你开发的一系列测试说明了代码的运行机制，这种程序自我编档的方式促进了交流。

It encourages communication by making your programs self-documenting-the set of tests you develop show how the code works in a way that a manual can't.

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在一个实际项目中，不像这些简单的例子这样，你可以很容易地达到模仿实现需要它的自我测试这一阶段，因为有那么多的代码。

In a real project, unlike in these simple examples, you can easily reach the stage where the mock implementation needs its own tests because it contains so much code.

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