Adopt modern python packaging (#68)

pyproject.toml

@@ -0,0 +1,12 @@
+[build-system]
+requires = [
+  "pip >= 19.3.1",
+  "setuptools >= 42",
+  "setuptools_scm[toml] >= 3.5.0",
+  "setuptools_scm_git_archive >= 1.1",
+  "wheel >= 0.33.6",
+]
+build-backend = "setuptools.build_meta"
+
+[tool.setuptools_scm]
+local_scheme = "no-local-version"

setup.cfg

@@ -1,7 +1,7 @@
 [metadata]
 name = doc8
 summary = Style checker for Sphinx (or other) RST documentation
-description-file =
+description_file =
     README.rst
 author = OpenStack
 author_email = openstack-discuss@lists.openstack.org
@@ -40,3 +40,9 @@ extend_ignore = E203
 
 [options]
 python_requires = >=3.6
+# These are required in actual runtime:
+install_requires =
+    docutils
+    restructuredtext-lint>=0.7
+    stevedore
+    Pygments

tox.ini

@@ -1,13 +1,17 @@
 [tox]
-minversion = 3.8
+minversion = 3.24.4
 envlist = lint,py,docs,packaging
+isolated_build = True
 
 [testenv]
 deps =
   -r{toxinidir}/test-requirements.txt
 commands = pytest {posargs}
 whitelist_externals =
   rm
+  sh
+setenv =
+  PIP_DISABLE_PIP_VERSION_CHECK=1
 
 [testenv:lint]
 deps =
@@ -19,25 +23,33 @@ commands =
 deps =
   -r{toxinidir}/doc/requirements.txt
 commands =
-  doc8 -e .rst doc CONTRIBUTING.rst README.rst
+  python -m doc8 -e .rst doc CONTRIBUTING.rst README.rst
   sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:packaging]
 description =
-    Do packagin/distribution. If tag is not present or PEP440 compliant upload to
-    PYPI could fail
-# `usedevelop = true` overrides `skip_install` instruction, it's unwanted
+  Build package, verify metadata, install package and assert behavior
+deps =
+  build >= 0.7.0, < 0.8.0
+  twine
 usedevelop = false
-# don't install molecule itself in this env
 skip_install = true
-deps =
-    collective.checkdocs >= 0.2
-    pep517 >= 0.5.0
-    twine >= 1.14.0
-setenv =
+# Ref: https://twitter.com/di_codes/status/1044358639081975813
 commands =
-    rm -rfv {toxinidir}/dist/
-    python setup.py sdist bdist_wheel
-    # metadata validation
-    python -m setup checkdocs --verbose
-    python -m twine check {toxinidir}/dist/*
+  # build wheel and sdist using PEP-517
+  {envpython} -c 'import os.path, shutil, sys; \
+  dist_dir = os.path.join("{toxinidir}", "dist"); \
+  os.path.isdir(dist_dir) or sys.exit(0); \
+  print("Removing \{!s\} contents...".format(dist_dir), file=sys.stderr); \
+  shutil.rmtree(dist_dir)'
+  {envpython} -m build \
+    --outdir {toxinidir}/dist/ \
+    {toxinidir}
+  # Validate metadata using twine
+  twine check --strict {toxinidir}/dist/*
+  # Ensure package is not installed
+  pip uninstall -y doc8
+  # Install the wheel
+  sh -c "python3 -m pip install {toxinidir}/dist/*.whl"
+  # Ensure package can be uninstalled
+  pip uninstall -y doc8