dirty_association_test.rb

require "test/unit"
require "rubygems"
gem "activerecord", :version => "2.3.4"
require "active_record"

ActiveRecord::Base.establish_connection(
  :adapter => "sqlite3",
  :dbfile  => ":memory:"
)

ActiveRecord::Schema.define do
  create_table :albums do |table|
    table.string  :title
    table.integer :artist_id
  end

  create_table :artists do |table|
    table.string :name
  end
end

class Album < ActiveRecord::Base
  belongs_to :artist
end

class Artist < ActiveRecord::Base
  has_many :albums
end

class DirtyAssociationTest < Test::Unit::TestCase
  def test_changed_includes_new_record_assignments
    album = Album.create! :title => "Give Up the Ghost"
    album.artist = Artist.new :name => "Brandi Carlile"
    assert album.changes.any?
  end

  def test_changed_includes_persistent_record_assignments
    album = Album.create! :title => "Give Up the Ghost"
    album.artist = Artist.create! :name => "Brandi Carlile"
    assert album.changes.any?
  end
end