to be used when you really want to safeguard
that some other test has not run first.

This slot doesn't really do what it's says it does (redefining it
doesn't change things the way you'd expect) and it causes no end of
headaches by confusing compile-time definitions with run-time
definitions.

Added *num-trials*, *max-trials* and checking of whether the test code is ever run in a FOR-ALL test

Initial import of FiveAM code. This is exactly equal to to bese-2004@common-lisp.net/FiveAM--dev--1.2--patch-20