javascript - Chai/诗农 : How to spy on the return value of a promise returned by a function?

Question

我正在为 onAfterDelete 设置单元+集成测试:

Assessment.onAfterDelete = async () => {
  ...

  // Log assessment deleted
  await Activity.create({
    assessmentId,
    activityTypeId: ACTIVITY_TYPE.ASSESSMENT_DELETED,
  }, options);

  ...
};

虽然我知道如何测试 Activity.create 被调用，但我真的很想测试 Activity 是否已成功创建。

如果它不是异步的，那么我会使用Sinon.spy，如下所示:

it('logs the assessment deleted activity', async () => {
  sinon.spy(Activity, 'create');
  await Assessment.onAfterDelete(...);
  expect(Activity.create).returned({
    activityTypeId: ACTIVITY_TYPE.ASSESSMENT_DELETED,
    assessmentId: standardAssessmentData.id,
  });
  Activity.create.restore();
});

当然，这不起作用，因为 Activity.create 返回一个 Promise。

在谷歌上搜索了 Chai 和 Sinon 的各种风格并 promise 了一个小时后，我还没有找到这个用例的解决方案。如何测试这个返回值？

Answer 1

您可以使用chai-as-promised :

const chai           = require('chai');
const chaiAsPromised = require('chai-as-promised');
chai.use(chaiAsPromised);

it('logs the assessment deleted activity', async () => {
  sinon.spy(Activity, 'create');
  await Assessment.onAfterDelete();

  // Make sure `Activity.create()` got called.
  expect(Activity.create.called).to.be.true;

  // Check the resolved value.
  await expect(Activity.create.firstCall.returnValue).to.eventually.equal({
    activityTypeId : ACTIVITY_TYPE.ASSESSMENT_DELETED,
    assessmentId   : standardAssessmentData.id,
  });

  // Restore the original.
  Activity.create.restore();
});