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

Stub帮助我们运行测试。怎么做?它给出了有助于运行测试的值。这些值本身不是真实的,我们创建这些值只是为了运行测试。例如,我们创建一个HashMap来提供与数据库表中的值相似的值。因此,我们不直接与数据库交互,而是与Hashmap交互。

Mock是一个运行测试的伪对象。我们在这里输入assert。

其他回答

Mock——Mock拦截对一个方法或函数的调用(或者像模拟类那样的一组方法和函数)。它不是该方法或函数的替代品。在那次拦截中,mock可以做任何它想做的事情,比如记录输入和输出,决定短路调用,更改返回值,等等。

存根——存根是一个有效的方法或函数(或一组方法和函数,就像存根类一样)的完整工作实现,它与它存根的方法、函数或一组方法和函数具有相同的接口/签名。stub实现通常只会做在单元测试上下文中可以接受的事情,这意味着它不会做IO,同时模仿它要stub的东西的行为。

这张幻灯片很好地解释了主要的区别。

*选自CSE 403第16讲,华盛顿大学(幻灯片由“Marty Stepp”制作)

测试双打:

Fake: Fakes are objects that have working implementations, but not the same as production one. Such as: in-memory implementation of Data Access Object or Repository. Stub: Stub is an object that holds predefined data and uses it to answer calls during tests. Such as: an object that needs to grab some data from the database to respond to a method call. Mocks: Mocks are objects that register calls they receive. In test assertion, we can verify on Mocks that all expected actions were performed. Such as: a functionality that calls e-mail sending service. for more just check this.

我在阅读《单元测试的艺术》时,偶然发现了以下定义:

fake是一个通用术语,可以用来描述存根或模拟对象(手写或其他),因为它们看起来都像真实的对象。赝品是存根还是mock取决于它在当前测试中的使用方式。如果它用于检查交互(根据其断言),则它是一个模拟对象。否则,它就是存根。

Stubs vs. Mocks Stubs provide specific answers to methods calls ex: myStubbedService.getValues() just return a String needed by the code under test used by code under test to isolate it cannot fail test ex: myStubbedService.getValues() just returns the stubbed value often implement abstract methods Mocks "superset" of stubs; can assert that certain methods are called ex: verify that myMockedService.getValues() is called only once used to test behaviour of code under test can fail test ex: verify that myMockedService.getValues() was called once; verification fails, because myMockedService.getValues() was not called by my tested code often mocks interfaces