Jasmine spy not being called

I have created an angular service which I am testing without any issue, I then started trying to inject a dependency into the tests when I started having an issue.

I want to make sure that a function in the dependency has been called but it's coming back undefined.

Here's my service:

angular.module('enigmaApp.services', [])
    .factory('auth', function($window, $http, SS){
        var auth = {};

        auth.register = function(user){
            return $http.post('/register', user)
            .success(function(data){
                if(data.token){
                    SS.setObj('appToken', data.token);
                }
            });
        };
    });

My test:

describe('Auth Service Tests', function () {
  var $httpBackend, auth, defer, registerReqHandler, setObjSpy, SS, SSMock, user;

  beforeEach(module('enigmaApp'));

  beforeEach(function () {    
    // Create spies
    setObjSpy = jasmine.createSpy('setObj');

    SSMock = {
      setObj: setObjSpy
    }

    SS = SSMock;

    module(function ($provide) {
      $provide.value('SS', SSMock);
    });
  });

  beforeEach(inject(function (_$httpBackend_, $injector, $q) {
    $httpBackend = _$httpBackend_; 
    defer = $q.defer();
    registerReqHandler = $httpBackend.when('POST', '/register').respond(defer.promise);
    auth = $injector.get('auth');
  }));

  afterEach(function () {
    $httpBackend.flush();
    $httpBackend.verifyNoOutstandingExpectation();
    $httpBackend.verifyNoOutstandingRequest();
  });

  describe('auth.register(user)', function () {
    beforeEach(function () {
      user = {
        email: 'bwayne@wayneenterprise.com',
        first_name: 'Bruce',
        last_name: 'Wyane',
        password: 'password123'
      };
    });

    it('should call SS.setObj on successful registration', function () {
      $httpBackend.expectPOST('/register').respond({ token: 'fakeToken' });
      auth.register(user);
      expect(SS.setObj).toHaveBeenCalled();
    });
  });

When I run the tests I get a failed test that says "Expected spy setObj to have been called." Any idea on what I'm doing wrong here? I thought I set up a mock for SS.setObj and provided it to the module,