Cannot send an action from the controller to the route in a unit test

In my unit test I'm invoking an action in my controller, which in its turn sends an action to the route:

this.send('setRandomPage', this._generateRandomPage(this.get('count')));

And on this line it breaks with:

TypeError: Cannot read property 'trigger' of undefined
    at Class.send 

Is there a way to override the send method with Sinon so that it passes? this points correctly to my controller.