testing-anti-patterns

Mock-based anti-patterns occur when tests verify mock mechanics instead of real behavior. Common signs include assertions on mock calls without validating actual output, test-only methods in production code, and mocks that leak into production logic. Audit your test suite to replace mock-existence checks with real-behavior verification.

Testing mock behavior verifies that a mock was called or configured correctly—a test anti-pattern. Testing actual behavior validates that your code produces the correct output under real conditions. Replace assertions like "mock.called" with assertions on actual return values, side effects, and integration results.

Test-only production methods create tight coupling between tests and code, making tests brittle. Refactor by moving setup and teardown logic into proper test utilities, using dependency injection instead of test hooks, and ensuring mock management stays in the test layer, not production.

Yes, but with discipline. Integration tests using mocks must still assert on real behavior outcomes, not mock invocations. Ensure mocks augment real code paths rather than replacing them, manage mock setup and cleanup through proper test utilities, and avoid test-only conditionals in production logic.

Use a quality checklist covering mock-existence checks, test-only production code, and mock-focused assertions. Run gate checks against your test suite to flag these patterns. Replace each anti-pattern by rewriting assertions to verify real behavior, moving test utilities into proper helper functions, and removing production code branches that only serve tests.