Add test to ensure query times out when server returns bad ID

client_test.go

@@ -175,6 +175,31 @@ func TestClientSyncBadID(t *testing.T) {
 	m := new(Msg)
 	m.SetQuestion("miek.nl.", TypeSOA)
 
+	c := &Client{
+		Timeout: 1 * time.Second,
+	}
+	if _, _, err := c.Exchange(m, addrstr); err == nil || !strings.Contains(err.Error(), "timeout") {
+		t.Errorf("query did not time out")
+	}
+	// And now with plain Exchange().
+	if _, err = Exchange(m, addrstr); err == nil || !strings.Contains(err.Error(), "timeout") {
+		t.Errorf("query did not time out")
+	}
+}
+
+func TestClientSyncBadThenGoodID(t *testing.T) {
+	HandleFunc("miek.nl.", HelloServerBadThenGoodID)
+	defer HandleRemove("miek.nl.")
+
+	s, addrstr, err := RunLocalUDPServer(":0")
+	if err != nil {
+		t.Fatalf("unable to run test server: %v", err)
+	}
+	defer s.Shutdown()
+
+	m := new(Msg)
+	m.SetQuestion("miek.nl.", TypeSOA)
+
 	c := new(Client)
 	r, _, err := c.Exchange(m, addrstr)
 	if err != nil {

server_test.go

@@ -33,6 +33,16 @@ func HelloServerBadID(w ResponseWriter, req *Msg) {
 	m.Extra = make([]RR, 1)
 	m.Extra[0] = &TXT{Hdr: RR_Header{Name: m.Question[0].Name, Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"Hello world"}}
 	w.WriteMsg(m)
+}
+
+func HelloServerBadThenGoodID(w ResponseWriter, req *Msg) {
+	m := new(Msg)
+	m.SetReply(req)
+	m.Id++
+
+	m.Extra = make([]RR, 1)
+	m.Extra[0] = &TXT{Hdr: RR_Header{Name: m.Question[0].Name, Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"Hello world"}}
+	w.WriteMsg(m)
 
 	m.Id--
 	w.WriteMsg(m)