I have considered providing a pretest to assess student skill and comprehension of previous material. However, in the past, when I have done so, I have been met with a considerable amount hostility from students. They often feel that it is unfair to test them without letting them prepare.
I assure them that it will not affect their grades, but this does little to assuage their fears.
Any suggestions as to how I can make the pre-test more palatable?