appendseed is an additional option exposed by the randomized runner which I ported in this custom runner too: http://labs.carrotsearch.com/download/randomizedtesting/2.0.0/api/randomizedtesting-runner/com/carrotsearch/randomizedtesting/SysGlobals.html#SYSPROP_APPEND_SEED() .

It addresses a visualization issue that you might have when executing tests with some GUIs. It just allows to always add the seed to each test description (by default enabled only when running multiple iterations).