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pytest-parametrize-names-wrong-type (PT006)#

Derived from the flake8-pytest-style linter.

Fix is sometimes available.

What it does#

Checks for the type of parameter names passed to pytest.mark.parametrize.

Why is this bad?#

The argnames argument of pytest.mark.parametrize takes a string or a sequence of strings. For a single parameter, it's preferable to use a string. For multiple parameters, it's preferable to use the style configured via the flake8-pytest-style.parametrize-names-type setting.

Example#

import pytest


# single parameter, always expecting string
@pytest.mark.parametrize(("param",), [1, 2, 3])
def test_foo(param):
    ...


# multiple parameters, expecting tuple
@pytest.mark.parametrize(["param1", "param2"], [(1, 2), (3, 4)])
def test_bar(param1, param2):
    ...


# multiple parameters, expecting tuple
@pytest.mark.parametrize("param1,param2", [(1, 2), (3, 4)])
def test_baz(param1, param2):
    ...

Use instead:

import pytest


@pytest.mark.parametrize("param", [1, 2, 3])
def test_foo(param):
    ...


@pytest.mark.parametrize(("param1", "param2"), [(1, 2), (3, 4)])
def test_bar(param1, param2):
    ...

Options#

References#