Test for AR5's OR feature (https://www.reddit.com/r/ruby/comments/4ltroo/rails_5_adds_or_support_in_active_record/)

test_ar5_or.rb

# rubocop:disable Style/DotPosition
# rubocop:disable Style/GlobalVars
# test Rails 5's ActiveRecord OR
system 'rm Gemfile' if File.exist?('Gemfile')

$ar_version = ENV['AR_VERSION']
$ar_version ||= '5.0.0.rc1'

$try_patch = ENV['TRY_PATCH'] == 'true'
$enable_byebug = false

File.write('Gemfile', <<-GEMFILE)
  source 'https://rubygems.org'
  gem 'activerecord',
    #{$ar_version.inspect}
  gem 'sqlite3'
  #{"gem 'byebug'" if $enable_byebug}
GEMFILE

system 'bundle install'

require 'byebug' if $enable_byebug
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 :companies do |t|
    t.string   :name
    t.datetime :created_at
    t.integer  :employees_count
  end
end

class Company < ActiveRecord::Base
end

puts Company.
  where(name: 'ACME').
  to_sql
# SELECT "companies".*
#   FROM "companies"
#   WHERE "companies"."name" = 'ACME'
puts Company.
  where(name: 'ACME').
  or(Company.where('employees_count > ?', 10)).
  to_sql
# SELECT "companies".*
#   FROM "companies"
#   WHERE ("companies"."name" = 'ACME' OR (employees_count > 10))
puts Company.
  where(name: 'ACME').
  or(Company.where('employees_count > ?', 10)).
  where('created_at > ?', 1.year.ago).
  to_sql
# SELECT "companies".*
#   FROM "companies"
#   WHERE ("companies"."name" = 'ACME' OR (employees_count > 10))
#     AND (created_at > '2015-05-31 20:25:08.996444')
puts Company.
  where(name: 'ACME').
  where('created_at > ?', 1.year.ago).
  or(Company.where('employees_count > ?', 10)).
  to_sql
# SELECT "companies".*
#   FROM "companies"
#   WHERE ("companies"."name" = 'ACME' AND (created_at > '2015-05-31 20:25')
#     OR (employees_count > 10))