Adding selector on ember-growl-notification flash message

I am using ember growl notification.On save below condition is checked and displays flash message.I need to add ember selector to this flash message.When i add attr using jquery it doesn't display selector on flash message inspect element.

On controller save click i call this function

    if(productDontAllow && (!!userManagement))
    {
      this.get('emberGrowlService').showNotification({
        message: messageDisplay,
        type: success
      });
      Ember.$('.ember-growl-notification-item').attr('data-test-flash-failure','')
      return;
    }