update factories + tests

app/models/comment.rb

@@ -1,7 +1,6 @@
 class Comment < ApplicationRecord
   include Mentionable
 
-  validate :validate_post_exists, :on => :create
   validate :validate_creator_is_not_limited, :on => :create
   validates_presence_of :body, :message => "has no content"
   belongs_to :post

app/models/note.rb

@@ -5,7 +5,7 @@ class Note < ApplicationRecord
   belongs_to :post
   belongs_to_creator
   has_many :versions, -> {order("note_versions.id ASC")}, :class_name => "NoteVersion", :dependent => :destroy
-  validates_presence_of :post_id, :creator_id, :x, :y, :width, :height, :body
+  validates_presence_of :creator_id, :x, :y, :width, :height, :body
   validate :post_must_exist
   validate :note_within_image
   after_save :update_post