Testing Anti-Patterns Guide

Tests often pass because they verify mock behavior rather than real component output. Testing Mock Behavior—asserting mocks exist instead of validating actual results—is a fundamental anti-pattern. Ensure tests verify real behavior by removing unnecessary mocks and confirming assertions check actual functionality, not mock interactions.

Over-mocking breaks tests by replacing methods whose side effects your test depends on. Identify Mocking Without Understanding by reviewing which dependencies you mock and why. Before mocking, trace dependency chains to confirm whether isolation is genuinely needed or whether the mock setup suggests reconsidering your testing approach entirely.

Avoid adding test-only methods like destroy() to production classes—this is the Test-Only Methods anti-pattern. Instead, place cleanup logic in dedicated test utilities. This keeps your codebase clean while ensuring proper resource teardown during test execution.

Test-Driven Development forces you to observe tests fail against real implementations before adding mocks. This process naturally reveals whether mocks are genuinely needed and prevents Integration Tests as Afterthought. Writing tests first surfaces what actually requires mocking versus what should remain real.

Incomplete Mocks—partial mock objects that pass tests but fail in real integration—occur when code accesses unmocked fields. Tests pass locally while failing when dependencies behave differently in production. Ensure all mocked dependencies are fully configured or avoid mocking in favor of real instances.

Review the test suite to identify mocks and anti-patterns, remove test-only methods, and ensure tests verify real behavior rather than mocks. Start by examining assertions to confirm they check actual component output, not mock interactions, then refactor mocks based on genuine isolation needs.