如何构造异步功能的测试? [英] How do I structure tests for asynchronous functions?

问题描述

我习惯于使用像这样的标准NodeJs assert 库编写Mocha测试:

I'm accustomed to writing Mocha tests using the standard NodeJs assert library like this:

describe('Some module', () => {
   var result = someCall();
   it('Should <something>', () => {
      assert.ok(...);
   });
})

但是现在我的电话返回了一个承诺...所以我要写:

but now my call returns a promise... so I want to write:

describe('Some module', async () => {
   var result = await someCall();
   it('Should <something>', () => {
      assert.ok(...);
   });
})

但是它不起作用.我的测试根本没有运行.奇怪的是，

but it doesn't work. My tests don't run at all. Curiously,

describe('Some module', async () => {
   it('Should <something>', () => {
      var result = await someCall();
      assert.ok(...);
   });
})

工作正常，但问题是我想打一个电话并对它进行很多测试，所以我想在it()调用之外打这个电话

works fine but the problem is that I want to make a single call and run many tests against it, so I want to make the call outside the it() calls

我如何使其工作?

和请不推荐柴.我想使用标准的断言库

and please don't recommend Chai. I want to use the standard assert library

推荐答案

before接受async函数，因此您可以在测试运行之前获取result并将其用于测试中，如下所示:

before accepts an async function so you can get the result before your tests run and use it in your tests like this:

const assert = require('assert');

const someCall = () => Promise.resolve('hi');

describe('Some module', () => {
  let result;

  before(async () => {
    result = await someCall();
  });

  it('Should <something>', () => {
    assert.equal(result, 'hi');  // Success!
  });
});

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