API Testing

Expert knowledge for testing HTTP APIs with Supertest (TypeScript/JavaScript) and httpx/pytest (Python).

TypeScript/JavaScript (Supertest)

Installation

# Using Bun
bun add -d supertest @types/supertest

# or: npm install -D supertest @types/supertest

Basic Setup

import { describe, it, expect } from 'vitest'
import request from 'supertest'
import { app } from './app'

describe('API Tests', () => {
  it('returns health status', async () => {
    const response = await request(app)
      .get('/api/health')
      .expect(200)

    expect(response.body).toEqual({ status: 'ok' })
  })

  it('creates a user', async () => {
    const response = await request(app)
      .post('/api/users')
      .send({ name: 'John Doe', email: '[email protected]' })
      .expect(201)

    expect(response.body).toMatchObject({
      id: expect.any(Number),
      name: 'John Doe',
    })
  })

  it('validates required fields', async () => {
    await request(app)
      .post('/api/users')
      .send({ name: 'John Doe' })
      .expect(400)
  })
})

Request Methods

// GET
await request(app).get('/api/users').expect(200)

// POST with body
await request(app)
  .post('/api/users')
  .send({ name: 'John' })
  .expect(201)

// PUT
await request(app)
  .put('/api/users/1')
  .send({ name: 'Jane' })
  .expect(200)

// DELETE
await request(app).delete('/api/users/1').expect(204)

Headers and Query Parameters

// Set headers
await request(app)
  .get('/api/protected')
  .set('Authorization', 'Bearer token123')
  .expect(200)

// Query parameters
await request(app)
  .get('/api/users')
  .query({ page: 1, limit: 10 })
  .expect(200)

Authentication Testing

describe('Authentication', () => {
  let authToken: string

  beforeAll(async () => {
    const response = await request(app)
      .post('/api/auth/login')
      .send({ email: '[email protected]', password: 'password123' })
      .expect(200)

    authToken = response.body.token
  })

  it('accesses protected endpoint', async () => {
    await request(app)
      .get('/api/protected')
      .set('Authorization', `Bearer ${authToken}`)
      .expect(200)
  })

  it('rejects without token', async () => {
    await request(app).get('/api/protected').expect(401)
  })
})