心跳监视器和单元测试它的方法

我有一个"服务模块"，它侦听周期性的心跳（通过socket.io），然后如果错过了心跳，则在事件总线（Backbone.Events）上发布事件。此外，如果稍后心跳恢复，则会发布事件。

我的单元测试看起来像这样：

describe('Heartbeat service', function() {
  var HeartbeatService;
  var heartbeatInterval = 1;
  //the server is expected to send heartbeats FASTER actually.
  //otherwise we risk false alarms
  jasmine.require(['services/HeartbeatService'], function(Service) {
    HeartbeatService = Service;
  });
  /*Since these tests use setInterval, it'd be erroneous to allow
    mocks to be overwritten by another test. Thus not using beforeEach()*/
  function createMocks(){
    var mockEventAggregator = jasmine.createSpyObj('Events',['trigger']);
    return {
      target : new HeartbeatService(heartbeatInterval, mockEventAggregator),
      ea     : mockEventAggregator
    };
  }
  it('should raise an event on the FIRST missed beat', function() {
    var mocks = createMocks();
    mocks.target.start();
    setTimeout(function(){
      expect(mocks.ea.trigger).toHaveBeenCalled();
    }, 2);
  });
  //..other similar tests
});

我不喜欢这个测试，因为如果它失败了，那么报告工具很可能会在不同的测试下列出失败——因为实际的断言将发生在it（）函数之外。