diff --git a/spec/api/comment_spec.rb b/spec/api/comment_spec.rb
index 6e9c256..587c3d9 100644
--- a/spec/api/comment_spec.rb
+++ b/spec/api/comment_spec.rb
@@ -1,186 +1,208 @@
 require 'spec_helper'
 require 'unicode_shared_examples'
 
-describe "app" do
+BLOCKED_BODY = 'BLOCKED POST'
 
+describe 'Comment API' do
   before(:each) { set_api_key_header }
+  let(:thread) { create_comment_thread_and_comments }
 
-  describe "comments" do
-    before(:each) { init_without_subscriptions }
-
-    describe "GET /api/v1/comments/:comment_id" do
-      it "returns JSON" do
-        comment = Comment.first
-        get "/api/v1/comments/#{comment.id}"
-        last_response.should be_ok
-        last_response.content_type.should == "application/json;charset=utf-8"
-      end
-      it "retrieve information of a single comment" do
-        comment = Comment.first
-        get "/api/v1/comments/#{comment.id}"
-        last_response.should be_ok
-        retrieved = parse last_response.body
-        retrieved["body"].should == comment.body
-        retrieved["endorsed"].should == comment.endorsed
-        retrieved["id"].should == comment.id.to_s
-        retrieved["children"].should be_nil
-        retrieved["votes"]["point"].should == comment.votes_point
-        retrieved["depth"].should == comment.depth
-        retrieved["parent_id"].should == comment.parent_ids.map(&:to_s)[-1]
-      end
-      it "retrieve information of a single comment with its sub comments" do
-        comment = Comment.order_by(_id: 'asc').first
-        get "/api/v1/comments/#{comment.id}", recursive: true
-        last_response.should be_ok
-        retrieved = parse last_response.body
-        retrieved["body"].should == comment.body
-        retrieved["endorsed"].should == comment.endorsed
-        retrieved["id"].should == comment.id.to_s
-        retrieved["votes"]["point"].should == comment.votes_point
-        retrieved["children"].length.should == comment.children.length
-        retrieved["children"].select{|c| c["body"] == comment.children.first.body}.first.should_not be_nil
-        retrieved["children"].each{|c| c["parent_id"].should == comment.id.to_s}
-      end
-      it "returns 400 when the comment does not exist" do
-        get "/api/v1/comments/does_not_exist"
-        last_response.status.should == 400
-        parse(last_response.body).first.should == I18n.t(:requested_object_not_found)
-      end
-
-      def test_unicode_data(text)
-        comment = make_comment(User.first, CommentThread.first, text)
-        get "/api/v1/comments/#{comment.id}"
-        last_response.should be_ok
-        retrieved = parse last_response.body
-        retrieved["body"].should == text
-      end
-
-      include_examples "unicode data"
+  describe 'GET /api/v1/comments/:comment_id' do
+    it 'returns JSON' do
+      comment = thread.comments.first
+      get "/api/v1/comments/#{comment.id}"
+      last_response.should be_ok
+      last_response.content_type.should == 'application/json;charset=utf-8'
     end
 
