问使用templateUrl对AngularJS指令进行单元测试

EN

describe('module: my.module', function () {
    beforeEach(module('my.module'));

    describe('my-directive directive', function () {
        var scope, $compile;
        beforeEach(inject(function (_$rootScope_, _$compile_, $injector) {
            scope = _$rootScope_;
            $compile = _$compile_;
            $httpBackend = $injector.get('$httpBackend');
            $httpBackend.whenGET('path/to/template.html').passThrough();
        }));

        describe('test', function () {
            var element;
            beforeEach(function () {
                element = $compile(
                    '<my-directive></my-directive>')(scope);
                angular.element(document.body).append(element);
            });

            afterEach(function () {
                element.remove();
            });

            it('test', function () {
                expect(element.html()).toBe('asdf');
            });

        });
    });
});

TypeError: Object #<Object> has no method 'passThrough'