single_ar_polymorph_spec.rb

require 'rubygems'
require 'active_record'
require 'spec'

ActiveRecord::Base.establish_connection( {
  :adapter => 'mysql',
  :host => 'localhost',
  :database => 'testbed',
  :username => 'root',
  :password => ''
})

describe 'association modeling' do
  before :all do
    ActiveRecord::Migration.instance_eval do 
      create_table :users, :force => true do |t|
        t.string :name
      end
    
      create_table :affiliations, :force => true do |t|
        t.integer :user_id
        t.references :affiliatable, :polymorphic => true
        t.string :relationship_type
      end
    
      create_table :networks, :force => true do |t|
        t.string :name
      end
    
      create_table :communities, :force => true do |t|
        t.string :name
      end
    end
  end
  
  after :all do
      ActiveRecord::Migration.instance_eval do 
        drop_table :users
        drop_table :affiliations
        drop_table :networks
        drop_table :communities
      end
    end
    
  class User < ActiveRecord::Base
    has_many :affiliations
    has_many :communities, :through => :affiliations, :source => :community,
             :conditions => "affiliations.affiliatable_type = 'Community'"
             
    has_many :networks, :through => :affiliations,
             :conditions => "affiliations.affiliatable_type = 'Network'"
    
    named_scope :in_network, lambda{ |network| {:joins => :networks, :conditions => ['affiliations.affiliatable_id = ?', network]} }
    
    def fellow_members
      self.class.scoped({:conditions => [ 
        "users.id IN 
          (SELECT u.id from users u 
            INNER JOIN affiliations ON (u.id = affiliations.user_id)
            INNER JOIN affiliations my_affiliations ON (affiliations.affiliatable_id = my_affiliations.affiliatable_id AND affiliations.affiliatable_type = 'Community')
            WHERE (my_affiliations.user_id = ?))", id]})
    end
  end
  
  class Affiliation < ActiveRecord::Base
    belongs_to :user
    belongs_to :affiliatable, :polymorphic => true

    belongs_to :community, :class_name => "Community", :foreign_key => "affiliatable_id"
    belongs_to :network, :class_name => "Network", :foreign_key => "affiliatable_id"
  end
  
  class Network < ActiveRecord::Base
    has_many :affiliations, :as => :affiliatable
    has_many :users, :through => :affiliations
  end
  
  class Community < ActiveRecord::Base
    has_many :affiliations, :as => :affiliatable
    has_many :users, :through => :affiliations
  end  
  
  it 'has_many all around' do
    me = User.create
    network = Network.create
    community = Community.create
    
    me.affiliations.create(:affiliatable => network)
    me.affiliations.create(:affiliatable => community)
    me.should have(2).affiliations
    
    network.should have(1).user
    community.should have(1).user
    me.should have(1).community
    me.should have(1).network
  end
  
  it 'can do something special' do
    community1 = Community.create
    community2 = Community.create
    me = User.create(:name => 'ME')
    sally = User.create(:name => 'sally')
    harry = User.create(:name => 'harry')
    
    me.affiliations.create(:affiliatable => community1)
    me.affiliations.create(:affiliatable => community2)
    
    harry.affiliations.create(:affiliatable => community1)
    me.fellow_members.should include(harry)
    me.fellow_members.should_not include(sally)
    
    sally.affiliations.create(:affiliatable => community2)    
    me.fellow_members.should include(harry, sally)
  end
   
  it 'can do something even better' do
    community = Community.create
    network = Network.create
    me = User.create(:name => 'ME')
    sally = User.create(:name => 'sally')
    harry = User.create(:name => 'harry')
    [me, sally, harry].each{|user| user.affiliations.create(:affiliatable => community) }
    [me, sally].each{|user| user.affiliations.create(:affiliatable => network) }
   
   
    me.networks.should_not be_empty
    me.fellow_members.in_network(network).should include(sally)
    me.fellow_members.in_network(network).should_not include(harry)
  end
  
end