unit testing angularjs $ q.all - promise永远不会完成

Question

我正在尝试测试我构建的服务,该服务使用Angular的$ q Promise实现.我正在使用Karma,Mocha,Chai,Sinon,Sinon Chai和Chai的组合作为承诺.

我写的所有测试和返回的承诺都是通过但拒绝或使用的$q.all([ ... ]).我已经尝试了所有我能想到的但是我似乎无法找到问题所在.

以下是我正在测试的超薄版本:

"use strict";


describe("Promise", function () {

    var $rootScope,
        $scope,
        $q;

    beforeEach(angular.mock.inject(function (_$rootScope_, _$q_) {
        $rootScope = _$rootScope_;
        $q = _$q_;
        $scope = $rootScope.$new();
    }));

    afterEach(function () {
        $scope.$apply();
    });

    it("should resolve promise and eventually return", function () {

        var defer = $q.defer();

        defer.resolve("incredible, this doesn't work at all");

        return defer.promise.should.eventually.deep.equal("incredible, this doesn't work at all");
    });

    it("should resolve promises as expected", function () {

        var fst = $q.defer(),
            snd = $q.defer();

        fst
            .promise
            .then(function (value) {
                value.should.eql("phew, this works");
            });

        snd
            .promise
            .then(function (value) {
                value.should.eql("wow, this works as well");
            });

        fst.resolve("phew, this works");
        snd.resolve("wow, this works as well");

        var all = $q.all([
            fst.promise,
            snd.promise
        ]);

        return all.should.be.fullfiled;
    });

    it("should reject promise and eventually return", function () {
        return $q.reject("no way, this doesn't work either?").should.eventually.deep.equal("no way, this doesn't work either?");
    });

    it("should reject promises as expected", function () {

        var promise = $q.reject("sadly I failed for some stupid reason");

        promise
            ["catch"](function (reason) {
                reason.should.eql("sadly I failed for some stupid reason");
            });

        var all = $q.all([
            promise
        ]);

        return all.should.be.rejected;
    });

});

第三次,最后一次和第一次测试是失败的.实际上它没有失败,它只是在超时超时后解决,我得到了 Error: timeout of 2000ms exceeded.

编辑:我刚刚尝试用Kris Kowal对承诺的实施进行测试,它的工作原理很好.

PS 我实际上发现在Mocha,Chai或Chai As Promised的碗里花了一些时间,并且afterEach挂钩在超时之后被调用.

Answer 1

afterEach()用于清理,而不是在准备之后但在测试之前执行代码.$scope.$apply()也不是清理.

您需要执行以下操作:

// setup async behavior
var all = $q.all(x.promise, y.promise)

// resolve your deferreds/promises
x.reject(); y.reject();

// call $scope.$apply() to 'digest' all the promises
$scope.$apply();

// test the results
return all.should.be.rejected;

您正在进行$apply()测试,而不是在设置和评估之间.

Answer 2

我试图找出为什么测试没有通过，尽管乍一看应该通过。当然，我必须$scope.$apply();从afterEach这不是 @proloser 提到的调用位置。

即使我已经这样做了，测试仍然没有通过。我还打开了关于chai-as-promised和Angular 的问题，看看我是否得到任何输入/反馈，实际上我被告知它很可能不起作用。原因可能是因为 Angular$q对摘要阶段的依赖，而 chai-as-promsied 库中没有考虑到这一点。

因此，我用Q而不是$q检查了测试，它工作得很好，从而加强了我的假设，即错误不在 chai-as-promised 库中。

我最终放弃了 chai-as-promised，并使用 Mocha 的回调重写了我的测试done（即使在幕后，chai-as-promised 也做了同样的事情）：

"use strict";


describe("Promise", function () {

    var $rootScope,
        $scope,
        $q;

    beforeEach(angular.mock.inject(function (_$rootScope_, _$q_) {
        $rootScope = _$rootScope_;
        $q = _$q_;
        $scope = $rootScope.$new();
    }));

    it("should resolve promise and eventually return", function (done) {

        var defer = $q.defer();

        defer
            .promise
            .then(function (value) {
                value.should.eql("incredible, this doesn't work at all");
                done();
            });

        defer.resolve("incredible, this doesn't work at all");

        $scope.$apply();

    });

    it("should resolve promises as expected", function (done) {

        var fst = $q.defer(),
            snd = $q.defer();

        fst
            .promise
            .then(function (value) {
                value.should.eql("phew, this works");
            });

        snd
            .promise
            .then(function (value) {
                value.should.eql("wow, this works as well");
            });

        fst.resolve("phew, this works");
        snd.resolve("wow, this works as well");

        var all = $q.all([
            fst.promise,
            snd.promise
        ]);

        all
            .then(function () {
                done();
            });

        $scope.$apply();

    });

    it("should reject promise and eventually return", function (done) {

        $q
            .reject("no way, this doesn't work either?")
            .catch(function (value) {
                value.should.eql("no way, this doesn't work either?");
                done();
            });

        $scope.$apply();

    });

    it("should reject promises as expected", function (done) {

        var promise = $q.reject("sadly I failed for some stupid reason");

        promise
            ["catch"](function (reason) {
                reason.should.eql("sadly I failed for some stupid reason");
            });

        var all = $q.all([
            promise
        ]);

        all
            .catch(function () {
                done();
            });

        $scope.$apply();

    });

});

上述测试将按预期全部通过。可能还有其他方法可以做到这一点，但我不知道还有什么方法，所以如果其他人这样做，最好将其发布，以便其他人可以从中受益。