has_one_replace_issue.rb

gem 'activerecord', '4.0.1'
require 'active_record'
require 'minitest/autorun'
require 'logger'

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :users do |t|
  end

  create_table :addresses do |t|
    t.integer :user_id
    t.string :street
  end
end

class User < ActiveRecord::Base
  has_one :address, :dependent => :destroy
end

class Address < ActiveRecord::Base
  belongs_to :user
end

class BugTest < MiniTest::Unit::TestCase
  def test_association_stuff
    user = User.create!
    address = user.create_address
    address.street = '1 Some St.'
    
    assert user.address = address
  end
end