@ def test_get_entrypoints_no_entrypoints():
     assert gui == {}
 
 
-@pytest.mark.parametrize("outrows, expected", [
-    ([
-        (u'', '', 'a'),
-        (u'', '', ''),
-    ], [
-        ('', '', ''),
-        ('', '', 'a'),
-    ]),
-    ([
-        # Include an int to check avoiding the following error:
-        # > TypeError: '<' not supported between instances of 'str' and 'int'
-        (u'', '', 1),
-        (u'', '', ''),
-    ], [
-        ('', '', ''),
-        ('', '', '1'),
-    ]),
-    ([
-        # Test the normalization correctly encode everything for csv.writer().
-        (u'😉', '', 1),
-        (u'', '', ''),
-    ], [
-        ('', '', ''),
-        ('😉', '', '1'),
-    ]),
-])
+@pytest.mark.parametrize(
+    "outrows, expected",
+    [
+        (
+            [
+                (u"", "", "a"),
+                (u"", "", ""),
+            ],
+            [
+                ("", "", ""),
+                ("", "", "a"),
+            ],
+        ),
+        (
+            [
+                # Include an int to check avoiding the following error:
+                # > TypeError: '<' not supported between instances of 'str' and 'int'
+                (u"", "", 1),
+                (u"", "", ""),
+            ],
+            [
+                ("", "", ""),
+                ("", "", "1"),
+            ],
+        ),
+        (
+            [
+                # Test the normalization correctly encode everything for csv.writer().
+                (u"😉", "", 1),
+                (u"", "", ""),
+            ],
+            [
+                ("", "", ""),
+                ("😉", "", "1"),
+            ],
+        ),
+    ],
+)
 def test_normalized_outrows(outrows, expected):
     actual = wheel._normalized_outrows(outrows)
     assert actual == expected
 
 
 def call_get_csv_rows_for_installed(tmpdir, text):
-    path = tmpdir.joinpath('temp.txt')
+    path = tmpdir.joinpath("temp.txt")
     path.write_text(text)
 
     # Test that an installed file appearing in RECORD has its filename
     # updated in the new RECORD file.
-    installed = {u'a': 'z'}
+    installed = {u"a": "z"}
     changed = set()
     generated = []
-    lib_dir = '/lib/dir'
+    lib_dir = "/lib/dir"
 
-    with open(path, **wheel.csv_io_kwargs('r')) as f:
+    with open(path, **wheel.csv_io_kwargs("r")) as f:
         record_rows = list(csv.reader(f))
     outrows = wheel.get_csv_rows_for_installed(
-        record_rows, installed=installed, changed=changed,
-        generated=generated, lib_dir=lib_dir,
+        record_rows,
+        installed=installed,
+        changed=changed,
+        generated=generated,
+        lib_dir=lib_dir,
     )
     return outrows
 
 
 def test_get_csv_rows_for_installed(tmpdir, caplog):
-    text = textwrap.dedent("""\
+    text = textwrap.dedent(
+        """\
     a,b,c
     d,e,f
-    """)
+    """
+    )
     outrows = call_get_csv_rows_for_installed(tmpdir, text)
 
     expected = [
-        ('z', 'b', 'c'),
-        ('d', 'e', 'f'),
+        ("z", "b", "c"),
+        ("d", "e", "f"),
     ]
     assert outrows == expected
     # Check there were no warnings.
@@ -193,47 +211,50 @@ def test_get_csv_rows_for_installed(tmpdir, caplog):
 
 
 def test_get_csv_rows_for_installed__long_lines(tmpdir, caplog):
-    text = textwrap.dedent("""\
+    text = textwrap.dedent(
+        """\
     a,b,c,d
     e,f,g
     h,i,j,k
-    """)
+    """
+    )
     outrows = call_get_csv_rows_for_installed(tmpdir, text)
 
     expected = [
-        ('z', 'b', 'c'),
-        ('e', 'f', 'g'),
-        ('h', 'i', 'j'),
+        ("z", "b", "c"),
+        ("e", "f", "g"),
+        ("h", "i", "j"),
     ]
     assert outrows == expected
 
     messages = [rec.message for rec in caplog.records]
     expected = [
         "RECORD line has more than three elements: ['a', 'b', 'c', 'd']",
-        "RECORD line has more than three elements: ['h', 'i', 'j', 'k']"
+        "RECORD line has more than three elements: ['h', 'i', 'j', 'k']",
     ]
     assert messages == expected
 
