How to run backend unit tests in Replit

1# For Node.js (Express.js) projects:
2npm install --save-dev jest supertest
3
4# For Python (Flask) projects:
5pip install pytest requests

1{
2  "scripts": {
3    "test": "jest --verbose --forceExit",
4    "test:watch": "jest --watch",
5    "start": "node index.js"
6  },
7  "jest": {
8    "testEnvironment": "node",
9    "testMatch": ["**/__tests__/**/*.js", "**/*.test.js"]
10  }
11}

1// app.js - Express configuration (exported for testing)
2const express = require('express');
3const cors = require('cors');
4const app = express();
5
6app.use(cors());
7app.use(express.json());
8
9app.get('/api/health', (req, res) => {
10  res.json({ status: 'ok' });
11});
12
13app.post('/api/users', (req, res) => {
14  const { email, name } = req.body;
15  if (!email || !name) {
16    return res.status(400).json({ error: 'Email and name are required' });
17  }
18  res.status(201).json({ id: Date.now(), email, name });
19});
20
21app.get('/api/users/:id', (req, res) => {
22  const { id } = req.params;
23  if (id === '0') {
24    return res.status(404).json({ error: 'User not found' });
25  }
26  res.json({ id, email: 'test@example.com', name: 'Test User' });
27});
28
29module.exports = app;
30
31// index.js - Server startup (not imported by tests)
32const app = require('./app');
33const PORT = process.env.PORT || 3000;
34app.listen(PORT, '0.0.0.0', () => {
35  console.log(`Server running on port ${PORT}`);
36});

1// __tests__/api.test.js
2const request = require('supertest');
3const app = require('../app');
4
5describe('Health Check', () => {
6  test('GET /api/health returns 200 with status ok', async () => {
7    const response = await request(app).get('/api/health');
8    expect(response.status).toBe(200);
9    expect(response.body.status).toBe('ok');
10  });
11});
12
13describe('User API', () => {
14  test('POST /api/users creates a user with valid data', async () => {
15    const response = await request(app)
16      .post('/api/users')
17      .send({ email: 'new@example.com', name: 'New User' });
18    expect(response.status).toBe(201);
19    expect(response.body).toHaveProperty('id');
20    expect(response.body.email).toBe('new@example.com');
21  });
22
23  test('POST /api/users returns 400 when email is missing', async () => {
24    const response = await request(app)
25      .post('/api/users')
26      .send({ name: 'No Email User' });
27    expect(response.status).toBe(400);
28    expect(response.body.error).toBe('Email and name are required');
29  });
30
31  test('GET /api/users/:id returns user data', async () => {
32    const response = await request(app).get('/api/users/123');
33    expect(response.status).toBe(200);
34    expect(response.body).toHaveProperty('email');
35  });
36
37  test('GET /api/users/0 returns 404 for non-existent user', async () => {
38    const response = await request(app).get('/api/users/0');
39    expect(response.status).toBe(404);
40    expect(response.body.error).toBe('User not found');
41  });
42});

1# Run all tests
2npm test
3
4# Run tests in watch mode (re-runs on file changes)
5npm run test:watch
6
7# Run a specific test file
8npx jest __tests__/api.test.js
9
10# Run tests matching a pattern
11npx jest --testPathPattern="user"

1[deployment]
2run = ["sh", "-c", "node index.js"]
3build = ["sh", "-c", "npm install && npm test && npm run build"]
4deploymentTarget = "cloudrun"