x86 Gentoo Installed with X 3.x:
https://buildbot.python.org/all/#/builders/464/builds/445

0:05:51 load avg: 4.73 [104/425/1] test_pty failed -- running: test_unparse (1 min 3 sec)

test_fork (test.test_pty.PtyTest) ... calling pty.fork()
Waiting for child (3734) to finish.
Child (3734) exited with code 4 (status 1024).
ok

test_master_read (test.test_pty.PtyTest) ... Calling pty.openpty()
Got master_fd '3', slave_fd '4'
Closing slave_fd
Reading from master_fd
ok

test_openpty (test.test_pty.PtyTest) ... Setting pty.STDIN_FILENO window size
Calling pty.openpty()
Got master_fd '3', slave_fd '4'
Writing to slave_fd
Writing chunked output
unexpected success

test__copy_eof_on_all (test.test_pty.SmallPtyTests)
Test the empty read EOF case on both master_fd and stdin. ... ok

test__copy_to_each (test.test_pty.SmallPtyTests)
Test the normal data case on both master_fd and stdin. ... ok

----------------------------------------------------------------------

Ran 5 tests in 0.054s

FAILED (unexpected successes=1)
test test_pty failed