 
-@pytest.mark.parametrize("text,expected", [
-    ("Root-Is-Purelib: true", True),
-    ("Root-Is-Purelib: false", False),
-    ("Root-Is-Purelib: hello", False),
-    ("", False),
-    ("root-is-purelib: true", True),
-    ("root-is-purelib: True", True),
-])
+@pytest.mark.parametrize(
+    "text,expected",
+    [
+        ("Root-Is-Purelib: true", True),
+        ("Root-Is-Purelib: false", False),
+        ("Root-Is-Purelib: hello", False),
+        ("", False),
+        ("root-is-purelib: true", True),
+        ("root-is-purelib: True", True),
+    ],
+)
 def test_wheel_root_is_purelib(text, expected):
     assert wheel.wheel_root_is_purelib(message_from_string(text)) == expected
 
 
 class TestWheelFile(object):
-
     def test_unpack_wheel_no_flatten(self, tmpdir):
-        filepath = os.path.join(DATA_DIR, 'packages',
-                                'meta-1.0-py2.py3-none-any.whl')
+        filepath = os.path.join(DATA_DIR, "packages", "meta-1.0-py2.py3-none-any.whl")
         unpack_file(filepath, tmpdir)
-        assert os.path.isdir(os.path.join(tmpdir, 'meta-1.0.dist-info'))
+        assert os.path.isdir(os.path.join(tmpdir, "meta-1.0.dist-info"))
 
 
 class TestInstallUnpackedWheel(object):
@@ -247,7 +268,7 @@ def prep(self, data, tmpdir):
         # `compileall.compile_file`) can cause failures, so we normalize it
         # to a string here.
         tmpdir = str(tmpdir)
-        self.name = 'sample'
+        self.name = "sample"
         self.wheelpath = make_wheel(
             "sample",
             "1.2.0",
@@ -294,20 +315,20 @@ def main():
                 "gui_scripts": ["sample2 = sample:main"],
             },
         ).save_to_dir(tmpdir)
-        self.req = Requirement('sample')
-        self.src = os.path.join(tmpdir, 'src')
-        self.dest = os.path.join(tmpdir, 'dest')
+        self.req = Requirement("sample")
+        self.src = os.path.join(tmpdir, "src")
+        self.dest = os.path.join(tmpdir, "dest")
         self.scheme = Scheme(
-            purelib=os.path.join(self.dest, 'lib'),
-            platlib=os.path.join(self.dest, 'lib'),
-            headers=os.path.join(self.dest, 'headers'),
-            scripts=os.path.join(self.dest, 'bin'),
-            data=os.path.join(self.dest, 'data'),
+            purelib=os.path.join(self.dest, "lib"),
+            platlib=os.path.join(self.dest, "lib"),
+            headers=os.path.join(self.dest, "headers"),
+            scripts=os.path.join(self.dest, "bin"),
+            data=os.path.join(self.dest, "data"),
         )
-        self.src_dist_info = os.path.join(
-            self.src, 'sample-1.2.0.dist-info')
+        self.src_dist_info = os.path.join(self.src, "sample-1.2.0.dist-info")
         self.dest_dist_info = os.path.join(
-            self.scheme.purelib, 'sample-1.2.0.dist-info')
+            self.scheme.purelib, "sample-1.2.0.dist-info"
+        )
 
     def assert_permission(self, path, mode):
         target_mode = os.stat(path).st_mode & 0o777
@@ -315,19 +336,17 @@ def assert_permission(self, path, mode):
 
     def assert_installed(self, expected_permission):
         # lib
-        assert os.path.isdir(
-            os.path.join(self.scheme.purelib, 'sample'))
+        assert os.path.isdir(os.path.join(self.scheme.purelib, "sample"))
         # dist-info
-        metadata = os.path.join(self.dest_dist_info, 'METADATA')
+        metadata = os.path.join(self.dest_dist_info, "METADATA")
         self.assert_permission(metadata, expected_permission)
-        record = os.path.join(self.dest_dist_info, 'RECORD')
+        record = os.path.join(self.dest_dist_info, "RECORD")
         self.assert_permission(record, expected_permission)
         # data files
-        data_file = os.path.join(self.scheme.data, 'my_data', 'data_file')
+        data_file = os.path.join(self.scheme.data, "my_data", "data_file")
         assert os.path.isfile(data_file)
         # package data
-        pkg_data = os.path.join(
-            self.scheme.purelib, 'sample', 'package_data.dat')
+        pkg_data = os.path.join(self.scheme.purelib, "sample", "package_data.dat")
         assert os.path.isfile(pkg_data)
 
     def test_std_install(self, data, tmpdir):
@@ -340,11 +359,10 @@ def test_std_install(self, data, tmpdir):
         )
         self.assert_installed(0o644)
 
