diff --git a/tox.ini b/tox.ini
index b432aa9..2bbc4db 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,13 +4,16 @@
 # and then run "tox" from this directory.
 
 [tox]
-envlist = dummy, py26, py27, py32, py33, py34
+envlist = py26, py27, py32, py33, py34
 
 [testenv]
-commands = py.test {posargs:--cov pipdeptree --cov-report xml --cov-report html --cov-report term-missing tests/}
+commands =
+    tox -e dummy
+    py.test {posargs:--cov pipdeptree --cov-report xml --cov-report html --cov-report term-missing tests/}
 deps =
     pytest
     pytest-cov
+whitelist_externals = tox
 
 # ---------------------------------------------------------------------------
 # Dummy virtualenvs that get created and used by the tests