I have written a test case of dup2()
This is dup2() functionality test case. The dup2() makes newfd be the copy of oldfd, closing newfd first if necessary.
This test case covers below scenarios
* Provide invalid file descriptor to dup2()
* Fill up all file descriptor table and try to duplicate a file descriptor using dup2().
* Using dup2() duplicate both file descriptor return by the pipe.
* Check inode number after passing newfd and oldfd to fstat(). inode number should be same.
Upon successful execution this program will return zero value, otherwise, it will return -1.