广播后的单元测试指令范围功能

Question

我有一个简单的指令，并且在link函数中是一个$ broadcast receiver $ on。收到后，将调用范围函数：

return {
    restrict: 'E',
    link: function($scope, element, attrs) {


        $scope.createCart = function () {
             // Create cart
        }

        function getProductList() {
             // get products lists
        }


        $scope.$on('create-shopping-cart', function() {
            $scope.createCart();
            getProductList();
        });

    }
};

我试过了：

describe('<-- myDirective Spec ------>', function () {

    var scope, $compile, element, $httpBackend;

    beforeEach(angular.mock.module('myApp'));

    beforeEach(inject(function (_$rootScope_, _$compile_, _$httpBackend_) {
        scope = _$rootScope_.$new();
        $compile = _$compile_;
        $httpBackend = _$httpBackend_;

        var html = '<my-directive"></my-directive>';
        element = $compile(angular.element(html))(scope);

        spyOn(scope, '$on').and.callThrough();
        scope.$digest();
    }));

    it('should be defined', function () {
        expect(element).toBeDefined();
    });

    it('should broadcast ', function () {
        scope.$broadcast('create-shopping-cart');
        scope.$digest();
        expect(element.isolateScope().createCart()).toHaveBeenCalled();
    });
});

有了上述内容，我看到了错误：

TypeError: 'undefined' is not an object (evaluating 'element.isolateScope().createCart')

我如何测试$ scope.createCart（）; AND getProductList（）;被称为？