| name | testing-discipline |
| description | Universal testing discipline — pyramid, test quality, what never to mock. Load when writing or reviewing tests in any stack. |
Skill: Testing Discipline
Stack-agnostic: frameworks come from memory-long §stack; targets from TESTS.md. This is the discipline layer.
Non-negotiables
- Test behavior, not implementation — a refactor that preserves behavior must not break tests; if it does, the test was wrong
- EARS criteria map to tests: every acceptance criterion of a feature has at least one test asserting it
- Failing test first for bug fixes (reproduce → fix → green) — a fix without a regression test is half a fix
- Never: skipped tests left behind (
.only/.skip), assertions on internals, test-order dependence, weakening coverage configs to pass (hook-enforced)
Pyramid (defaults — TESTS.md overrides)
Unit ~70% (fast, isolated, logic) · Integration ~20% (boundaries: API contracts, DB access) · E2E ~10% (critical user paths only — expensive, flaky-prone).
What never to mock
The unit under test · the project's type system · pure functions · time/randomness (inject instead). Mock only true boundaries: network, filesystem, third-party services, clocks.
Quality bar
Each test: one behavior, named as a sentence (rejects expired tokens), arrange-act-assert visible, failure message diagnosable without reading the test body.