-    describe "PUT /api/v1/comments/:comment_id" do
-      def test_update_endorsed(true_val, false_val)
-        comment = Comment.first
-        before = DateTime.now
-        put "/api/v1/comments/#{comment.id}", endorsed: true_val, endorsement_user_id: "#{User.first.id}"
-        after = DateTime.now
-        last_response.should be_ok
-        comment.reload
-        comment.endorsed.should == true
-        comment.endorsement.should_not be_nil
-        comment.endorsement["user_id"].should == "#{User.first.id}"
-        comment.endorsement["time"].should be_between(before, after)
-        put "/api/v1/comments/#{comment.id}", endorsed: false_val
-        last_response.should be_ok
-        comment.reload
-        comment.endorsed.should == false
-        comment.endorsement.should be_nil
-      end
-      it "updates endorsed correctly" do
-        test_update_endorsed(true, false)
-      end
-      it "updates endorsed correctly with Pythonic values" do
-        test_update_endorsed("True", "False")
-      end
-      it "updates body correctly" do
-        comment = Comment.first
-        put "/api/v1/comments/#{comment.id}", body: "new body"
-        last_response.should be_ok
-        comment.reload
-        comment.body.should == "new body"
-      end
-      it "can update endorsed and body simultaneously" do
-        comment = Comment.first
-        put "/api/v1/comments/#{comment.id}", body: "new body", endorsed: true
-        last_response.should be_ok
-        comment.reload
-        comment.body.should == "new body"
-        comment.endorsed.should == true
-      end
-      it "returns 400 when the comment does not exist" do
-        put "/api/v1/comments/does_not_exist", body: "new body", endorsed: true
-        last_response.status.should == 400
-        parse(last_response.body).first.should == I18n.t(:requested_object_not_found)
-      end
-      it "returns 503 and does not update when the post hash is blocked" do
-        comment = Comment.first
-        original_body = comment.body
-        put "/api/v1/comments/#{comment.id}", body: "BLOCKED POST", endorsed: true
-        last_response.status.should == 503
-        parse(last_response.body).first.should == I18n.t(:blocked_content_with_body_hash, :hash => Digest::MD5.hexdigest("blocked post"))
-        comment.reload
-        comment.body.should == original_body
-      end
-
-      def test_unicode_data(text)
-        comment = Comment.first
-        put "/api/v1/comments/#{comment.id}", body: text
-        last_response.should be_ok
-        comment = Comment.find(comment.id)
-        comment.body.should == text
-      end
-
-      include_examples "unicode data"
+    it 'retrieve information of a single comment' do
+      comment = thread.comments.first
+      get "/api/v1/comments/#{comment.id}"
+      last_response.should be_ok
+      retrieved = parse last_response.body
+      retrieved['body'].should == comment.body
+      retrieved['endorsed'].should == comment.endorsed
+      retrieved['id'].should == comment.id.to_s
+      retrieved['children'].should be_nil
+      retrieved['votes']['point'].should == comment.votes_point
+      retrieved['depth'].should == comment.depth
+      retrieved['parent_id'].should == comment.parent_ids.map(&:to_s)[-1]
     end
 
-    describe "POST /api/v1/comments/:comment_id" do
-      it "create a sub comment to the comment" do
-        comment = Comment.first.to_hash(recursive: true)
-        user = User.first
-        post "/api/v1/comments/#{comment["id"]}", body: "new comment", course_id: "1", user_id: User.first.id
-        last_response.should be_ok
-        changed_comment = Comment.find(comment["id"]).to_hash(recursive: true)
-        changed_comment["children"].length.should == comment["children"].length + 1
-        subcomment = changed_comment["children"].select{|c| c["body"] == "new comment"}.first
-        subcomment.should_not be_nil
-        subcomment["user_id"].should == user.id
-      end
-      it "returns 400 when the comment does not exist" do
-        post "/api/v1/comments/does_not_exist", body: "new comment", course_id: "1", user_id: User.first.id
-        last_response.status.should == 400
-        parse(last_response.body).first.should == I18n.t(:requested_object_not_found)
-      end
-      it "returns 503 and does not create when the post hash is blocked" do
-        comment = Comment.first.to_hash(recursive: true)
-        user = User.first
-        post "/api/v1/comments/#{comment["id"]}", body: "BLOCKED POST", course_id: "1", user_id: User.first.id
-        last_response.status.should == 503
-        parse(last_response.body).first.should == I18n.t(:blocked_content_with_body_hash, :hash => Digest::MD5.hexdigest("blocked post"))
-        Comment.where(body: "BLOCKED POST").to_a.should be_empty
-      end
+    it 'retrieve information of a single comment with its sub comments' do
+      comment = thread.comments.first
+      get "/api/v1/comments/#{comment.id}", recursive: true
+      last_response.should be_ok
+      retrieved = parse last_response.body
+      retrieved['body'].should == comment.body
+      retrieved['endorsed'].should == comment.endorsed
+      retrieved['id'].should == comment.id.to_s
+      retrieved['votes']['point'].should == comment.votes_point
 
-      def test_unicode_data(text)
-        parent = Comment.first
-        post "/api/v1/comments/#{parent.id}", body: text, course_id: parent.course_id, user_id: User.first.id
-        last_response.should be_ok
-        parent.children.where(body: text).should_not be_empty
-      end
+      retrieved_children = retrieved['children']
+      retrieved_children.length.should == comment.children.length
 
-      include_examples "unicode data"
+      comment.children.each_with_index do |child, index|
+        expect(retrieved_children[index]).to include('body' => child.body, 'parent_id' => comment.id.to_s)
+      end
     end
 
