diff -r dcfc446d8eae -r e5453b19bc6e tox.ini
--- a/tox.ini	Mon Jun 27 14:17:19 2016 +0200
+++ b/tox.ini	Tue Jun 28 15:02:04 2016 +0200
@@ -44,11 +44,10 @@
 
 [testenv:doc]
 changedir = doc
-whitelist_externals =
-  sphinx-build
 deps =
   sphinx
-commands = sphinx-build -b html -d {envtmpdir}/doctrees .  {envtmpdir}/html
+commands =
+  {envpython} -c 'import sphinx; sphinx.main()' -b html -d {envtmpdir}/doctrees .  {envtmpdir}/html
 
 [pytest]
 python_files = *test_*.py