Modify the 'tox.ini' file
Since the horizon remove the 'run_tests.sh' file,
so there should remove '.venv' from the '.tox.ini' file.
@@ -158,7 +158,7 @@ commands =
[flake8]
filename = *.py,django.wsgi
-exclude = .venv,.git,.tox,dist,*lib/python*,*egg,build,panel_template,dash_template,local_settings.py,*/local/*,*/test/test_plugins/*,.ropeproject,node_modules,openstack_dashboard/enabled/*
+exclude = .git,.tox,dist,*lib/python*,*egg,build,panel_template,dash_template,local_settings.py,*/local/*,*/test/test_plugins/*,.ropeproject,node_modules,openstack_dashboard/enabled/*
ignore =
# Enable the following hacking rules which are disabled by default
# H106 Do not put vim configuration in source files.