-    describe "DELETE /api/v1/comments/:comment_id" do
-      it "delete the comment and its sub comments" do
-        comment = Comment.first
-        cnt_comments = comment.descendants_and_self.length
-        prev_count = Comment.count
-        delete "/api/v1/comments/#{comment.id}"
-        Comment.count.should == prev_count - cnt_comments
-        Comment.all.select{|c| c.id == comment.id}.first.should be_nil
-      end
-      it "can delete a sub comment" do
-        child_comment = Comment.where(:parent.exists => true).first
-        parent_comment = child_comment.parent
-        delete "/api/v1/comments/#{child_comment.id}"
+    it 'returns 400 when the comment does not exist' do
+      get '/api/v1/comments/does_not_exist'
+      last_response.status.should == 400
+      parse(last_response.body).first.should == I18n.t(:requested_object_not_found)
+    end
 
-        Comment.where(:id => child_comment.id).should be_empty
-        parent_comment.children.where(:id => child_comment.id).should be_empty
-      end
-      it "returns 400 when the comment does not exist" do
-        delete "/api/v1/comments/does_not_exist"
-        last_response.status.should == 400
-        parse(last_response.body).first.should == I18n.t(:requested_object_not_found)
-      end
+    def test_unicode_data(text)
+      comment = create(:comment, body: text)
+      get "/api/v1/comments/#{comment.id}"
+      last_response.should be_ok
+      parse(last_response.body)['body'].should == text
+    end
+
+    include_examples 'unicode data'
+  end
+
+  describe 'PUT /api/v1/comments/:comment_id' do
+    def test_update_endorsed(true_val, false_val)
+      comment = thread.comments.first
+      before = DateTime.now
+      put "/api/v1/comments/#{comment.id}", endorsed: true_val, endorsement_user_id: "#{User.first.id}"
+      after = DateTime.now
+      last_response.should be_ok
+      comment.reload
+      comment.endorsed.should == true
+      comment.endorsement.should_not be_nil
+      comment.endorsement["user_id"].should == "#{User.first.id}"
+      comment.endorsement["time"].should be_between(before, after)
+      put "/api/v1/comments/#{comment.id}", endorsed: false_val
+      last_response.should be_ok
+      comment.reload
+      comment.endorsed.should == false
+      comment.endorsement.should be_nil
+    end
+
+    it 'updates endorsed correctly' do
+      test_update_endorsed(true, false)
+    end
+
+    it 'updates endorsed correctly with Pythonic values' do
+      test_update_endorsed('True', 'False')
+    end
+
+    it 'updates body correctly' do
+      comment = thread.comments.first
+      put "/api/v1/comments/#{comment.id}", body: 'new body'
+      last_response.should be_ok
+      comment.reload
+      comment.body.should == 'new body'
+    end
+
+    it 'can update endorsed and body simultaneously' do
+      comment = thread.comments.first
+      put "/api/v1/comments/#{comment.id}", body: 'new body', endorsed: true
+      last_response.should be_ok
+      comment.reload
+      comment.body.should == 'new body'
+      comment.endorsed.should == true
+    end
+
+    it 'returns 400 when the comment does not exist' do
+      put '/api/v1/comments/does_not_exist', body: 'new body', endorsed: true
+      last_response.status.should == 400
+      parse(last_response.body).first.should == I18n.t(:requested_object_not_found)
+    end
+
+    it 'returns 503 and does not update when the post hash is blocked' do
+      blocked_hash = block_post_body(BLOCKED_BODY)
+      comment = thread.comments.first
+      original_body = comment.body
+      put "/api/v1/comments/#{comment.id}", body: BLOCKED_BODY, endorsed: true
+      last_response.status.should == 503
+      parse(last_response.body).first.should == I18n.t(:blocked_content_with_body_hash, :hash => blocked_hash)
+      comment.reload
+      comment.body.should == original_body
+    end
+
+    def test_unicode_data(text)
+      comment = thread.comments.first
+      put "/api/v1/comments/#{comment.id}", body: text
+      last_response.should be_ok
+      comment.reload
+      comment.body.should == text
+    end
+
+    include_examples 'unicode data'
+  end
+
+  describe 'POST /api/v1/comments/:comment_id' do
+    it 'creates a sub comment to the comment' do
+      comment = thread.comments.first
+      previous_child_count = comment.children.length
+      user = thread.author
+      body = 'new comment'
+      course_id = '1'
+      post "/api/v1/comments/#{comment.id}", body: body, course_id: course_id, user_id: user.id
+      last_response.should be_ok
+
+      comment.reload
+      comment.children.length.should == previous_child_count + 1
+      sub_comment = comment.children.order_by(created_at: :desc).first
+      sub_comment.body.should == body
+      sub_comment.course_id.should == course_id
+      sub_comment.author.should == user
+    end
+
+    it 'returns 400 when the comment does not exist' do
+      post '/api/v1/comments/does_not_exist', body: 'new comment', course_id: '1', user_id: thread.author.id
+      last_response.status.should == 400
+      parse(last_response.body).first.should == I18n.t(:requested_object_not_found)
+    end
+
+    it 'returns 503 and does not create when the post hash is blocked' do
+      blocked_hash = block_post_body(BLOCKED_BODY)
+      comment = thread.comments.first
+      user = comment.author
+      post "/api/v1/comments/#{comment.id}", body: BLOCKED_BODY, course_id: '1', user_id: user.id
+      last_response.status.should == 503
+      parse(last_response.body).first.should == I18n.t(:blocked_content_with_body_hash, :hash => blocked_hash)
+      Comment.where(body: BLOCKED_BODY).to_a.should be_empty
+    end
+
+    def test_unicode_data(text)
+      parent = thread.comments.first
+      post "/api/v1/comments/#{parent.id}", body: text, course_id: parent.course_id, user_id: User.first.id
+      last_response.should be_ok
+      parent.children.where(body: text).should_not be_empty
+    end
+
+    include_examples 'unicode data'
+  end
+
+  describe 'DELETE /api/v1/comments/:comment_id' do
+    it 'delete the comment and its sub comments' do
+      comment = thread.comments.first
+      cnt_comments = comment.descendants_and_self.length
+      prev_count = Comment.count
+      delete "/api/v1/comments/#{comment.id}"
+      Comment.count.should == prev_count - cnt_comments
+      Comment.all.select { |c| c.id == comment.id }.first.should be_nil
+    end
+
+    it 'can delete a sub comment' do
+      # Sort to ensure we get the thread's first comment, rather than the child of that comment.
+      parent_comment = thread.comments.sort_by(&:_id).first
+      child_comment = parent_comment.children.first
+      delete "/api/v1/comments/#{child_comment.id}"
+
+      Comment.where(:id => child_comment.id).should be_empty
+      parent_comment.children.where(:id => child_comment.id).should be_empty
+    end
+
+    it 'returns 400 when the comment does not exist' do
+      delete '/api/v1/comments/does_not_exist'
+      last_response.status.should == 400
+      parse(last_response.body).first.should == I18n.t(:requested_object_not_found)
     end
   end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 854c27c..65d3560 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -59,6 +59,20 @@ def create_test_user(id)
   User.create!(external_id: id.to_s, username: "user#{id}")
 end
 
