add some tests, yay!

actionpack/test/routing/helper_test.rb

+require 'abstract_unit'
+
+module ActionDispatch
+  module Routing
+    class HelperTest < ActiveSupport::TestCase
+      class Duck
+        def to_param
+          nil
+        end
+      end
+
+      def test_exception
+        rs = ::ActionDispatch::Routing::RouteSet.new
+        rs.draw do
+          resources :ducks do
+            member do
+              get :pond
+            end
+          end
+        end
+
+        x = Class.new {
+          include rs.url_helpers
+        }
+        assert_raises ActionController::RoutingError do
+          x.new.pond_duck_path Duck.new
+        end
+      end
+    end
+  end
+end