I used to work for Sony Ericsson and my first job for the company was developing the J2ME SDK. The last thing I did as a developer was initiating the Mobile jUnit development (another guy finished it, though, and he should get the credit for it becoming a great tool.)
This was a couple of years ago and now when I am in the need for a unit testing framework for Java ME it seems not much has happened. There seems to be basically three options and none of them seems very actively developed. I wonder why.