Damn. If assertSameElements has already shipped with the existing implementation then we can't change it. The documentation really needs clarifying to make it clear that it ignores duplicates.

I would be happy with a 'check_order' argument to assertSequenceEqual defaulting to True, and slightly prefer that to a new method.

FWIW the http://code.google.com/p/python-unittest-backport/ project is quite out of date. I am intending to do my own port (before PyCon) that subclasses unittest so that it can interoperate with code using the Python 2.4-2.6 standard library unittest. I may get in touch with the project owner to see if I can join him on his project.