Well wish

Example 1

You : I heard you are going to have an exam tomorrow. Good luck.
Friends : Thank you.

Example 2

You : Are you ready for a test tomorrow?
Friend : No. I'm afraid not.
You : Come on. I am sure you will do well.
Friend : Thank you. I hope so.

Example 3

You : Don't study too hard. It's not good for your health
Friend : I have a test tomorrow.
You : Really? Wish you luck my friend.
Friend : Thanks.