Testing

Testing is important. In actuality, it is easy to test Hono's applications. The way to create a test environment differs from each runtime, but the basic steps are the same. In this section, let's test with Cloudflare Workers and Vitest.

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Cloudflare recommends using Vitest with @cloudflare/vitest-pool-workers. For more details, please refer to Vitest integration in the Cloudflare Workers docs.

Request and Response

All you do is create a Request and pass it to the Hono application to validate the Response. And, you can use app.request the useful method.

TIP

For a typed test client see the testing helper.

For example, consider an application that provides the following REST API.

app.get('/posts', (c) => {
  return c.text('Many posts')
})

app.post('/posts', (c) => {
  return c.json(
    {
      message: 'Created',
    },
    201,
    {
      'X-Custom': 'Thank you',
    }
  )
})

Make a request to GET /posts and test the response.

describe('Example', () => {
  test('GET /posts', async () => {
    const res = await app.request('/posts')
    expect(res.status).toBe(200)
    expect(await res.text()).toBe('Many posts')
  })
})

To make a request to POST /posts, do the following.

test('POST /posts', async () => {
  const res = await app.request('/posts', {
    method: 'POST',
  })
  expect(res.status).toBe(201)
  expect(res.headers.get('X-Custom')).toBe('Thank you')
  expect(await res.json()).toEqual({
    message: 'Created',
  })
})

To make a request to POST /posts with JSON data, do the following.

test('POST /posts', async () => {
  const res = await app.request('/posts', {
    method: 'POST',
    body: JSON.stringify({ message: 'hello hono' }),
    headers: new Headers({ 'Content-Type': 'application/json' }),
  })
  expect(res.status).toBe(201)
  expect(res.headers.get('X-Custom')).toBe('Thank you')
  expect(await res.json()).toEqual({
    message: 'Created',
  })
})

To make a request to POST /posts with multipart/form-data data, do the following.

test('POST /posts', async () => {
  const formData = new FormData()
  formData.append('message', 'hello')
  const res = await app.request('/posts', {
    method: 'POST',
    body: formData,
  })
  expect(res.status).toBe(201)
  expect(res.headers.get('X-Custom')).toBe('Thank you')
  expect(await res.json()).toEqual({
    message: 'Created',
  })
})

You can also pass an instance of the Request class.

test('POST /posts', async () => {
  const req = new Request('http://localhost/posts', {
    method: 'POST',
  })
  const res = await app.request(req)
  expect(res.status).toBe(201)
  expect(res.headers.get('X-Custom')).toBe('Thank you')
  expect(await res.json()).toEqual({
    message: 'Created',
  })
})

In this way, you can test it as like an End-to-End.

Env

To set c.env for testing, you can pass it as the 3rd parameter to app.request. This is useful for mocking values like Cloudflare Workers Bindings:

const MOCK_ENV = {
  API_HOST: 'example.com',
  DB: {
    prepare: () => {
      /* mocked D1 */
    },
  },
}

test('GET /posts', async () => {
  const res = await app.request('/posts', {}, MOCK_ENV)
})