test: add test for when nodes are connected before the DHT is created

dht_test.go

@@ -2023,3 +2023,73 @@ func TestBootStrapWhenRTIsEmpty(t *testing.T) {
 			rt.Find(bootstrappers[2].self) != "" && rt.Find(bootstrapcons[1].self) != "" && rt.Find(bootstrapcons[2].self) != ""
 	}, 5*time.Second, 500*time.Millisecond)
 }
+
+func TestPreconnectedNodes(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	// If this test fails it may hang so set a timeout
+	ctx, cancel = context.WithTimeout(ctx, time.Second*10)
+	defer cancel()
+
+	opts := []Option{
+		testPrefix,
+		DisableAutoRefresh(),
+		Mode(ModeServer),
+	}
+
+	// Create hosts
+	h1 := bhost.New(swarmt.GenSwarm(t, ctx, swarmt.OptDisableReuseport))
+	h2 := bhost.New(swarmt.GenSwarm(t, ctx, swarmt.OptDisableReuseport))
+
+	// Setup first DHT
+	d1, err := New(ctx, h1, opts...)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Connect the first host to the second
+	if err := h1.Connect(ctx, peer.AddrInfo{ID: h2.ID(), Addrs: h2.Addrs()}); err != nil {
+		t.Fatal(err)
+	}
+
+	// Wait until we know identify has completed by checking for supported protocols
+	// TODO: Is this needed? Could we do h2.Connect(h1) and that would wait for identify to complete.
+	for {
+		h1Protos, err := h2.Peerstore().SupportsProtocols(h1.ID(), d1.protocolsStrs...)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if len(h1Protos) > 0 {
+			break
+		}
+
+		select {
+		case <-time.After(time.Millisecond * 100):
+		case <-ctx.Done():
+			t.Fatal("test hung")
+		}
+	}
+
+	// Setup the second DHT
+	d2, err := New(ctx, h2, opts...)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// See if it works
+	peerCh, err := d2.GetClosestPeers(ctx, "testkey")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	select {
+	case p := <-peerCh:
+		if p == h1.ID() {
+			break
+		}
+		t.Fatal("could not find peer")
+	case <-ctx.Done():
+		t.Fatal("test hung")
+	}
+}