Ruby custom extend/include

# created by Huynh Quang Thao
# on 02/04/2017
require 'test/unit'

# ------------------------------------------------------------
# implementation
class Class
  def custom_include(module_name)
    module_name.instance_methods.each do |method|
      puts method
      define_method(method) do |*args, &block|
        # my fault. cannot send here. because module cannot be initialized
        module_name.send(method, *args, &block)
      end
    end
  end

  def custom_extend(module_name)
    module_name.methods(false).each do |method|
      define_singleton_method(method) do |*args, &block|
        module_name.send(method, *args, &block)
      end
    end
  end
end

# -------------------------------------------------------------
# Demonstration
module SimpleModule
  def self.class_hello_world
    puts 'i am a simple module boss'
  end

  def hello_world
    puts 'i am a simple module client'
  end
end

class SimpleClass
  custom_include SimpleModule
  custom_extend  SimpleModule
end

SimpleClass.class_hello_world

# -----------------------------------------------------------------
# Testing
class TestUsing < Test::Unit::TestCase
  def test_custom_extend
    message = SimpleClass.class_hello_world
    assert message == SimpleModule.class_hello_world
  end
end

TestUsing.new("test extend/include")