Extend discovery to find *_test.py files, matching Pytest better (#204)

* Update docs on test discovery

* Stop clean recipe adjusting packages

* Extend test file pattern to include '*_test.py' files

* Add bad example '*_test.py' file

* Add a tiny bit of typing to other bad examples

* Fix tox.ini: meta commands missing label

* Add new test file to test examples run

* Update Changelog

CHANGELOG.rst

@@ -20,15 +20,22 @@ Additional markers for types of change copied from ``README``:
 Unreleased_
 -----------
 
+See also `latest documentation
+<https://flake8-aaa.readthedocs.io/en/latest/#__unreleased_marker__>`_.
+
+Added
+.....
+
+* 🎈 Files ending in ``_test.py`` are now linted. `Pull #204
+  <https://github.com/jamescooke/flake8-aaa/pull/204>`_ fixes `issue #185
+  <https://github.com/jamescooke/flake8-aaa/issues/185>`_.
+
 Changed
 .......
 
 * ⛏️ Release notes updated to use a better method of updating Flake8 version
   strings. Also reduce use of ``vx.y.z`` version strings - use just ``x.y.z``
-  instead.
-
-See also `latest documentation
-<https://flake8-aaa.readthedocs.io/en/latest/#__unreleased_marker__>`_.
+  instead. `Pull #207 <https://github.com/jamescooke/flake8-aaa/pull/207>`_.
 
 0.13.1_ - 2023/02/27
 --------------------

docs/discovery.rst

@@ -5,19 +5,30 @@ When running as a Flake8 plugin, Flake8-AAA filters the Python code passed to
 it by Flake8. It finds code that looks like test code and then checks that code
 matches the AAA pattern. When all checks pass, then no error is raised.
 
-Filtering
----------
+File filtering
+--------------
 
-First, the filename is checked. It must either ``test.py``, ``tests.py`` or
-start with ``test_``. For those files that match, every function that has a
-name that starts with "test" is checked. This includes class methods.
+First, the filename is checked. It must match one of the following patterns:
+
+* Is called ``test.py`` or ``tests.py``.
+
+* Starts with ``test_``, i.e match ``test_*.py``
+
+* Ends with ``_test.py``, i.e. match ``*_test.py``.
+
+For every file that matches the patterns above, Flake8-AAA checks every
+function and class method whose name starts with "test".
 
 Test functions and methods that contain only comments, docstrings or ``pass``
 are skipped.
 
-The aim of this process is to mirror Pytest's default collection strategy as
-closely as possible. It also aims to work with popular testing tutorials such
-as Django's `Writing your first Django app
+Rationale
+.........
+
+The aim of this process is to mirror `Pytest's default collection strategy
+<https://docs.pytest.org/en/7.2.x/explanation/goodpractices.html#test-discovery>`_
+as closely as possible. It also aims to work with popular testing tutorials
+such as Django's `Writing your first Django app
 <https://docs.djangoproject.com/en/3.0/intro/tutorial05/#create-a-test-to-expose-the-bug>`_
 which states:
 

examples/bad/bad_expected.out

@@ -1,3 +1,4 @@
+examples/bad/file_pattern_test.py:4:1: AAA01 no Act block found in test
 examples/bad/test.py:4:1: AAA01 no Act block found in test
 examples/bad/test_aaa01.py:8:1: AAA01 no Act block found in test
 examples/bad/test_aaa01_cm_import.py:11:1: AAA01 no Act block found in test

examples/bad/file_pattern_test.py

@@ -0,0 +1,5 @@
+# Ensure that files with '*_test.py' patterns are found
+
+
+def test() -> None:
+    assert 1 + 1 == 2

examples/bad/test.py

@@ -1,6 +1,6 @@
 # Check that files named "test.py" are checked
 
 
-def test():
+def test() -> None:
     action = sorted([3, 2, 1])
     assert action == [1, 2, 3]

examples/bad/tests.py

@@ -1,6 +1,6 @@
 # Check that files named "tests.py" are checked
 
 
-def test():
+def test() -> None:
     action = sorted([3, 2, 1])
     assert action == [1, 2, 3]

src/flake8_aaa/helpers.py

@@ -7,13 +7,13 @@
 
 from asttokens.util import Token
 
-test_file_pattern = re.compile(r'test(_.*|s)?\.py$')
+test_file_pattern = re.compile(r'^(test(_.*|s)?|.*_test)\.py$')
 
 
 def is_test_file(filename: str) -> bool:
     """
-    Check that path to file being checked passed by flake8 looks like a pytest
-    test file.
+    Returns:
+        Path to file passed by Flake8 looks like a Pytest test file.
     """
     return bool(test_file_pattern.match(os.path.basename(filename)))
 

tests/helpers/test_is_test_file.py

@@ -9,17 +9,23 @@
         # Non-test files give False.
         ('./helper.py', False),
         ('tests/conftest.py', False),
+        ('./greatest.py', False),
+        ('./greatest_dancer.py', False),
         # Finds files that start with 'test_' to be test files.
         ('./test_helpers.py', True),
+        ('test_.py', True),
         ('tests/helpers/test_is_test_file.py', True),
+        # Finds files that end with '_test' as test files
+        ('./helpers_test.py', True),
+        ('tests/helpers/is_test_file_test.py', True),
         # Finds simple test file names "test.py" and "tests.py".
         ('./test.py', True),
         ('project/app/tests.py', True),
         # Finds accidental additional underscore test file
         ('project/app/test_.py', True),
     ]
 )
-def test(path, expected_result):
+def test(path: str, expected_result: bool) -> None:
     result = is_test_file(path)
 
     assert result is expected_result

tox.ini

@@ -105,6 +105,7 @@ commands =
         examples/good/test_comments.py \
         examples/good/test_with_statement.py \
         examples/good/test_with_statement_unittest.py \
+        examples/bad/file_pattern_test.py \
         examples/bad/test_aaa03.py \
         examples/bad/test_aaa03_04.py \
         examples/bad/test_aaa04.py \
@@ -149,6 +150,9 @@ allowlist_externals =
 # are as expected.
 [testenv:py3{7,8,9,10,11}-meta_command]
 description = 🎈 Run command "-m flake8_aaa" on all examples
+labels =
+    meta
+    meta_cmd
 commands =
     make cmd
     make cmdbad