Best not to go over unless you're sure you can see the other side
Ahhh, another good reason not to go over is that "VFR" flight is flight conducted with
visual reference to the ground. If you're on top of cloud, you have probably reduced or eliminated your practical reference to the ground. That's very bad for safety, and regulatory compliance.
If in doubt, turn away, while considering a descent. Do not commit yourself to flying under until you believe that is safe - meaning don't allow turning away to stop being an option. If you have approached a cloud to a point where a rapid descent, or circling or "S" turns are required to prevent entering it, you were not paying attention far enough ahead. Failing to think far enough ahead is a cause of unsafe situations in aviation.
Good luck on your test..