I've been putting a LOT of effort into getting miniunit (still needs a better name... c'mon ppl!) flushed out and polished. This is the release I think is finally ready to replace test/unit in 1.9, but I need your feedback to know how it is. You can help by installing the gem and flipping it on:
% sudo gem install miniunit
% sudo use_miniunit yes
The second command will install symlinks into your sitelib directory. That comes before the stdlib dir in $LOAD_PATH so it'll take over for test/unit. You can roll it out by providing "no" as an argument instead. It should be totally easy and safe.
I've added a lot of really great stuff in this release. The biggies:
- New useful assertions like
assert_includes. - A
refutemirrors everyassert. egrefute_empty ary - I added
mini/specandmini/mockand they can work side-by-side withmini/test.
One of the things I did was put a lot of effort into making it work with abusive frameworks like rails (they do bad things to test frameworks). But we used the rails tests in very particular ways, so I don't know if there are other ways that don't work with miniunit.
One thing I'm proud of: Even with all the extra assertions, the spec framework, the mock framework, I still blow test/unit away. Check it:
miniunit
lib loc 641 total
test loc 905 total
totl loc 1546 total
flog = 707.623602773533
test/unit
lib loc 3571 total
test loc 2464 total
totl loc 6035 total
flog = 3103.27739878118
Rad eh?
So, install it and take it for a spin. Report bugs on rubyforge.
NOTE: Do not report bugs against it if you're trying to use it integrated into a GUI IDE/test-runner like komodo. It isn't meant to be compatible with GUI runners and the like. It is meant to be compatible with your tests.

Looks nice...I'm about to give it a go.
A mini unit, a small unit, of measure. Pico?
I will check it out !
A name... huh... meanunit ?