diff --git a/gobject/tests/testcommon.h b/gobject/tests/testcommon.h
index 0fdaea892..a2b69b7b7 100644
--- a/gobject/tests/testcommon.h
+++ b/gobject/tests/testcommon.h
@@ -40,7 +40,8 @@ prefix ## _get_type (void)					\
 	  NULL,           /* class_data */			\
 	  sizeof (name),					\
 	  0,             /* n_prelocs */			\
-	  (GInstanceInitFunc) instance_init			\
+	  (GInstanceInitFunc) instance_init,			\
+	  (const GTypeValueTable *) NULL,			\
 	};							\
 								\
       object_type = g_type_register_static (parent_type,	\