An extension of this principle is the fact that testing that has been performed on a function that has not changed may still be considered valid.
此原则的一个扩展是这样一个事实，对一个没有变更的功能执行的测试可能仍旧认为是有效的。
2
You don't want to upload the extension and start testing, because it will be publicly visible right away.
你不应该先上传扩展，然后才开始测试，因为它马上会被大家所发现。
3
The idea of using of model programs and state space exploration is a natural extension of finite state machine based techniques that fits well with black-box testing of software.