testing-anti-patterns

Testing mock behavior verifies the mock itself, not your actual component. Never test mocks—instead test real behavior by calling actual methods and asserting on their side effects. This ensures your tests validate production code, not test artifacts.

Test-only methods pollute production classes and create maintenance debt. Keep production code clean by testing through public interfaces only. If you need special test access, redesign the class or use dependency injection—never add methods solely for testing.

Mocking without understanding a method's side effects breaks test logic and creates brittle tests. Before mocking, understand what the dependency does, what it returns, and what external effects it triggers. This prevents false positives and misleading test results.

Detect testing anti-patterns during test reviews and CI validation by checking for over-mocked behavior, test-only production methods, and mocks used without understanding dependencies. Integrate pattern detection into linters and quality gates to emit actionable signals before code merges.

Testing real behavior verifies actual component logic and side effects against requirements. Testing mocks only verifies the mock exists or responds correctly, missing real production failures. TDD enforces testing real behavior to catch actual bugs and ensure reliable code.

Yes. Over-mocking, test-only production code, and mocks without understanding dependencies create flaky tests that pass locally but fail in production. Eliminating these anti-patterns ensures tests accurately reflect real component behavior and reduce false failures.