Bug report test created from the ActiveRecord template for gems for rails/rails#12505.

rails_issue_12505_bug_report.rb

# Activate the gem you are reporting the issue against.
gem 'activerecord', '4.0.0'
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|
    t.string :name
  end
end

class User < ActiveRecord::Base
  serialize :name
end

class BugTest < MiniTest::Unit::TestCase
  def test_changed_attributes_of_serialized_attribute
    user = User.new
  
    assert !user.name_changed?
    assert_equal Hash.new, user.changed_attributes
  end
end