Mocking service containing http request for unit testing in angular

I got a controller like that:

  .controller('MainCtrl', function ($scope, API) {
  $scope.eventsQuantity = 0;
  $scope.localsQunatity = 0;

  API.newRequest('getCitiesList').success(function (data) {
      $scope.cities = data.data;
      for (var i = 0; i < $scope.cities.length; i++) {
          $scope.eventsQuantity += parseInt($scope.cities[i].EventCount);
          $scope.localsQunatity += parseInt($scope.cities[i].LocalCount);
      }
  });

})

which is using API service with http request:

angular.module('sandboxApp').factory('API', function ($http) {
return {
    'newRequest': function (path, conf) {
        return $http.get('http://ift.tt/1tGnrLm' + path, conf);
    },
    'baseURL': 'http://ift.tt/1tGnrLm'
};

})

how can i mock this service when im writing unit test for my controller so i dont have to send real http request during testing ? I have tried something like this:

describe('Controller: MainCtrl', function () {

// load the controller's module
beforeEach(module('sandboxApp'));

var MainCtrl, scope, mockAPI;

beforeEach(function () {
    var mockAPI = {};
    module('sandboxApp', function ($provide) {
        $provide.value('API', mockAPI);
    });

    inject(function ($q) {
        mockAPI.newRequest = function (path, conf) {
            var defer = $q.defer();
            defer.resolve({ "status": 1, "message": "", "validation_errors": [], "data": [{ "Id": 25, "Name": "Warszawa", "LocalCount": 25, "EventCount": 39 }] });
            return defer.promise;
        };
    });
});

    // Initialize the controller and a mock scope
    beforeEach(inject(function ($controller, $rootScope, API) {
        API = API;
        scope = $rootScope.$new();
        MainCtrl = $controller('MainCtrl', {
            $scope: scope,
            API : API
        });
    }));

    it('checks if MainCtrl exist', function () {
        expect(MainCtrl).toBeDefined();
    });
});

but it fails. Im using Jasmine and Karma.