And that's basically trying to make sure our program has not regressed, as to say, gone backwards in how well it works. And so we always test it on everything.

这只是从根本上确保,我们的程序并没往后退，也就是说在可用性方面倒退了,因此我们在任何东西上,都要进行这样的测试。

麻省理工公开课 - 计算机科学及编程导论课程节选