在TDD中模拟值 [英] Mocking values in TDD

问题描述

在 GOOS 一书中。它被告知不要模拟价值观，让我困惑。这是否意味着值没有任何行为？

In the book GOOS. It is told not to mock values, which leaves me confused. Does it means that values don't have any behavior?

我不太了解值对象，但AFAIK值对象是不可变的。是否有任何启发式决定何时创建值对象？

I dont' much knowledge about the value object but AFAIK the value objects are those which are immutable. Is there any heuristic on deciding when to create a value object?

推荐答案

并非所有不可变对象都是值对象。顺便说一下，在设计时，考虑理想对象只有不可变字段和无参数方法。

Not all immutable objects are value objects. By the way, when designing, consider that the ideal object has only immutable fields and no-arg methods.

关于启发式，一种有效的方法可以考虑对象将如何使用：如果你构建一个实例，调用一些方法然后完成它（或将它存储在一个字段中）可能它不会是一个值对象。相反，如果您将对象保留在某些数据结构中并进行比较（使用 .equals（）），您可能会拥有值对象。对于将用于键入的对象尤其如此 Map s

Regarding the heuristic, a valid approach can be considering how objects will be used: if you build an instance, invoke some methods and then are done with it (or store it in a field) likely it won't be a value object. On the contrary, if you keep objects in some data structure and compare them (with .equals()) likely you have a value object. This is especially true for objects that will be used to key Maps

值对象应自行进行自我测试（并且测试通常是阅读和编写的乐趣，因为它很简单）但是模仿它们没有意义：模拟接口的主要实际原因是实现类

Value objects should be automatic-tested themselves (and tests are usually a pleasure to read and write because are straightforward) but there's no point in mocking them: the main practical reasons for mocking interfaces is that implementation classes

• 通常很难构建（需要很多合作者）


• 运行成本很高（访问网络，文件系统......）。

既不适用于价值对象。

这篇关于在TDD中模拟值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！