Use of class level configuration, singleton pattern makes testing difficult

[CloCkWeRX]

The way the code is put together implies There Will Only Ever Be One Filter.

This is particularly annoying to test, as:

• You have to proxy the implementation to apply common stubbing techniques (Try RubyCAS::Filter.any_instance.expects(...) for example)
• @@config is global state
• The common way in which RubyCAS::Filter is recommended to be used (in a before_filter), and how it relies on the global configuration behaviour is complex

Having looked at the origins of this, I understand it's from the depths of 2006 or earlier, but it could do with a bit of love to remove the singleton nature and configuration pattern in favour of something more DI flavoured.

ie:

    class YourController
      before_filter :configurize, :restrict
      
      def configurize
        client = CASClient.new()
        @filter = RubyCAS::Filter.new(client, config.rubycas)
      end




      def restrict
        @filter.filter(self)
      end
    end