Ask your teacher if he or she will give out a practice test or sample problems before the next exam. They might be able to give you an old version of a test from the same class.
If that fails, try searching online for problems from the subject you're studying and you might find something more challenging than the textbook examples.
The main point of the tests, of course, is to measure how well you actually comprehend the material being taught. Try to work on the problems in your book enough that you actually *understand* them and what they're really getting at. If you get the concepts and their relevance to the big picture instead of just memorizing formulas, you'll be better suited to figure out answers come test day.
Good luck!
