Source and Documentation are available.
In case they're of use to others, I share a few notes I made. Take them with a pinch of salt though 'cos I'm new to Lisp and hoping to rush through several libs this evening.
- explicitly modelled on JUnit, docs include an analysis of how and why it differs
- defines CLOS class test-case, subclass of test; subclass this to place your test methods
- defines test-suite, subclass of test, so you can make nesting test trees
- supports set-up and tear-down in the normal way
- the addition of a test method causes it to be run as well as being added to the relevant suite, for your code-and-run convenience