backbone.js click event spy is not getting called using jasmine.js and sinon.js

Question

I am trying to test a button click using backbone.js, jasmine.js and sinon.js. But the following test case fails. I am using a spy to track whether it is getting called or not. Can you please help me with this?

Thanks.

New Task Template

<script id='new_task_template' type='text/template'>
  <input type='text' id='new_task_name' name='new_task_name'></input>
  <button type='button' id='add_new_task' name='add_new_task'>Add Task</button>
</script>

NewTaskView

T.views.NewTaskView = Backbone.View.extend({
  tagName: 'section',
  id: 'new_task_section',
  template : _.template ( $("#new_task_template").html() ),
  initialize: function(){
    _.bindAll( this, 'render', 'addTask');
  },
  events:{
    "click #add_new_task" : "addTask"
  },
  render: function(){
    $(this.el).html( this.template() );
    return this;
  },
  addTask: function(event){
    console.log("addTask");
  }
});

Jasmine Test Case

describe("NewTaskView", function(){
  beforeEach( function(){    
    this.view = new T.views.NewTaskView();
    this.view.render();
  });

  it("should #add_new_task is clicked, it should trigger the addTask method", function(){
    var clickSpy = sinon.spy( this.view, 'addTask');
    $("#add_new_task").click();
    expect( clickSpy ).toHaveBeenCalled();
  });
});

Jasmine Output

NewTaskView
  runEvents
    runshould #add_new_task is clicked, it should trigger the addTask method
      Expected Function to have been called.

Answer 1

The problem is you add your spy after backbone has already bound the click event directly to the addTask function (it does that during construction of the View). Therefore your spy will not get called.

Try attaching the spy to a prototype of the View before you construct it. Like this:

this.addTaskSpy = sinon.spy(T.views.NewViewTask.prototype, 'addTaskSpy');
this.view = new T.views.NewTaskView();

and then remember to remove it:

T.views.NewViewTask.prototype.addTaskSpy.restore()