Add doc build

.travis.yml

@@ -35,6 +35,8 @@ matrix:
         - sudo apt-get install -qq ubuntu-restricted-extras ffmpeg
       before_script:
         ffmpeg --help
+    - python: 3.6
+      env: TOXENV=doc
     - python: 3.6
       env: TOXENV=check
   allow_failures:

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py{35,36,37},check
+envlist = py{35,36,37}
 skip_missing_interpreters = True
 
 [travis]
@@ -27,3 +27,11 @@ commands =
     python setup.py checkdocs
     python setup.py check --strict --metadata
     check-manifest {toxinidir}
+
+[testenv:doc]
+whitelist_externals = make
+deps =
+    -r {toxinidir}/requirements-doc.txt
+usedevelop = true
+commands =
+    make -C docs html