使用Sinon的假定时器时不会触发setTimeout

Question

我有一个类似于下面显示的测试.基本上我想测试特定方法是否会延迟.

以下示例按预期工作,即调用resolve方法并且测试通过:

it(`should delay execution by 1 second`, function () {
  const clock = sandbox.useFakeTimers();

  const p = new Promise(function (resolve) {
    setTimeout(resolve, 1000);
  });

  clock.tick(1000);

  return p;
});

但是,如果我将setTimeout包装在另一个Promise中,则决不会调用该解析:

it(`should delay execution by 1 second`, function () {
  const clock = sandbox.useFakeTimers();

  const p = Promise.resolve()
    .then(() => {
      return new Promise(function (resolve) {
        setTimeout(resolve, 1000); // resolve never gets called
      });
    });

    clock.tick(1000);

    return p;
  });

这有什么问题？

我正在使用Sinon 2.1.0和本地的承诺Node 6.9.5.

Answer 1

问题似乎是你在超时开始之前滴答作响 - 这是在你的第二个片段中的一个承诺回调中异步发生的.

这应该工作:

it(`should delay execution by 1 second`, function () {
  const clock = sandbox.useFakeTimers();

  return Promise.resolve().then(() => {
    return new Promise(function (resolve) {
      setTimeout(resolve, 1000); // resolve never gets called
      clock.tick(1000);
    });
  });
});