diff --git a/spec/objectify/objectify_spec.rb b/spec/objectify/objectify_spec.rb
index <HASH>..<HASH> 100644
--- a/spec/objectify/objectify_spec.rb
+++ b/spec/objectify/objectify_spec.rb
@@ -10,6 +10,8 @@ describe Objectify do
 
       objectify :test
 
+      property :id, Serial
+
       property :mesg, String
 
       parameter :x
Added a primary key to the TestObject class.