说明：  在VS2010中，单元测试的功能很强大，使得建立单元测试和编写单元测试代码，以及管理和运行单元测试都变得简单起来，通过私有访问器可以对私有方法也能进行单元测试，并且支持数据驱动的单元测试。
(In VS2010, unit testing is very powerful, which makes it easy to build and write unit testing code, manage and run unit testing. Private methods can also be unit tested through private accessors, and data-driven unit testing can be supported.)