这问题如何答好？
设计就是OOD。
然后测试的话，想到几点：
capability: how many planes it can deal with?
efficiency: how many seconds it takes to schedule the planes?
Robust: how about when a plane arrives late/early?
How about the system is suddenly out of electricity?
Safety: What if two planes require to land on the same plane with
in the same time slot?
欢迎提出看法
