Little Languages for Testing?

[Eric Kidd <address@hidden>]

Extensive unit testing seems to be getting more popular, thanks to
better testing libraries, and test-intensive methodologies like XP. 
Tool support is fairly good: JUnit and similar libraries are pleasant to
use, and increasingly standard.

But could we do better?  Some questions:

* Should there be an intermediate level of access between 'public' and
'private' for use by unit tests?

* If it were possible to declare unit tests in the same file as the
source code--without code bloat--would this lead to better or worse
programs?

* Are there any really good macro libraries for unit testing?  Harlequin
Dylan included a pretty slick one--and I've seen a few LISP packages
floating around--but I'd love to hear of other libraries which do this
well.

Cheers,
Eric