| name | test-design-and-coverage |
| description | Use to design tests for new behavior, bug fixes, refactors, APIs, migrations, security controls, concurrency, failure handling, observability, accessibility, or performance-sensitive code. |
Test Design and Coverage Skill
Workflow
- Convert acceptance criteria and invariants into a requirement-to-test matrix.
- Select the lowest-cost test layer that proves each behavior without coupling to implementation.
- Reuse existing fixtures and test utilities.
- Cover expected, boundary, malformed, denied, timeout, retry, duplicate, concurrency, cleanup, and recovery behavior according to risk.
- Control nondeterminism through injected clocks/randomness, fixed seeds, ephemeral resources, and observable synchronization.
- Verify telemetry and redaction when operational behavior is part of the contract.
- Run focused tests, then broader suites and coverage/mutation tools supported by the repository.
- Report remaining untested risks rather than manufacturing low-value tests.
Test quality bar
Every test must have a meaningful failure mode, deterministic setup, explicit assertion, clear ownership, bounded runtime, and cleanup. Avoid sleeps, private-method mocks, implementation duplication, and broad snapshots that conceal semantics.
