Redmine

    normalized_address = arg.to_s.strip

    # Convert internationalized domain name (IDN) to Punycode

    # e.g. 'marie@société.example' => 'marie@xn--socit-esab.example'

    local_part, _at, domain = normalized_address.partition('@')

    if domain.present?

      ascii_domain = Addressable::IDNA.to_ascii(domain)

      normalized_address = "#{local_part}@#{ascii_domain}"

    end

    write_attribute(:address, normalized_address)

  def test_should_normalize_idn_email_address

    email = EmailAddress.new(address: 'marie@société.example')

    assert_equal 'marie@xn--socit-esab.example', email.address

    assert email.valid?

  end