-    @pytest.mark.parametrize("user_mask, expected_permission", [
-        (0o27, 0o640)
-    ])
-    def test_std_install_with_custom_umask(self, data, tmpdir,
-                                           user_mask, expected_permission):
+    @pytest.mark.parametrize("user_mask, expected_permission", [(0o27, 0o640)])
+    def test_std_install_with_custom_umask(
+        self, data, tmpdir, user_mask, expected_permission
+    ):
         """Test that the files created after install honor the permissions
         set when the user sets a custom umask"""
 
@@ -371,7 +389,7 @@ def test_std_install_requested(self, data, tmpdir):
             requested=True,
         )
         self.assert_installed(0o644)
-        requested_path = os.path.join(self.dest_dist_info, 'REQUESTED')
+        requested_path = os.path.join(self.dest_dist_info, "REQUESTED")
         assert os.path.isfile(requested_path)
 
     def test_std_install_with_direct_url(self, data, tmpdir):
@@ -393,11 +411,9 @@ def test_std_install_with_direct_url(self, data, tmpdir):
             req_description=str(self.req),
             direct_url=direct_url,
         )
-        direct_url_path = os.path.join(
-            self.dest_dist_info, DIRECT_URL_METADATA_NAME
-        )
+        direct_url_path = os.path.join(self.dest_dist_info, DIRECT_URL_METADATA_NAME)
         self.assert_permission(direct_url_path, 0o644)
-        with open(direct_url_path, 'rb') as f:
+        with open(direct_url_path, "rb") as f:
             expected_direct_url_json = direct_url.to_json()
             direct_url_json = f.read().decode("utf-8")
             assert direct_url_json == expected_direct_url_json
@@ -406,7 +422,7 @@ def test_std_install_with_direct_url(self, data, tmpdir):
             assert DIRECT_URL_METADATA_NAME in f.read()
 
     def test_install_prefix(self, data, tmpdir):
-        prefix = os.path.join(os.path.sep, 'some', 'path')
+        prefix = os.path.join(os.path.sep, "some", "path")
         self.prep(data, tmpdir)
         scheme = get_scheme(
             self.name,
@@ -423,9 +439,9 @@ def test_install_prefix(self, data, tmpdir):
             req_description=str(self.req),
         )
 
-        bin_dir = 'Scripts' if WINDOWS else 'bin'
-        assert os.path.exists(os.path.join(tmpdir, 'some', 'path', bin_dir))
-        assert os.path.exists(os.path.join(tmpdir, 'some', 'path', 'my_data'))
+        bin_dir = "Scripts" if WINDOWS else "bin"
+        assert os.path.exists(os.path.join(tmpdir, "some", "path", bin_dir))
+        assert os.path.exists(os.path.join(tmpdir, "some", "path", "my_data"))
 
     def test_dist_info_contains_empty_dir(self, data, tmpdir):
         """
@@ -440,13 +456,9 @@ def test_dist_info_contains_empty_dir(self, data, tmpdir):
             req_description=str(self.req),
         )
         self.assert_installed(0o644)
-        assert not os.path.isdir(
-            os.path.join(self.dest_dist_info, 'empty_dir'))
+        assert not os.path.isdir(os.path.join(self.dest_dist_info, "empty_dir"))
 
-    @pytest.mark.parametrize(
-        "path",
-        ["/tmp/example", "../example", "./../example"]
-    )
+    @pytest.mark.parametrize("path", ["/tmp/example", "../example", "./../example"])
     def test_wheel_install_rejects_bad_paths(self, data, tmpdir, path):
         self.prep(data, tmpdir)
         wheel_path = make_wheel(
@@ -465,15 +477,9 @@ def test_wheel_install_rejects_bad_paths(self, data, tmpdir, path):
         assert "example" in exc_text
 
