Unittest test_distributed_port_binding_deleted_by_port_deletion fails: DeprecationWarning('ssl.PROTOCOL_TLS is deprecated')

[Anton Kurbatov]

I got an error in the test_distributed_port_binding_deleted_by_port_deletion test on my CI run [1].
Also I found the same failure in another CI run [2]

FAIL: neutron.tests.unit.plugins.ml2.test_db.Ml2DvrDBTestCase.test_distributed_port_binding_deleted_by_port_deletion
tags: worker-0
----------------------------------------------------------------------
stderr: {{{
/home/zuul/src/opendev.org/openstack/neutron/.tox/shared/lib/python3.10/site-packages/ovs/stream.py:794: DeprecationWarning: ssl.PROTOCOL_TLS is deprecated
  ctx = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
/home/zuul/src/opendev.org/openstack/neutron/.tox/shared/lib/python3.10/site-packages/ovs/stream.py:794: DeprecationWarning: ssl.PROTOCOL_TLS is deprecated
  ctx = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
}}}

Traceback (most recent call last):
  File "/home/zuul/src/opendev.org/openstack/neutron/neutron/tests/base.py", line 182, in func
    return f(self, *args, **kwargs)
  File "/home/zuul/src/opendev.org/openstack/neutron/neutron/tests/unit/plugins/ml2/test_db.py", line 535, in test_distributed_port_binding_deleted_by_port_deletion
    self.assertEqual(
  File "/home/zuul/src/opendev.org/openstack/neutron/.tox/shared/lib/python3.10/site-packages/testtools/testcase.py", line 393, in assertEqual
    self.assertThat(observed, matcher, message)
  File "/home/zuul/src/opendev.org/openstack/neutron/.tox/shared/lib/python3.10/site-packages/testtools/testcase.py", line 480, in assertThat
    raise mismatch_error
testtools.matchers._impl.MismatchError: [] != [<warnings.WarningMessage object at 0x7f65a6cdd3c0>]: Warnings: {message : DeprecationWarning('ssl.PROTOCOL_TLS is deprecated'), category : 'DeprecationWarning', filename : '/home/zuul/src/opendev.org/openstack/neutron/.tox/shared/lib/python3.10/site-packages/ovs/stream.py', lineno : 794, line : None}

I have spent some time and seem to have found the reason for this behavior on python 3.10.
First of all, since python3.10 we get a warning when using ssl.PROTOCOL_TLS [3]:

[root@node0 neutron]# python
Python 3.10.8+ (heads/3.10-dirty:ca3c480, Nov 30 2022, 12:16:40) [GCC 4.8.5 20150623 (Red Hat 4.8.5-44)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import ssl
>>> ssl.SSLContext(ssl.PROTOCOL_SSLv23)
<stdin>:1: DeprecationWarning: ssl.PROTOCOL_TLS is deprecated
<ssl.SSLContext object at 0x7f98620223c0>
>>>

I also found that the `test_ssl_connection` test case affects catching warnings in the test_distributed_port_binding_deleted_by_port_deletion test case.
I was then able to reproduce the issue like this:

[root@node0 neutron]# cat run_list.txt
neutron.tests.unit.agent.ovsdb.native.test_connection.ConfigureSslConnTestCase.test_ssl_connection
neutron.tests.unit.plugins.ml2.test_db.Ml2DvrDBTestCase.test_distributed_port_binding_deleted_by_port_deletion
[root@node0 neutron]# git diff
diff --git a/neutron/tests/unit/plugins/ml2/test_db.py b/neutron/tests/unit/plugins/ml2/test_db.py
index 578a01a..d837871 100644
--- a/neutron/tests/unit/plugins/ml2/test_db.py
+++ b/neutron/tests/unit/plugins/ml2/test_db.py
@@ -531,6 +531,8 @@ class Ml2DvrDBTestCase(testlib_api.SqlTestCase):
             router_id='router_id',
             status=constants.PORT_STATUS_DOWN).create()
         with warnings.catch_warnings(record=True) as warning_list:
+ import time
+ time.sleep(0.1)
             port.delete()
             self.assertEqual(
                 [], warning_list,
[root@node0 neutron]# source .tox/shared/bin/activate
(shared) [root@node0 neutron]# stestr run --concurrency=1 --load-list ./run_list.txt
...
neutron.tests.unit.plugins.ml2.test_db.Ml2DvrDBTestCase.test_distributed_port_binding_deleted_by_port_deletion
--------------------------------------------------------------------------------------------------------------
Captured traceback:
~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):
      File "/root/github/neutron/neutron/tests/base.py", line 182, in func
    return f(self, *args, **kwargs)
      File "/root/github/neutron/neutron/tests/unit/plugins/ml2/test_db.py", line 537, in test_distributed_port_binding_deleted_by_port_deletion
    self.assertEqual(
      File "/root/github/neutron/.tox/shared/lib/python3.10/site-packages/testtools/testcase.py", line 393, in assertEqual
    self.assertThat(observed, matcher, message)
      File "/root/github/neutron/.tox/shared/lib/python3.10/site-packages/testtools/testcase.py", line 480, in assertThat
    raise mismatch_error
    testtools.matchers._impl.MismatchError: [] != [<warnings.WarningMessage object at 0x7f701cb5f640>]: Warnings: {message : DeprecationWarning('ssl.PROTOCOL_TLS is deprecated'), category : 'DeprecationWarning', filename : '/root/github/neutron/.tox/shared/lib/python3.10/site-packages/ovs/stream.py', lineno : 794, line : None}

======
Totals
======
Ran: 2 tests in 1.3571 sec.
 - Passed: 1
 - Skipped: 0
 - Expected Fail: 0
 - Unexpected Success: 0
 - Failed: 1
Sum of execute time for each test: 1.3053 sec.

[1] https://zuul.opendev.org/t/openstack/build/8e0dd6e817394911aa0baffe07798b13
[2] https://zuul.opendev.org/t/openstack/build/9f7881818f7842b38d31ed44ffa8a4f3
[3] https://github.com/python/cpython/blob/3.10/Modules/_ssl.c#L3038

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/neutron/+/866178

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron/+/866178
Committed: https://opendev.org/openstack/neutron/commit/26c55efe34f317409e4277154bac4617db0d57cc
Submitter: "Zuul (22348)"
Branch: master

commit 26c55efe34f317409e4277154bac4617db0d57cc
Author: Anton Kurbatov <email address hidden>
Date: Wed Nov 30 15:04:34 2022 +0000

    Do not emit ssl warnings in the test_ssl_connection test

    Since python3.10 we get a warning inside the ovs.stream module:

    Warnings: {message : DeprecationWarning('ssl.PROTOCOL_TLS is
    deprecated'), category : 'DeprecationWarning', filename :
    'python3.10/site-packages/ovs/stream.py', lineno : 794, line : None}

    or using python console:

    >>> ssl.SSLContext(ssl.PROTOCOL_SSLv23)
    <stdin>:1: DeprecationWarning: ssl.PROTOCOL_TLS is deprecated
    <ssl.SSLContext object at 0x7f98620223c0>
    >>>

    This patch mocks the 'Connection.run' method that emits this warning
    inside a thread. This patch also fixes a failure in the
    test_distributed_port_binding_deleted_by_port_deletion test that was
    catching the ssl warning from test_ssl_connection and therefore
    failing.

    Closes-Bug: #1998343
    Signed-off-by: Anton Kurbatov <email address hidden>
    Change-Id: I6a4b9222a63a0d0271069eb12d0c97dd3821a2cc

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 22.0.0.0rc1 release candidate.