collapse Post#last_three_comments and Commentable#last_three_comments, do not double query comments in CommentsController#index for a JSON response, remove spec that tests ordering as it's not deterministic on psql without specified order

app/controllers/comments_controller.rb

@@ -71,7 +71,7 @@ class CommentsController < ApplicationController
     if @post
       @comments = @post.comments.includes(:author => :profile).order('created_at ASC')
       respond_with do |format|
-        format.json  { render :json => @post.comments.as_api_response(:backbone), :status => 200 }
+        format.json  { render :json => @comments.as_api_response(:backbone), :status => 200 }
         format.mobile{render :layout => false}
       end
     else

app/models/post.rb

@@ -64,14 +64,6 @@ class Post < ActiveRecord::Base
   def raw_message; ""; end
   def mentioned_people; []; end
 
-  # gives the last three comments on the post
-  def last_three_comments
-    return if self.comments_count == 0
-    # DO NOT USE .last(3) HERE.  IT WILL FETCH ALL COMMENTS AND RETURN THE LAST THREE
-    # INSTEAD OF DOING THE FOLLOWING, AS EXPECTED (THX AR):
-    self.comments.order('created_at DESC').limit(3).includes(:author => :profile).reverse!
-  end
-
   def self.excluding_blocks(user)
     people = user.blocks.map{|b| b.person_id}
     scope = scoped

lib/diaspora/commentable.rb

@@ -11,9 +11,12 @@ module Diaspora
     end
 
     # @return [Array<Comment>]
-    def last_three_comments
-      self.comments.order('created_at DESC').limit(3).includes(:author => :profile).reverse
-    end
+  def last_three_comments
+    return if self.comments_count == 0
+    # DO NOT USE .last(3) HERE.  IT WILL FETCH ALL COMMENTS AND RETURN THE LAST THREE
+    # INSTEAD OF DOING THE FOLLOWING, AS EXPECTED (THX AR):
+    self.comments.order('created_at DESC').limit(3).includes(:author => :profile).reverse
+  end
 
     # @return [Integer]
     def update_comments_counter

spec/models/post_spec.rb

@@ -215,36 +215,6 @@ describe Post do
     end
   end
 
-  describe '#comments' do
-    it 'returns the comments of a post in created_at order' do
-      post = bob.post :status_message, :text => "hello", :to => 'all'
-      created_at = Time.now - 100
-
-      # Posts are created out of time order.
-      # i.e. id order is not created_at order
-      alice.comment 'comment a', :post => post, :created_at => created_at + 10
-      eve.comment   'comment d', :post => post, :created_at => created_at + 50
-      bob.comment   'comment b', :post => post, :created_at => created_at + 30
-      alice.comment 'comment e', :post => post, :created_at => created_at + 90
-      eve.comment   'comment c', :post => post, :created_at => created_at + 40
-
-      post.comments.map(&:text).should == [
-        'comment a',
-        'comment b',
-        'comment c',
-        'comment d',
-        'comment e',
-      ]
-      post.comments.map(&:author).should == [
-        alice.person,
-        bob.person,
-        eve.person,
-        eve.person,
-        alice.person,
-      ]
-    end
-  end
-
   describe 'Likeable#update_likes_counter' do
     before do
       @post = bob.post :status_message, :text => "hello", :to => 'all'