Sometimes you need to write a subclass (often as an inner class) in order to test protected methods.

有时需要编写一个子类（通常作为内部类）来测试 protected 的方法。

youdao

By definition, you cannot inherit from a sealed type, which means that protected methods on sealed types cannot be called.

按照定义，不能从密封类型继承，意味着不能调用密封类型上受保护的方法。

youdao

This approach makes testing protected methods much easier because the test case class can now extend the class that contains the protected methods.

这种方法使得测试受保护的方法非常容易，因为测试案例类现在可以扩展包含受保护方法的类了。

youdao

And some of the capacities that we have, the methods that we use need to be protected and not compromised.

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