package net

import (
	"testing"
	"net"
	"github.com/benburkert/dns"
)

func TestPreferIPV4Resolver(t *testing.T) {
	var (
		cli   = &dns.Client{Resolver: &PreferIPV4Resolver{}}
		addrs []net.IP
		err   error
	)
	addrs, err = net.LookupIP("www.v6.facebook.com")
	if err == nil && len(addrs) != 0 && len(addrs[0]) == net.IPv6len {
		err = nil
		t.Log("checked AAAA dns reponse")
	} else {
		t.Fatal("unknown error : ", err)
	}

	net.DefaultResolver.PreferGo = true
	net.DefaultResolver.Dial = cli.Dial

	addrs, err = net.LookupIP("www.v6.facebook.com")
	if len(addrs) != 0 {
		t.Fatal("ipv6 address isn't empty")
	} else if err == nil {
		t.Fatal("no error in AAAA record")
	} else if dnserr, ok := err.(*net.DNSError); !ok || dnserr.Err != "no such host" {
		t.Fatal("unknown error : ", err)
	} else {
		err = nil
		t.Log("AAAA dns request filtered")
	}
}