rails--rails/activesupport/test/multibyte_proxy_test.rb

require 'abstract_unit'

class MultibyteProxyText < ActiveSupport::TestCase
  class AsciiOnlyEncoder
    attr_reader :wrapped_string
    alias to_s wrapped_string

    def initialize(string)
      @wrapped_string = string.gsub(/[^\u0000-\u007F]/, '?')
    end
  end

  def with_custom_encoder(encoder)
    original_proxy_class = ActiveSupport::Multibyte.proxy_class

    begin
      ActiveSupport::Multibyte.proxy_class = encoder

      yield
    ensure
      ActiveSupport::Multibyte.proxy_class = original_proxy_class
    end
  end

  test "custom multibyte encoder" do
    with_custom_encoder(AsciiOnlyEncoder) do
      assert_equal "s?me string 123", "søme string 123".mb_chars.to_s
    end

    assert_equal "søme string 123", "søme string 123".mb_chars.to_s
  end
end