Using rake test_unit on Bitkeeper repository

I’m writing an RoR application on a source-control system Bitkeeper.
for each source file yyy.zzz in Directory XXX it saves a file called
x.yyy.zzz in subdirectory XXX/SCCS.
when I try to run ‘rake test_unit’ it also tries to execute the files of
the bitkeeper as unit tests, which of course fails.

Is there a way to tell rake to skip all the files in the SCCS directory

thanks a lot,