diff --git a/tox.ini b/tox.ini
index 592b724..07860fc 100644
--- a/tox.ini
+++ b/tox.ini
@@ -74,3 +74,10 @@ commands =
 
 [pytest]
 junit_family=xunit2
+filterwarnings =
+  error
+# there is nothing we can do about that
+  ignore:defusedxml.lxml is no longer supported:DeprecationWarning:openpyxl.xml.functions
+  ignore:Using or importing the ABCs from 'collections':DeprecationWarning:django.*
+# remind us later
+  once:.*staticfiles.*::django\..*