let mouseDownStream = Rx.Observable.fromEvent(document.body, 'mousedown');

let haveBeenCalled = false;

mouseDownStream.delay(200).subscribe(() => haveBeenCalled = true);

​

describe('mouse down event', () => {

  it('it should emit an event stream after 200ms', (done) => {

    document.body.dispatchEvent(new MouseEvent('mousedown'))

    expect(haveBeenCalled).toBeFalsy

    // Don't want this setTimeout should use Angular's tick(200) method instead but it's not working.

    setTimeout(() => {

      expect(haveBeenCalled).toBeTruthy();

      done();

    }, 200)

  });

});