fix and improve (#172)

Author: Juliya Smith

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 envlist =
-    py{38,37,36,35,27}
+    py{38,37,36,35}
     docs
     style
 skip_missing_interpreters = true
@@ -25,8 +25,11 @@ deps =
     recommonmark
     sphinx_rtd_theme
     sphinx-click
+whitelist_externals = bash
 
-commands = sphinx-build -W -b html -d {envtmpdir}/doctress docs {envtmpdir}/html
+commands =
+    sphinx-build -W -b html -d "{envtmpdir}/doctrees" docs "{envtmpdir}/html"
+    bash -c "open {envtmpdir}/html/index.html || true"
 
 [testenv:style]
 deps = pre-commit