dirty_rails_5_2_bug_test.rb

begin
  require 'bundler/inline'
rescue LoadError => e
  warn 'Bundler version 1.10 or later is required. Please update your Bundler'
  raise e
end

gemfile(true) do
  source 'https://rubygems.org'
  # gem 'activerecord', '5.1.5'
  gem 'activerecord', '5.2.0'
  gem 'pg', '~> 0.19'
end

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

# Ensure backward compatibility with Minitest 4
Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection('postgres://user:password@host/test_db')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :people, force: true do |t|
  end
end

class Person < ActiveRecord::Base
  define_attribute_method :first_name

  attr_reader :first_name

  def first_name=(value)
    first_name_will_change!
    @first_name = value
  end
end

class BugTest < Minitest::Test
  def test_dirty_attrs
    person = Person.new
    assert_equal person.changed?, false
    person.first_name = 'First Name'
    assert_equal person.changed?, true
    assert_equal person.changes, 'first_name' => [nil, 'First Name']
  end
end