@pytest.fixture(params=; ) def param_fixture(request): return request.param

Testing Patterns

Meaning

A pytest fixture that provides parameterized values (10, 20, 30) to test functions that request it via request.param.

Primary Function

Supplies parameterized test inputs to test functions through the fixture's request.param mechanism.

Communicative Purpose

Communicates that the fixture supplies a set of parameter values for test parametrization.

Pattern

@pytest.fixture(params=[<values>])\ndef <fixture_name>(request): return request.param

Core Structure

@pytest.fixture(params=[<list of values>])\ndef <fixture_name>(request): return request.param

Função primária

Supplies parameterized test inputs to test functions through the fixture's request.param mechanism.

Propósito comunicativo

Communicates that the fixture supplies a set of parameter values for test parametrization.

Situações de gatilho

Used when writing parametrized tests where the same test logic should run with multiple input values and the fixture encapsulates the parameter set.

Contextos

Inside pytest test modules where test functions request the fixture named 'param_fixture'.

Padrão

@pytest.fixture(params=[<values>])\ndef <fixture_name>(request): return request.param

Estrutura central

@pytest.fixture(params=[<list of values>])\ndef <fixture_name>(request): return request.param

Slots de substituição

<fixture_name>, <list of values>

Colocados típicos

@pytest.fixture
request
request.param
@pytest.mark.parametrize
test_

Substituições comuns

Different param lists (e.g.
[1
2
3]
['a'
'b'])
different fixture names
adding scope or autouse.

Erros comuns

Forgetting to return request.param, misplacing the params argument, confusing fixture params with @pytest.mark.parametrize arguments, using request.param incorrectly in setup.

Similar / contraste

Using @pytest.mark.parametrize directly on test functions vs. fixture-based parametrization; using a plain @pytest.fixture without params for fixed setup.

Interferências

Mixing fixture param usage with mark parametrization can cause unexpected duplicate test invocations.

Família do chunk

pytest-fixture

Nuance

Allows varying fixture setup per test iteration while keeping the test function signature clean.

Efeito pragmático

Enables reusable test setup with multiple input configurations, reducing boilerplate.

Dica de memória

param_fixture

Nota

The params argument accepts any iterable; using scope='module' or 'function' controls fixture lifetime, and autouse=True applies the fixture automatically to all tests in its scope.

Upgrade path

Could evolve to using @pytest.mark.parametrize directly on test functions for simpler cases, or adding fixture scope/autouse for broader setup.

Tipo de construção: fixture definition with paramsTag de espaçamento: Medium-term

Examples

import pytest @pytest.fixture(params=[10, 20, 30]) def param_fixture(request): return request.param def test_square(param_fixture): assert param_fixture ** 2 in {100, 400, 900}

import pytest @pytest.fixture(params=['admin', 'user', 'guest'], scope='module') def user_role(request): return request.param def test_permissions(user_role): assert user_role in ['admin', 'user', 'guest']

import pytest @pytest.fixture(params=[(1, 'a'), (2, 'b'), (3, 'c')]) def id_and_label(request): return request.param def test_id_label(id_and_label): idx, label = id_and_label assert isinstance(idx, int) assert isinstance(label, str)