The attached patch against 2.7 adds a new fixer to 2to3 that replaces deprecated unittest method names with the correct ones.
There are a few issues:
1) only the "safe" renamings are included; the assert[SameElements|ItemsEqual|CountEqual] and the  assert*Regexp*->assert*Regex* changes are missing;
2) unless 2to3 provides a way to specify a target version (e.g. 3.2 rather than just 3.x), the missing renamings can't be included;
3) the patch is against 2.7 but I'm not sure in what versions could/should be included, or if the fixer should (also|only) go on PyPI;
4) this fixer is useful from 3.1 to 3.2 too, is there a way to use it with 3.x versions only?
5) doc is still missing;

2to3 patches should currently be made against and checked into the sandbox.

Should this still go to the sandbox? and if so, what is the right sandbox?

Ping.

Bikeshedding, but the fixer name of 'asserts' bugs me.  I'd suggest 'unittest' or 'unittest_asserts'.

Looks fine, though. Make sure to add docs to library/2to3.rst.

Can this still go on 2.7/3.2/3.3?

Yes! 2to3 features are allowed in stable releases.
On Mar 2, 2013 5:17 AM, "Ezio Melotti" <report@bugs.python.org> wrote:

>
> Ezio Melotti added the comment:
>
> Can this still go on 2.7/3.2/3.3?
>
> ----------
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <http://bugs.python.org/issue10712>
> _______________________________________
>

I've converted Ezio's patch to Mercurial format, updated the lib2to3 documentation and added tests for assertRegexpMatches and assertRaisesRegexp aliases[1].

[1] http://docs.python.org/3.4/library/unittest.html#deprecated-aliases

There are reasons why Ezio did not include assert*Regexp*->assert*Regex* in his patch.

Here is an updated patch that is the same as my first patch but also includes the documentation provided by Berker (thanks!).

LGTM.

New changeset cc0fc4e9b494 by Ezio Melotti in branch 'default':
#10712: 2to3 has a new "asserts" fixer that replaces deprecated names of unittest methods.
http://hg.python.org/cpython/rev/cc0fc4e9b494

Committed in 3.4, I'll backport it to 2.7/3.3 later.
Thanks for the review!

I committed this to 2.7 in 9336b470544b but screwed up the copy and paste of the issue number so it didn't auto post.

Thanks!