mercadodevida/work/artifacts/F-018/implementer.md

Implementer — F-018 Cart module

Summary

Implemented authenticated cart persistence that stores only product id, variant id and quantity, and recalculates totals/availability through injected PricingService and InventoryService on every read.

Files changed

• project/migrations/013_cart.js
• project/src/app/build-app.ts
• project/src/app/tests/cart.itest.ts
• project/src/modules/cart/**
• project/src/modules/inventory/index.ts
• project/src/modules/pricing/index.ts

Acceptance evidence

• AC1 price changed after add: cart.itest.ts adds item at one price, changes server price, then GET /cart returns recalculated totals.
• AC2 out of stock: cart.itest.ts sets stock to zero and verifies cart item is flagged unavailable.
• AC3 client price ignored: cart.itest.ts sends bogus price fields; response uses server-side pricing and cart_items has no price/tax/stock columns.
• verify.sh: passed.

Commands run

• cd project && npm run lint — passed
• cd project && npm run typecheck — passed
• cd project && npm run build — passed
• cd project && npm test — passed; DB tests skipped without TEST_DATABASE_URL
• cd project && TEST_DATABASE_URL='postgres://mdv:mdv_dev_only@localhost:5432/mdv_test' npm run test:integration -- cart.itest migrations.itest — passed; 10 files, 42 tests
• ./scripts/verify.sh — passed

Notes

• Cart routes require authentication; no guest cart persistence in this slice.
• Cart imports only public pricing/inventory interfaces, not internals.
• Added public service factories in inventory/pricing module indexes for composition-root injection.