FIX: Update post replies when we move posts. (#4324)

spec/models/post_mover_spec.rb

@@ -29,6 +29,8 @@ describe PostMover do
     let!(:p4) { Fabricate(:post, topic: topic, reply_to_post_number: p2.post_number, user: user)}
 
     before do
+      p1.replies << p3
+      p2.replies << p4
       # add a like to a post, enable observers so we get user actions
       ActiveRecord::Base.observers.enable :all
       @like = PostAction.act(another_user, p4, PostActionType.types[:like])
@@ -72,6 +74,62 @@ describe PostMover do
         TopicLink.extract_from(p2)
       end
 
+      context "post replies" do
+        describe "when a post with replies is moved" do
+          it "should update post replies correctly" do
+            topic.move_posts(
+              user,
+              [p2.id],
+              title: 'GOT is a very addictive showw', category_id: category.id
+            )
+
+            expect(p2.reload.replies).to eq([])
+          end
+        end
+
+        describe "when replies of a post have been moved" do
+          it "should update post replies correctly" do
+            p5 = Fabricate(
+              :post,
+              topic: topic,
+              reply_to_post_number: p2.post_number,
+              user: another_user
+            )
+
+            p2.replies << p5
+
+            topic.move_posts(
+              user,
+              [p4.id],
+              title: 'GOT is a very addictive showw', category_id: category.id
+            )
+
+            expect(p2.reload.replies).to eq([p5])
+          end
+        end
+
+        describe "when only one reply is left behind" do
+          it "should update post replies correctly" do
+            p5 = Fabricate(
+              :post,
+              topic: topic,
+              reply_to_post_number: p2.post_number,
+              user: another_user
+            )
+
+            p2.replies << p5
+
+            topic.move_posts(
+              user,
+              [p2.id, p4.id],
+              title: 'GOT is a very addictive showw', category_id: category.id
+            )
+
+            expect(p2.reload.replies).to eq([p4])
+          end
+        end
+      end
+
       context "to a new topic" do
 
         it "works correctly" do

spec/models/post_reply_spec.rb

@@ -1,8 +1,27 @@
 require 'rails_helper'
 
 describe PostReply do
+  let(:topic) { Fabricate(:topic) }
+  let(:post) { Fabricate(:post, topic: topic) }
+  let(:other_post) { Fabricate(:post, topic: topic) }
 
   it { is_expected.to belong_to :post }
   it { is_expected.to belong_to :reply }
 
+  context "validation" do
+    it "should ensure that the posts belong in the same topic" do
+      expect(PostReply.new(post: post, reply: other_post)).to be_valid
+
+      other_topic = Fabricate(:topic)
+      other_post.update_attributes!(topic_id: other_topic.id)
+      other_post.reload
+
+      post_reply = PostReply.new(post: post, reply: other_post)
+      expect(post_reply).to_not be_valid
+
+      expect(post_reply.errors[:base]).to include(
+        I18n.t("activerecord.errors.models.post_reply.base.different_topic")
+      )
+    end
+  end
 end