Testing

Current Test Stack

• Runner: Vitest (npm test)
• Config: vitest.config.ts
  • Node test environment
  • @ alias resolves to src

Current Coverage (High-Value Tests)

Unit tests (src/lib/*)

1. src/lib/rules.test.ts
   • Verifies pipeline execution order and rounding behavior (multiply -> percentAdjust -> roundNearest9).
2. src/lib/tier-pricing-policy.test.ts
   • Verifies circular dependency handling in tier computation while independent tiers still compute.
3. src/lib/products-csv.test.ts
   • Verifies CSV header alias handling (cost accepted as cogs) and product field mapping.

API route tests (src/app/api/*)

1. src/app/api/rulesets/route.test.ts
   • POST /api/rulesets returns 400 when ruleset id is missing.
2. src/app/api/rule-assignments/route.test.ts
   • PUT /api/rule-assignments returns 400 when an assignment references an unknown ruleset.
3. src/app/api/products/upload/route.test.ts
   • Returns 400 for multipart uploads missing the file field.
   • Verifies raw CSV uploads call storage and return Cache-Control: no-store.

How to Run Tests

npm test

For local quality checks:

npm test
npm run lint
npx tsc --noEmit

Testing Approach

• Prioritize logic-heavy pure modules and API validation boundaries first.
• Keep tests deterministic by mocking S3/storage adapters in route tests.
• Add E2E later for critical user flows (ruleset save/assign/export) once unit+route coverage is stable.