find correct policy when model is namespaced

lib/pundit/policy_finder.rb

@@ -15,7 +15,7 @@ module Pundit
 
     def policy
       klass = find
-      klass = namespace.const_get(klass) if klass.is_a?(String)
+      klass = namespace.const_get(klass.demodulize) if klass.is_a?(String)
       klass
     rescue NameError
       nil

spec/pundit_spec.rb

@@ -4,6 +4,7 @@ describe Pundit do
   let(:user) { double }
   let(:post) { Post.new(user) }
   let(:comment) { Comment.new }
+  let(:nested_comment) { Admin::Comment.new }
   let(:article) { Article.new }
   let(:controller) { Controller.new(user, { :action => 'update' }) }
   let(:artificial_blog) { ArtificialBlog.new }
@@ -199,6 +200,7 @@ describe Pundit do
 
     it "looks up the policy class based on the caller's namespace" do
       expect(nested_controller.policy(comment).class).to eq Admin::CommentPolicy
+      expect(nested_controller.policy(nested_comment).class).to eq Admin::CommentPolicy
     end
 
     it "falls back to the non-namespaced policy class if there isn't a namespaced one" do

spec/spec_helper.rb

@@ -32,6 +32,9 @@ class CommentPolicy::Scope < Struct.new(:user, :scope)
   end
 end
 class Comment; extend ActiveModel::Naming; end
+module Admin
+  class Comment; end
+end
 
 class Article; end