How to test the done and fail Deferred Object by using jasmine

Question

Here is the code about the javascript submit request (1).
Here is the test about mocking the ajax request by using jasmine (2).

I would like to mock the server b

Answer 1

It would be much easier to test if you had a var with the ajax request promise object. In that case you could do:

 it('should do an async thing', function() {     
   var mutex = 1;
   var promF = jasmine.createSpy('prF');

   runs( function() {
     var promise1 = $.ajax();
     promise1.always(function(){
       mutex--;
     });
     promise1.fail(function(){
       promF();
     });
   });

   waitsFor(function(){
     return !mutex;
   }, 'Fetch should end', 10000);

   runs( function() {
      expect(promF).toHaveBeenCalled();
   });
 });

Below I post untested code that might suit you. I suppose that the ajax call is initialized from the .submit() class? Maybe you should initialize the ajax request from a runs() block and not from beforeEach(), but you should try which one works.

describe('When Submit button handler fired and city is defined', function () {
    var ajaxRequestSpy,
        failSpy, successSpy, alwaysSpy,
        mutex;
    beforeEach(function () {
        ajaxRequestSpy = spyOn(backendController, 'ajaxRequest').andCallThrough();
        failSpy = spyOn(ajaxRequestSpy(), 'fail').andCallThrough()
        successSpy = spyOn(ajaxRequestSpy(), 'success').andCallThrough();
        mutex = 1; // num of expected ajax queries
        alwaysSpy =  spyOn(ajaxRequestSpy(), 'always').andCallFake(function() {
             mutex--;
        });
        this.view = new MyView({
            el: $('
' +
                '' +
                '' +
                '
')
        });
        this.view.$el.find('form').submit();
    });
    it('backendController.ajaxRequest should be called', function () {
        runs( function() {
            // maybe init ajax here ?   
        });

        waitsFor( function() {
            return !mutex;
        }, 'ajax request should happen', 5000);

        runs( function() {
            expect(ajaxRequestSpy).toHaveBeenCalled(); // true
            expect(failSpy).toHaveBeenCalled(); // Error: Expected spy fail 
                                            // to have been called.
        });

    });
});

But, I am not sure that the line

failSpy = spyOn(ajaxRequestSpy(), 'fail').andCallThrough();

does what you want. Is it possible to spy on another spy? And if yes why are you calling the spy ? Maybe you should try

failSpy = spyOn(ajaxRequestSpy, 'fail').andCallThrough();