     @pytest.mark.xfail(strict=True)
-    @pytest.mark.parametrize(
-        "entrypoint", ["hello = hello", "hello = hello:"]
-    )
-    @pytest.mark.parametrize(
-        "entrypoint_type", ["console_scripts", "gui_scripts"]
-    )
-    def test_invalid_entrypoints_fail(
-        self, data, tmpdir, entrypoint, entrypoint_type
-    ):
+    @pytest.mark.parametrize("entrypoint", ["hello = hello", "hello = hello:"])
+    @pytest.mark.parametrize("entrypoint_type", ["console_scripts", "gui_scripts"])
+    def test_invalid_entrypoints_fail(self, data, tmpdir, entrypoint, entrypoint_type):
         self.prep(data, tmpdir)
         wheel_path = make_wheel(
             "simple", "0.1.0", entry_points={entrypoint_type: [entrypoint]}
@@ -499,21 +505,15 @@ class TestMessageAboutScriptsNotOnPATH(object):
     )
 
     def _template(self, paths, scripts):
-        with patch.dict('os.environ', {'PATH': os.pathsep.join(paths)}):
+        with patch.dict("os.environ", {"PATH": os.pathsep.join(paths)}):
             return wheel.message_about_scripts_not_on_PATH(scripts)
 
     def test_no_script(self):
-        retval = self._template(
-            paths=['/a/b', '/c/d/bin'],
-            scripts=[]
-        )
+        retval = self._template(paths=["/a/b", "/c/d/bin"], scripts=[])
         assert retval is None
 
     def test_single_script__single_dir_not_on_PATH(self):
-        retval = self._template(
-            paths=['/a/b', '/c/d/bin'],
-            scripts=['/c/d/foo']
-        )
+        retval = self._template(paths=["/a/b", "/c/d/bin"], scripts=["/c/d/foo"])
         assert retval is not None
         assert "--no-warn-script-location" in retval
         assert "foo is installed in '/c/d'" in retval
@@ -521,8 +521,7 @@ def test_single_script__single_dir_not_on_PATH(self):
 
     def test_two_script__single_dir_not_on_PATH(self):
         retval = self._template(
-            paths=['/a/b', '/c/d/bin'],
-            scripts=['/c/d/foo', '/c/d/baz']
+            paths=["/a/b", "/c/d/bin"], scripts=["/c/d/foo", "/c/d/baz"]
         )
         assert retval is not None
         assert "--no-warn-script-location" in retval
@@ -531,8 +530,8 @@ def test_two_script__single_dir_not_on_PATH(self):
 
     def test_multi_script__multi_dir_not_on_PATH(self):
         retval = self._template(
-            paths=['/a/b', '/c/d/bin'],
-            scripts=['/c/d/foo', '/c/d/bar', '/c/d/baz', '/a/b/c/spam']
+            paths=["/a/b", "/c/d/bin"],
+            scripts=["/c/d/foo", "/c/d/bar", "/c/d/baz", "/a/b/c/spam"],
         )
         assert retval is not None
         assert "--no-warn-script-location" in retval
@@ -542,11 +541,8 @@ def test_multi_script__multi_dir_not_on_PATH(self):
 
     def test_multi_script_all__multi_dir_not_on_PATH(self):
         retval = self._template(
-            paths=['/a/b', '/c/d/bin'],
-            scripts=[
-                '/c/d/foo', '/c/d/bar', '/c/d/baz',
-                '/a/b/c/spam', '/a/b/c/eggs'
-            ]
+            paths=["/a/b", "/c/d/bin"],
+            scripts=["/c/d/foo", "/c/d/bar", "/c/d/baz", "/a/b/c/spam", "/a/b/c/eggs"],
         )
         assert retval is not None
         assert "--no-warn-script-location" in retval
@@ -556,37 +552,29 @@ def test_multi_script_all__multi_dir_not_on_PATH(self):
 
     def test_two_script__single_dir_on_PATH(self):
         retval = self._template(
-            paths=['/a/b', '/c/d/bin'],
-            scripts=['/a/b/foo', '/a/b/baz']
+            paths=["/a/b", "/c/d/bin"], scripts=["/a/b/foo", "/a/b/baz"]
         )
         assert retval is None
 
     def test_multi_script__multi_dir_on_PATH(self):
         retval = self._template(
-            paths=['/a/b', '/c/d/bin'],
-            scripts=['/a/b/foo', '/a/b/bar', '/a/b/baz', '/c/d/bin/spam']
+            paths=["/a/b", "/c/d/bin"],
+            scripts=["/a/b/foo", "/a/b/bar", "/a/b/baz", "/c/d/bin/spam"],
         )
         assert retval is None
 
     def test_multi_script__single_dir_on_PATH(self):
         retval = self._template(
-            paths=['/a/b', '/c/d/bin'],
-            scripts=['/a/b/foo', '/a/b/bar', '/a/b/baz']
+            paths=["/a/b", "/c/d/bin"], scripts=["/a/b/foo", "/a/b/bar", "/a/b/baz"]
         )
         assert retval is None
 
