POC: Reconfigure existing streams

.travis.yml

@@ -12,7 +12,6 @@ python:
  - 3.6
  - 3.7
  - 3.8-dev
- - pypy3
 jobs:
  include:
   - os: windows
@@ -24,6 +23,6 @@ jobs:
 script:
  - python --version
  - pip list
- - pytest --cov=src
+ - PYTHONUNBUFFERED=1 pytest --cov=src
  - if (( $PYTHON_MAJOR == 3 && $PYTHON_MINOR == 7 )); then tox -e flake8; else echo "No flake8."; fi
  - if (( $PYTHON_MAJOR == 3 && $PYTHON_MINOR == 7 )); then codecov; else echo "No codecov."; fi

azure-job.yml

@@ -37,5 +37,5 @@ jobs:
         - script: ${{ cmd.value.cmd }}
           displayName: ${{ cmd.value.name }}
 
-      - script: pytest
+      - script: python -u -m pytest
         displayName: Run pytest (Python ${{ python.value.spec }})

azure-pipelines.yml

@@ -75,7 +75,7 @@ jobs:
     - script: pip install -r requirements-ci.txt
       displayName: Install CI requirements
 
-    - script: pytest -v -W error::Warning
+    - script: PYTHONUNBUFFERED=1 pytest -v -W error::Warning
       displayName: Run pytest, exposing underlying warnings (Python 3.7)
 
 - job: docs_display_warnings

conftest.py

@@ -29,11 +29,12 @@
 import os
 import sys
 import warnings
+from io import TextIOBase
 
 import _pytest.warnings
 import pytest
 
-from stdio_mgr import stdio_mgr
+from stdio_mgr.stdio_mgr import _choose_inject_impl, BufferReplaceStdioManager
 
 
 @pytest.fixture(scope="session")
@@ -74,10 +75,23 @@ def enable_warnings_plugin(request):
         yield
 
 
+def pytest_generate_tests(metafunc):
+    """Parametrize fixture stdio_mgr."""
+    if "stdio_mgr" not in metafunc.fixturenames:
+        return
+
+    if isinstance(sys.stdin, TextIOBase):
+        impls = [BufferReplaceStdioManager, _choose_inject_impl()]
+    else:
+        impls = [BufferReplaceStdioManager]
+
+    metafunc.parametrize("stdio_mgr", impls)
+
+
 @pytest.fixture(autouse=True, scope="session")
 def add_stdio_mgr(doctest_namespace):
     """Add stdio_mgr to doctest namespace."""
-    doctest_namespace["stdio_mgr"] = stdio_mgr
+    doctest_namespace["stdio_mgr"] = BufferReplaceStdioManager
     doctest_namespace["os"] = os
 
 

src/stdio_mgr/compat.py

@@ -0,0 +1,65 @@
+r"""``stdio_mgr.compat`` *code module*.
+
+``stdio_mgr.compat`` provides backports of Python standard library.
+
+**Author**
+    John Vandenberg (jayvdb@gmail.com)
+
+**File Created**
+    6 Sep 2019
+
+**Copyright**
+    \(c) Brian Skinn 2018-2019
+
+**Source Repository**
+    http://www.github.com/bskinn/stdio-mgr
+
+**Documentation**
+    See README.rst at the GitHub repository
+
+**License**
+    The Python-2.0 License.
+
+**Members**
+
+"""
+import abc
+
+# AbstractContextManager was introduced in Python 3.6
+# and may be used with typing.ContextManager.
+# See https://github.com/jazzband/contextlib2/pull/21 for more complete backport
+try:
+    from contextlib import AbstractContextManager
+except ImportError:  # pragma: no cover
+    # Copied from _collections_abc
+    def _check_methods(cls, *methods):
+        mro = cls.__mro__
+        for method in methods:
+            for base in mro:
+                if method in base.__dict__:
+                    if base.__dict__[method] is None:
+                        return NotImplemented
+                    break
+            else:
+                return NotImplemented
+        return True
+
+    # Copied from contextlib
+    class AbstractContextManager(abc.ABC):
+        """An abstract base class for context managers."""
+
+        def __enter__(self):
+            """Return `self` upon entering the runtime context."""
+            return self
+
+        @abc.abstractmethod
+        def __exit__(self, exc_type, exc_value, traceback):
+            """Raise any exception triggered within the runtime context."""
+            return None
+
+        @classmethod
+        def __subclasshook__(cls, subclass):
+            """Check whether subclass is considered a subclass of this ABC."""
+            if cls is AbstractContextManager:
+                return _check_methods(subclass, "__enter__", "__exit__")
+            return NotImplemented