Did some tests and scope black magic on the preferences.

app/models/preference.rb

@@ -1,13 +1,17 @@
-class Preference < ActiveRecord::Base
-  attr_accessible :like, :user_id, :restaurant_id
-  belongs_to :user
-  belongs_to :restaurant
-
-  def self.likes
-  	#self.all.map { |pref| pref.likes }
-  end
-
-  def self.evaluate
-    # stuff
-  end
-end
+class Preference < ActiveRecord::Base
+  attr_accessible :like, :dislikes, :user_id, :restaurant_id
+  belongs_to :user
+  belongs_to :restaurant
+
+  scope :likes, where(like: true)
+  scope :dislikes, where(like: false)
+
+  #def self.likes
+  	#self.find_all_by_like(true).map { |pref| pref.like }
+  #	where(:like => true)
+  #end
+
+  def self.evaluate
+    # stuff
+  end
+end

spec/models/preference_spec.rb

@@ -1,32 +1,37 @@
-require "spec_helper"
-
-describe Preference do
-  before(:each) do
-    @pref = Preference.new
-  end
-
-  describe "Associations" do
-    it "belongs_to a Restaurant" do
-      @pref.restaurant = Restaurant.new
-      @pref.should have(:no).errors_on(:restaraunt)
-    end
-
-    it "belongs_to a User" do
-      @pref.user = User.new
-      @pref.should have(:no).errors_on(:user)
-    end
-  end
-
-  describe "Like Method" do
-    it "Likes should default to false" do
-      @pref.like.should be_false
-    end
-
-    it "Likes should" do
-      Preference.likes.all? { |p| p.like == true }.should be_true
-    end
-
-
-
-  end
-end
+require "spec_helper"
+
+describe Preference do
+  before(:each) do
+    @pref = Preference.new
+  end
+
+  describe "Associations" do
+    it "belongs_to a Restaurant" do
+      @pref.restaurant = Restaurant.new
+      @pref.should have(:no).errors_on(:restaraunt)
+    end
+
+    it "belongs_to a User" do
+      @pref.user = User.new
+      @pref.should have(:no).errors_on(:user)
+    end
+  end
+
+  describe "Like/Dislike Method" do
+    it "Like should default to false" do
+      @pref.like.should be_false
+    end
+
+    it "Likes method should all return like as true" do
+      Preference.likes.all? { |p| p.like == true }.should be_true
+    end
+
+    it "Dislikes method should all return like as false" do
+      Preference.dislikes.all? { |p| p.like == true }.should be_false
+    end 
+
+    it "The count should equal the likes + dislikes" do
+      Preference.count.should == Preference.likes.count + Preference.dislikes.count
+    end
+  end
+end