When I run test_socket.py, I got a error. Looks it's a problem of security group.
My env: a vm of centos
May be I need add `EHOSTUNREACH` in support.get_socket_conn_refused_errs()?

======================================================================
FAIL: test_create_connection (test.test_socket.NetworkConnectionNoServer)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/shihai/workspace/cpython/Lib/test/test_socket.py", line 4961, in test_create_connection
    self.assertIn(cm.exception.errno, expected_errnos)
AssertionError: 113 not found in [111, 101, 99, 97]

----------------------------------------------------------------------
Ran 814 tests in 25.929s

FAILED (failures=1, errors=117, skipped=197)

Victor handled similar errors in issue36629 where this helper was introduced.

So I add this 113 error in `get_socket_conn_refused_errs` too ;)

Can you copy/paste the full output of test_socket, or better: of the whole test suite? Put it in a file and attach it to the issue.

sure, i copied the full output of test_socket. more failed test case looks like need add two property functions.

ping :)

I don't understand such error:


======================================================================
ERROR: testSendmsgBadMultiCmsg (test.test_socket.SendmsgTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/shihai/workspace/cpython/Lib/test/test_socket.py", line 2649, in setUp
    self.serv_sock.settimeout(self.fail_timeout)
AttributeError: 'SendmsgTests' object has no attribute 'serv_sock'

Oh, sorry, victor. I use ./python -m unittest xxx before.

Updating the test result again.

New changeset 1ac2a83f30312976502fda042db5ce18d10ceec2 by Victor Stinner (Hai Shi) in branch 'master':
bpo-37583: Add err 113 to support.get_socket_conn_refused_errs() (GH-14729)
https://github.com/python/cpython/commit/1ac2a83f30312976502fda042db5ce18d10ceec2

New changeset ee989512528d178d6f088916aba3e67ea9487ceb by Miss Islington (bot) in branch '3.8':
bpo-37583: Add err 113 to support.get_socket_conn_refused_errs() (GH-14729)
https://github.com/python/cpython/commit/ee989512528d178d6f088916aba3e67ea9487ceb

New changeset fbb0c032e89c42ab44f5372df40fffb34a91b575 by Victor Stinner (Hai Shi) in branch '3.7':
bpo-37583: Add err 113 to support.get_socket_conn_refused_errs() (GH-15259)
https://github.com/python/cpython/commit/fbb0c032e89c42ab44f5372df40fffb34a91b575

Thanks Hai Shi for the bug report and the fix. It's now fixd in 3.7, 3.8 and master branches.

First I understood that you wanted to modify transient_internet() which is used in many places. Fixing support.get_socket_conn_refused_errs() is fine, it's only used in 2 test functions.

I don't think that it's worth it to fix Python 2.7 (which doesn't have get_socket_conn_refused_errs() function but build errno list directly in test_socket).