test-writer

Writing unit tests with proper mocking in pytest means using AsyncMock with spec= to isolate external dependencies and prevent real API calls. This ensures tests are deterministic, fast, and independent of external services.

Structure async tests using pytest-asyncio by defining async test functions, applying the Arrange-Act-Assert pattern, using AsyncMock for external service calls, and enforcing await patterns throughout. This prevents common async pitfalls and ensures test reliability.

Test-Driven Development follows a Red-Green-Refactor cycle: write a failing test first, implement minimal code to pass it, then refactor. This approach ensures code is well-tested from the start and reduces debugging time significantly.

Mocking external services prevents flaky tests, eliminates unnecessary API costs, ensures test determinism, and enables faster test execution. Strict mocking with spec= guarantees test isolation and reproducible results.

Yes, pytest-asyncio works with strict mocking by combining AsyncMock with spec= for all external dependencies. This enforces test isolation and prevents accidental real API calls while supporting asynchronous test patterns.

Unit tests alone don't catch integration issues or infrastructure problems. Combine unit tests with integration and infrastructure layer tests, apply consistent mocking standards, and use CI/CD pipelines to ensure comprehensive coverage and prevent deployment failures.