net/portmapper: add start of self-contained portmapper integration tests

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

net/portmapper/portmapper_test.go

@@ -10,6 +10,9 @@ import (
 	"strconv"
 	"testing"
 	"time"
+
+	"inet.af/netaddr"
+	"tailscale.com/types/logger"
 )
 
 func TestCreateOrGetMapping(t *testing.T) {
@@ -55,3 +58,30 @@ func TestClientProbeThenMap(t *testing.T) {
 	ext, err := c.createOrGetMapping(context.Background())
 	t.Logf("createOrGetMapping: %v, %v", ext, err)
 }
+
+func TestProbeIntegration(t *testing.T) {
+	igd, err := NewTestIGD()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer igd.Close()
+
+	logf := t.Logf
+	var c *Client
+	c = NewClient(logger.WithPrefix(logf, "portmapper: "), func() {
+		logf("portmapping changed.")
+		logf("have mapping: %v", c.HaveMapping())
+	})
+
+	c.SetGatewayLookupFunc(func() (gw, self netaddr.IP, ok bool) {
+		return netaddr.IPv4(127, 0, 0, 1), netaddr.IPv4(1, 2, 3, 4), true
+	})
+
+	res, err := c.Probe(context.Background())
+	if err != nil {
+		t.Fatalf("Probe: %v", err)
+	}
+	t.Logf("Probe: %+v", res)
+	t.Logf("IGD stats: %+v", igd.stats())
+	// TODO(bradfitz): finish
+}