commit df3148f9cb843b68f4c65bb152c176eb201a99c8
Author: Kouhei Sutou <kou@clear-code.com>
Date:   Wed Jul 20 22:19:55 2011 +0900

    support Ruby Enterprise Edition. fix #29325
    
    Reported by Hans de Graaff. Thanks!!!

diff --git a/lib/test/unit/attribute.rb b/lib/test/unit/attribute.rb
index c91fc32..13c794c 100644
--- a/lib/test/unit/attribute.rb
+++ b/lib/test/unit/attribute.rb
@@ -36,7 +36,7 @@ module Test
           return unless defined?(@current_attributes)
 
           attributes = {}
-          kept_attributes = {}
+          kept_attributes = StringifyKeyHash.new
           @current_attributes.each do |attribute_name, attribute|
             attributes[attribute_name] = attribute[:value]
             kept_attributes[attribute_name] = attribute if attribute[:keep]