Gemfile

source "https://rubygems.org"

git_source(:github) { |repo| "https://github.com/#{repo}.git" }

# ここに依存する gem を記述する
gem "activerecord", "6.0.3"
# gem "rails", github: "rails/rails"
gem "sqlite3"
gem "ruby_jard"

sample.rb

# frozen_string_literal: true

require "stringio"
# require "ruby_jard"

temp_io = $stdout
$stdout = StringIO.new

require "active_record"
# require "minitest/autorun"
require "logger"

# メモリ上に DB を構築する
ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
# ActiveRecord::Base.logger = Logger.new(STDOUT)

# DB の schema を定義する
ActiveRecord::Schema.define do
  create_table :users, force: true do |t|
    t.boolean :active
  end
end

$stdout = temp_io


class User < ActiveRecord::Base
  $debug = true
  scope :actives, -> { where(active: true) }
  $debug = false

  scope(:owners, -> { where(owner: true) }) do
    def order_by_created_at(order_ = "asc")
      order(created_at: order_)
    end
  end
end

p User.method :actives
# puts User.owners.order_by_created_at.to_sql