testing-anti-patterns

Testing anti-patterns include mocking real behavior instead of verifying it, incomplete mocks that don't reflect actual APIs, and adding test-only methods to production code. Review test design to ensure mocks are complete, tests verify real code paths, and production remains clean.

Testing mock behavior verifies how your mock works, not whether your real code functions correctly. Effective tests verify real code by using mocks only to isolate external dependencies, ensuring tests catch actual bugs rather than passing falsely.

Incomplete mocks don't mirror the real API structure, so tests pass in isolation but fail in production when code encounters missing methods or properties. Complete mocks prevent silent failures by accurately reflecting real dependencies.

No. Adding test-only methods pollutes production code and masks design issues. Instead, refactor code to be testable through public APIs and use proper mocking to isolate external dependencies without modifying production classes.

Over-mocking or poorly aligned mocks hide real failures and create false confidence in your test suite. Strict mocking practices—complete, accurate mocks used only for external dependencies—ensure tests reliably verify production behavior.

Follow TDD principles: mock only external dependencies, ensure mocks match real API signatures exactly, verify real code behavior not mock internals, and keep production code free of test-specific logic. This produces robust, maintainable tests.