我读过各种关于测试中模仿和存根的文章,包括Martin Fowler的《Mocks Aren't Stubs》,但我仍然不理解其中的区别。


当前回答

我偶然看到了《小嘲笑者鲍勃叔叔》的一篇有趣的文章。它以一种非常容易理解的方式解释了所有的术语,因此对初学者很有用。Martin fowler的文章很难读,尤其是对于像我这样的初学者。

其他回答

非常清楚和实际:

Stub:实现要伪造的类/对象的方法的类或对象,并且总是返回你想要的东西。

JavaScript示例:

var Stub = {
   method_a: function(param_a, param_b){
      return 'This is an static result';
   }
}

Mock:与存根相同,但是它增加了一些逻辑,当一个方法被调用时“验证”,这样你就可以确定某个实现正在调用该方法。

正如@mLevan所说,假设你正在测试一个用户注册类。在调用Save之后,它应该调用SendConfirmationEmail。

一个非常愚蠢的代码

var Mock = {
   calls: {
      method_a: 0
   }

   method_a: function(param_a, param_b){
     this.method_a++; 
     console.log('Mock.method_a its been called!');
   }
}

他使用的通用术语是测试替身(想想特技替身)。Test Double是一个通用术语,用于为测试目的替换生产对象的任何情况。杰拉德列出了各种各样的替身:

Dummy objects are passed around but never actually used. Usually they are just used to fill parameter lists. Fake objects actually have working implementations, but usually take some shortcut which makes them not suitable for production (an InMemoryTestDatabase is a good example). Stubs provide canned answers to calls made during the test, usually not responding at all to anything outside what's programmed in for the test. Spies are stubs that also record some information based on how they were called. One form of this might be an email service that records how many messages it was sent(also called Partial Mock). Mocks are pre-programmed with expectations which form a specification of the calls they are expected to receive. They can throw an exception if they receive a call they don't expect and are checked during verification to ensure they got all the calls they were expecting.

Stub

我相信最大的区别是您已经编写了带有预定行为的存根。所以你会有一个实现依赖的类(很可能是抽象类或接口),你是为了测试目的而伪造的,方法只是用设置的响应来存根。它们不会做任何花哨的事情,而且您应该已经在测试之外为它编写了存根代码。

Mock

模拟是测试的一部分,你必须根据你的期望来设置。mock并不是预先设定好的,所以您可以在测试中使用它。模拟在某种程度上是在运行时确定的,因为设置期望的代码必须在它们执行任何操作之前运行。

mock和stub的区别

使用模拟编写的测试通常遵循初始化->设置期望->练习->验证模式进行测试。而预先编写的存根将遵循初始化->练习->验证。

mock和stub之间的相似性

这两种方法的目的都是为了消除对类或函数的所有依赖项的测试,从而使您的测试在试图证明的内容方面更加集中和简单。

存根不会让你考试不及格,mock可以。

存根用于您在测试中设置的具有预期返回值的方法。 mock用于void方法,这些方法在调用时的Assert中进行验证。