recently I've been shocked by how many people write their unit tests without actually putting any assertions in them. Can you imagine that?
Long story short a good friend of mine proposed that we write an application/maven plugin called JTK (which stands for Java Test Killer) that will check the test cases and will provide a clear overview of how many of the tests that the project has make no sense based on the fact that they don't call any assertions.
You can check out the sources on bitbucket.org (it's obviously managed under Mercurial so you'll have to have the client installed which you can get from here)
The maven repository (in case you'd like to give it a spin) is here (snapshots only as of this moment but we're planning on releasing it eventually).
We're at a very early stage but if you're interested in helping out let me know!