Test Script for rails/rails#15176

unless File.exist?('Gemfile')
  File.write('Gemfile', <<-GEMFILE)
source 'https://rubygems.org'
gem 'rails', github: 'rails/rails'
gem 'arel', github: 'rails/arel'
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_null_relation_in_direct_and_association_subquery
    post = Post.create!
    post.comments << Comment.create!

    assert_equal 1, Post.count

    # Direct
    assert_equal 0, Post.none.count
    # assert_equal 0, Post.where(id: Post.none).count

    # Select parent with children condition
    assert_equal 0, Post.includes(:comments).references(:comments).where(comments: {id: Comment.none}).count

    # Select children with children condition
    assert_equal 0, post.comments.none.count
    assert_equal 0, post.comments.where(comments: {id: Comment.none}).count
  end
end