Reported by Axel Luttgens.
Running :mod:`test.regrtest` directly allows what resources are available for
tests to use to be set. You do this by using the ``-u`` command-line
option. Specifying ``all`` as the value for the ``-u`` option enables all
-possible resources: :program:`python -m test -uall`.
+possible resources: :program:`python -m test.regrtest -uall`.
If all but one resource is desired (a more common case), a
comma-separated list of resources that are not desired may be listed after
``all``. The command :program:`python -m test.regrtest -uall,-audio,-largefile`