skip v6 test when no v6 interface

netroute_linux.go

@@ -29,5 +29,5 @@ func New() (routing.Router, error) {
 	if err != nil {
 		return nil, err
 	}
-	return router{r}, nil
+	return &router{r}, nil
 }

netroute_test.go

@@ -18,6 +18,7 @@ func TestRoute(t *testing.T) {
 	}
 
 	var localAddr net.IP
+	var hasV6 bool
 	addrs, err := ifs[0].Addrs()
 	for _, addr := range addrs {
 		if strings.HasPrefix(addr.Network(), "ip") {
@@ -25,6 +26,15 @@ func TestRoute(t *testing.T) {
 			break
 		}
 	}
+	for _, addr := range addrs {
+		if strings.HasPrefix(addr.Network(), "ip") {
+			_, ipn, _ := net.ParseCIDR(addr.String())
+			if ipn.IP.To4() == nil {
+				hasV6 = true
+				break
+			}
+		}
+	}
 
 	_, gw, src, err := r.Route(localAddr)
 	if err != nil {
@@ -44,6 +54,9 @@ func TestRoute(t *testing.T) {
 	}
 
 	// Route to v4 and v6 should differ.
+	if !hasV6 {
+		return
+	}
 	_, v6gw, _, err := r.Route(net.ParseIP("2607:f8b0:400a:809::200e")) // at one point google.
 	if err != nil {
 		t.Fatal(err)