Looks like the tests may need updating for a changed exception message:

http://buildbot.python.org/all/builders/x86%20Ubuntu%20Shared%203.x/builds/12996/steps/test/logs/stdio
======================================================================
FAIL: test_stat (test.test_posix.PosixTester)
----------------------------------------------------------------------
TypeError: stat: path should be string, bytes or integer, not NoneType

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/srv/buildbot/buildarea/3.x.bolen-ubuntu/build/Lib/test/test_posix.py", line 415, in test_stat
    posix.stat, None)
AssertionError: "can't specify None for path argument" does not match "stat: path should be string, bytes or integer, not NoneType"

======================================================================
FAIL: test_stat_dir_fd (test.test_posix.PosixTester)
----------------------------------------------------------------------
TypeError: argument should be integer or None, not str

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/srv/buildbot/buildarea/3.x.bolen-ubuntu/build/Lib/test/test_posix.py", line 867, in test_stat_dir_fd
    posix.stat, support.TESTFN, dir_fd=posix.getcwd())
AssertionError: "should be integer, not" does not match "argument should be integer or None, not str"