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

We actually ran into the same problem, trying to test Deferred objects that represent AJAXed template scripts for on-the-fly templating. Our testing solution involves using the Jasmine-Ajax library in conjunction with Jasmine itself.

So probably it will be something like this:

describe('When Submit button handler fired', function () {
  jasmine.Ajax.useMock();

  describe('if the message is empty', function () {

    beforeEach(function() {
      spyOn(backendController, 'submitForm').andCallThrough();
      // replace with wherever your callbacks are defined
      spyOn(this, 'onSuccess');
      spyOn(this, 'onFailure');
      this.view.$el.find('#message').text('');
      this.view.$el.find('form').submit();
    });

    it('backendController.submitForm and fail Deferred Object should be called', function () {
      expect(backendController.submitForm).toHaveBeenCalledWith('');
      mostRecentAjaxRequest().response({
        status: 500, // or whatever response code you want
        responseText: ''
      });

      expect( this.onSuccess ).not.toHaveBeenCalled();
      expect( this.onFailure ).toHaveBeenCalled();
    });
});

Another thing, if you can, try to break up the functionality so you're not testing the entire DOM-to-response-callback path in one test. If you're granular enough, you can actually test asynchronous Deferred resolutions by using Deferred objects themselves inside your tests!

The key is to actually use Deferred objects within your tests themselves, so that the scope of the expect call is still within your it function block.

describe('loadTemplate', function() {
  it('passes back the response text', function() {
    jasmine.Ajax.mock();
    loadTemplate('template-request').done(function(response) {
      expect(response).toBe('foobar');
    });
    mostRecentAjaxRequest().response({ status:200, responseText:'foobar' });
  });
});