Bit rot explained

It wasn’t bit rot that was breaking my Batik tests.  It was maven.  I emerged to the latest version of maven, and dutifully upgraded the various plugins, and all my Batik tests were failing.  I even tried upping the version of junit, etc., to no avail.  But when I finally figured out how to test in Eclipse (just press the run button, who knew that meant test as well?), the tests passed. I’d file a bug with Maven, but I haven’t a clue how to reproduce the bug in a simple way.