Team DoD: Challenge 10 BullMQ Valkey checkout integration

[Vasanthadithya-mundrathi]

Challenge

Challenge 10: Checkout with Inventory Tracking

Integration

BullMQ + Valkey checkout backend for the Valkey e-commerce demo.

What changed

• Adds a focused TypeScript checkout service under backend/checkout.
• Uses BullMQ queues backed by Valkey for inventory reservation, payment processing, order confirmation, reservation release, and delivery dispatch.
• Adds atomic Valkey Lua scripts for reserve/confirm/release inventory mutations.
• Adds idempotency keys, order persistence, order stream events, seed fixtures, docs, and focused tests.
• Keeps the existing frontend intact, with only test-environment fixes needed for reliable validation.

Validation

• cd backend/checkout && npm run build
• cd backend/checkout && npm test: 10 tests passed
• cd frontend && CI=true npm test -- --watchAll=false
• cd frontend && npm run build
• Chrome browser verification: storefront rendered at 127.0.0.1:3000 and checkout API E2E passed through the browser.

Browser E2E edge cases covered

• Missing auth returns 401 unauthorized.
• Missing Idempotency-Key returns 400 missing_idempotency_key.
• Insufficient stock returns 409 insufficient_stock without completing checkout.
• Start checkout reserves inventory and returns pending_payment.
• Idempotency replay returns the same order.
• Confirm before payment returns 409 invalid_order_state.
• Payment authorization transitions to payment_authorized.
• Confirm transitions to confirmed.
• Payment decline returns 402 payment_failed.
• Cancel declined order transitions to cancelled and releases reservation.
• Order listing returns the browser-created orders.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds a new backend/checkout service that implements a BullMQ-powered checkout workflow backed by Valkey, and updates docs/tests to support and validate it.

Changes:

• Introduces a standalone TypeScript checkout backend (Express + BullMQ + ioredis) with inventory reservation/commit via Lua + Valkey JSON.
• Adds unit/integration test suites (Vitest) for Valkey connection parsing, idempotency, auth, and end-to-end checkout flows.
• Updates frontend test setup and repository docs to accommodate the new demo backend.

Reviewed changes

Copilot reviewed 24 out of 26 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
frontend/src/setupTests.js	Adds window.matchMedia shim for Jest DOM usage.
frontend/src/App.test.js	Reworks App render test using mocks for route-level components.
backend/checkout/vitest.config.ts	Adds Vitest configuration for the checkout backend.
backend/checkout/tsconfig.json	TypeScript compiler settings for backend build output.
backend/checkout/test/unit/connection.test.ts	Unit tests for env-based Valkey connection construction.
backend/checkout/test/integration/checkout.test.ts	Integration tests for checkout flow, idempotency, auth, and inventory correctness.
backend/checkout/src/types.ts	Defines shared types for products, orders, and events.
backend/checkout/src/store.ts	Implements Valkey JSON persistence, order creation, listing, and stream event emission.
backend/checkout/src/server.ts	Express API endpoints for checkout, orders, and SSE order events.
backend/checkout/src/seed.ts	Seeds Valkey with product fixtures.
backend/checkout/src/runtime.ts	Wires config, Valkey connection, scripts, queues, and server lifecycle.
backend/checkout/src/queues.ts	Defines BullMQ queues/workers for reserve/payment/confirm/release/dispatch.
backend/checkout/src/payment.ts	Stub deterministic payment processor logic.
backend/checkout/src/inventoryScripts.ts	Lua scripts wrapper for atomic reserve/commit/release inventory mutations.
backend/checkout/src/index.ts	Service entrypoint with startup/shutdown and logging.
backend/checkout/src/ids.ts	Order ID + sortable timestamp helpers (uuidv7).
backend/checkout/src/idempotency.ts	Idempotency replay + locking using Valkey keys.
backend/checkout/src/fixtures.ts	Product fixtures for seeding/integration tests.
backend/checkout/src/errors.ts	API error type and normalization helpers.
backend/checkout/src/connection.ts	Valkey connection parsing (URL vs discrete env vars) + reachability check.
backend/checkout/src/config.ts	Loads service config (port, concurrency, TTL, queue prefix) from env.
backend/checkout/package.json	Adds backend package scripts/deps for build/dev/test/seed.
backend/checkout/README.md	Documents backend run steps, env vars, and API endpoints.
README.md	Documents optional backend usage and adds repository structure/commands.
.gitignore	Adds ignore rules for node_modules, dist, coverage, env files, etc.

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