Merge pull request #152 from jamescooke/context-manager-no-vacuum

Make context manager analysis non-greedy

CHANGELOG.rst

@@ -14,6 +14,12 @@ Unreleased_
 See also `latest documentation
 <https://flake8-aaa.readthedocs.io/en/latest/#__unreleased_marker__>`_.
 
+Added
+.....
+
+* Test examples are intended to be real but simple examples. All examples added
+  or updated are now executed with pytest and no imports and must be green.
+
 Changed
 .......
 
@@ -22,6 +28,15 @@ Changed
   <https://github.com/kylelobo/The-Documentation-Compendium>`_.  `#141
   <https://github.com/jamescooke/flake8-aaa/issues/141>`_.
 
+* Behaviour of context managers in tests has been changed. Going forwards only
+  with statements that are used to catch exceptions are considered actions, for
+  example, ``with pytest.raises(...):``. Otherwise, the with statement is
+  arrangement or assertion and must be separated from the Act block by a blank
+  line as usual. `#146 <https://github.com/jamescooke/flake8-aaa/issues/146>`_.
+
+  Implementing this feature meant changing the line-by-line analysis that
+  happens on test function bodies.
+
 0.9.0_ - 2020/03/07
 -------------------
 

Makefile

@@ -54,6 +54,9 @@ lintexamples:
 	@echo "=== flake8 ==="
 	flake8 examples | sort > flake8.out
 	diff examples/bad/flake8_expected.out flake8.out
+	@echo "=== mypy ==="
+	mypy examples examples/good --ignore-missing-imports
+	mypy examples/bad --ignore-missing-imports
 	@echo "=== black ==="
 	black --check --diff --verbose examples/good/black
 
@@ -92,7 +95,7 @@ cmdbad:
 
 .PHONY: clean
 clean:
-	rm -rf dist build .tox .pytest_cache flake8_aaa.egg-info
+	rm -rf dist build .tox .pytest_cache src/flake8_aaa.egg-info
 	find . -name '*.pyc' -delete
 
 .PHONY: sdist

examples/bad/bad_expected.out

@@ -1,7 +1,11 @@
 examples/bad/test_aaa01.py:8:1: AAA01 no Act block found in test
+examples/bad/test_aaa03_04.py:10:5: AAA04 expected 1 blank line before Assert block, found none
 examples/bad/test_aaa03_04.py:3:5: AAA03 expected 1 blank line before Act block, found none
 examples/bad/test_aaa03_04.py:4:5: AAA04 expected 1 blank line before Assert block, found none
+examples/bad/test_aaa03_04.py:9:9: AAA03 expected 1 blank line before Act block, found none
+examples/bad/test_aaa03.py:10:9: AAA03 expected 1 blank line before Act block, found none
 examples/bad/test_aaa03.py:3:5: AAA03 expected 1 blank line before Act block, found none
+examples/bad/test_aaa04.py:12:5: AAA04 expected 1 blank line before Assert block, found none
 examples/bad/test_aaa04.py:5:5: AAA04 expected 1 blank line before Assert block, found none
 examples/bad/test_aaa05.py:24:1: AAA05 blank line in block
 examples/bad/test_aaa05.py:35:1: AAA05 blank line in block

examples/bad/test_aaa03.py

@@ -1,5 +1,12 @@
-def test():
+def test() -> None:
     x = 1
     result = x**2
 
-    assert result == 4
+    assert result == 1
+
+
+def test_b(hello_world_path) -> None:
+    with open(hello_world_path) as f:
+        result = f.read()
+
+    assert result == 'Hello World!\n'

examples/bad/test_aaa03_04.py

@@ -1,4 +1,10 @@
-def test():
-    x = 1
-    result = x**2
-    assert result == 4
+def test() -> None:
+    x = 3
+    result = x**5
+    assert result == 243
+
+
+def test_b(hello_world_path) -> None:
+    with open(hello_world_path) as f:
+        result = f.read()
+    assert result == 'Hello World!\n'

examples/bad/test_aaa04.py

@@ -1,5 +1,12 @@
-def test():
-    x = 1
+def test() -> None:
+    x = 3
 
-    result = x**2
-    assert result == 4
+    result = x**5
+    assert result == 243
+
+
+def test_b(hello_world_path) -> None:
+    with open(hello_world_path) as f:
+
+        result = f.read()
+    assert result == 'Hello World!\n'

examples/conftest.py

@@ -0,0 +1,11 @@
+import pathlib
+
+import pytest
+
+
+@pytest.fixture
+def hello_world_path() -> pathlib.Path:
+    """
+    Location of hello_world.txt
+    """
+    return pathlib.Path(__file__).parent / 'data' / 'hello_world.txt'

examples/data/hello_world.txt

@@ -0,0 +1 @@
+Hello World!

examples/good/README.rst

@@ -7,8 +7,16 @@ Arrange Act Assert as checked for by Flake8-AAA.
 See `test_example.py <test_example.py>`_ for the simplest example of an
 AAA-style test.
 
