Qa Backend Mean

Purpose

Write and run backend tests for MEAN stack applications. Cover API endpoint testing with Supertest, MongoDB operation testing with in-memory database, authentication flow testing, middleware testing, and integration testing.

Key Patterns

Test Structure

• server/__tests__/setup.js — Global test setup (DB connection, cleanup)
• server/__tests__/fixtures/ — Test data factories
• server/__tests__/integration/ — API endpoint tests
• server/__tests__/unit/models/ — Model and utility tests
• server/__tests__/middleware/ — Middleware tests

Test Setup (MongoDB Memory Server)

• Use MongoMemoryServer for isolated test database
• beforeAll: create memory server, connect mongoose
• afterAll: disconnect, stop server
• afterEach: clear all collections (full isolation between tests)
• Set NODE_ENV=test and JWT_SECRET=test-secret

Integration Test Pattern (Supertest)

• Import app (not listening server) from server.js
• Use request(app).get/post/put/delete to test endpoints
• Chain .send() for body, .set() for headers, .expect() for status
• Assert: response status, body shape, key field values, side effects (DB state)

Fixture Factory Pattern

• Default valid data objects for each model
• createX() function that saves to DB and returns document
• getAuthToken() helper: creates user + signs JWT, returns { user, token }
• Override defaults with spread: createUser({ role: 'admin' })

Auth Testing Pattern

• Test register: success (201), duplicate email (409), validation errors (422)
• Test login: success (200 + token), wrong password (401), non-existent user (404)
• Test protected routes: with valid token (200), without token (401), with invalid token (401)
• Test role-based: authorized role (200), unauthorized role (403)

Conventions

• Jest as test runner with --detectOpenHandles --forceExit flags
• mongodb-memory-server for isolated test DB — NEVER test against real database
• Supertest for HTTP integration tests — test full request/response cycle
• Test file naming: {name}.test.js
• Each test file: describe block per endpoint, it blocks per scenario
• Test happy path first, then error cases, then edge cases
• Coverage: aim for 80%+ on controllers and middleware, 100% on auth flow
• Export app (not listening server) from server.js for Supertest

Knowledge Strategy

• Patterns to capture: Test patterns for common MEAN features (CRUD, auth, file upload, pagination)
• Examples to collect: Complete test files for standard endpoints, fixture factories
• Update permission: Agents may freely add/update files in references/. Changes to SKILL.md or scripts/ require user approval.