Vitest, shared config in tooling/vitest/. API tests use createTestCaller() for authed tRPC calls. Run via root pnpm test—scripts/run-tests.sh routes DB-touching suites to the zrm_test database. Coverage v8 (text + lcov). Running one package has two traps: pnpm test -- --filter=… forwards --filter to every package's vitest, and a bare pnpm --filter … test skips the wrapper and writes to the dev zrm DB. Correct invocation in services/api/CLAUDE.md.