v6Address.getHostAddress(), v6Address.getAddress(), interfaceIndex);
      }
      try {
        NetworkInterface asInterface = NetworkInterface.getByName(scope);
        if (asInterface == null) {
          throw formatIllegalArgumentException("No such interface: '%s'", scope);
        }
        return Inet6Address.getByAddress(
            v6Address.getHostAddress(), v6Address.getAddress(), asInterface);

            v6Address.getHostAddress(), v6Address.getAddress(), interfaceIndex);
      }
      try {
        NetworkInterface asInterface = NetworkInterface.getByName(scope);
        if (asInterface == null) {
          throw formatIllegalArgumentException("No such interface: '%s'", scope);
        }
        return Inet6Address.getByAddress(
            v6Address.getHostAddress(), v6Address.getAddress(), asInterface);

            final String hostname = ia.getHostName();
            if (StringUtil.isNotBlank(hostname)) {
                buf.append(hostname);
            }
            final String ip = ia.getHostAddress();
            if (StringUtil.isNotBlank(ip)) {
                if (buf.length() > 0) {
                    buf.append(" : ");
                }
                buf.append(ip);
            }

            return env.get("COMPUTERNAME");
        }
        if (env.containsKey("HOSTNAME")) {
            return env.get("HOSTNAME");
        }
        try {
            return InetAddress.getLocalHost().getHostAddress();
        } catch (final UnknownHostException e) {
            logger.debug("Unknown hostname.", e);
        }
        return "Unknown";
    }

        IllegalArgumentException.class,
        () -> InetAddresses.forString("1180::b059:65f4:e877:c40%eth9"));
  }

  public void testToAddrStringIPv4() {
    // Don't need to test IPv4 much; it just calls getHostAddress().
    assertEquals("1.2.3.4", InetAddresses.toAddrString(InetAddresses.forString("1.2.3.4")));
  }

  public void testToAddrStringIPv6() {
    assertEquals(