使用 $timeout 和 Jasmine 的模拟时钟的单元测试 Angular 服务 [英] Unit Testing Angular Service that uses $timeout with Jasmine's Mock Clock

问题描述

我的一个 Angular 服务中有一个函数，我希望定期重复调用该函数.我想使用 $timeout 来做到这一点.它看起来像这样:

I have a function inside one of my angular services that I'd like to be called repeatedly at a regular interval. I'd like to do this using $timeout. It looks something like this:

var interval = 1000; // Or something

var _tick = function () {
     $timeout(function () {
        doStuff();
        _tick();
    }, interval);
};

_tick();

目前，我对如何使用 Jasmine 进行单元测试感到困惑 - 我该怎么做?如果我使用 $timeout.flush() 那么函数调用会无限期地发生.如果我使用 Jasmine 的模拟时钟，$timeout 似乎不受影响.基本上，如果我能做到这一点，我应该很高兴:

I'm stumped on how to unit test this with Jasmine at the moment - How do I do this? If I use $timeout.flush() then the function calls occur indefinitely. If I use Jasmine's mock clock, $timeout seems to be unaffected. Basically if I can get this working, I should be good to go:

describe("ANGULAR Manually ticking the Jasmine Mock Clock", function() {
    var timerCallback, $timeout;

    beforeEach(inject(function($injector) {
        $timeout = $injector.get('$timeout');
        timerCallback = jasmine.createSpy('timerCallback');
        jasmine.Clock.useMock();
    }));

    it("causes a timeout to be called synchronously", function() {
        $timeout(function() {
            timerCallback();
        }, 100);
        expect(timerCallback).not.toHaveBeenCalled();
        jasmine.Clock.tick(101);
        expect(timerCallback).toHaveBeenCalled();
    });
});

这两种变体有效，但对我没有帮助:

These two variations work, but do not help me:

describe("Manually ticking the Jasmine Mock Clock", function() {
    var timerCallback;

    beforeEach(function() {
        timerCallback = jasmine.createSpy('timerCallback');
        jasmine.Clock.useMock();
    });

    it("causes a timeout to be called synchronously", function() {
        setTimeout(function() {
            timerCallback();
        }, 100);
        expect(timerCallback).not.toHaveBeenCalled();
        jasmine.Clock.tick(101);
        expect(timerCallback).toHaveBeenCalled();
    });
});

describe("ANGULAR Manually flushing $timeout", function() {
    var timerCallback, $timeout;

    beforeEach(inject(function($injector) {
        $timeout = $injector.get('$timeout');
        timerCallback = jasmine.createSpy('timerCallback');
    }));

    it("causes a timeout to be called synchronously", function() {
        $timeout(function() {
            timerCallback();
        }, 100);
        expect(timerCallback).not.toHaveBeenCalled();
        $timeout.flush();
        expect(timerCallback).toHaveBeenCalled();
    });
});

提前致谢！

推荐答案

不要使用 Jasmine 的时钟使您的测试异步.相反，使用 $timeout.flush() 来同步维护测试流程.设置起来可能有点棘手，但一旦你得到它，你的测试就会更快，更可控.

Do not make your test Async by using Jasmine's clock. Instead, use $timeout.flush() to synchronously maintain the flow of the test. It may be a bit tricky to setup, but once you get it then your tests will be faster and more controlled.

下面是一个使用这种方法进行测试的示例:https://github.com/angular/angular.js/blob/master/test/ngAnimate/animateSpec.js#L618

Here's an example of a test that does it using this approach: https://github.com/angular/angular.js/blob/master/test/ngAnimate/animateSpec.js#L618

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