Ensure an embedded object within an embedded object can be sorted

spec/features/smoke_spec.rb

@@ -231,19 +231,29 @@
 
         context 'with an embedded document' do
           before do
-            Post.where(body: 'The quick brown fox jumps over the lazy dog.').update_all(author: {name: 'Bob'})
-            post.author = Author.new name: 'Adam'
+            Post.where(body: 'The quick brown fox jumps over the lazy dog.').update_all(author: { name: 'Bob', city: { name: 'Washington' } })
+            post.author = Author.new name: 'Adam', city: { name: 'California' }
             post.save!
+            Post.all.each{|p| p.author.city }
           end
 
-          it 'sorts by author name' do
+          it 'sorts by the embedded document field' do
             click_on 'Posts'
             visit '/admin/posts?order=author.name_desc'
             page.first('#index_table_posts > tbody > tr').should have_content 'Bob'
 
             visit '/admin/posts?order=author.name_asc'
             page.first('#index_table_posts > tbody > tr').should have_content 'Adam'
           end
+
+          it 'sorts by embedded document fields of the the embedded document' do
+            click_on 'Posts'
+            visit '/admin/posts?order=author.city.name_desc'
+            page.first('#index_table_posts > tbody > tr').should have_content 'Washington'
+
+            visit '/admin/posts?order=author.city.name_asc'
+            page.first('#index_table_posts > tbody > tr').should have_content 'California'
+          end
         end
       end
 

test_app/app/admin/posts.rb

@@ -16,6 +16,10 @@
     column 'Author Name', :'author.name' do |post|
       post.author.name if post.author.present?
     end
+    column 'Author City Name', :'author.city.name' do |post|
+      author = post.author
+      author.city.name if author.present? and author.city.present?
+    end
     default_actions
   end
 

test_app/app/models/author.rb

@@ -3,5 +3,7 @@ class Author
   include Mongoid::Timestamps
 
   embedded_in :post
+  embeds_one :city
+
   field :name
 end

test_app/app/models/city.rb

@@ -0,0 +1,7 @@
+class City
+  include Mongoid::Document
+  include Mongoid::Timestamps
+
+  embedded_in :author
+  field :name
+end

test_app/app/models/post.rb

@@ -9,5 +9,5 @@ class Post
   belongs_to :other_user, class_name: 'AdminUser'
 
   embeds_one :author
-  field :'author.name'
+  field :'author.city.name'
 end