networking-bgpvpn-functional-full job fails with ModuleNotFoundError: No module named 'mock'

networking-bgpvpn-functional-full job is failing 100% on master and on freshly cut stable/ussuri branches with the following exception:
2020-04-28 22:56:15.630615 | controller | =========================
2020-04-28 22:56:15.630635 | controller | Failures during discovery
2020-04-28 22:56:15.630654 | controller | =========================
2020-04-28 22:56:15.630673 | controller | --- import errors ---
2020-04-28 22:56:15.630694 | controller | Failed to import test module: networking_bgpvpn.tests.functional.db.test_migrations
2020-04-28 22:56:15.630714 | controller | Traceback (most recent call last):
2020-04-28 22:56:15.630734 | controller | File "/usr/lib/python3.6/unittest/loader.py", line 428, in _find_test_path
2020-04-28 22:56:15.630753 | controller | module = self._get_module_from_name(name)
2020-04-28 22:56:15.630773 | controller | File "/usr/lib/python3.6/unittest/loader.py", line 369, in _get_module_from_name
2020-04-28 22:56:15.630792 | controller | __import__(name)
2020-04-28 22:56:15.630812 | controller | File "/home/zuul/src/opendev.org/openstack/networking-bgpvpn/networking_bgpvpn/tests/functional/db/test_migrations.py", line 17, in <module>
2020-04-28 22:56:15.630832 | controller | from neutron.tests.functional.db import test_migrations
2020-04-28 22:56:15.630852 | controller | File "/usr/local/lib/python3.6/dist-packages/neutron/tests/functional/db/test_migrations.py", line 25, in <module>
2020-04-28 22:56:15.630872 | controller | from oslotest import base as oslotest_base
2020-04-28 22:56:15.630892 | controller | ModuleNotFoundError: No module named 'oslotest'
2020-04-28 22:56:15.630911 | controller |
2020-04-28 22:56:15.630930 | controller | Failed to import test module: networking_bgpvpn.tests.functional.test_placeholder
2020-04-28 22:56:15.630949 | controller | Traceback (most recent call last):
2020-04-28 22:56:15.630968 | controller | File "/usr/lib/python3.6/unittest/loader.py", line 428, in _find_test_path
2020-04-28 22:56:15.630987 | controller | module = self._get_module_from_name(name)
2020-04-28 22:56:15.631007 | controller | File "/usr/lib/python3.6/unittest/loader.py", line 369, in _get_module_from_name
2020-04-28 22:56:15.631026 | controller | __import__(name)
2020-04-28 22:56:15.631045 | controller | File "/home/zuul/src/opendev.org/openstack/networking-bgpvpn/networking_bgpvpn/tests/functional/test_placeholder.py", line 1, in <module>
2020-04-28 22:56:15.631065 | controller | from neutron.tests import base
2020-04-28 22:56:15.631084 | controller | File "/usr/local/lib/python3.6/dist-packages/neutron/tests/base.py", line 29, in <module>
2020-04-28 22:56:15.631104 | controller | import mock
2020-04-28 22:56:15.631124 | controller | ModuleNotFoundError: No module named 'mock'
2020-04-28 22:56:15.631142 | controller |
2020-04-28 22:56:15.631161 | controller | ================================================================================
2020-04-28 22:56:15.631181 | controller | The above traceback was encountered during test discovery which imports all the found test modules in the specified test_path.