javascript 使用 Moxios 模拟 Axios 调用以测试 API 调用

Mocking Axios calls using Moxios in order to test API calls

提问by César Alberca

I have the following custom Axios instance:

我有以下自定义 Axios 实例：

import axios from 'axios'

export const BASE_URL = 'http://jsonplaceholder.typicode.com'

export default axios.create({
  baseURL: BASE_URL
})

With the corresponding service:

配合相应的服务：

import http from './http'

export async function fetchUserPosts(id) {
  const reponse = await http.get(`/users/${id}/posts`)
  return reponse.data
}

And this is the test for said service:

这是对上述服务的测试：

import moxios from 'moxios'
import sinon from 'sinon'
import http from '@/api/http'
import { fetchUserPosts } from '@/api/usersService'

describe('users service', () => {
  beforeEach(() => {
    moxios.install(http)
  })

  afterEach(() => {
    moxios.uninstall(http)
  })

  it('fetches the posts of a given user', (done) => {
    const id = 1
    const expectedPosts = ['Post1', 'Post2']

    moxios.stubRequest(`/users/${id}/posts`, {
      status: 200,
      response: expectedPosts
    })

    const onFulfilled = sinon.spy()
    fetchUserPosts(1).then(onFulfilled)

    moxios.wait(() => {
      expect(onFulfilled.getCall(0).args[0].data).toBe(expectedPosts)
      done()
    })
  })
})

Which when executed using Karma + Jasmine raises the following error:

使用 Karma + Jasmine 执行时会引发以下错误：

Uncaught TypeError: Cannot read property 'args' of null thrown

What I would like to test is that when the endpoint /users/{id}/postsis hit a mocked response is sent back. All this while using my custom axios instance http.

我想测试的是，当端点/users/{id}/posts被击中时，会发回模拟响应。所有这些都是在使用我的自定义 axios 实例时http。

I've tried stubbing as the first example of the documentation of moxios shows. However I don't think that fits my use case, as I would like to check that the request is formed correctly in my service.

我已经尝试将 stubbing 作为 moxios 文档的第一个示例显示。但是我认为这不适合我的用例，因为我想检查请求是否在我的服务中正确形成。

I've also tried with the following code, which works as expected, however I would like to test my service (which the following code does not do):

我还尝试了以下代码，它按预期工作，但是我想测试我的服务（以下代码不这样做）：

import axios from 'axios'
import moxios from 'moxios'
import sinon from 'sinon'

describe('users service', () => {
  beforeEach(() => {
    moxios.install()
  })

  afterEach(() => {
    moxios.uninstall()
  })

  it('fetches the posts of a given user', (done) => {
    const id = 1
    const expectedPosts = ['Post1', 'Post2']

    moxios.stubRequest(`/users/${id}/posts`, {
      status: 200,
      response: expectedPosts
    })

    const onFulfilled = sinon.spy()
    axios.get(`/users/${id}/posts`).then(onFulfilled)

    moxios.wait(() => {
      expect(onFulfilled.getCall(0).args[0].data).toBe(expectedPosts)
      done()
    })
  })
})

Any ideas on how could I fix the error?

关于如何修复错误的任何想法？

回答by Elmer Dantas

I know that is an old question but as I came across with it with the same problem, I'll post my approach:

我知道这是一个老问题，但当我遇到同样的问题时，我将发布我的方法：

You don't need to use sinonin this case, as you have an instance of axios, use it to configure moxios(as you already have done)

sinon在这种情况下您不需要使用，因为您有一个 实例axios，使用它来配置moxios（正如您已经完成的那样）

beforeEach(() => {
    moxios.install(http)
  })
  afterEach(() => {
    moxios.uninstall(http)
})

then you test your method like this:

然后你像这样测试你的方法：

it('test get', async () => {
     const expectedPosts = ['Post1', 'Post2']

     moxios.wait(() => {
          const request = moxios.requests.mostRecent()
          request.respondWith({ status: 200, response: expectedPosts }) //mocked response
     })

     const result = await fetchUserPosts(1)
     console.log(result) // ['Post1','Post2'] 
     expect(result).toEqual(expectedPosts)
})

That's it.

而已。

Regards

问候