单元测试必须作为一级应用程序代码管理。

Unit tests must be managed as first-class application code.

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您会看到，一旦您习惯了从高阶和一级函数的角度思考，您就能减少（一语双关）代码中无用的部分。

You can see that once you become accustomed to thinking in terms of higher-order and first-class functions, you can reduce (pun intended) a lot of noise in your code.

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函数语言结构，如高阶和一级函数，能让我对抽象的理解更进一步，让我更多地将精力放在代码能做什么 而不是怎么做 上。

Functional language constructs such as higher-order and first-class functions allow me to climb one more rung up the abstraction ladder and focus more on what the code does rather than how it does it.

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