pytest-api-testing

Use FastAPI's TestClient with pytest to write automated tests for endpoints. TestClient simulates HTTP requests without running a live server, letting you verify status codes, response schemas, and behavior across typical and edge-case scenarios in a single test file.

Yes. Write pytest tests that simulate both authenticated and unauthenticated access by passing credentials or tokens through TestClient requests. Test protected routes separately to verify authorization logic and error responses for denied access.

Assert HTTP status codes and inspect response JSON structure in pytest tests. Validate that endpoints return correct field names, data types, and values matching your API schema, catching mismatches between implementation and specification.

Use pytest fixtures to set up shared test data, mock databases, or TestClient instances once and reuse them across multiple tests. Fixtures reduce duplication and make tests more maintainable when testing multiple endpoints with similar setup requirements.

Pass query parameters directly in TestClient request URLs and assert that endpoints return paginated results with correct offsets, limits, and metadata. Test boundary conditions like empty pages and invalid parameter values.

Yes. TestClient captures error responses from FastAPI's built-in validation and custom error handlers. Write tests that send malformed data, missing fields, or invalid types to verify the endpoint returns appropriate status codes and error messages.