regression testing system for the S-Lang scripting language

 TESS is the (Te)st (S)ystem for (S)-Lang, which aims at reducing the
 workload and ad-hoc nature of regression testing S-Lang software, by
 collecting common testing elements into a single, easy-to-use
 framework.
 .
 TESS provides the S-Lang developer nominal mechanisms for tailoring
 the S-Lang environment and invoking functions with arbitrary inputs,
 while transparently inspecting and cleaning the stack, gathering
 pass/fail statistics, and providing error recovery from selected
 exceptions.