     def test_single_script__single_dir_on_PATH(self):
-        retval = self._template(
-            paths=['/a/b', '/c/d/bin'],
-            scripts=['/a/b/foo']
-        )
+        retval = self._template(paths=["/a/b", "/c/d/bin"], scripts=["/a/b/foo"])
         assert retval is None
 
     def test_PATH_check_case_insensitive_on_windows(self):
-        retval = self._template(
-            paths=['C:\\A\\b'],
-            scripts=['c:\\a\\b\\c', 'C:/A/b/d']
-        )
+        retval = self._template(paths=["C:\\A\\b"], scripts=["c:\\a\\b\\c", "C:/A/b/d"])
         if WINDOWS:
             assert retval is None
         else:
@@ -595,36 +583,36 @@ def test_PATH_check_case_insensitive_on_windows(self):
 
     def test_trailing_ossep_removal(self):
         retval = self._template(
-            paths=[os.path.join('a', 'b', '')],
-            scripts=[os.path.join('a', 'b', 'c')]
+            paths=[os.path.join("a", "b", "")], scripts=[os.path.join("a", "b", "c")]
         )
         assert retval is None
 
     def test_missing_PATH_env_treated_as_empty_PATH_env(self, monkeypatch):
-        scripts = ['a/b/foo']
+        scripts = ["a/b/foo"]
 
-        monkeypatch.delenv('PATH')
+        monkeypatch.delenv("PATH")
         retval_missing = wheel.message_about_scripts_not_on_PATH(scripts)
 
-        monkeypatch.setenv('PATH', '')
+        monkeypatch.setenv("PATH", "")
         retval_empty = wheel.message_about_scripts_not_on_PATH(scripts)
 
         assert retval_missing == retval_empty
 
     def test_no_script_tilde_in_path(self):
-        retval = self._template(
-            paths=['/a/b', '/c/d/bin', '~/e', '/f/g~g'],
-            scripts=[]
-        )
+        retval = self._template(paths=["/a/b", "/c/d/bin", "~/e", "/f/g~g"], scripts=[])
         assert retval is None
 
     def test_multi_script_all_tilde__multi_dir_not_on_PATH(self):
         retval = self._template(
-            paths=['/a/b', '/c/d/bin', '~e/f'],
+            paths=["/a/b", "/c/d/bin", "~e/f"],
             scripts=[
-                '/c/d/foo', '/c/d/bar', '/c/d/baz',
-                '/a/b/c/spam', '/a/b/c/eggs', '/e/f/tilde'
-            ]
+                "/c/d/foo",
+                "/c/d/bar",
+                "/c/d/baz",
+                "/a/b/c/spam",
+                "/a/b/c/eggs",
+                "/e/f/tilde",
+            ],
         )
         assert retval is not None
         assert "--no-warn-script-location" in retval
@@ -635,11 +623,14 @@ def test_multi_script_all_tilde__multi_dir_not_on_PATH(self):
 
     def test_multi_script_all_tilde_not_at_start__multi_dir_not_on_PATH(self):
         retval = self._template(
-            paths=['/e/f~f', '/c/d/bin'],
+            paths=["/e/f~f", "/c/d/bin"],
             scripts=[
-                '/c/d/foo', '/c/d/bar', '/c/d/baz',
-                '/e/f~f/c/spam', '/e/f~f/c/eggs'
-            ]
+                "/c/d/foo",
+                "/c/d/bar",
+                "/c/d/baz",
+                "/e/f~f/c/spam",
+                "/e/f~f/c/eggs",
+            ],
         )
         assert retval is not None
         assert "--no-warn-script-location" in retval
@@ -649,17 +640,18 @@ def test_multi_script_all_tilde_not_at_start__multi_dir_not_on_PATH(self):
 
 
 class TestWheelHashCalculators(object):
-
     def prep(self, tmpdir):
         self.test_file = tmpdir.joinpath("hash.file")
         # Want this big enough to trigger the internal read loops.
         self.test_file_len = 2 * 1024 * 1024
         with open(str(self.test_file), "w") as fp:
             fp.truncate(self.test_file_len)
-        self.test_file_hash = \
-            '5647f05ec18958947d32874eeb788fa396a05d0bab7c1b71f112ceb7e9b31eee'
-        self.test_file_hash_encoded = \
-            'sha256=VkfwXsGJWJR9ModO63iPo5agXQurfBtx8RLOt-mzHu4'
+        self.test_file_hash = (
+            "5647f05ec18958947d32874eeb788fa396a05d0bab7c1b71f112ceb7e9b31eee"
+        )
+        self.test_file_hash_encoded = (
+            "sha256=VkfwXsGJWJR9ModO63iPo5agXQurfBtx8RLOt-mzHu4"
+        )
 
