Comment 3 for bug 1433800

Much shorter script to reproduce the bug:

python -m testtools.run oslo_utils.tests.test_netutils.TestIsIPv6Enabled.test_disabled tests.test_excutils.SaveAndReraiseTest.test_save_and_reraise_exception_dropped

I'm working a fix. It's a bug in test_netutils.TestIsIPv6Enabled which never stops a mock.