How to build a simple $http post test script using angular js

I'm just beginning to understand Angularjs and planning to build an app. I'm really a PHP programmer and have little background in javascript. Angularjs was introduced to me by a friend. I was warned that I have to also learn its Jasmine/karma testing before the functionality of the app gets bigger. So here goes, for now I have a $http post which submits an email and a password which if success return a token. Basically if success will redirect the user to the user/profile page

Controller code:

function MainCtrl($scope, $location, Api, localStorageService, Security) {
 $scope.loginUser = function () {
    Api.authenticatePlayer({
        email    : $scope.main.email,
        password : $scope.main.password
    }).then(function (result){
        //success
        $location.path('/user/profile');
    }, function(result) {
        //error also this will catch error 400, 401, and 500
        console.log(result.data);
    });
 };
}

And here is my testscript:

beforeEach(function() {
    module('myApp.services'),
    module("myApp.controllers")
});

beforeEach(inject(function($controller, $rootScope, $location, Api, localStorageService, $httpBackend, Security) {
    this.$location = $location;
    this.$httpBackend = $httpBackend;
    this.scope = $rootScope.$new();
    this.redirect = spyOn($location, 'path');

    $controller("MainCtrl", {
        $scope : this.scope,
        $location : $location,
        localStorageService : localStorageService,
        Security : Security
    });

}));

describe("successfully logging in", function () {
    it("should redirect you to /user/profile", function() {
        //arrange
        var postData = {
            email : this.scope.main.email,
            password : this.scope.main.password
        }
        this.$httpBackend.expectPOST('login', postData).respond(200);
        //act
        this.scope.loginUser();
        this.$httpBackend.flush();
        //assert
        expect(this.redirect).toHaveBeenCalledWith('/user/profile');
    });
});

Here is my service.js code:

return {

  /**
   * Authenticate player
   * @param   object postData      Email and password of the user
   * @return object
   */
  authenticatePlayer: function(postData) {
    return $http({
      method  : 'POST',
      url     : api + 'auth/player',
      data    : postData,
      headers : {'Content-Type' : 'application/json'}
    });
  }
 }

The testscript failed :(. Here is the error:

Chrome 24.0 (Linux) controller: MainCtrl successfully logging in should redirect you to /user/profile FAILED
Error: Unexpected request: POST http://domain.com/auth/player
Expected POST login

Can anyone please help. So sorry for the trouble though.