What is your strategy for automated backend testing in Node.js?

In Simple Words:

• Unit Testing: Vitest or Jest for fast isolated tests of business logic and domain services with mocked repository dependencies.
• Integration Testing: Supertest against real Fastify/Express HTTP servers, paired with Testcontainers to spin up ephemeral PostgreSQL and Redis Docker containers in CI, verifying real queries and migrations.
• Database Rollbacks: Running test transactions with rollbacks or schema isolation to ensure complete test hermeticity.

// Supertest integration test against Express/Fastify:
import request from 'supertest';
import { app } from '../src/app';

describe('GET /health', () => {
  it('should return 200 OK with runtime status', async () => {
    const res = await request(app).get('/health');
    expect(res.status).toBe(200);
    expect(res.body.status).toBe('ok');
  });
});