Even if I (...) I still wouldn't copy in a test.
This is presenting a hypothetical situation. When you make a hypothetical statement you normally first establish an unreal situation as either something that has happened in the past or describe a present situation. The words you use may be past or present but if it is just hypothetical as in your example ("Even if" implies that it is a hypothetical situation) then it is sometimes referred to as the unreal past. You would then go on to state what you would do, in future terms.
I believe the correct answer to your question is:
Even if I hadn't studied I still wouldn't copy in a test.
This is because you are saying that if you had not studied (past tense) you would not cheat (future tense). Even if you were speaking about a future test where you might have the opportunity to study in the future, at the point you were taking the test any study opportunity would then be in the past.