For testing, only load rubygems if mocha is missing

activesupport/test/abstract_unit.rb

@@ -1,8 +1,15 @@
 ORIG_ARGV = ARGV.dup
 
-require 'rubygems'
 require 'test/unit'
 
+begin
+  require 'mocha'
+rescue LoadError
+  $stderr.puts 'Loading rubygems'
+  require 'rubygems'
+  require 'mocha'
+end
+
 ENV['NO_RELOAD'] = '1'
 $:.unshift "#{File.dirname(__FILE__)}/../lib"
 require 'active_support'