Pytest

Testing helpers for FastAPI applications with async client, database sessions, and parallel worker support.

Installation

=== "uv" bash uv add "fastapi-toolsets[pytest]"

=== "pip" bash pip install "fastapi-toolsets[pytest]"

Overview

The pytest module provides utilities for setting up async test clients, managing test database sessions, and supporting parallel test execution with pytest-xdist.

Creating an async client

Use create_async_client to get an httpx.AsyncClient configured for your FastAPI app:

from fastapi_toolsets.pytest import create_async_client

@pytest.fixture
async def http_client(db_session):
    async def _override_get_db():
        yield db_session

    async with create_async_client(
        app=app,
        base_url="http://127.0.0.1/api/v1",
        dependency_overrides={get_db: _override_get_db},
    ) as c:
        yield c

Database sessions in tests

Use create_db_session to create an isolated AsyncSession for a test, combined with create_worker_database to set up a per-worker database:

from fastapi_toolsets.pytest import create_worker_database, create_db_session

@pytest.fixture(scope="session")
async def worker_db_url():
    async with create_worker_database(
        database_url=str(settings.SQLALCHEMY_DATABASE_URI)
    ) as url:
        yield url


@pytest.fixture
async def db_session(worker_db_url):
    async with create_db_session(
        database_url=worker_db_url, base=Base, cleanup=True
    ) as session:
        yield session

!!! info In this example, the database is reset between each test using the argument cleanup=True.

Use worker_database_url to derive the per-worker URL manually if needed:

from fastapi_toolsets.pytest import worker_database_url

url = worker_database_url("postgresql+asyncpg://user:pass@localhost/test_db", default_test_db="test")
# e.g. "postgresql+asyncpg://user:pass@localhost/test_db_gw0" under xdist

Parallel testing with pytest-xdist

The examples above are already compatible with parallel test execution with pytest-xdist.

Cleaning up tables

!!! warning Since V2.1.0 cleanup_tables now live in fastapi_toolsets.db. For backward compatibility the function is still available in fastapi_toolsets.pytest, but this will be remove in V3.0.0.

If you want to manually clean up a database you can use cleanup_tables, this will truncate all tables between tests for fast isolation:

from fastapi_toolsets.db import cleanup_tables

@pytest.fixture(autouse=True)
async def clean(db_session):
    yield
    await cleanup_tables(session=db_session, base=Base)

:material-api: API Reference

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