*shrug* I'm too focused on developing my own abilities to really worry about anyone else's. (Except when I'm the person teaching the class.)
As for testing a potential teacher, I've been fortunate enough to study with teachers who are well beyond my ability to actually test them. If you don't feel that testing your teacher would be pointless, perhaps it's time to find another teacher.
Kind of my point.
If you have to test your teacher, IMO you haven't chose your teacher wisely. I think there should be no doubt walking on that mat.
And only the person in charge should be testing any one's ability. To test some one you are putting yourself in a position that states that you "know better" than the person being tested. Unless you are the Sensei or instructor, you are being quite arrogant in my opinion.