I agree that a test suite is needed, both for syntax-case and for all of
the macros it defines, like cond, case, etc., and for that matter for the
rest of R6RS.  I have started a test suite for syntax-case, but it
presently depends on Chez Scheme extensions.  At some point I'll migrate
it to use only R6RS features.  In the meantime, contributions are welcome.

Kent Dybvig