ironic-ui got a bug in unittest coverage

Failed to import test module: ironic_ui.test.tests.test_registration
Traceback (most recent call last):
  File "/opt/jenkins_work/workspace/ironic-ui-debug/.tox/cover/lib/python3.6/site-packages/unittest2/loader.py", line 456, in _find_test_path
    module = self._get_module_from_name(name)
  File "/opt/jenkins_work/workspace/ironic-ui-debug/.tox/cover/lib/python3.6/site-packages/unittest2/loader.py", line 395, in _get_module_from_name
    __import__(name)
  File "/opt/jenkins_work/workspace/ironic-ui-debug/ironic_ui/test/tests/test_registration.py", line 17, in <module>
    from ironic_ui.content.ironic import panel as i_panel
  File "/opt/jenkins_work/workspace/ironic-ui-debug/ironic_ui/content/ironic/panel.py", line 20, in <module>
    from openstack_dashboard.api import base
  File "/opt/jenkins_work/workspace/ironic-ui-debug/.tox/cover/lib/python3.6/site-packages/openstack_dashboard/api/__init__.py", line 37, in <module>
    from openstack_dashboard.api import keystone
  File "/opt/jenkins_work/workspace/ironic-ui-debug/.tox/cover/lib/python3.6/site-packages/openstack_dashboard/api/keystone.py", line 31, in <module>
    from openstack_auth import backend
  File "/opt/jenkins_work/workspace/ironic-ui-debug/.tox/cover/lib/python3.6/site-packages/openstack_auth/backend.py", line 26, in <module>
    from openstack_auth import user as auth_user
  File "/opt/jenkins_work/workspace/ironic-ui-debug/.tox/cover/lib/python3.6/site-packages/openstack_auth/user.py", line 17, in <module>
    from django.contrib.auth import models
  File "/opt/jenkins_work/workspace/ironic-ui-debug/.tox/cover/lib/python3.6/site-packages/django/contrib/auth/models.py", line 2, in <module>
    from django.contrib.auth.base_user import AbstractBaseUser, BaseUserManager
  File "/opt/jenkins_work/workspace/ironic-ui-debug/.tox/cover/lib/python3.6/site-packages/django/contrib/auth/base_user.py", line 47, in <module>
    class AbstractBaseUser(models.Model):
  File "/opt/jenkins_work/workspace/ironic-ui-debug/.tox/cover/lib/python3.6/site-packages/django/db/models/base.py", line 103, in __new__
    app_config = apps.get_containing_app_config(module)
  File "/opt/jenkins_work/workspace/ironic-ui-debug/.tox/cover/lib/python3.6/site-packages/django/apps/registry.py", line 252, in get_containing_app_config
    self.check_apps_ready()
  File "/opt/jenkins_work/workspace/ironic-ui-debug/.tox/cover/lib/python3.6/site-packages/django/apps/registry.py", line 135, in check_apps_ready
    raise AppRegistryNotReady("Apps aren't loaded yet.")
django.core.exceptions.AppRegistryNotReady: Apps aren't loaded yet.