Inverse Of

inverse_of.rb

unless File.exist?('Gemfile')
  File.write('Gemfile', <<-GEMFILE)
source 'https://rubygems.org'
gem 'rails', '4.1.5'
gem 'sqlite3', '~> 1.3.9'
gem 'minitest'
  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 :users, force: true do |t|
    t.timestamps
  end

  create_table :posts, force: true do |t|
    t.references :user
    t.boolean :enabled, default: :false

    t.timestamps
  end
end
 
class User < ActiveRecord::Base
  attr_accessor :name

  has_many :posts do
    def enabled
      where(enabled: true)
    end
  end
end

class Post < ActiveRecord::Base
  belongs_to :user
end
 
class BugTest < ::Minitest::Test

  def test_inverse_of
    user = User.create
    user.posts.create
    user.posts.create(enabled: true)
    user = User.last
    user.name = "KD"
    assert_equal user.name, user.posts.enabled.sample.user.name
  end
end