add regression test for issue 371

gossipsub_test.go

@@ -1183,6 +1183,92 @@ func TestGossipsubDirectPeers(t *testing.T) {
 	}
 }
 
+func TestGossipsubDirectPeersFanout(t *testing.T) {
+	// regression test for #371
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	h := getNetHosts(t, ctx, 3)
+	psubs := []*PubSub{
+		getGossipsub(ctx, h[0]),
+		getGossipsub(ctx, h[1], WithDirectPeers([]peer.AddrInfo{peer.AddrInfo{h[2].ID(), h[2].Addrs()}})),
+		getGossipsub(ctx, h[2], WithDirectPeers([]peer.AddrInfo{peer.AddrInfo{h[1].ID(), h[1].Addrs()}})),
+	}
+
+	connect(t, h[0], h[1])
+	connect(t, h[0], h[2])
+
+	// Join all peers except h2
+	var subs []*Subscription
+	for _, ps := range psubs[:2] {
+		sub, err := ps.Subscribe("test")
+		if err != nil {
+			t.Fatal(err)
+		}
+		subs = append(subs, sub)
+	}
+
+	time.Sleep(time.Second)
+
+	// h2 publishes some messages to build a fanout
+	for i := 0; i < 3; i++ {
+		msg := []byte(fmt.Sprintf("message %d", i))
+		psubs[2].Publish("test", msg)
+
+		for _, sub := range subs {
+			assertReceive(t, sub, msg)
+		}
+	}
+
+	// verify that h0 is in the fanout of h2, but not h1 who is a direct peer
+	result := make(chan bool, 2)
+	psubs[2].eval <- func() {
+		rt := psubs[2].rt.(*GossipSubRouter)
+		fanout := rt.fanout["test"]
+		_, ok := fanout[h[0].ID()]
+		result <- ok
+		_, ok = fanout[h[1].ID()]
+		result <- ok
+	}
+
+	inFanout := <-result
+	if !inFanout {
+		t.Fatal("expected peer 0 to be in fanout")
+	}
+
+	inFanout = <-result
+	if inFanout {
+		t.Fatal("expected peer 1 to not be in fanout")
+	}
+
+	// now subscribe h2 too and verify tht h0 is in the mesh but not h1
+	_, err := psubs[2].Subscribe("test")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	time.Sleep(2 * time.Second)
+
+	psubs[2].eval <- func() {
+		rt := psubs[2].rt.(*GossipSubRouter)
+		mesh := rt.mesh["test"]
+		_, ok := mesh[h[0].ID()]
+		result <- ok
+		_, ok = mesh[h[1].ID()]
+		result <- ok
+	}
+
+	inMesh := <-result
+	if !inMesh {
+		t.Fatal("expected peer 0 to be in mesh")
+	}
+
+	inMesh = <-result
+	if inMesh {
+		t.Fatal("expected peer 1 to not be in mesh")
+	}
+}
+
 func TestGossipsubFloodPublish(t *testing.T) {
 	// uses a star topology without PX and publishes from the star to verify that all
 	// messages get received