STRUCTURE

Here is an example revised plugin directory structure for the hypothetical plugin 'WildChicken'.

  vendor/
    plugins/
      plugin_name/
        init.rb
        install.rb
        lib/
          wild_chicken.rb
        Rakefile
        README
        tasks/
          wild_chicken_tasks.rake
        test/
          app/
            chicken_controller.rb
            chicken.rb
          config/
            database.yml
          fixtures/
            chickens.yml
          functional/
            chicken_controller_test.rb
          helpers/
            wild_chicken_test_helper.rb
            ptk_helper.rb
          integration/
            chicken_integration_test.rb
          mocks/
            mock_chicken.rb
          performance/
            fast_chicken.rb
          unit/
            plugin_name_test.rb
          views/

GEM

Rails Plugin Development Kit
  * generator for out-of-application plugin generation
  * generators: generator_plugin, model_plugin, controller_plugin, external_plugin, monkey_patch
  * test development kit: require_library, require_suite, require_environment, require_application
  * test development suites & libraries:
      - gems: activerecord, actionpack, actionmailer, rails (dispatcher, etc.)
      - assertions: difference, change, keys, flash, cookies, sessions
      - dependencies: plugins, gems, load paths
      - performance: benchmarks, stress tests