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.