diff --git a/ChangeLog b/ChangeLog
index acf4910591..1659d899e0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Fri Jun 29 05:08:41 2012  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* lib/test/unit/parallel.rb: workaround fix for rubygems.
+	  RubyGems can't find rake if the source directory is not equal to
+	  the directory which is running the test. [Bug #6604]
+
 Thu Jun 28 20:33:15 2012  Luis Lavena  <luislavena@gmail.com>
 
 	* test/win32ole/test_win32ole.rb (test_s_codepage_changed):
diff --git a/lib/test/unit/parallel.rb b/lib/test/unit/parallel.rb
index b3f2eeae05..65a8264ea2 100644
--- a/lib/test/unit/parallel.rb
+++ b/lib/test/unit/parallel.rb
@@ -169,6 +169,10 @@ if $0 == __FILE__
       end
     end
   end
+  require 'rubygems'
+  class Gem::TestCase < MiniTest::Unit::TestCase
+    @@project_dir = File.expand_path('../../../..', __FILE__)
+  end
 
   Test::Unit::Worker.new.run(ARGV)
 end