Many students are very tense on test days. Help to ease this stress by talking with students beforehand about the purpose of the test. Rather than making them think that this one score will determine their grade in the class, tell them that the point of the test is for them to simply show what they have learned. It helps you to know what they understand and what they may still need help with. It also is a guide for them to know what they are not understanding. They should realize that there are many things that determine grades in the class, and that the most important of these is that they are a hard worker. Also discuss how the test will only test what they should know from learning in class; there won't be any new information, so they should be completely confident when they take it.