# Willyu1007 AI First Template Testing Guide > Testing Guide - Skill: `tomevault-io/willyu1007-ai-first-template-testing-guide` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/willyu1007-ai-first-template-testing-guide` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/willyu1007-ai-first-template-testing-guide/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/willyu1007-ai-first-template-testing-guide --- # Testing Guide This skill provides a pragmatic testing strategy for backend services. --- ## 1. Principles - Prefer **fast unit tests** for business logic (service layer). - Use **integration tests** for routes and repositories when needed. - Keep tests deterministic (fixed inputs, stable fixtures, clear assertions). --- ## 2. What to test by layer ### Routes/controllers - HTTP status codes and response shape - Input validation behavior (invalid input → 400) - Auth/permission behavior (missing/invalid auth → 401/403) ### Services - Business rules and edge cases - Idempotency and invariants - Error conditions (typed domain errors) ### Repositories - Query correctness and filtering/pagination behavior - Transactional behavior (multi-write operations) --- ## 3. Common anti-patterns - Tests that depend on real clocks (use time injection or fakes) - Tests that require external services without a stable harness - "Golden" snapshots for dynamic responses without normalization --- ## 4. Checklist (before merging changes) - [ ] Service logic covered by unit tests - [ ] At least one integration test covers the route(s) you changed - [ ] Failure paths are tested (validation/auth/not found) - [ ] Monitoring/error capture behavior is testable where possible --- ## Related Skills - `architecture-overview` - `services-and-repositories` --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/willyu1007) — claim your Tome and manage your conversions.