Reply from Sun Microsystems: Don't worry about automated tests. We stopped using automated testing several years ago. Your assignment specs probably mentioned about software testing. The software testing only tests the following:
1) Your JAR file contents. They must conform to the specs (such as the folders you must have and so on).
2) Test if you illegally modify the interface given to you, and test if your implementation class implements that interface (once again, indirect implementation is allowed).