Add sphinx tests to tox and travis ci

.travis.yml

@@ -39,6 +39,10 @@ matrix:
     - name: "3.7 pydocstyle Check"
       python: 3.7
       env: TOXENV=pydocstyle
+
+    - name: "3.7 sphinx Check"
+      python: 3.7
+      env: TOXENV=sphinx
 # Dependencies needed to run tox tests and update coverage.
 install:
   - pip install tox

tox.ini

@@ -4,7 +4,7 @@
 # and then run "tox" from this directory.
 
 [tox]
-envlist = py36, py37, lint, pydocstyle
+envlist = py36, py37, lint, pydocstyle, sphinx
 skip_missing_interpreters = True
 skipsdist=True
 
@@ -31,3 +31,11 @@ deps =
     -r{toxinidir}/requirements.txt
 
 commands = coverage run -m unittest discover -s tests
+
+[testenv:sphinx]
+deps =
+     -r{toxinidir}/requirements.txt
+     -r{toxinidir}/requirements-docs.txt
+commands =
+     sphinx-build -M dummy {toxinidir}/docs/source {toxinidir}/docs/build
+     sphinx-build -M linkcheck {toxinidir}/docs/source {toxinidir}/docs/build