This all goes exactly counter to the attempt to devise tests that the students will pass. I have often sat frightened the night before a test, faced with a class that cannot do anything, wondering how to ask questions someone might get right. In truth my job is devise questions that will not be got right except by those who understand.
Still experience shows that most students will only get questions for which they have been specifically prepared, ones which look like the ones in class, and require no additional thinking. Whether to ask such questions is a matter for ones own conscience,a s the outsider cannot tell whether one has prepared ones class for the questions or not.
Still even with the best intentions, we all know that students get right those tests which were written by his own teacher more often than those written by others. For this reason we used to make sure the teacher of a grad course never wrote the prelim in that subject. years later we did the opposite, the teacher who prepared the students also wrote the prelim. we got a lot more passes that way.