diff --git a/test/py/SerializationTest.py b/test/py/SerializationTest.py
index a99bce6..296a50a 100755
--- a/test/py/SerializationTest.py
+++ b/test/py/SerializationTest.py
@@ -16,6 +16,7 @@
   def setUp(self):
       self.v1obj = VersioningTestV1(
           begin_in_both=12345,
+          old_string='aaa',
           end_in_both=54321,
           )