pytest-backend-testing

FastAPI tests with pytest should be structured across three layers: repository, service, and router. This approach isolates database logic, business rules, and API endpoints, enforcing the AAA pattern and achieving at least 80% test coverage.

Testing async FastAPI endpoints requires pytest-asyncio to handle asynchronous execution. This Skill demonstrates async testing patterns to properly evaluate non-blocking API routes, ensuring asynchronous database operations and network requests are validated correctly.

Mocking and fixtures in FastAPI integration testing isolate external dependencies and manage test setups. This guide provides practical examples of using pytest fixtures to mock database sessions and external APIs, ensuring reliable and repeatable integration tests.

Yes, TestClient is used to achieve high test coverage in production-grade FastAPI projects. Combined with structured test organization and the AAA pattern, it enables comprehensive validation of API routes to reach a target of 80% or higher coverage.

FastAPI backend test coverage often stalls below 80% due to untested service layers or missing integration tests. This Skill addresses the challenge by providing strategies for organizing tests, mocking dependencies, and analyzing coverage across all application layers.