api-testing

# API Testing

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

## Core Expertise

**API Testing Capabilities**
- **Request testing**: Headers, query params, request bodies
- **Response validation**: Status codes, headers, JSON schemas
- **Authentication**: Bearer tokens, cookies, OAuth flows
- **Error handling**: 4xx/5xx responses, validation errors
- **Integration**: Database state, external services
- **Performance**: Response times, load testing basics

## TypeScript/JavaScript (Supertest)

### Installation

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

# Using npm
npm install -D supertest @types/supertest
```

### Basic Setup with Express

```typescript
// app.ts
import express from 'express'

export const app = express()
app.use(express.json())

app.get('/api/health', (req, res) => {
  res.json({ status: 'ok' })
})

app.post('/api/users', (req, res) => {
  const { name, email } = req.body
  if (!name || !email) {
    return res.status(400).json({ error: 'Missing required fields' })
  }
  res.status(201).json({ id: 1, name, email })
})
```

```typescript
// app.test.ts
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: 'john@example.com' })
      .expect(201)

    expect(response.body).toMatchObject({
      id: expect.any(Number),
      name: 'John Doe',
      email: 'john@example.com',
    })
  })

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

    expect(response.