// for testing purposes.
type networkInterfacer interface {
	InterfaceByName(intfName string) (*net.Interface, error)
	Addrs(intf *net.Interface) ([]net.Addr, error)
	Interfaces() ([]net.Interface, error)
}

// networkInterface implements the networkInterfacer interface for production code, just
// wrapping the underlying net library function calls.
type networkInterface struct{}

    ImmutableSet.Builder<String> builder = ImmutableSet.builder();
    Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
    assertTrue(interfaces.hasMoreElements());
    while (interfaces.hasMoreElements()) {
      NetworkInterface i = interfaces.nextElement();
      builder.add(i.getName()).add(String.valueOf(i.getIndex()));
    }
    return builder.build();

		if !ip.Equal(tc.expected) {
			t.Errorf("case[%v]: expected %v, got %v .err : %v", tc.tcase, tc.expected, ip, err)
		}
	}
}

func TestAddrs(t *testing.T) {
	var nw networkInterfacer = validNetworkInterface{}
	intf := net.Interface{Index: 0, MTU: 0, Name: "eth3", HardwareAddr: nil, Flags: 0}
	addrs, err := nw.Addrs(&intf)
	if err != nil {
		t.Errorf("expected no error got : %v", err)
	}

      if (interfaceIndex != -1) {
        return Inet6Address.getByAddress(
            v6Address.getHostAddress(), v6Address.getAddress(), interfaceIndex);
      }
      try {
        NetworkInterface asInterface = NetworkInterface.getByName(scope);
        if (asInterface == null) {
          throw formatIllegalArgumentException("No such interface: '%s'", scope);
        }
        return Inet6Address.getByAddress(

      if (interfaceIndex != -1) {
        return Inet6Address.getByAddress(
            v6Address.getHostAddress(), v6Address.getAddress(), interfaceIndex);
      }
      try {
        NetworkInterface asInterface = NetworkInterface.getByName(scope);
        if (asInterface == null) {
          throw formatIllegalArgumentException("No such interface: '%s'", scope);
        }
        return Inet6Address.getByAddress(