+# Add the given body of text to the list of blocked texts/hashes.
+def block_post_body(body='blocked post')
+  body = body.strip.downcase.gsub(/[^a-z ]/, '').gsub(/\s+/, ' ')
+  blocked_hash = Digest::MD5.hexdigest(body)
+  Content.mongo_client[:blocked_hash].insert_one(hash: blocked_hash)
+
+  # reload the global holding the blocked hashes
+  CommentService.blocked_hashes = Content.mongo_client[:blocked_hash].find(nil, projection: {hash: 1}).map do |d|
+    d['hash']
+  end
+
+  blocked_hash
+end
+
 def init_without_subscriptions
   commentable = Commentable.new("question_1")
 
@@ -139,11 +153,7 @@ def init_without_subscriptions
     users[2, 9].each { |user| user.vote(c, [:up, :down].sample) }
   end
 
-  Content.mongo_client[:blocked_hash].insert_one(hash: Digest::MD5.hexdigest("blocked post"))
-  # reload the global holding the blocked hashes
-  CommentService.blocked_hashes = Content.mongo_client[:blocked_hash].find(nil, projection: {hash: 1}).map do |d|
-    d["hash"]
-  end
+  block_post_body
 end
 
 # this method is used to test results produced using the helper function handle_threads_query
@@ -370,3 +380,16 @@ def setup_10_threads
   end
   @default_order = 10.times.map { |i| "t#{i}" }.reverse
 end
+
+# Creates a CommentThread with a Comment, and nested child Comment.
+# The author of the thread is subscribed to the thread.
+def create_comment_thread_and_comments
+  # Create a new comment thread, and subscribe the author to the thread
+  thread = create(:comment_thread, :subscribe_author)
+
+  # Create a comment along with a nested child comment
+  comment = create(:comment, comment_thread: thread)
+  create(:comment, parent: comment)
+
+  thread
+end