Testing find_in_batches/reverse_order bug

active_record_gem.rb

# Activate the gem you are reporting the issue against.
gem 'activerecord', '4.1.8'
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(adapter: 'sqlite3', database: ':memory:')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :posts do |t|
  end

  create_table :comments do |t|
    t.integer :post_id
  end
end

class Post < ActiveRecord::Base
  has_many :comments
end

class Comment < ActiveRecord::Base
  belongs_to :post
end

class BugTest < Minitest::Test
  def test_find_each_should_find_every_one
    number_of_posts = 30
    number_of_posts.times { post = Post.create! }

    assert_equal number_of_posts, Post.count

    ids = []
    Post.where('id < ?', 1000).reverse_order.find_each(batch_size: 10) do |post|
      ids << post.id
    end

    assert_equal number_of_posts, ids.length
    assert_equal (1..number_of_posts).to_a, ids
  end
end

active_record_master.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|
  end

  create_table :comments do |t|
    t.integer :post_id
  end
end

class Post < ActiveRecord::Base
  has_many :comments
end

class Comment < ActiveRecord::Base
  belongs_to :post
end

class BugTest < Minitest::Test
  def test_find_each_should_find_every_one
    number_of_posts = 30
    number_of_posts.times { post = Post.create! }

    assert_equal number_of_posts, Post.count

    ids = []
    Post.where('id < ?', 1000).reverse_order.find_each(batch_size: 10) do |post|
      ids << post.id
    end

    assert_equal number_of_posts, ids.length
    assert_equal (1..number_of_posts).to_a, ids
  end
end