When JUnit first appeared, it was perfectly named, however as time has moved on so has its use.
Jim Webber's recent blog post (here) made a very valid point about when a Unit Test is not really a Unit Test. Test and Behavioural Driven Design push JUnit into an area that is not adequately described as unit testing. Driving a design through testing in this manner means you aren't (at least initially) writing unit tests.
I've also used JUnit in the past to do things which are decidedly not unit testing, its a useful framework to control other sorts of testing. And on more than one occasion have had to explain to a member of management why I used a free unit testing framework instead of using their big expensive shiny testing metaframework thingy.
I am not suggesting that Kent and Eric should rush out and re-release their work under a different name. It was (to me at least) interesting to reflect on naming, and how things progress over time, so once perfectly named entities may gradually slip to the almost perfect. And it is also a reminder that not quite perfect risks gradually slipping to the not relevant at all.
What the perfect name would be today, I don't know, I think the name is still perfect enough.