One way to do it would be to introduce our own HV Clock. Per default it would just delegate to the system clock, but we can prime it for testing. Actually I like the idea. It gives us more control and avoids any problems in the tests. Also, it might be interesting to expose the capability to provide a clock to the user!? Btw, got inspired by this - http://www.javapractices.com/topic/TopicAction.do?Id=234