added validation for comments if not super comment

app.rb

@@ -22,8 +22,7 @@ end
 # create a new top-level comment
 post '/api/v1/commentables/:commentable_type/:commentable_id/comments' do |commentable_type, commentable_id|
   comment_thread = CommentThread.find_or_create_by_commentable_type_and_commentable_id(commentable_type, commentable_id)
-  comment_params = params.select {|key, value| %w{body title user_id course_id}.include? key}
-  comment_params.merge :comment_thread_id => comment_thread.id
+  comment_params = params.select {|key, value| %w{body title user_id course_id}.include? key}.merge({:comment_thread_id => comment_thread.id})
   comment = comment_thread.root_comments.create(comment_params)
   if comment.valid?
     comment.to_json
@@ -49,8 +48,7 @@ post '/api/v1/comments/:comment_id' do |comment_id|
   if comment.nil? or comment.is_root?
     error 400, {:error => "invalid comment id"}.to_json
   else
-    comment_params = params.select {|key, value| %w{body title user_id course_id}.include? key}
-    comment_params.merge :comment_thread_id => comment.root.comment_thread.id
+    comment_params = params.select {|key, value| %w{body title user_id course_id}.include? key}.merge({:comment_thread_id => comment.comment_thread_id})
     sub_comment = comment.children.create(comment_params)
     if comment.valid?
       comment.to_json

models/comment.rb

@@ -11,6 +11,11 @@ class Comment < ActiveRecord::Base
 
   belongs_to :comment_thread
 
+  validates_presence_of :body, :unless => :is_root?
+  validates_presence_of :user_id, :unless => :is_root?
+  validates_presence_of :course_id, :unless => :is_root?
+  validates_presence_of :comment_thread_id
+
   def self.hash_tree(nodes)
     nodes.map do |node, sub_nodes|
       {

spec/app_spec.rb

@@ -168,8 +168,10 @@ describe "app" do
     end
     describe "PUT on /api/v1/votes/comments/:comment_id/users/:user_id" do
       before :each do
-        CommentThread.create! :commentable_type => "questions", :commentable_id => 1
-        CommentThread.first.root_comments.create :body => "top comment", :title => "top", :user_id => 1, :course_id => 1
+        comment_thread = CommentThread.create! :commentable_type => "questions", :commentable_id => 1
+        comment = CommentThread.first.root_comments.create :body => "top comment", :title => "top", :user_id => 1, :course_id => 1
+        comment.comment_thread = comment_thread
+        comment.save!
       end
       it "votes up on a comment" do
         comment = CommentThread.first.comments.first