diff --git a/tox.ini b/tox.ini
index cde448c7..bf59df29 100644
--- a/tox.ini
+++ b/tox.ini
@@ -21,6 +21,12 @@ setenv = DJANGO_SETTINGS_MODULE=manila_ui.tests.settings
 [testenv:py36]
 setenv = DJANGO_SETTINGS_MODULE=manila_ui.tests.settings
 
+[testenv:py3-dev]
+setenv = DJANGO_SETTINGS_MODULE=manila_ui.tests.settings
+commands =
+  pip install {env:HORIZON_REPO:git+git://git.openstack.org/openstack/horizon}
+  {[testenv]commands}
+
 [testenv:pep8]
 basepython = python3
 commands = flake8