It is haraam for students to cheat in tests
Question

What is the ruling on students cheating in tests at school?.
Praise be to Allah.The hadeeth, “Whoever cheats us is not one of us” is saheeh, and it is general in meaning, including cheating in buying and selling, in giving advice, and in promises and covenants, in trusts, in exams in schools and institutes, and so on. That includes copying out material from books, taking answers from other students and giving them answers, whether spoken or written down on papers passed among them. 
And Allah is the Source of strength.