From: Paul McMahon <pm@...>
Date: 2008-04-08T15:32:50+09:00
Subject: Re: testing a singleton method....

I'm not exactly sure what you are trying to test, but this works:

   def test_singleton_method
     string1 = "hello"
     string2 = "world"
     def string1.only_one
       puts "PLEASE WORK"
     end
     assert string1.respond_to?(:only_one)
     assert !string2.respond_to?(:only_one)
   end