You will not be able to look at anything. They strictly tell you before you even walk into testing room. You leave everything in a locker and can not touch you locker until after test, not even to grab your snack. At least that was the case in my center.
I guess you can have a few dolars with you to buy something, but they told me All I can have in my pocket is my ID and nothing else.
BTW, I would not think about eating lunch immediately before test or during break. reason one: "Rest and digest": you will get a bit slow and that is not what you want. You may also trow up or get dizzy due to being nervous. So eat some sort of slow release energy bar an hour prior IMO.