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pytest-raises-too-broad (PT011)

Added in v0.0.208 · Related issues · View source

Derived from the flake8-pytest-style linter.

What it does

Checks for pytest.raises calls without a match or check parameter.

Why is this bad?

pytest.raises(Error) will catch any Error and may catch errors that are unrelated to the code under test. To avoid this, pytest.raises should be called with a match parameter (to constrain the exception message) or a check parameter (to constrain the exception itself). The exception names that require a match or check parameter can be configured via the lint.flake8-pytest-style.raises-require-match-for and lint.flake8-pytest-style.raises-extend-require-match-for settings.

Example

import pytest


def test_foo():
    with pytest.raises(ValueError):
        ...

    # empty string is also an error
    with pytest.raises(ValueError, match=""):
        ...

Use instead:

import pytest


def test_foo():
    with pytest.raises(ValueError, match="expected message"):
        ...

Or, for pytest 8.4.0 and later:

import pytest


def test_foo():
    with pytest.raises(OSError, check=lambda e: e.errno == 42):
        ...

Options

References