testing-anti-patterns

A testing anti-pattern is a flawed practice like testing mock behavior instead of real code, which creates brittle and misleading unit tests that fail to verify actual software behavior.

To stop polluting production code, avoid adding test-only methods like _cleanupForTest() to production classes; instead, use dedicated test utilities and refactor dependencies to keep the main codebase clean.

Mocking dependencies without understanding them leads to unreliable tests because you risk verifying the mock's internal behavior rather than the actual business logic, resulting in false confidence in your codebase.

TDD prevents common unit testing anti-patterns by driving design through tests first, ensuring you mock dependencies properly and write maintainable tests that verify real behavior rather than implementation details.

The best way to refactor brittle tests is to stop verifying mock interactions and instead assert observable outcomes, removing test-only production methods and ensuring tests validate genuine business requirements.

You should not use mocking when you lack a clear understanding of the dependency's behavior, as mocking without comprehension creates misleading tests that validate mock interactions instead of actual application logic.