Comment 3 for bug 1958513

[root@e2527900d3c2 neutron]# tox -e py36 neutron.tests.unit.services.ovn_l3.test_plugin.TestOVNL3RouterPlugin.test_schedule_unhosted_gateways
py36 create: /root/neutron/.tox/py36
py36 installdeps: -chttps://releases.openstack.org/constraints/upper/master, -r/root/neutron/requirements.txt, -r/root/neutron/test-requi

run tox, will request "releases.openstack.org", due to the regional network, it is time-consuming. Don't consider supporting testools? the modification is not complicated and has no adverse effect. It seems that other unit test files can be directly used with testtools