I have the following error when running test_fileio on AIX:

======================================================================
FAIL: testAbles (test.test_fileio.OtherFileTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/san_cis/home/cis/.buildbot/python-aix6/3.x.phenix.xlc/build/Lib/test/test_fileio.py", line 269, in testAbles
    self.assertEqual(f.seekable(), False)
AssertionError: True != False

----------------------------------------------------------------------
Ran 34 tests in 0.032s

FAILED (failures=1)

I haven't investigated yet.

This looks vaguely similar to http://bugs.python.org/issue6236#msg91007, although the latter has been fixed.

Some AIX systems have seekable /dev/tty, as is the case here and in msg90762, and on my system too.
There is already an exemption in test_fileio.py for systems that have a seekable /dev/tty. AIX just needs to be exempt too. (from my experience, AIX and Solaris behave similarly in many cases, so it makes sense to add aix next to sunos).
I'm submitting a patch to fix this test case on AIX.

I see that the test pass on AIX, on Python 2.7 and Python 3.6 buildbots, so I close the issue.

This issue was opened 4 years ago. The test is now skipped on many platforms:

            if sys.platform != "win32":
                try:
                    f = self.FileIO("/dev/tty", "a")
                except OSError:
                    # When run in a cron job there just aren't any
                    # ttys, so skip the test.  This also handles other
                    # OS'es that don't support /dev/tty.
                    pass
                else:
                    self.assertEqual(f.readable(), False)
                    self.assertEqual(f.writable(), True)
                    if sys.platform != "darwin" and \
                       'bsd' not in sys.platform and \
                       not sys.platform.startswith('sunos'):
                        # Somehow /dev/tty appears seekable on some BSDs
                        self.assertEqual(f.seekable(), False)
                    self.assertEqual(f.isatty(), True)
                    f.close()

(I'm not 100% sure that the line was this f.seekable() check.)