api-testing

Test FastAPI endpoints with pytest by using the FastAPI TestClient to make requests to your endpoints in test functions. Write test cases that verify expected responses, status codes, and behavior for each endpoint you've defined.

Yes, pytest-based tests can validate authentication and authorization by simulating authenticated requests using the TestClient. Pass credentials or tokens in request headers to verify that your endpoints correctly enforce access controls.

Use pytest fixtures and the TestClient to send invalid inputs and edge cases to your endpoints, then assert that the correct error responses and status codes are returned. This ensures input validation and error handling work as expected.

Organize pytest fixtures in a conftest.py file to share reusable test utilities like the TestClient instance, mock data, and database setup across all your test modules. This reduces duplication and keeps tests maintainable.

Yes, FastAPI automatically generates OpenAPI documentation at /docs. Your pytest tests can validate that endpoints match their OpenAPI specifications, and test data can serve as documentation examples.

Pytest supports load and stress testing through integration with performance testing libraries. Write tests that send multiple concurrent or sequential requests to your FastAPI endpoints to measure response times and reliability under load.