diff --git a/tox.ini b/tox.ini
index 193ccc0949..2cd69e946d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,7 +4,9 @@ envlist = py34,py27,pep8
 skipsdist = True
 
 [testenv]
-setenv = VIRTUAL_ENV={envdir}
+setenv =
+  VIRTUAL_ENV={envdir}
+  PYTHONWARNINGS=default::DeprecationWarning
 usedevelop = True
 install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}
 deps = -r{toxinidir}/test-requirements.txt