Its fine to test, but not fair when it goes beyond 3.5 hrs. You should try to have checkboxes of you expectation, listen to what candidate say and limit it to 5 or ,,6 ques. If not that might prove that you are inefficient with your interview taking skills.
My Mind voice: Is this a kind of question do you ask? when you are 8+ years experienced and I have already mentioned in my resume and the interviewer is holding my resume + I have submitted my assignments. And I did answer this stupid question. rest of the questions I leave it to your imagination.