testinglisted

# Testing This skill is self-contained for day-to-day use. Deeper reference (needs the full harness checkout): `patterns/testing/TDD.md` (full TDD workflow), `patterns/testing/COVERAGE_REQUIREMENTS.md` (80% rule and pragma), `patterns/testing/PLAYWRIGHT_UI_TESTING.md` (E2E screenshots), `patterns/testing/COMPLETION_CHECKLIST.md`. ## Rigor tiers — apply the right standard, not the maximum | Tier | Coverage | TDD | Notes | |---|---|---|---| | **Production** | **≥ 80%** line+branch | Required | Libraries, agents, shipped services | | **Internal** | Must have tests | Recommended | No numeric floor; cover what's expensive to get wrong | | **Prototype** | None required | Optional | Skip freely; document the decision | Check `.agentharness-profile` or `.github/CODING_GUIDELINES.md` for the project's tier before assuming 80% applies. ## Red-Green-Refactor 1. **Red** — write a failing test for the *one* behavior you're adding. 2. **Green** — write the minimum code to make it pass (not the final code — the correct code comes in the next step). 3. **Refactor** — clean up duplication and naming while tests stay green. Never skip Red — a test that never fails doesn't prove anything. ## Test one behavior per test ```python # WRONG: five assertions for one behavior — one failure hides the rest def test_user_creation(): user = User.create(email="a@b.com", password="s3cr3t") assert user.id is not None assert user.email == "a@b.com" assert user.password_hash is not