Testing-Anti-Patterns

Testing anti-patterns include testing mock behavior instead of actual logic, polluting production code with test-only methods, and over-mocking dependencies. These practices create brittle, misleading, and unmaintainable test suites that fail to validate real behavior.

To write maintainable tests, avoid testing mock behavior by ensuring your mocks are simple and your assertions are comprehensive. Consolidate fragmented assertions into single, clear checks to test actual function behavior rather than the mock setup itself.

Polluting production code with test-only functions harms code quality by coupling test logic to production namespaces. It complicates the codebase, making it harder to maintain and obscuring the actual behavior of the production code.

The best way to structure assertions in TDD is to use single, comprehensive assertions rather than fragmented checks. This approach keeps tests robust and maintainable, ensuring you validate actual behavior without creating complex mock setups.

You should avoid mocking dependencies when it leads to incomplete mocks or over-mocking, which obscures your understanding of the dependency. If a mock setup becomes overly complex, it indicates you are testing the mock rather than the actual behavior.