Question

我想用Mocha测试异步代码。

我遵循了本教程testing-promises-with-mocha。最后，它说最好的方法是异步/等待。

以下是我的代码，我打算将setTimeout设置为比Mocha默认设置更长。

describe('features', () => {
  it('assertion success', async() => {
    const resolvingPromise = new Promise( resolve => {
      setTimeout(() => {
        resolve('promise resolved')
      }, 3000)
    })

    const result = await resolvingPromise
    expect(result).to.equal('promise resolved')
  })
})

摩卡给我以下错误：

Error: Timeout of 2000ms exceeded. For async tests and hooks, 
ensure "done()" is called; if returning a Promise, ensure it resolves...

如何解决该错误？简单设置mocha --timeout 10000更长？

感谢您的时间！

Mocha: 5.2.0
Chai: 4.2.0

Answer 1

对于异步测试，您应该调用done()回调。

describe('features', () => {
  it('assertion success', async(done) => { // pass done here
    const resolvingPromise = new Promise( resolve => {
      setTimeout(() => {
        resolve('promise resolved')
      }, 3000)
    })

    const result = await resolvingPromise
    expect(result).to.equal('promise resolved')
    done() // invoke at end
  })
})

Answer 2

Mocha具有超时控件。 Mocha docs

语法是：

it('should take less than 500ms', function(done) {
  this.timeout(5000); // 5 seconds
  setTimeout(done, 3000);
});

您的示例：

describe('features', () => {
  it('assertion success', async (done) => {
    this.timeout(5000);
    const resolvingPromise = new Promise(resolve => {
      setTimeout(() => resolve('promise resolved'), 3000)
    });

    const result = await resolvingPromise();
    expect(result).to.equal('promise resolved');
    done();
  });
});

摩卡异步/等待测试失败，超时

2 个答案: