> I think we should be moving *away* from having special infrastructure
> in regrtest.  As much stuff as makes sense should be moved to
> unittest, and we've been slowly doing that.  Correspondingly, we
> should use Sphinx's native test facilities, not add special stuff to
> regrtest.  If Sphinx doesn't have the ability to run individual files,
> we should add that ability to Sphinx, not regrtest.  (Note: I
> personally do not use the ability recently added to regrtest to select
> unit tests from the command line, instead I use the unittest CLI
> directly, and I think that's the better way to do it.  IMO regrtest
> should be focused on running the test *suite*, not on running
> individual tests.)

The main reason to add it to regrtest was to allow special test modes
with it (such as -R or -F). (and, also, the unittest CLI's poor online
help makes it rather unusable for me :-)).
But I agree on the principle that unittest should be expanded to better
accomodate the needs of regrtest.