cleanup favorite references on item deletion

app/models/base_item.rb

@@ -10,9 +10,10 @@ class BaseItem
   has_and_belongs_to_many :groups, :inverse_of => nil
 
   validates_presence_of :title
-
   validate :groups_are_allowed
 
+  after_destroy :cleanup_references
+
   def self.group_ids
     all.only(:group_ids).collect{ |ms| ms.group_ids }.flatten.uniq
   end
@@ -31,4 +32,13 @@ def groups_are_allowed
 
     errors.add(:base, "The following groups are invalid `#{invalid_groups.join(', ')}'") unless invalid_groups.empty?
   end
+
+  def cleanup_references
+    favorites = Favorite.where(:item_type => self.class.name, :item_id => self._id)
+
+    favorites.each do |favorite|
+      user = favorite.user
+      user.favorites.find(favorite._id).destroy
+    end
+  end
 end

app/models/user.rb

@@ -14,7 +14,7 @@ class User
   index :username, :unique => true
 
   has_and_belongs_to_many :groups
-  has_many :favorites
+  has_many :favorites, :dependent => :destroy
 
   validates_presence_of :username
   validates_uniqueness_of :username, :case_sensitive => false

test/models/favorite_test.rb

@@ -1,11 +1,4 @@
-require "minitest_helper"
+require 'minitest_helper'
 
 describe Favorite do
-  before do
-    @favorite = Favorite.new
-  end
-
-  it "must be valid" do
-    @favorite.valid?.must_equal true
-  end
 end

test/models/user_test.rb

@@ -37,4 +37,16 @@
     @user.favorites.size.must_equal 1
   end
 
+  it "removes items from a users favorites after item deletion" do
+    note = FactoryGirl.create(:note)
+
+    @user.favorite!(note)
+    @user.reload
+    @user.favorites.size.must_equal 1
+
+    note.destroy
+    @user.reload
+    @user.favorites.must_be :empty?
+  end
+
 end