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pytest-composite-assertion (PT018)#

Derived from the flake8-pytest-style linter.

Fix is sometimes available.

What it does#

Checks for assertions that combine multiple independent conditions.

Why is this bad?#

Composite assertion statements are harder debug upon failure, as the failure message will not indicate which condition failed.


def test_foo():
    assert something and something_else

def test_bar():
    assert not (something or something_else)

Use instead:

def test_foo():
    assert something
    assert something_else

def test_bar():
    assert not something
    assert not something_else