test.rb

# coding: cp932
gem 'psych', '~> 1.2.0'
require 'psych'
require 'yaml'
require 'minitest/autorun'

class TestEnc < MiniTest::Unit::TestCase
  def setup
    @oldenc = Encoding.default_internal
    @v = {"a"=>"‚ "}
  end

  def teardown
    Encoding.default_internal = @oldenc
  end

  def test_no_default
    hash = YAML.load YAML.dump @v
    assert_equal @v['a'], hash['a'].encode('CP932')
    assert_equal @v['a'].encode('UTF-8'), hash['a']
  end

  def test_with_default
    Encoding.default_internal = Encoding::CP932

    hash = YAML.load YAML.dump @v
    assert_equal @v['a'], hash['a']
  end
end