-Testing
--------
+Valid tests
+-----------
+
+The goal is that all tests in both good and bad examples will target features
+of the Python 3 standard library. They will all be executable with a vanilla
+install of ``pytest``. Currently only the ``with`` statement examples support
+this.
+
+Testing Flake8-AAA
+------------------
 
 To prevent false negatives our test suite runs Flake8-AAA against this
 directory and checks no linting errors are raised.

examples/good/black/test_context_block_act.py

@@ -1,13 +1,12 @@
-from project.auth import user_perms_changed
+# You know it"s black because it does the double quotes :D
 
-from .helpers import catch_signal
 
+def test_simple(hello_world_path) -> None:
+    """
+    `with` statement is part of arrange. Blank lines are maintained around Act.
+    """
+    with open(hello_world_path) as f:
 
-def test(api_client, url):
-    data = {"user_id": 0, "project_permission": "admin"}
+        result = f.read()
 
-    with catch_signal(user_perms_changed) as callback:
-        result = api_client.put(url, data=data)
-
-    assert result.status_code == 400
-    assert callback.call_count == 0
+    assert result == "Hello World!\n"

examples/good/test_django_fakery_factories.py

@@ -4,8 +4,8 @@
 from django.db.utils import IntegrityError
 from django.test import TestCase
 
-from ..django_fakery_factories import ItemFactory, UserFactory
-from ..models import Item
+from .django_fakery_factories import ItemFactory, UserFactory
+from .models import Item
 
 
 class TestItemFactory(TestCase):

examples/good/test_with_statement.py

@@ -0,0 +1,86 @@
+import io
+
+import pytest
+
+
+def test_simple(hello_world_path) -> None:
+    """
+    `with` statement is part of arrange. Blank lines are maintained around Act.
+    """
+    with open(hello_world_path) as f:
+
+        result = f.read()
+
+    assert result == 'Hello World!\n'
+
+
+def test_whole(hello_world_path) -> None:
+    """
+    `with` statement wraps whole of test
+    """
+    with open(hello_world_path) as f:
+
+        result = f.read()
+
+        assert result == 'Hello World!\n'
+
+
+def test_extra_arrange(hello_world_path) -> None:
+    """
+    Any extra arrangement goes in the `with` block.
+    """
+    with open(hello_world_path) as f:
+        f.read()
+
+        result = f.read()
+
+    assert result == ''
+
+
+def test_assert_in_block(hello_world_path) -> None:
+    """
+    Any assertion that needs the `with` block open, goes after Act and a BL.
+    """
+    with open(hello_world_path) as f:
+        f.read()
+
+        result = f.read()
+
+        assert not f.closed
+    assert f.closed
+    assert result == ''
+
+
+def test_pytest_assert_raises_in_block(hello_world_path) -> None:
+    """
+    Checking on a raise in a with block works with Pytest.
+    """
+    with open(hello_world_path) as f:
+
+        with pytest.raises(io.UnsupportedOperation):
+            f.write('hello back')
+
+        assert f.read() == 'Hello World!\n'
+
+
+def test_pytest_assert_raises_on_with(hello_world_path) -> None:
+    """
+    Checking on the raise from a with statement works with Pytest.
+    """
+    with pytest.raises(ValueError) as excinfo:
+        with open(hello_world_path, 'zz'):
+            pass
+
+    assert 'invalid mode' in str(excinfo.value)
+
+
+def test_with_in_assert(hello_world_path) -> None:
+    """
+    Using with statement in Assert block is valid
+    """
+    words = ['Hello', 'World!\n']
+
+    result = ' '.join(words)
+
+    with open(hello_world_path) as f:
+        assert result == f.read()

examples/good/test_with_statement_unittest.py

@@ -0,0 +1,30 @@
+import io
+import pathlib
+import unittest
+
+
+class Test(unittest.TestCase):
+
+    def setUp(self):
+        self.hello_world_path = pathlib.Path(__file__).parent.parent / 'data' / 'hello_world.txt'
+
+    def test_assert_raises_in_block(self):
+        """
+        Checking on a raise in a with block works with unittest.
+        """
+        with open(self.hello_world_path) as f:
+
+            with self.assertRaises(io.UnsupportedOperation):
+                f.write('hello back')
+
+            self.assertEqual(f.read(), 'Hello World!\n')
+
+    def test_assert_raises_on_with(self):
+        """
+        Checking on the raise from a with statement works with Pytest.
+        """
+        with self.assertRaises(ValueError) as cm:
+            with open(self.hello_world_path, 'zz'):
+                pass
+
+        self.assertIn('invalid mode', str(cm.exception))

requirements/lintexamples.in → requirements/examples.in

@@ -1,2 +1,4 @@
 black
 flake8
+mypy
+pytest

requirements/examples.txt

@@ -0,0 +1,30 @@
+#
+# This file is autogenerated by pip-compile
+# To update, run:
+#
+#    pip-compile --output-file=examples.txt examples.in
+#
+appdirs==1.4.3            # via black
+attrs==19.3.0             # via black, pytest
+black==19.10b0            # via -r examples.in
+click==7.1.1              # via black
+entrypoints==0.3          # via flake8
+flake8==3.7.9             # via -r examples.in
+mccabe==0.6.1             # via flake8
+more-itertools==8.2.0     # via pytest
+mypy-extensions==0.4.3    # via mypy
+mypy==0.770               # via -r examples.in
+packaging==20.3           # via pytest
+pathspec==0.7.0           # via black
+pluggy==0.13.1            # via pytest
+py==1.8.1                 # via pytest
+pycodestyle==2.5.0        # via flake8
+pyflakes==2.1.1           # via flake8
+pyparsing==2.4.7          # via packaging
+pytest==5.4.1             # via -r examples.in
+regex==2020.2.20          # via black
+six==1.14.0               # via packaging
+toml==0.10.0              # via black
+typed-ast==1.4.1          # via black, mypy
+typing-extensions==3.7.4.2  # via mypy
+wcwidth==0.1.9            # via pytest

setup.cfg

@@ -16,4 +16,4 @@ column_limit = 120
 
 [tool:pytest]
 addopts=--tb=short --color=yes
-log_print=False
+show_capture = false