The Java Engine for Testing (JET) is a system for running distributed automated tests. It has been used by Sun for testing the High Availability DataBase (HADB), JavaDB, PostgreSQL, Memcached, and the MySQL Cluster Manager. JET should be a good way to write your tests if the product you want to test is distributed or has a client/server architecture, if it is natural for you to write the tests in Java, and if you want to invest time in developing tests and abstractions for later reuse.