Seems to be an issue within (or triggered by) multiprocessing (test_threads and test_threading pass OK, fwiw):
$ ./python -m test.test_multiprocessing
Fatal Python error: Invalid thread state for this thread
Traceback (most recent call last):
  File "/home/dmalcolm/coding/python-svn/py3k-clean/Lib/runpy.py", line 160, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/home/dmalcolm/coding/python-svn/py3k-clean/Lib/runpy.py", line 73, in _run_code
    exec(code, run_globals)
  File "/home/dmalcolm/coding/python-svn/py3k-clean/Lib/test/test_multiprocessing.py", line 2127, in <module>
    main()
  File "/home/dmalcolm/coding/python-svn/py3k-clean/Lib/test/test_multiprocessing.py", line 2124, in main
    test_main(unittest.TextTestRunner(verbosity=2).run)
  File "/home/dmalcolm/coding/python-svn/py3k-clean/Lib/test/test_multiprocessing.py", line 2103, in test_main
    ManagerMixin.pool = ManagerMixin.manager.Pool(4)
  File "/home/dmalcolm/coding/python-svn/py3k-clean/Lib/multiprocessing/managers.py", line 644, in temp
    token, exp = self._create(typeid, *args, **kwds)
  File "/home/dmalcolm/coding/python-svn/py3k-clean/Lib/multiprocessing/managers.py", line 542, in _create
    conn = self._Client(self._address, authkey=self._authkey)
  File "/home/dmalcolm/coding/python-svn/py3k-clean/Lib/multiprocessing/connection.py", line 149, in Client
    answer_challenge(c, authkey)
  File "/home/dmalcolm/coding/python-svn/py3k-clean/Lib/multiprocessing/connection.py", line 383, in answer_challenge
    message = connection.recv_bytes(256)         # reject large message
EOFError