Add tox env to build docs

In django-based projects, we need to specify DJANGO_SETTINGS_MODULE
when running docs build. It is required to addresses the failure of
docs build job in the gate.

Change-Id: I33a867bc00c70f333c4dc62add411f833e418424
Closes-Bug: #1302532

1 files changed, 4 insertions, 0 deletions

diff --git a/tox.ini b/tox.ini
index 2453f31..8c2d0db 100644
--- a/tox.ini
+++ b/tox.ini
@@ -30,6 +30,10 @@ commands = flake8
 [testenv:venv]
 commands = {posargs}
 
+[testenv:docs]
+setenv = DJANGO_SETTINGS_MODULE=openstack_auth.tests.settings
+commands = python setup.py build_sphinx
+
 [tox:jenkins]
 downloadcache = ~/cache/pip