diff --git a/test/irb/helper.rb b/test/irb/helper.rb
index 9d41a98237..a51e9a84b9 100644
--- a/test/irb/helper.rb
+++ b/test/irb/helper.rb
@@ -1,4 +1,8 @@
 require "test/unit"
+begin
+  require_relative "../lib/helper"
+rescue LoadError # ruby/ruby defines helpers differently
+end
 
 module IRB
   class InputMethod; end