JayDubya said:If it's the only way you can stay up to browse some unfamiliar material that you know will be on the test? Maybe.
Still, try to get some sleep. Even if it's just a little bit, you'll need it. And hopefully you don't have anything after the test so you can come home and crash hard.
Listen to this man. (for once) Sleep has a much greater effect on test performance than all-nighters spent cramming.