testland/unittest-tests
Configures and runs Python's stdlib unittest - TestCase + setUp/tearDown lifecycle hooks, assertion catalog (assertEqual / assertRaises / assertIn / assertAlmostEqual), unittest.mock module (Mock / MagicMock / patch / patch.object / patch.dict), test discovery via `python -m unittest discover`, subTest for parametrized cases, expectedFailure decorator. Use when constrained to stdlib-only (no pip install) or migrating legacy unittest codebases.
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assertions-and-mock.mdreferences/
unittest assertions and mock reference
Companion catalog for the unittest-tests skill: the full assertion table and
the unittest.mock patterns, pulled out of the SKILL spine.
Assertion catalog
Per ut-docs:
| Method | Use |
|---|---|
assertEqual(a, b) / assertNotEqual(a, b) | Equality |
assertTrue(x) / assertFalse(x) | Boolean |
assertIs(a, b) / assertIsNot(a, b) | Identity (is) |
assertIsNone(x) / assertIsNotNone(x) | None |
assertIn(a, b) / assertNotIn(a, b) | Membership |
assertIsInstance(a, type) | Type check |
assertRaises(Exception) | Sync raise (context manager + decorator forms) |
assertRaisesRegex(Exception, regex) | Raise + message match |
assertWarns(Warning) | Warning emission |
assertAlmostEqual(a, b, places=N) | Float comparison |
assertGreater(a, b) / assertGreaterEqual(a, b) | Numeric |
assertCountEqual(a, b) | Same elements regardless of order |
assertDictContainsSubset(subset, dict) | Partial dict match (deprecated; use <= operator) |
Prefer the specific assert over assertTrue(x == y): the specific method prints
a useful diff on failure.
unittest.mock patterns
Per docs.python.org/3/library/unittest.mock.html:
from unittest.mock import Mock, MagicMock, patch
# Standalone mocks
m = Mock()
m.method.return_value = 42
result = m.method(5)
m.method.assert_called_once_with(5)
# MagicMock supports magic methods (__len__, __iter__, etc.)
mm = MagicMock()
mm.__len__.return_value = 5
assert len(mm) == 5
# Patch a function in the target module
@patch('mymodule.fetch_user')
def test_with_patched_fetch(mock_fetch):
mock_fetch.return_value = {'id': 1}
result = my_function()
assert result == 'expected'
# Context-manager form
def test_with_context_patch():
with patch('mymodule.fetch_user') as mock_fetch:
mock_fetch.return_value = {'id': 1}
result = my_function()
# Patch an attribute
@patch.object(SomeClass, 'method', return_value='mocked')
def test_class_method(mock_method):
obj = SomeClass()
assert obj.method() == 'mocked'
# Patch a dictionary
@patch.dict('os.environ', {'API_KEY': 'test-key'})
def test_with_env():
assert os.environ['API_KEY'] == 'test-key'Patch target rule: patch where the function is used, not where it's
defined. If mymodule.py does from api import fetch_user, patch
mymodule.fetch_user, not api.fetch_user.