     def test_hash_file(self, tmpdir):
         self.prep(tmpdir)
diff --git a/tests/unit/test_wheel_builder.py b/tests/unit/test_wheel_builder.py
index dcaa1e793ad..0fca3a48635 100644
--- a/tests/unit/test_wheel_builder.py
+++ b/tests/unit/test_wheel_builder.py
@@ -14,11 +14,9 @@
     [
         # Trivial.
         ("pip-18.0", True),
-
         # Ambiguous.
         ("foo-2-2", True),
         ("im-valid", True),
-
         # Invalid.
         ("invalid", False),
         ("im_invalid", False),
@@ -30,7 +28,6 @@ def test_contains_egg_info(s, expected):
 
 
 class ReqMock:
-
     def __init__(
         self,
         name="pendulum",
@@ -128,9 +125,7 @@ def test_should_cache(req, expected):
 
 def test_should_cache_git_sha(script, tmpdir):
     repo_path = _create_test_package(script, name="mypkg")
-    commit = script.run(
-        "git", "rev-parse", "HEAD", cwd=repo_path
-    ).stdout.strip()
+    commit = script.run("git", "rev-parse", "HEAD", cwd=repo_path).stdout.strip()
 
     # a link referencing a sha should be cached
     url = "git+https://g.c/o/r@" + commit + "#egg=mypkg"
@@ -147,44 +142,47 @@ def test_format_command_result__INFO(caplog):
     caplog.set_level(logging.INFO)
     actual = format_command_result(
         # Include an argument with a space to test argument quoting.
-        command_args=['arg1', 'second arg'],
-        command_output='output line 1\noutput line 2\n',
+        command_args=["arg1", "second arg"],
+        command_output="output line 1\noutput line 2\n",
     )
     assert actual.splitlines() == [
         "Command arguments: arg1 'second arg'",
-        'Command output: [use --verbose to show]',
+        "Command output: [use --verbose to show]",
     ]
 
 
-@pytest.mark.parametrize('command_output', [
-    # Test trailing newline.
-    'output line 1\noutput line 2\n',
-    # Test no trailing newline.
-    'output line 1\noutput line 2',
-])
+@pytest.mark.parametrize(
+    "command_output",
+    [
+        # Test trailing newline.
+        "output line 1\noutput line 2\n",
+        # Test no trailing newline.
+        "output line 1\noutput line 2",
+    ],
+)
 def test_format_command_result__DEBUG(caplog, command_output):
     caplog.set_level(logging.DEBUG)
     actual = format_command_result(
-        command_args=['arg1', 'arg2'],
+        command_args=["arg1", "arg2"],
         command_output=command_output,
     )
     assert actual.splitlines() == [
         "Command arguments: arg1 arg2",
-        'Command output:',
-        'output line 1',
-        'output line 2',
-        '----------------------------------------',
+        "Command output:",
+        "output line 1",
+        "output line 2",
+        "----------------------------------------",
     ]
 
 
-@pytest.mark.parametrize('log_level', ['DEBUG', 'INFO'])
+@pytest.mark.parametrize("log_level", ["DEBUG", "INFO"])
 def test_format_command_result__empty_output(caplog, log_level):
     caplog.set_level(log_level)
     actual = format_command_result(
-        command_args=['arg1', 'arg2'],
-        command_output='',
+        command_args=["arg1", "arg2"],
+        command_output="",
     )
     assert actual.splitlines() == [
         "Command arguments: arg1 arg2",
-        'Command output: None',
+        "Command output: None",
     ]
diff --git a/tests/yaml/linter.py b/tests/yaml/linter.py
index ac17bbc41be..7baefe4ef2b 100644
--- a/tests/yaml/linter.py
+++ b/tests/yaml/linter.py
@@ -4,8 +4,8 @@
 
 import yaml
 
-sys.path.insert(0, '../../src')
-sys.path.insert(0, '../..')
+sys.path.insert(0, "../../src")
+sys.path.insert(0, "../..")
 
 
 def check_dict(d, required=None, optional=None):
@@ -21,8 +21,9 @@ def check_dict(d, required=None, optional=None):
     allowed_keys.update(optional)
     for key in d.keys():
         if key not in allowed_keys:
-            sys.exit("key %r is not allowed.  Allowed keys are: %r" %
-                     (key, allowed_keys))
+            sys.exit(
+                "key %r is not allowed.  Allowed keys are: %r" % (key, allowed_keys)
+            )
 
 
 def lint_case(case, verbose=False):
@@ -32,7 +33,7 @@ def lint_case(case, verbose=False):
         print("--- linting case ---")
         pprint(case)
 
