settings storage class

settings.rb

require 'yaml'
require 'test/unit'

TEST_CONFIG = <<END_OF_CONFIG
filename: settings.rb
development:
  database: settings-development
  port: 3366
test:
  hostname: localhost
  port: 8000
END_OF_CONFIG

class Settings
  def initialize(raw_opts)
    mod = Module.new

    raw_opts.each { |key, value|
      var = to_var(key)

      if value.instance_of?(Hash)
        instance_variable_set(var, Settings.new(value))
      else
        instance_variable_set(var, value)
      end

      mod.send(:define_method, key) {
        return instance_variable_get(var)
      }
    }

    self.extend(mod)
  end

private

  def to_var(key)
    ("@"+key.to_s).to_sym
  end
end

class SettingsTest < Test::Unit::TestCase
  def setup
    @settings = Settings.new(YAML.load(TEST_CONFIG))
  end

  def test_all_values_loaded
    assert_equal("settings.rb",          @settings.filename)
    assert_equal("settings-development", @settings.development.database)
    assert_equal(3366,                   @settings.development.port)
    assert_equal("localhost",            @settings.test.hostname)
    assert_equal(8000,                   @settings.test.port)
  end

  def test_to_var
    assert_equal(@settings.send(:to_var, :key), :@key)
  end
end

Thanks for advice.