Seems like it would be considered cheating by the teacher. Once a test is given, there will be some knowledge of the test out there, so that, unless it is explicitly made public and widely available to potential test takers, some will have an advantage in knowing what some of the questions are. Of course, if it is explicitly made public and widely available, the teacher should make a new test the following year.
It is similar in concept to the College Board reusing entire old SATs.