qa: add docs tox env (using -W) and use it on Travis

Author: blueyed

.travis.yml

@@ -32,7 +32,7 @@ jobs:
       env: TOXENV=pypy3-dj110-sqlite
 
     - python: 3.6
-      env: TOXENV=checkqa
+      env: TOXENV=checkqa,docs
 
     - stage: PyPI Release
       if: tag IS present

setup.py

@@ -31,6 +31,12 @@ def read(fname):
     python_requires='>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*',
     setup_requires=['setuptools_scm>=1.11.1'],
     install_requires=['pytest>=3.6'],
+    extras_require={
+        'docs': [
+            'sphinx',
+            'Flask-Sphinx-Themes',
+        ]
+    },
     classifiers=['Development Status :: 5 - Production/Stable',
                  'Framework :: Django',
                  'Framework :: Django :: 1.8',

tox.ini

@@ -59,6 +59,11 @@ deps =
 commands =
     doc8 docs/
 
+[testenv:docs]
+deps =
+extras = docs
+commands = sphinx-build -W -b html -d docs/_build/doctrees docs docs/_build/html
+
 [testenv:readme]
 basepython = python3.5
 deps =