# Lerianstudio Ring Testing Anti Patterns > Testing Anti-Patterns - Skill: `tomevault-io/lerianstudio-ring-testing-anti-patterns` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/lerianstudio-ring-testing-anti-patterns` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/lerianstudio-ring-testing-anti-patterns/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/lerianstudio-ring-testing-anti-patterns --- # Testing Anti-Patterns ## Overview Tests must verify real behavior, not mock behavior. Mocks are a means to isolate, not the thing being tested. **Core principle:** Test what the code does, not what the mocks do. **Following strict TDD prevents these anti-patterns.** ## The Iron Laws ``` 1. NEVER test mock behavior 2. NEVER add test-only methods to production classes 3. NEVER mock without understanding dependencies ``` ## Anti-Pattern 1: Testing Mock Behavior **BAD:** `expect(screen.getByTestId('sidebar-mock')).toBeInTheDocument()` - testing mock exists, not real behavior. **GOOD:** `expect(screen.getByRole('navigation')).toBeInTheDocument()` - test real component or don't mock. **Gate:** Before asserting on mock element → "Am I testing real behavior or mock existence?" If mock → delete assertion or unmock. ## Anti-Pattern 2: Test-Only Methods in Production **BAD:** `session.destroy()` method only used in tests - pollutes production, dangerous if called. **GOOD:** `cleanupSession(session)` in test-utils/ - keeps production clean. **Gate:** "Is this method only used by tests?" → Put in test utilities. "Does this class own this lifecycle?" → If no, wrong class. ## Anti-Pattern 3: Mocking Without Understanding **BAD:** Mocking `discoverAndCacheTools` breaks config write test depends on - test passes for wrong reason. **GOOD:** Mock only the slow part (`MCPServerManager`), preserve behavior test needs. **Gate:** Before mocking → (1) What side effects does real method have? (2) Does test depend on them? If yes → mock at lower level. **Red flags:** "Mock to be safe", "might be slow", mocking without understanding. ## Anti-Pattern 4: Incomplete Mocks **BAD:** Partial mock missing `metadata` field - breaks when downstream code accesses `response.metadata.requestId`. **GOOD:** Complete mock mirroring real API - ALL fields real API returns. **Iron Rule:** Mock COMPLETE data structure, not just fields your test uses. Partial mocks fail silently. **Gate:** Before mock → Check real API response, include ALL fields. If uncertain → include all documented fields. ## Anti-Pattern 5: Integration Tests as Afterthought **BAD:** "Implementation complete" without tests. **FIX:** TDD cycle: write test → implement → refactor → claim complete. ## When Mocks Become Too Complex **Warning signs:** Mock setup longer than test logic, mocking everything, mocks missing methods real components have. **Consider:** Integration tests with real components often simpler than complex mocks. ## TDD Prevents These Anti-Patterns TDD forces: (1) Think about what you're testing, (2) Watch fail confirms real behavior not mocks, (3) See what test needs before mocking. **If testing mock behavior, you violated TDD.** ## Quick Reference | Anti-Pattern | Fix | |--------------|-----| | Assert on mock elements | Test real component or unmock it | | Test-only methods in production | Move to test utilities | | Mock without understanding | Understand dependencies first, mock minimally | | Incomplete mocks | Mirror real API completely | | Tests as afterthought | TDD - tests first | | Over-complex mocks | Consider integration tests | ## Red Flags - Assertion checks for `*-mock` test IDs - Methods only called in test files - Mock setup is >50% of test - Test fails when you remove mock - Can't explain why mock is needed - Mocking "just to be safe" ## The Bottom Line **Mocks are tools to isolate, not things to test.** If TDD reveals you're testing mock behavior, you've gone wrong. Fix: Test real behavior or question why you're mocking at all. ## Blocker Criteria STOP and report if: | Decision Type | Blocker Condition | Required Action | |---|---|---| | Mock Justification | Cannot explain what real behavior the mock enables testing | STOP and report | | Test-Only Method | Method exists only for test purposes in production code | STOP and report | | Incomplete Mock | Mock missing fields that real API returns | STOP and report | | TDD Violation | Tests written after implementation complete | STOP and report | ### Cannot Be Overridden The following requirements CANNOT be waived: - Tests MUST verify real behavior, not mock existence - Production code CANNOT contain test-only methods - Mocks MUST mirror real API structures completely - Understanding dependencies is REQUIRED before mocking ## Severity Calibration | Severity | Condition | Required Action | |---|---|---| | CRITICAL | Asserting on mock elements (`*-mock` test IDs) | MUST fix immediately | | CRITICAL | Test-only methods in production classes | MUST fix immediately | | HIGH | Mocking without understanding side effects | MUST fix before completing | | HIGH | Incomplete mocks missing required fields | MUST fix before completing | | MEDIUM | Mock setup exceeds 50% of test logic | Should fix | | LOW | Test coverage gaps in non-critical paths | Fix in next iteration | ## Pressure Resistance | User Says | Your Response | |---|---| | "Just mock it to make the test pass quickly" | "CANNOT mock without understanding what behavior I'm enabling tests for. Let me analyze the real dependencies first." | | "Add a test-only method, it's the fastest solution" | "CANNOT add test-only methods to production code. I'll create a test utility instead." | | "The mock doesn't need all those fields" | "CANNOT use incomplete mocks. Partial mocks fail silently when downstream code accesses missing fields." | | "Skip TDD, we're behind schedule" | "CANNOT skip TDD. Writing tests after leads to testing mock behavior instead of real behavior." | ## Anti-Rationalization Table | Rationalization | Why It's WRONG | Required Action | |---|---|---| | "Mock makes the test simpler" | Simpler test ≠ correct test. You may be testing mock existence, not behavior. | **MUST verify assertion tests real behavior** | | "Test-only method is small, doesn't hurt" | Any test pollution in production is dangerous if called accidentally. | **MUST move to test utilities** | | "I know what the mock needs" | Assumption ≠ verification. Check real API response. | **MUST verify mock completeness against real API** | | "Tests after is the same as TDD" | Order matters. TDD reveals what to mock; tests-after tests mocks blindly. | **MUST follow RED-GREEN-REFACTOR** | | "Mocking to be safe" | "Safe" mocking without understanding breaks tests that depend on real behavior. | **MUST understand dependencies before mocking** | --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/lerianstudio) — claim your Tome and manage your conversions.