hono-testing

What this skill does

# Hono Testing Patterns

## Overview

Hono provides a simple testing approach: create a Request, pass it to your app, and validate the Response. The framework includes a typed test client for even better DX.

**Key Features**:
- Simple `app.request()` API
- Typed test client with full inference
- Environment mocking for Workers
- Works with Vitest, Jest, or any test runner

## When to Use This Skill

Use Hono testing when:
- Writing unit tests for route handlers
- Integration testing API endpoints
- Testing middleware behavior
- Mocking Cloudflare Workers bindings
- Validating request/response cycles

## Basic Testing

### Using app.request()

```typescript
import { Hono } from 'hono'
import { describe, it, expect } from 'vitest'

const app = new Hono()

app.get('/hello', (c) => c.text('Hello!'))
app.get('/json', (c) => c.json({ message: 'Hello' }))

describe('Basic routes', () => {
  it('should return text', async () => {
    const res = await app.request('/hello')

    expect(res.status).toBe(200)
    expect(await res.text()).toBe('Hello!')
  })

  it('should return JSON', async () => {
    const res = await app.request('/json')

    expect(res.status).toBe(200)
    expect(res.headers.get('Content-Type')).toContain('application/json')
    expect(await res.json()).toEqual({ message: 'Hello' })
  })
})
```

### Request Options

```typescript
// GET with query params
const res = await app.request('/search?q=hono&page=1')

// POST with JSON body
const res = await app.request('/users', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({ name: 'Alice', email: '[email protected]' })
})

// POST with form data
const formData = new FormData()
formData.append('name', 'Alice')
formData.append('email', '[email protected]')

const res = await app.request('/users', {
  method: 'POST',
  body: formData
})

// With custom headers
const res = await app.request('/protected', {
  headers: {
    'Authorization': 'Bearer token123',
    'X-Custom-Header': 'value'
  }
})

// DELETE request
const res = await app.request('/users/123', {
  method: 'DELETE'
})
```

## Typed Test Client

The test client provides full type inference:

```typescript
import { Hono } from 'hono'
import { testClient } from 'hono/testing'
import { describe, it, expect } from 'vitest'

const app = new Hono()
  .get('/users', (c) => c.json({ users: [] }))
  .post('/users', async (c) => {
    const body = await c.req.json()
    return c.json({ id: '1', ...body }, 201)
  })
  .get('/users/:id', (c) => {
    return c.json({ id: c.req.param('id'), name: 'Alice' })
  })

describe('Users API', () => {
  const client = testClient(app)

  it('should list users', async () => {
    const res = await client.users.$get()

    expect(res.status).toBe(200)
    const data = await res.json()
    expect(data.users).toEqual([])
  })

  it('should create user', async () => {
    const res = await client.users.$post({
      json: { name: 'Alice', email: '[email protected]' }
    })

    expect(res.status).toBe(201)
    const data = await res.json()
    expect(data.name).toBe('Alice')
  })

  it('should get user by id', async () => {
    const res = await client.users[':id'].$get({
      param: { id: '123' }
    })

    expect(res.status).toBe(200)
    const data = await res.json()
    expect(data.id).toBe('123')
  })
})
```

## Testing with Validation

```typescript
import { Hono } from 'hono'
import { zValidator } from '@hono/zod-validator'
import { z } from 'zod'

const app = new Hono()

const createUserSchema = z.object({
  name: z.string().min(1),
  email: z.string().email()
})

app.post('/users', zValidator('json', createUserSchema), async (c) => {
  const data = c.req.valid('json')
  return c.json({ id: '1', ...data }, 201)
})

describe('Validation', () => {
  it('should accept valid data', async () => {
    const res = await app.request('/users', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        name: 'Alice',
        email: '[email protected]'
      })
    })

    expect(res.status).toBe(201)
  })

  it('should reject invalid email', async () => {
    const res = await app.request('/users', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        name: 'Alice',
        email: 'invalid-email'
      })
    })

    expect(res.status).toBe(400)
  })

  it('should reject missing name', async () => {
    const res = await app.request('/users', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        email: '[email protected]'
      })
    })

    expect(res.status).toBe(400)
  })
})
```

## Mocking Environment (Cloudflare Workers)

### Mock Bindings

```typescript
import { Hono } from 'hono'

type Bindings = {
  DB: D1Database
  KV: KVNamespace
  API_KEY: string
}

const app = new Hono<{ Bindings: Bindings }>()

app.get('/data', async (c) => {
  const result = await c.env.DB.prepare('SELECT * FROM users').all()
  return c.json(result)
})

app.get('/config', (c) => {
  return c.json({ apiKey: c.env.API_KEY.slice(0, 4) + '...' })
})

describe('With mocked bindings', () => {
  // Mock D1 database
  const mockDB = {
    prepare: () => ({
      all: async () => ({ results: [{ id: 1, name: 'Alice' }] }),
      first: async () => ({ id: 1, name: 'Alice' }),
      run: async () => ({ success: true })
    })
  }

  // Mock KV namespace
  const mockKV = {
    get: async (key: string) => 'cached-value',
    put: async (key: string, value: string) => {},
    delete: async (key: string) => {}
  }

  const mockEnv: Bindings = {
    DB: mockDB as unknown as D1Database,
    KV: mockKV as unknown as KVNamespace,
    API_KEY: 'test-api-key-12345'  // pragma: allowlist secret
  }

  it('should use mocked database', async () => {
    const res = await app.request('/data', {}, mockEnv)

    expect(res.status).toBe(200)
    const data = await res.json()
    expect(data.results).toHaveLength(1)
  })

  it('should use mocked API key', async () => {
    const res = await app.request('/config', {}, mockEnv)

    const data = await res.json()
    expect(data.apiKey).toBe('test...')
  })
})
```

### Using Miniflare

For more realistic Cloudflare Workers testing:

```typescript
import { Miniflare } from 'miniflare'
import { describe, it, expect, beforeAll, afterAll } from 'vitest'

describe('With Miniflare', () => {
  let mf: Miniflare

  beforeAll(async () => {
    mf = new Miniflare({
      script: `
        import app from './src/index'
        export default app
      `,
      modules: true,
      d1Databases: ['DB'],
      kvNamespaces: ['KV']
    })
  })

  afterAll(async () => {
    await mf.dispose()
  })

  it('should work with real bindings', async () => {
    const res = await mf.dispatchFetch('http://localhost/data')
    expect(res.status).toBe(200)
  })
})
```

## Testing Middleware

```typescript
import { Hono } from 'hono'
import { createMiddleware } from 'hono/factory'

// Middleware to test
const authMiddleware = createMiddleware(async (c, next) => {
  const token = c.req.header('Authorization')?.replace('Bearer ', '')

  if (!token) {
    return c.json({ error: 'Unauthorized' }, 401)
  }

  if (token !== 'valid-token') {
    return c.json({ error: 'Invalid token' }, 403)
  }

  c.set('userId', 'user-123')
  await next()
})

const app = new Hono()

app.use('/protected/*', authMiddleware)

app.get('/protected/data', (c) => {
  const userId = c.get('userId')
  return c.json({ userId, data: 'secret' })
})

describe('Auth middleware', () => {
  it('should reject request without token', async () => {
    const res = await app.request('/protected/data')

    expect(res.status).toBe(401)
    expect(await res.json()).toEqual({ error: 'Unauthorized' })
  })

  it('should reject invalid token', async () => {
    const res = await app.request('/protected/data', {
      headers: { 'Authorization': 'Bearer inv