diff --git a/nutils/testing.py b/nutils/testing.py
index c813f8068..451a97261 100644
--- a/nutils/testing.py
+++ b/nutils/testing.py
@@ -184,6 +184,7 @@ def setUp(self):
         self.enter_context(treelog.set(treelog.LoggingLog('nutils')))
         self.enter_context(_builtin_warnings.catch_warnings())
         _builtin_warnings.simplefilter('error', warnings.NutilsWarning)
+        _builtin_warnings.simplefilter('error', DeprecationWarning)
 
     def assertAllEqual(self, actual, desired):
         actual = numpy.asarray(actual)