gistfile1.rb

unless File.exist?('Gemfile')
  File.write('Gemfile', <<-GEMFILE)
    source 'https://rubygems.org'
    gem 'rails', github: 'rails/rails'
    gem 'arel', github: 'rails/arel'
    gem 'rack', github: 'rack/rack'
    gem 'i18n', github: 'svenfuchs/i18n'
    gem 'sqlite3'
  GEMFILE

  system 'bundle'
end

require 'bundler'
Bundler.setup(:default)

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 :posts do |t|
    t.string :title
  end

  create_table :posts_temp, id: :uuid do |t|
    t.string :title
  end
end

class Post < ActiveRecord::Base
end

class PostTemp < ActiveRecord::Base
  self.table_name = :posts_temp
end

class BugTest < Minitest::Test
  def test_stuff
    post = Post.create!(title: 'foobar')

    assert_equal post.title, 'foobar'

    post_temp = post.dup.becomes(PostTemp)

    assert_equal post_temp.title, 'foobar'
    assert_equal post_temp.save, true
    
    post_temp.reload
    
    assert_equal post_temp.title, 'foobar'
  end
end