-    check_dict(case, optional=['available', 'request', 'response', 'skip'])
+    check_dict(case, optional=["available", "request", "response", "skip"])
     available = case.get("available", [])
     requests = case.get("request", [])
     responses = case.get("response", [])
@@ -46,21 +47,21 @@ def lint_case(case, verbose=False):
             package = convert_to_dict(package)
         if verbose:
             pprint(package)
-        check_dict(package,
-                   required=['name', 'version'],
-                   optional=['depends', 'extras'])
-        version = package['version']
+        check_dict(
+            package, required=["name", "version"], optional=["depends", "extras"]
+        )
+        version = package["version"]
         assert isinstance(version, str), repr(version)
 
     for request, response in zip(requests, responses):
-        check_dict(request, optional=['install', 'uninstall', 'options'])
-        check_dict(response, optional=['state', 'error'])
+        check_dict(request, optional=["install", "uninstall", "options"])
+        check_dict(response, optional=["state", "error"])
         assert len(response) >= 1
-        assert isinstance(response.get('state') or [], list)
-        error = response.get('error')
+        assert isinstance(response.get("state") or [], list)
+        error = response.get("error")
         if error:
-            check_dict(error, optional=['code', 'stderr'])
-            stderr = error.get('stderr')
+            check_dict(error, optional=["code", "stderr"])
+            stderr = error.get("stderr")
             if stderr:
                 if isinstance(stderr, str):
                     patters = [stderr]
@@ -81,7 +82,7 @@ def lint_yml(yml_file, verbose=False):
     if verbose:
         pprint(data)
 
-    check_dict(data, required=['cases'], optional=['base'])
+    check_dict(data, required=["cases"], optional=["base"])
     base = data.get("base", {})
     cases = data["cases"]
     for _, case_template in enumerate(cases):
@@ -90,19 +91,20 @@ def lint_yml(yml_file, verbose=False):
         lint_case(case, verbose)
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     from optparse import OptionParser
 
-    p = OptionParser(usage="usage: %prog [options] FILE ...",
-                     description="linter for pip's yaml test FILE(s)")
+    p = OptionParser(
+        usage="usage: %prog [options] FILE ...",
+        description="linter for pip's yaml test FILE(s)",
+    )
 
-    p.add_option('-v', '--verbose',
-                 action="store_true")
+    p.add_option("-v", "--verbose", action="store_true")
 
     opts, args = p.parse_args()
 
     if len(args) < 1:
-        p.error('at least one argument required, try -h')
+        p.error("at least one argument required, try -h")
 
     for yml_file in args:
         lint_yml(yml_file, opts.verbose)
diff --git a/tools/automation/release/__init__.py b/tools/automation/release/__init__.py
index 042723100a8..1bcecd3ca6e 100644
--- a/tools/automation/release/__init__.py
+++ b/tools/automation/release/__init__.py
@@ -29,7 +29,7 @@ def get_version_from_arguments(session: Session) -> Optional[str]:
     cmd = [
         os.path.join(session.bin, "python"),
         "tools/automation/release/check_version.py",
-        version
+        version,
     ]
     not_ok = subprocess.run(cmd).returncode
     if not_ok:
@@ -47,8 +47,7 @@ def modified_files_in_git(*args: str) -> int:
 
 
 def get_author_list() -> List[str]:
-    """Get the list of authors from Git commits.
-    """
+    """Get the list of authors from Git commits."""
     # subprocess because session.run doesn't give us stdout
     # only use names in list of Authors
     result = subprocess.run(
@@ -76,8 +75,8 @@ def generate_authors(filename: str) -> None:
 
     # Write our authors to the AUTHORS file
     with io.open(filename, "w", encoding="utf-8") as fp:
-        fp.write(u"\n".join(authors))
-        fp.write(u"\n")
+        fp.write("\n".join(authors))
+        fp.write("\n")
 
 
 def commit_file(session: Session, filename: str, *, message: str) -> None:
@@ -103,13 +102,18 @@ def update_version_file(version: str, filepath: str) -> None:
             else:
                 f.write(line)
 
-    assert file_modified, \
-        "Version file {} did not get modified".format(filepath)
+    assert file_modified, "Version file {} did not get modified".format(filepath)
 
 
 def create_git_tag(session: Session, tag_name: str, *, message: str) -> None:
     session.run(
-        "git", "tag", "-m", message, tag_name, external=True, silent=True,
+        "git",
+        "tag",
+        "-m",
+        message,
+        tag_name,
+        external=True,
+        silent=True,
     )
 
