Call a controller function from Karma and Jasmine testing

This is my angular controller :-

 angular.module('authoring-controllers', []).
        controller('NavCtrl', function($scope, $location, BasketNavigationService) {

$scope.test= function() {
                $scope.testVar = BasketNavigationService.showBasketList();
            };
        });

TEST class

describe('NavCtrl', function() {
    var scope, $location, createController;

    beforeEach(inject(function ($rootScope, $controller, _$location_) {
        $location = _$location_;
        scope = $rootScope.$new();

        createController = function() {
            return $controller('NavCtrl', {
                '$scope': scope
            });
        };
    }));

    it('should create $scope.testVar when calling test', 
        function() {
          expect(scope.testVar).toBeUndefined();
          scope.test();
          expect(scope.testVar).toBedefined();
      });
});

Getting an error when i run that test case :- scope.test() is undefined..

If i removed BasketNavigationService functionality from controller then it is working..

Please help me to solve that karma test case.