1 files changed, 3 insertions, 1 deletions
diff --git a/Lib/test/test_userstring.py b/Lib/test/test_userstring.py
index 4d1d8b6..51b4f60 100644
--- a/Lib/test/test_userstring.py
+++ b/Lib/test/test_userstring.py
@@ -27,12 +27,14 @@ class UserStringTest(
             realresult
         )
 
-    def checkraises(self, exc, obj, methodname, *args):
+    def checkraises(self, exc, obj, methodname, *args, expected_msg=None):
         obj = self.fixtype(obj)
         # we don't fix the arguments, because UserString can't cope with it
         with self.assertRaises(exc) as cm:
             getattr(obj, methodname)(*args)
         self.assertNotEqual(str(cm.exception), '')
+        if expected_msg is not None:
+            self.assertEqual(str(cm.exception), expected_msg)
 
     def checkcall(self, object, methodname, *args):
         object = self.fixtype(object)