I think that depends on the test only. If you have a test which involves doing calculations provided to you - you shouldn't need any extra tools - it's the execution that's tested. On the other hand, if the test involves you figuring out the solution, then it shouldn't matter what you have with you. (As long as you can't communicate with others)

I know this is not that common, but for good tests, cheating like that should be irrelevant.