 
@@ -148,8 +152,8 @@ def have_files_in_folder(folder_name: str) -> bool:
 
 @contextlib.contextmanager
 def workdir(
-        nox_session: Session,
-        dir_path: pathlib.Path,
+    nox_session: Session,
+    dir_path: pathlib.Path,
 ) -> Iterator[pathlib.Path]:
     """Temporarily chdir when entering CM and chdir back on exit."""
     orig_dir = pathlib.Path.cwd()
@@ -163,35 +167,49 @@ def workdir(
 
 @contextlib.contextmanager
 def isolated_temporary_checkout(
-        nox_session: Session,
-        target_ref: str,
+    nox_session: Session,
+    target_ref: str,
 ) -> Iterator[pathlib.Path]:
     """Make a clean checkout of a given version in tmp dir."""
     with tempfile.TemporaryDirectory() as tmp_dir_path:
         tmp_dir = pathlib.Path(tmp_dir_path)
-        git_checkout_dir = tmp_dir / f'pip-build-{target_ref}'
+        git_checkout_dir = tmp_dir / f"pip-build-{target_ref}"
         nox_session.run(
-            'git', 'worktree', 'add', '--force', '--checkout',
-            str(git_checkout_dir), str(target_ref),
-            external=True, silent=True,
+            "git",
+            "worktree",
+            "add",
+            "--force",
+            "--checkout",
+            str(git_checkout_dir),
+            str(target_ref),
+            external=True,
+            silent=True,
         )
 
         try:
             yield git_checkout_dir
         finally:
             nox_session.run(
-                'git', 'worktree', 'remove', '--force',
+                "git",
+                "worktree",
+                "remove",
+                "--force",
                 str(git_checkout_dir),
-                external=True, silent=True,
+                external=True,
+                silent=True,
             )
 
 
 def get_git_untracked_files() -> Iterator[str]:
     """List all local file paths that aren't tracked by Git."""
     git_ls_files_cmd = (
-        "git", "ls-files",
-        "--ignored", "--exclude-standard",
-        "--others", "--", ".",
+        "git",
+        "ls-files",
+        "--ignored",
+        "--exclude-standard",
+        "--others",
+        "--",
+        ".",
     )
     # session.run doesn't seem to return any output:
     ls_files_out = subprocess.check_output(git_ls_files_cmd, text=True)
diff --git a/tools/tox_pip.py b/tools/tox_pip.py
index 5996dade6d2..17d46781da9 100644
--- a/tools/tox_pip.py
+++ b/tools/tox_pip.py
@@ -7,25 +7,33 @@
 import sys
 from glob import glob
 
-VIRTUAL_ENV = os.environ['VIRTUAL_ENV']
-TOX_PIP_DIR = os.path.join(VIRTUAL_ENV, 'pip')
+VIRTUAL_ENV = os.environ["VIRTUAL_ENV"]
+TOX_PIP_DIR = os.path.join(VIRTUAL_ENV, "pip")
 
 
 def pip(args):
     # First things first, get a recent (stable) version of pip.
     if not os.path.exists(TOX_PIP_DIR):
-        subprocess.check_call([sys.executable, '-m', 'pip',
-                               '--disable-pip-version-check',
-                               'install', '-t', TOX_PIP_DIR,
-                               'pip'])
-        shutil.rmtree(glob(os.path.join(TOX_PIP_DIR, 'pip-*.dist-info'))[0])
+        subprocess.check_call(
+            [
+                sys.executable,
+                "-m",
+                "pip",
+                "--disable-pip-version-check",
+                "install",
+                "-t",
+                TOX_PIP_DIR,
+                "pip",
+            ]
+        )
+        shutil.rmtree(glob(os.path.join(TOX_PIP_DIR, "pip-*.dist-info"))[0])
     # And use that version.
-    pypath = os.environ.get('PYTHONPATH')
+    pypath = os.environ.get("PYTHONPATH")
     pypath = pypath.split(os.pathsep) if pypath is not None else []
     pypath.insert(0, TOX_PIP_DIR)
-    os.environ['PYTHONPATH'] = os.pathsep.join(pypath)
-    subprocess.check_call([sys.executable, '-m', 'pip'] + args)
+    os.environ["PYTHONPATH"] = os.pathsep.join(pypath)
+    subprocess.check_call([sys.executable, "-m", "pip"] + args)
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     pip(sys.argv[1:])