[plt-scheme] testing modules

I want to introduce students to the basics of the PLT module system at a 
particular point in a course. They don't know about I/O yet. They've 
been writing tests in HtDP style. But, although expressions in a module 
are evaluated when run with the module language selected in DrScheme, 
their values are not reported. Is the best thing to do to put the tests 
in an auxiliary file which requires the new module? That seems a bit 
awkward. Is there something short of Schemeunit I should be telling them 
about? Thanks. --PR