test case showing unscope(:order) not working

uniq_through_4.1.rb

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'

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
    t.integer :user_id
  end

  create_table :users do |t|
  end
end

class Post < ActiveRecord::Base
    has_many :comments, -> {order(:id)}
    has_many :users, -> {unscope(:order).uniq}, :through => :comments
end

class Comment < ActiveRecord::Base
  belongs_to :post
  belongs_to :user
end

class User < ActiveRecord::Base
end

class BugTest < Minitest::Test
  def test_uniq_through_removes_order_to_work_with_postgresql
    post = Post.create!
    puts Gem.loaded_specs["activerecord"].version.to_s
    puts post.users.to_sql
    assert(!(post.users.to_sql =~ /order by/i), "generated sql includes ORDER BY")
  end
end