vitest-dev

A Claude Code skill for producing high-signal, low-flake, fast Vitest suites (TypeScript + Next.js 16) and for shaping Vitest configuration for optimal local DX and CI throughput.

Core outcomes

1. Correctness first: tests encode business behavior (not implementation details).
2. Deterministic: no network, no clocks, no global leakage, no order dependencies.
3. Fast:
   • fast feedback locally (watch mode + smart filtering)
   • scalable CI (parallel workers + sharding + cache + machine-readable reports)
4. Actionable failures: failures localize root cause quickly.

Default operating procedure

When asked to add or improve tests:

1. Map the unit under test
   • Identify public API / observable behavior