assertThat(parse(unicode, "a=b; domain=長崎.jp")).isNull()
    val punycode = "https://xn--ue5a.xn--ue5a.xn--8ltr62k.jp".toHttpUrl()
    assertThat(parse(punycode, "a=b; domain=xn--ue5a.xn--8ltr62k.jp")).isNotNull()
    assertThat(parse(punycode, "a=b; domain=xn--8ltr62k.jp")).isNull()
  }

  @Test fun hostOnly() {
    assertThat(parse(url, "a=b")!!.hostOnly).isTrue()
    assertThat(

      .isEqualTo("google.co.uk")
    assertThat("https://栃.栃木.jp".toHttpUrl().topPrivateDomain())
      .isEqualTo("xn--ewv.xn--4pvxs.jp")
    assertThat("https://xn--ewv.xn--4pvxs.jp".toHttpUrl().topPrivateDomain())
      .isEqualTo("xn--ewv.xn--4pvxs.jp")
    assertThat("https://co.uk".toHttpUrl().topPrivateDomain()).isNull()
    assertThat("https://square".toHttpUrl().topPrivateDomain()).isNull()

  private static final InternetDomainName UNICODE_EXAMPLE =
      InternetDomainName.from("j\u00f8rpeland.no");
  private static final InternetDomainName PUNYCODE_EXAMPLE =
      InternetDomainName.from("xn--jrpeland-54a.no");

  /** The Greek letter delta, used in unicode testing. */
  private static final String DELTA = "\u0394";

}

/**
 * If this is an IP address, this returns the IP address in canonical form.
 *
 * Otherwise, this performs IDN ToASCII encoding and canonicalize the result to lowercase. For
 * example this converts `☃.net` to `xn--n3h.net`, and `WwW.GoOgLe.cOm` to `www.google.com`.
 * `null` will be returned if the host cannot be ToASCII encoded or if the result contains
 * unsupported ASCII characters.
 */