initialize_role.rb

# Source: https://gist.github.com/neerajdotname/5187092
#gem 'activerecord', '4.0.0.rc2'
gem 'activerecord', '3.2.13'

require 'active_record'
require "minitest/autorun"
require 'minitest/pride'
require 'logger'

ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :notices, force: true do |t|
    t.string :title
  end

  create_table :entity_roles, force: true do |t|
    t.string :name

    t.integer :notice_id
    t.integer :entity_id
  end

  create_table :entities, force: true do |t|
    t.string :name, :address
  end
end

class Notice < ActiveRecord::Base
  has_many :entity_roles
  has_many :entities, through: :entity_roles
end

class EntityRole < ActiveRecord::Base
  belongs_to :entity
  belongs_to :notice
end

class Entity < ActiveRecord::Base
  has_many :entity_roles
  has_many :notices, through: :entity_roles
end

class TestInitializingRole < MiniTest::Unit::TestCase
  def setup
    @notice = Notice.new
  end

  def test_initialize_role
    @notice.entity_roles(name: 'role1').build.build_entity

    assert '', @notice.entity_roles.first.name
  end

  def test_initialize_role2
    @notice.entity_roles.build(name: 'role1').build_entity

    assert 'role1', @notice.entity_roles.first.name
  end

  def teardown
  end
end