Gist for https://github.com/rails/rails/issues/25892

25892.rb

begin
  require 'bundler/inline'
rescue LoadError => e
  $stderr.puts 'Bundler version 1.10 or later is required. Please update your Bundler'
  raise e
end
gemfile(true) do
  source 'https://rubygems.org'
  gem 'rails', '5.0.0'
  gem 'pg'
end

require 'active_record'
require 'minitest/autorun'
require 'logger'

DB_NAME = '25892'
ActiveRecord::Base.establish_connection(adapter: 'postgresql', database: DB_NAME)
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :posts, force: true do |t|
    t.integer :ptype
  end
end

class Post < ActiveRecord::Base
  alias_attribute :post_type, :ptype
  enum post_type: { main: 0, guest: 1 }
end

class BugTest < Minitest::Test
  def test_should_return_string_value_of_enum
    guest_post = Post.create(ptype: 1)
    assert_equal('guest', guest_post.post_type)
  end

  def test_should_detect_enum_value
    guest_post = Post.create(ptype: 1)
    assert_equal(true, guest_post.guest?)
  end
end