fastapi-toolsets/docs/module/pytest.md

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 client(app):
    async with create_async_client(app=app) as c:
        yield c

Database sessions in tests

Use create_db_session to create an isolated AsyncSession for a test:

from fastapi_toolsets.pytest import create_db_session

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

Parallel testing with pytest-xdist

When running tests in parallel, each worker needs its own database. Use these helpers to create and identify worker databases:

from fastapi_toolsets.pytest import create_worker_database, create_db_session

# In conftest.py session-scoped fixture
@pytest.fixture(scope="session")
async def worker_db_url():
    async with create_worker_database(database_url=DATABASE_URL) 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

Cleaning up tables

cleanup_tables truncates all tables between tests for fast isolation:

from fastapi_toolsets.pytest import cleanup_tables

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

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