test-coverage
Installation
SKILL.md
Test Coverage
Audit gaps, write targeted tests, enforce thresholds — across any ecosystem.
Mental Model
The testing pyramid encodes an economic truth: each tier tests what only it can test.
| Tier | Tests | Cost to write | Cost to run |
|---|---|---|---|
| Unit | Pure functions, domain logic, validation, parsing | Low | Milliseconds |
| Integration | Database queries, API boundaries, access control, service interactions | Medium | Seconds |
| Component | Rendered UI in a real browser, user interactions, visual states | Medium | Seconds |
| E2E | Full user flows across the entire stack | High | Minutes |
Coverage is a regression gate, not a quality metric. High coverage with bad tests is worse than moderate coverage with good tests. The goal is: new code cannot silently skip tests.
Exclusions are architecture, not exceptions. Every exclusion documents a deliberate decision about where code is tested. An exclusion at one tier should have coverage at another.