Axios 中的单元测试拦截器逻辑

Question

我在 Axios 中设置了一个拦截器，如果初始 HTTP 响应是 401，它将刷新令牌，然后重试调用。

我正在尝试通过模拟 Axios 请求以返回 401，然后返回有效响应（请参阅下面的简化版本）并断言它被调用两次来对该逻辑进行单元测试。

我的问题是因为我在模拟请求，所以拦截器似乎没有运行。我没有重试请求，而是返回了stubAuthError。

有什么方法可以实现我所追求的，或者有更好的方法来测试它吗？

index.js

const axios = require('axios');

axios.interceptors.response.use(
  response => response,
  error => {
    const status = error.response ? error.response.status : null;

    if (status === 401) {
      return makeRequest();
    } else {
      return Promise.reject(error);
    }
  }
);

async function makeRequest() {
  return axios.request('url');
}

module.exports = {
  makeRequest
};

index.spec.js

const axios = require('axios');

const { makeRequest } = require('./index');

const stubAuthError = { response: { status: 401 } };
const stubResponse = { data: { foo: 'bar' } };

it('should make the request twice', async () => {
  expect.assertions(1);

  axios.request = jest.fn();
  axios.request
    .mockRejectedValueOnce(stubAuthError)
    .mockResolvedValueOnce(stubResponse);

  try {
    await makeRequest();
  } catch (error) {}

  expect(axios.request).toHaveBeenCalledTimes(2);
});

Answer 1

拦截器是按顺序注册的，类似于express中间件，

您可以访问axios.interceptors.request 和axios.interceptors.response 以访问在拦截器管理器上注册的单元测试功能

例如：

在我的main.js：

let axios = require('axios');

axios.interceptors.response.use(
  response => response,
  error => {
    const status = error.response ? error.response.status : null;

    if (status === 401) {
      return makeRequest();
    } else {
      return Promise.reject(error);
    }
  }
);

async function makeRequest() {
  return axios.request('https://randomuser.me/api/');
}

module.exports = {
  makeRequest
};

在我的main.test.js：

let axios = require('axios');

// 
// based on your question, we don't want to test "makeRequest"
// so, I'm loading the file only to register the interceptors
//
require('./main');

let stubAuthError = { response: { status: 401 } };
let stubExceptionError = { response: { status: 500 } };
let stubResponse = { data: { foo: 'bar' } };

test("interceptor fulfilled", () => {
  let res = axios.interceptors.response.handlers[0].fulfilled(stubResponse);
  expect(res).toEqual(stubResponse);
});

test("interceptor rejected => makeRequest", () => {
  let originalAxiosRequest = axios.request;

  // this fn will be called by "makeRequest"
  axios.request = jest.fn();

  axios.interceptors.response.handlers[0].rejected(stubAuthError);

  expect(axios.request).toHaveBeenCalledTimes(1);

  axios.request = originalAxiosRequest;
});

test("interceptor rejected => exception", async () => {
  await expect(axios.interceptors.response.handlers[0].rejected(stubExceptionError)).rejects.toEqual(stubExceptionError)
});