py.test features for a new unittest

Hi all,

I'm working on a new design for Python's unittest to (hopefully) be
shipped with Python 3, and I'm interested in incorporating some of
py.test's features. (You can get a good overview of the heart of the
new design from http://oakwinter.com/code/a-new-unittest/.) The new
unittest is focused on ease of extensibility, while still
incorporating enough
user-facing functionality to be useful. To that end, I'm keen to
import py.test's traceback snipping/beautification, concept of
generative tests, print debugging and (possibly) module-level
setup/teardown.

I plan on bring this up on the new testing-in-python list soon, but I
thought I'd ask this more targeted audience first: is there anything
from py.test (or otherwise) that you'd like to see go into a
totally-rewritten unittest design? Is there anything you've tried to
do in terms of extending unittest that the old design made unworkable
or unnecessarily complicated?

Thanks,
Collin Winter