Comment 6 for bug 2009818

Reopened this BZ as it still reproduces.
The test is https://github.com/openstack/cinder-tempest-plugin/blob/master/cinder_tempest_plugin/rbac/v3/test_user_messages.py#L125

Traceback (most recent call last):
  File "/opt/stack/tempest/.tox/tempest/lib/python3.10/site-packages/cinder_tempest_plugin/rbac/v3/test_user_messages.py", line 125, in test_delete_message
    self._delete_message(expected_status=exceptions.Forbidden)
  File "/opt/stack/tempest/.tox/tempest/lib/python3.10/site-packages/cinder_tempest_plugin/rbac/v3/test_user_messages.py", line 95, in _delete_message
    self.do_request(
  File "/opt/stack/tempest/.tox/tempest/lib/python3.10/site-packages/cinder_tempest_plugin/rbac/v3/base.py", line 81, in do_request
    self.assertRaises(expected_status,
  File "/opt/stack/tempest/.tox/tempest/lib/python3.10/site-packages/testtools/testcase.py", line 468, in assertRaises
    self.assertThat(our_callable, matcher)
  File "/opt/stack/tempest/.tox/tempest/lib/python3.10/site-packages/testtools/testcase.py", line 481, in assertThat
    raise mismatch_error
testtools.matchers._impl.MismatchError: <bound method MessagesClient.delete_message of <tempest.lib.services.volume.v3.messages_client.MessagesClient object at 0x7f97ceac68f0>> returned {}