如何在角度控制器中测试本地功能？

Question

假设我有一个这样的控制器：

angular
    .module("app", [])
    .controller("NewsFeedController", [
        "$scope",
        "NewsFeedService",
        function ($scope, NewsFeedService) {
            $scope.news = [
                { stamp: 1 },
                { stamp: 9 },
                { stamp: 0 }
            ];

            $scope.onScroll = function () {
                /*
                    might do some stuff like debouncing, 
                    checking if there's news left to load, 
                    check for user's role, whatever. 
                */

                var oldestStamp = getOldestNews().stamp;
                NewsFeedService.getOlderThan(oldestStamp);

                /* handle the request, append the result, ... */
            };

            function getOldestNews () {
                /* code supposed to return the oldest news */
            }
        }
    ]);

getOldestNews 被声明为本地函数，因为没有必要在 $scope 中公开它。

我应该如何处理它？我该如何实际测试这个功能？

describe("NewsFeedController", function () {
    beforeEach(module("app"));

    var $controller, $scope, controller;

    beforeEach(inject(function (_$controller_) {
        $controller = _$controller_;
        $scope      = {};
        controller  = $controller("NewsFeedController", { $scope: $scope });
    }));

    it("should return the oldest news", function () {
        // How do I test getOldestNews?
    });
});

顺便说一句，如果该解决方案也适用于服务和指令中的本地函数，那就太好了。

---

相关问题：

• How can we test non-scope angular controller methods?
• How do I mock local variable for a function in a service? Jasmine/Karma tests

Answer 1

现在我看到了您真正想要在代码中执行的操作。我认为没有必要测试私有函数，因为它没有包含足够的逻辑。我建议您只在 NewsFeedService 上创建一个间谍来测试是否将正确的数据发送到该服务。

describe("NewsFeedController", function () {

    beforeEach(module("app"));

    var $controller, $scope, controller;
    var newsFeedServiceMock = jasmine.createSpyObj('NewsFeedService', ['getOlderThan']);

    beforeEach(inject(function (_$controller_) {
        $controller = _$controller_;
        $scope      = {};
        controller  = $controller("NewsFeedController", { $scope: $scope, NewsFeedService : newsFeedServiceMock });
    }));

    it("should return the oldest news", function () {
         $scope.news = [
            { stamp: 76 },
            { stamp: 4 },
            { stamp: 83 }
         ];

         $scope.onScroll();

         expect(newsFeedServiceMock.getOlderThan).toHaveBeenCalledWith(83);
    });
});

这样你可以检查你的 onScroll 方法是否正确的行为，而不需要检查私有方法。您只想测试公共方法，因此您可以灵活地创建私有方法来分离逻辑，而无需更改您的测试。