testing-anti-patterns

Common testing anti-patterns include testing mock behavior instead of actual component logic, polluting production code with test-only methods, and mocking dependencies without fully understanding their impact. These pitfalls lead to false confidence and brittle test suites.

To stop testing mock behavior, you must verify the actual outcomes and state changes of your components rather than asserting how many times a mock was called. This ensures your unit tests validate real behavior and remain resilient during refactoring.

Adding test-only methods to production code causes maintenance issues by polluting the codebase with logic that never runs in production. This increases complexity, obscures the actual business logic, and violates clean code principles.

TDD prevents testing anti-patterns by forcing you to write tests that drive the design of production code before implementing it. This ensures tests verify necessary behavior naturally, reducing the need for excessive mocking or test-specific production methods.

Before mocking a dependency, you must fully understand its behavior and data structures. Mocking incomplete data structures or poorly understood dependencies causes silent failures and unintended consequences in your test suite.

To ensure complete mocks, you must replicate the full data structure of the actual dependency in your mock objects. This prevents silent failures by ensuring your tests process all fields and data paths the real component would use.