在 Javascript 中模拟被测模块/函数的依赖关系 [英] Mocking dependency of module/function under test in Javascript

问题描述

假设我想测试以下内容，例如:

Let's say I want to test the following for example:

import {fetchResourceFromBackend} from './myfetch';

const fetchSomething = (dispatch) => {

  dispatch(2);

  return fetchResourceFromBackend('/api/abc').then( result => {
    dispatch(3);
  });
};

fetchResourceFromBackend 是一些复杂的函数.我如何测试这个，并且不受 fetchResourceFromBackend 代码的影响(任何模式或工具推荐，我使用 mocha 和 sinon 但无法实现)?

fetchResourceFromBackend is some complicated function. How can I test this, and not be affected by fetchResourceFromBackend code (any pattern or tool recommendations, I use mocha and sinon but cannot achieve)?

将 fetchResourceFromBackend 作为参数提供给 fetchSomething 是我唯一的选择吗?

Is my only option to provide fetchResourceFromBackend as an argument to fetchSomething so I can mock it?

推荐答案

Using jest 正如@Mikhail 建议的那样，我是这样解决的:

Using jest as @Mikhail suggested I solved like this:

// test/something-test.js

import {myFetch} from '../_mocks_/utilities';

jest.doMock('modules/utilities', () =>({
    myFetch: myFetch
}));


const {fetchSomething} = require('modules/something');

describe('#fetchSomething', ...

这里的 fetchSomething 是被测试的函数，它内部依赖于 'modules/utilities' 中的 myFetch 函数.我用 '../_mocks_/utilities' 中的 myFetch 来模拟这种依赖.

Here fetchSomething is function under test that has internal dependency on myFetch function from 'modules/utilities'. I mock that dependency with myFetch from '../_mocks_/utilities'.

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