diff --git a/tox.ini b/tox.ini
index def520cd5e8..2f49bbc46a9 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,6 +5,7 @@ skipsdist = True
 
 [testenv]
 setenv = VIRTUAL_ENV={envdir}
+         PYTHONWARNINGS=default::DeprecationWarning
 passenv = TRACE_FAILONLY GENERATE_HASHES http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
 usedevelop = True
 install_command =