dnsforward -- add a simple test that launches a server and queries well-known value through it

dnsforward/dnsforward_test.go

@@ -0,0 +1,49 @@
+package dnsforward
+
+import (
+	"net"
+	"testing"
+
+	"github.com/miekg/dns"
+)
+
+func TestServer(t *testing.T) {
+	s := Server{}
+	s.UDPListenAddr = &net.UDPAddr{Port: 0}
+	err := s.Start(nil)
+	if err != nil {
+		t.Fatalf("Failed to start server: %s", err)
+	}
+	if s.udpListen == nil {
+		t.Fatal("Started server has nil udpListen")
+	}
+
+	// server is running, send a message
+	addr := s.udpListen.LocalAddr()
+	req := dns.Msg{}
+	req.Id = dns.Id()
+	req.RecursionDesired = true
+	req.Question = []dns.Question{
+		{Name: "google-public-dns-a.google.com.", Qtype: dns.TypeA, Qclass: dns.ClassINET},
+	}
+
+	reply, err := dns.Exchange(&req, addr.String())
+	if err != nil {
+		t.Fatalf("Couldn't talk to server %s: %s", addr, err)
+	}
+	if len(reply.Answer) != 1 {
+		t.Fatalf("DNS server %s returned reply with wrong number of answers - %d", addr, len(reply.Answer))
+	}
+	if a, ok := reply.Answer[0].(*dns.A); ok {
+		if !net.IPv4(8, 8, 8, 8).Equal(a.A) {
+			t.Fatalf("DNS server %s returned wrong answer instead of 8.8.8.8: %v", addr, a.A)
+		}
+	} else {
+		t.Fatalf("DNS server %s returned wrong answer type instead of A: %v", addr, reply.Answer[0])
+	}
+
+	err = s.Stop()
+	if err != nil {
+		t.Fatalf("DNS server %s failed to stop: %s", addr, err)
+	}
+}