integration-testing

End-to-end integration tests validate system-wide functionality by identifying triggers, flows, and observable outcomes across all components. Start by defining test categories—smoke, progress, cancellation, or error—then map acceptance criteria to test scenarios, set up test data and prerequisites, and execute against a live environment to verify the entire feature chain works correctly.

Integration tests validate how multiple system components work together end-to-end, covering feature-level flows and acceptance criteria, while unit tests check individual functions in isolation. Integration testing catches failures that occur only when services interact, making it essential for verifying system reliability beyond individual component correctness.

Yes. Docker simplifies integration testing by containerizing all services, ensuring consistent test environments across development and CI/CD pipelines. Use Docker to spin up dependent services, verify service health and connectivity, then execute end-to-end tests against the containerized stack.

Integration tests for FastAPI endpoints involve calling the API endpoints end-to-end through HTTP requests, monitoring response outcomes, and validating system state changes. Define test triggers (API calls), observe flows (polling for progress or results), and verify observable outcomes (response codes, data changes, side effects) across dependent services.

Before running integration tests, verify service health and connectivity of all system components using quick health-check commands. Confirm test data and prerequisites are in place, the test environment is ready, and all dependent services are running and accessible.

Debug integration failures by isolating which component or service interaction broke: verify service health, check API responses and data state at each step, and review logs across all services. Common patterns include testing error scenarios explicitly and validating cancellation flows to catch edge cases early.