我什么时候应该在我的 Angular JS 单元测试中使用 $provide 和 Jasmine Spies

2022-01-11 00:00:00 unit-testing angularjs jasmine javascript

我在一个大型 Angular 应用程序上工作，最初我们通过使用 $provide 来模拟服务进行了很多测试.但是，我们现在在测试中使用了很多 Jasmine Spies，以便对服务进行存根和监视.

I work on a large Angular App and initially we done a lot of our tests by using $provide to mock services. However we now have a lot of Jasmine Spies in our tests in order to stub and spy on services.

即

spyOn(myService, 'myMethod').andReturn 'myValue'

我们真的应该为此使用 $provide，还是在某些情况下监视服务是最好的方法?

Should we really be using $provide for this or are there cases where spying on a service is the best approach?

在 Angular 测试中，他们使用间谍来监视 Jquery 我将其视为外部服务.

In the Angular Tests they use spies for spying on Jquery which I would see as an external service.

spyOn(jq.prototype, 'on');

$provide 似乎更多地用于内部服务.

$provide seems to be used more for internal services.

  module(function($provide){
    $provide.provider('$exceptionHandler', $ExceptionHandlerProvider);
  });

还有一个 Jasmine createSpy 函数，但现在我认为 $provide 应该始终优先于它.

There is also a Jasmine createSpy function but now I'm thinking that $provide should always take precedence over that.

对此的任何见解或帮助将不胜感激.

Any insights or help in this would be appreciated.

推荐答案

根据我自己的(有限的)经验，我会说做任何方法:

From my own (limited) experience, I would say do whatever approach makes:

  • 测试代码更简单/更清晰/更短
  • 限制关于您的测试在内部执行的代码的假设.
  • 减少其副作用(例如运行实际的 Ajax 请求)
  • 在条款或运行时间方面尽可能缩短测试时间.

通常 spyOn 方法会起作用，为了完成上述操作，我想从服务/工厂中存根单个方法.如果我需要模拟整个服务/工厂，请使用 $provide.

Usually the spyOn approach works when, in order to do the above, I would like to stub a single method from a service / factory. If I need to mock an entire service / factory, then use $provide.

我想到了一些需要其中之一的特定情况:

A few specific cases come to mind that require one or the other:

  • 如果您正在测试一项服务，然后要从该服务中存根其他方法，您必须使用 spyOn

为了确保稍后不会在被测代码中引入额外的依赖项，$provide 增加了一些保护.说，如果你想确保 ServiceA 只需要 ServiceB 中的 myMethod，那么 $provide 我认为会是走的路，好像 ServiceA 在测试期间从 ServiceB 调用任何未定义的方法，都会引发错误.

To ensure that extra dependencies aren't introduced later in the code under test, than $provide adds a bit more protection. Say, if you want to ensure that ServiceA only requires myMethod from ServiceB, then $provide I think would be the way to go, as if ServiceA calls any undefined methods from ServiceB during the test, errors would be raised.

$provide.provider('ServiceB', {
    myMethod: function() {}
});

  • 如果你想模拟一个返回函数的工厂，那么:

  • If you want to mock a factory that returns a function, so:

    app.factory('myFactory', function() {
  return function(option) {
    // Do something here
  }
});

    用作:

    myFactory(option);

    然后验证某些代码调用 myFactory(option) 我认为没有其他选择然后使用 $provide 来模拟工厂.

    Then to verify that some code calls myFactory(option) I think there is no alternative then to use $provide to mock the factory.

    顺便说一句，它们不是相互排斥的选项.您可以使用 $provide ，然后仍然涉及间谍.在前面的示例中，如果您想验证工厂是否使用选项调用，您可能必须:

    Just by the way, they're not mutually-exclusive options. You can use $provide and then still have spies involved. In the previous example, if you want to verify the factory was called with an option, you might have to:

    var myFactorySpy = jasmine.createSpy();
$provide.provider('myFactory', myFactorySpy);

    然后在适当的点进行测试:

    And then in the test at the appropriate point:

    expect(myFactorySpy).toHaveBeenCalledWith(option);

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