Test cases in C

Question

How to include test cases in C for competitive coding?
For eg:- if we give two kinds of inputs at the same time then it must give two different outputs at the same time.

Answer 1

Wouldn't that depend on the competition in question, on what they demand?
(Not sure what you are asking.)

Answer 2

If you search unit test libraries, there are a lot on github (well, I made one ... but that would not be objective to advise you to use it 😛), googling it, you can also find other libraries
But, as HonFu said, I also find this question not clear enough :/