node.js測試是否在不使用超時的情況下使用sinon.js發出了事件

Question

我試圖弄清楚當異步發出的事件發出時如何使用sinon.js進行測試？

到目前為止，我正在做的是設置一個超時，在該超時中，我知道事件將被意外發出，但這很丑陋，可能會加總測試運行的總時間，我不想這樣做：

it('check that event was called', function(done) {
    ...
    var spy = sinon.spy();
    var cbSpy = sinon.spy();
    obj.on('event', spy);
    obj.func(cbSpy); // emits event 'event' asynchronously and calls cbSpy after it was emitted
    setTimeout(function() {
        sinon.assert.calledOnce(spy, 'event "event" should be emitted once');
        sinon.assert.calledOnce(cbSpy, 'func() callback should be called once'); // won't work since the callback will be called only after the event has been emitted and all event listeners finished
    }, 1000);
});

Answer 1

可以在不使用Sinon的情況下進行刺探（這里確實不需要它）。

it('check that event was called', function(done) {
    var callbackCalled = false;
    var eventCalled = false;

    var checkIfDone() {
      if (callbackCalled && eventCalled) {
        done();
      }
    }

    var callbackSpy = function () {
      callbackCalled = true;
      checkIfDone();
    }

    var eventSpy = function () {
      // Spy was called.
      // Add assertions for the arguments that are passed if you want.
      eventCalled = true;
      checkIfDone();
    };

    obj.on('event', eventSpy);
    // emits event 'event' and invokes callback after it was emitted
    obj.func(callbackSpy); 
});

最好一次只測試一件事。

it('should emit `event`', function(done) {
    var callback = function () {}

    var eventSpy = function () {
      // Spy was called.
      // Add assertions for the arguments that are passed if you want.
      done()        
    };

    obj.on('event', eventSpy);
    // emits event 'event' and invokes callback after it was emitted
    obj.func(callback); 
});

it('should invoke the callback', function(done) {
    var callback = function () {
      // Callback was called.
      // Add assertions for the arguments that are passed if you want.
      done()        
    }

    obj.func(callback); 
});

無論哪種情況，異步過程完成后都將進行測試。 我將使用第二個示例，因為這意味着您可以一次專注於一件事，並且測試代碼更加簡潔。