Mocking dates in AngularJS / Jasmine tests

Question

I have a directive that initializes the Date object several times in several functions. When Unit testing the individual functions I can handle stubbing the date like this:

Answer 1

I was able to mock using a combination of sinon's fake timers to mock the window's timers and angular's mock interval service for angular to recognize time changes . Here, the countDownService under test makes use internally of both javscript Date and angular's normal interval service Something like:

  describe('when start time was 3000 milliseconds and 1001 milliseconds have passed', function() {
    var startTime;
    var elapse;
    beforeEach(function(){
      this.clock = sinon.useFakeTimers();
      startTime = 3000;
      elapse = 1001;
    });

    var elapseMillis = function(intervalMock,sinonClock,millis){
      sinonClock.tick(millis);
      intervalMock.flush(millis);
    };

    it('elapsedMillis + timeRemainingMillis should == startime', 
      inject(function($rootScope,$interval,countdownService) {
        countdownService.startTimer(startTime);
        elapseMillis($interval,this.clock,elapse);
        //jasmine clock does not mock Date
        //see https://github.com/pivotal/jasmine/issues/361
        var elapsedMillis = countdownService.getElapsedMillis();
        var timeRemainingMillis = countdownService.getTimeRemainingMillis();
        expect(elapsedMillis + timeRemainingMillis).toEqual(startTime);
        expect(elapsedMillis).toEqual(elapse);
    }));

    afterEach(function(){
      this.clock.restore();
        startTime = 0;
        elapse = 0;
    });
  });

You'll want to make sure and include sinon js's sinon-timers-1.8.1.js in your karma.conf.js files property, too.