Summary: If you have not already done so, delegate some or all of your advice logic to another class that you can test directly.
概述：如果还没有做的话，可以将一些或者全部建议逻辑委派给其他可以直接测试的类。
2
Personally I like the idea of keeping all the data access logic encapsulated in that class.
我个人倾向于将所有的数据访问逻辑封装到这个类中。
3
Design by Contract lets the class designer concentrate on the logic that implements the class functionality without worrying about the validity of arguments.