Mockito - doReturn（）和when（）之间的区别 [英] Mockito - difference between doReturn() and when()

问题描述

我目前正在使用Mockito来模拟Spring MVC应用程序中的服务层对象，我想在其中测试我的Controller方法。但是，正如我一直在阅读Mockito的细节，我发现方法 doReturn（...）。when（...）相当于时（...）。thenReturn（...）。所以，我的问题是，有两种方法可以做同样的事情或者什么是 doReturn（...）之间的细微差别。当（...）和当（...）。thenReturn（...）？

I am currently in the process of using Mockito to mock my service layer objects in a Spring MVC application in which I want to test my Controller methods. However, as I have been reading on the specifics of Mockito, I have found that the methods doReturn(...).when(...) is equivalent to when(...).thenReturn(...). So, my question is what is the point of having two methods that do the same thing or what is the subtle difference between doReturn(...).when(...) and when(...).thenReturn(...)?

任何帮助将不胜感激。

Any help would be appreciated.

推荐答案

存根的两种语法大致相同。但是，您可以始终使用 doReturn / when 进行存根;但有些情况下无法使用时/ thenReturn 。挖空虚方法就是其中之一。其他包括与Mockito间谍一起使用，并且不止一次地使用相同的方法。

The two syntaxes for stubbing are roughly equivalent. However, you can always use doReturn/when for stubbing; but there are cases where you can't use when/thenReturn. Stubbing void methods is one such. Others include use with Mockito spies, and stubbing the same method more than once.

当/ thenReturn 时有一件事给你， doReturn /当没有时，是在编译时对你返回的值进行类型检查。但是，我相信这几乎没有任何价值 - 如果你的类型错了，你会在你进行测试后立即发现。

One thing that when/thenReturn gives you, that doReturn/when doesn't, is type-checking of the value that you're returning, at compile time. However, I believe this is of almost no value - if you've got the type wrong, you'll find out as soon as you run your test.

我强烈建议仅使用 doReturn / when 。如果有的话，学习两种语法是没有意义的。

I strongly recommend only using doReturn/when. There is no point in learning two syntaxes when one will do.

您可以在形成Mockito语法 - 对一个非常密切相关的问题的更详细的答案。

You may wish to refer to my answer at Forming Mockito "grammars" - a more detailed answer to a very closely related question.

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