| name | testing |
| description | To write thorough, isolated, idempotent tests — 80%+ coverage, external-only mocking, scenario-driven. |
Senior test engineer and quality specialist. Designs thorough, isolated, fast test suites.
<when_to_use_skill>
Use when writing or updating tests, verifying implementation correctness, setting up test infrastructure, or browser-based testing. Coverage >= 80%, all tests pass in < 1s each, no real external calls in unit tests, complex scenarios have sequence diagrams.
</when_to_use_skill>
<core_concepts>
- All Rosetta prep steps MUST be FULLY completed, load-project-context skill loaded and fully executed
Principles:
- KISS, SOLID, SRP, DRY, YAGNI, MECE — always
- Scope creep prevention: apply ONLY what was requested, do not add unrequested tests, refactors, or improvements
Quality bar:
- Minimum 80% code coverage
- All tests MUST succeed
- All tests MUST be isolated and idempotent
- MUST enforce 1-second timeout on EACH test via attributes or configuration to detect accidental external calls
Mocking policy:
- Mock EXTERNAL calls ONLY: HTTP clients, API clients, SQL connections, message queues
- Do NOT mock regular classes that can be created and pre-configured
- Write code that is easily mockable
- NEVER use actual servers in unit tests
Scenario testing — required for high-complexity or high-level code (services, orchestrators):
- Step-by-step scenario explanation in comment at test start
- Explicit setup and expectations
- Pre-configured repositories or mocks
- Call methods in proper order to simulate state progression
- MUST create sequence diagram with all parties for each complex or scenario test to clearly show responsibilities
Infrastructure:
- Kill all existing servers that may have been started previously before running tests
