Teaspoon unit test ember notify message with promise

Question

I am testing this code, the syntax is in coffee script.

functionName: ->
    a = @get('content')
    a.on('didUpdate', =>
      @get("controllers.application").notify
            title: "Success!"
            message: "Updated!"
            type: "alert-success"
    )
    a.save()

1. There's a promise in it, I do not know how to get the .on method, if I stub it out, then the promise will not run...
2. for the notify, how do I check the assertion? I tried to check the object, but it seems to not be an object with properties.