diff --git a/activerecord/test/cases/primary_keys_test.rb b/activerecord/test/cases/primary_keys_test.rb
index adb4f4c4fbb9f512871bc8d09dfbcd50490f4851..e6e50a4cd43b7402b8ae285e28f78ef6ce6c67ed 100644
--- a/activerecord/test/cases/primary_keys_test.rb
+++ b/activerecord/test/cases/primary_keys_test.rb
@@ -1,5 +1,6 @@
 require "cases/helper"
 require 'models/topic'
+require 'models/reply'
 require 'models/subscriber'
 require 'models/movie'
 require 'models/keyboard'