I've been playing with infinitest (http://infinitest.github.com/), a Eclipse plugin that is executing continuously your tests. In fact it's not executing ALL your tests, but those afected for your last changes. So far, so good.
Mental reminder:As I'm using maven as my basic building tool, the main problem is to teach Eclipse where my tests are (Project preferences->Java Build Path, check 'Allow output folders for source folders', and insert tartget/test-classes where needed), and ask Eclipse to build project automatically. That's all...