Getting a good rest is a very important thing to put on your study agenda. Not only for your body, but also for your brain. It is much better to study and rest, then to cram all night and be dead tired for the test or exam the following day. With a good rest, you will be in a better position to logically and rationally choose more accurate or correct answers.
What's the point of staying up all night to cram for a test, when you (and your brain) will be to tired to function, let alone remember anything that you studied.