diff --git a/tox.ini b/tox.ini
index a5981ec1..7da60f5b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -9,6 +9,7 @@ install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstac
 setenv =
    VIRTUAL_ENV={envdir}
    OS_TEST_PATH=./karbor/tests/unit
+   PYTHONWARNINGS=default::DeprecationWarning
 deps = -r{toxinidir}/test-requirements.txt
 commands = python setup.py test --slowest --testr-args='{posargs}'