--- ./Lib/test/test_fileio.py_orig	2015-05-23 18:09:10.000000000 +0200
+++ ./Lib/test/test_fileio.py	2015-08-06 09:54:23.000000000 +0200
@@ -308,7 +308,8 @@
             self.assertEqual(f.writable(), True)
             if sys.platform != "darwin" and \
                'bsd' not in sys.platform and \
-               not sys.platform.startswith('sunos'):
+                not sys.platform.startswith('sunos') and \
+                not sys.platform.startswith('aix'):
                 # Somehow /dev/tty appears seekable on some BSDs
                 self.assertEqual(f.seekable(), False)
             self.assertEqual(f.isatty(), True)