http://kegel.com/wine/sweng/2010/#tests now points to a trivial test suite for cmd that is currently driven by a shell script (so on windows you need to install cygwin). Later I'll replace the shell script with a C program that bundles the test data into the executable to allow its use in WineTestBot and winetest. (I'm away from my office, so I haven't tested it on Wine yet.)
Austin also has a small test for cmd in http://code.google.com/p/winezeug/source/browse/trunk/appinstall/scripts/cmd...
The main difference between the two is that people writing tests have to do lots of escaping in Austin's (because his test data is inline in the script) but not in mine (because test data is stored in external files during authoring; it will be packed into the executable later when I translate this into C). - Dan