diff --git a/mesh/gossip_test.go b/mesh/gossip_test.go
index 5f622826..21d2b858 100644
--- a/mesh/gossip_test.go
+++ b/mesh/gossip_test.go
@@ -238,10 +238,10 @@ func (g *testGossiper) OnGossip(update []byte) (GossipData, error) {
 			g.state[v] = void
 		}
 	}
-	if len(delta) > 0 {
-		return NewSurrogateGossipData(delta), nil
+	if len(delta) == 0 {
+		return nil, nil
 	}
-	return nil, nil
+	return NewSurrogateGossipData(delta), nil
 }
 
 func (g *testGossiper) checkHas(t *testing.T, vs ...byte) {
diff --git a/mesh/router.go b/mesh/router.go
index c19556d7..69b26831 100644
--- a/mesh/router.go
+++ b/mesh/router.go
@@ -122,15 +122,6 @@ type TopologyGossipData struct {
 	update PeerNameSet
 }
 
-func (router *Router) BroadcastTopologyUpdate(update []*Peer) {
-	names := make(PeerNameSet)
-	for _, p := range update {
-		names[p.Name] = void
-	}
-	router.TopologyGossip.GossipBroadcast(
-		&TopologyGossipData{peers: router.Peers, update: names})
-}
-
 func (d *TopologyGossipData) Merge(other GossipData) GossipData {
 	names := make(PeerNameSet)
 	for name := range d.update {
@@ -146,6 +137,15 @@ func (d *TopologyGossipData) Encode() [][]byte {
 	return [][]byte{d.peers.EncodePeers(d.update)}
 }
 
+func (router *Router) BroadcastTopologyUpdate(update []*Peer) {
+	names := make(PeerNameSet)
+	for _, p := range update {
+		names[p.Name] = void
+	}
+	router.TopologyGossip.GossipBroadcast(
+		&TopologyGossipData{peers: router.Peers, update: names})
+}
+
 func (router *Router) OnGossipUnicast(sender PeerName, msg []byte) error {
 	return fmt.Errorf("unexpected topology gossip unicast: %v", msg)
 }