I'm going to check my classmate's test paper
Why do you want to check their paper?
Because I feel like helping them with their studies.
It's commendable that you are helping your classmate look over their test papers. It's good to make sure you complete your tests correctly to ensure the final score reflects your efforts accurately.
Thats is not it, I'm cheating so I can get a higher grade.
Then you should not be doing it, cheating could get both yourself and them in trouble.   Why not help each other out instead.