In my checkout of py3k (r83123), test_getgroups in test_posix fails - the right elements are returned but the ordering is different:

$ ./python -m test.regrtest test_posix
test_posix
test test_posix failed -- Traceback (most recent call last):
  File "/home/daz/src/py3k/Lib/test/test_posix.py", line 360, in test_getgroups
    self.assertEqual([int(x) for x in groups.split()], posix.getgroups())
AssertionError: Lists differ: [1000, 4, 6, 20, 24, 46, 105, ... != [4, 6, 20, 24, 46, 105, 119, 1...

First differing element 0:
1000
4

- [1000, 4, 6, 20, 24, 46, 105, 119, 122, 125, 126, 128]
+ [4, 6, 20, 24, 46, 105, 119, 122, 125, 126, 128, 1000]

1 test failed:
    test_posix

Platform is Ubuntu 10.04 x86_64, kernel is 2.6.32 - unfortunately my C sucks so I'm not sure what's going on.

After a quick chat with Ronald at the EP sprint he says the ordering didnt matter, so here's a quick patch to check only for deltas.

Committed a fix in:

3.2: r83133
3.1: r83134
2.7: r83135
2.6: r83136

I ended up committing a slightly different patch than attached here, the test now calls sorted to sort both lists before comparing, which IMO makes it slightly clearer.

Except for the 2.6 backport, you could also have used assertItemsEqual, which is a smart wrapper around the idiom you implemented.