pytest-multi-backend 2026.9.7

Installation

pip install pytest-multi-backend

This requires Python 3.12+.

Usage

Backends are the members of an Enum. The member name, in lower case, is what --skip-backend takes to skip the backend. The member value is the ID which pytest shows for it.

backend_fixture makes a fixture which runs each test which uses it once per backend. Assign the fixture to a module-level name in a conftest.py for pytest to find it.

"""Run each test against the real service and against a fake."""

from collections.abc import Generator
from enum import Enum

import pytest

from pytest_multi_backend import backend_fixture


class Backend(Enum):
    """The ways of running the service under test."""

    REAL = "Real service"
    FAKE = "In memory fake"


def _setup_backend(
    *,
    backend: Backend,
    request: pytest.FixtureRequest,
) -> Generator[None]:
    """Set a backend up, yield while the test runs, then tear it down.

    Anything else the setup needs comes from
    ``request.getfixturevalue``.
    """
    monkeypatch = request.getfixturevalue(argname="monkeypatch")
    if backend is Backend.FAKE:
        # Start the fake here, and point the code under test at it.
        monkeypatch.setenv(name="SERVICE_URL", value="http://localhost:8080")
        yield
        # Stop the fake here.
        return
    monkeypatch.setenv(name="SERVICE_URL", value="https://example.com")
    yield


fixture_backend = backend_fixture(
    name="backend",
    backends=list(Backend),
    setup_for=_setup_backend,
)

A test which requests the fixture runs once per backend, and gets the backend it is running against:

"""A test which runs against each backend."""

from enum import Enum


def test_something(backend: Enum) -> None:
    """Assert the same thing about every backend."""
    assert backend.value

$ pytest --skip-backend=real

$ pytest --skip-marker=requires_docker

Full documentation

See the full documentation.