node.js - Jest : tests can't fail within setImmediate or process. nextTick回调

我正在尝试为需要在其componentWillMount方法中完成异步操作的React组件编写测试。 componentWillMount调用作为prop传递的函数，该函数返回promise，然后在测试中模拟该函数。

这可以正常工作，但是如果在调用setImmediate或process.nextTick的过程中测试失败，则Jest不会处理该异常，并且该异常会过早退出。在下面，您可以看到我什至试图捕获此异常，但无济于事。

我如何在Jest中使用setImmediate或nextTick之类的东西？对于这个问题，可以接受的答案是我尝试实现的失败:React Enzyme - Test `componentDidMount` Async Call。

it('should render with container class after getting payload', (done) => {
  let resolveGetPayload;
  let getPayload = function() {
    return new Promise(function (resolve, reject) {
      resolveGetPayload = resolve;
    });
  }
  const enzymeWrapper = mount(<MyComponent getPayload={getPayload} />);

  resolveGetPayload({
    fullname: 'Alex Paterson'
  });

  try {
    // setImmediate(() => {
    process.nextTick(() => {
      expect(enzymeWrapper.hasClass('container')).not.toBe(true); // Should and does fail
      done();
    });
  } catch (e) {
    console.log(e); // Never makes it here
    done(e);
  }
});

笑话v18.1.0

Node v6.9.1

最佳答案

另一个可能更干净的解决方案，使用异步/等待并利用笑话/摩卡(mocha)的能力来检测返回的 promise :

function currentEventLoopEnd() {
  return new Promise(resolve => setImmediate(resolve));
}

it('should render with container class after getting payload', async () => {
  let resolveGetPayload;
  let getPayload = function() {
    return new Promise(function (resolve, reject) {
      resolveGetPayload = resolve;
    });
  }
  const enzymeWrapper = mount(<MyComponent getPayload={getPayload} />);

  resolveGetPayload({
    fullname: 'Alex Paterson'
  });

  await currentEventLoopEnd(); // <-- clean and clear !

  expect(enzymeWrapper.hasClass('container')).not.toBe(true);
});

关于node.js - Jest : tests can't fail within setImmediate or process. nextTick回调，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/41792927/