flake8-assertive 1.0.0

Flake8 unittest assert method checker

flake8-assertive is a Flake8 extension that encourages using more specific unittest assertions beyond just the typical assertEqual(a, b) and assertTrue(x) methods. The alternate methods suggested by this extension perform more precise checks and provide better failure messages than the generic methods.

Original	Suggestion	Code
assertTrue(a == b)	assertEqual(a, b)	A500
assertTrue(a != b)	assertNotEqual(a, b)	A500
assertFalse(a == b)	assertNotEqual(a, b)	A500
assertFalse(a != b)	assertEqual(a, b)	A500
assertTrue(a < b)	assertLess(a, b)	A500
assertTrue(a <= b)	assertLessEqual(a, b)	A500
assertTrue(a > b)	assertGreater(a, b)	A500
assertTrue(a >= b)	assertGreaterEqual(a, b)	A500
assertTrue(a is b)	assertIs(a, b)	A501
assertTrue(a is not b)	assertIsNot(a, b)	A501
assertFalse(a is b)	assertNotIs(a, b)	A501
assertFalse(a is not b)	assertIs(a, b)	A501
assertTrue(a in b)	assertIn(a, b)	A501
assertFalse(a in b)	assertNotIn(a, b)	A501
assertTrue(isinstance(a, b))	assertIsInstance(a, b)	A501
assertFalse(isinstance(a, b))	assertNotIsInstance(a, b)	A501
assertEqual(a, None)	assertIsNone(a)	A502
assertNotEqual(a, None)	assertIsNotNone(a)	A502
assertTrue(a is None)	assertIsNone(a)	A502
assertTrue(a is not None)	assertIsNotNone(a)	A502
assertFalse(a is None)	assertIsNotNone(a)	A502
assertFalse(a is not None)	assertIsNone(a)	A502
assertEqual(a, True)	assertTrue(a)	A502
assertEqual(a, False)	assertFalse(a)	A502

Note that some suggestions are normalized forms of the original, such as when a double-negative is used (assertFalse(a != b) → assertEqual(a, b)). There aren’t suggestions for things like assertFalse(a > b), which may or may not be equivalent to assertLessEqual(a, b).

Installation

Install from PyPI using pip:

$ pip install flake8-assertive

The extension will be activated automatically by flake8. You can verify that it has been loaded by inspecting the flake8 --version string.

$ flake8 --version
3.5.0 (assertive: 1.0.0, ...) CPython 2.7.15 on Darwin

Error Codes

This extension adds three new error codes (using the A50 prefix):

• A500: prefer {func} for ‘{op}’ comparisons

• A501: prefer {func} for ‘{op}’ expressions

• A502: prefer {func} instead of comparing to {obj}

Configuration

Configuration values are specified in the [flake8] section of your config file or as command line arguments (e.g. --assertive-snakecase).

• assertive-snakecase: suggest snake_case assert method names (e.g. assert_true()) instead of the standard names (e.g. assertTrue())

• assertive-test-pattern: fnmatch pattern for identifying unittest test files (and all other files will be skipped)

Changes

1.0.0 (2018-06-04)

• Suggest assertIsNone(a) for assertTrue(a is None), etc.

• Recognize assertEquals() and assertNotEquals() as aliases for assertEqual() and assertNotEqual().

0.9.0 (2018-05-14)

• Initial beta release