diff --git a/gossipsub_test.go b/gossipsub_test.go
index da5f630..3bbc0ad 100644
--- a/gossipsub_test.go
+++ b/gossipsub_test.go
@@ -1487,46 +1487,6 @@ func TestGossipsubPiggybackControl(t *testing.T) {
 	}
 }
 
-func TestGossipsubRPCFragmentation(t *testing.T) {
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	h := bhost.NewBlankHost(swarmt.GenSwarm(t, ctx))
-	ps := getGossipsub(ctx, h)
-	ps.maxMessageSize = 500
-
-	blah := peer.ID("bogotr0n")
-	msgch := make(chan *RPC, 10)
-	ps.peers[blah] = msgch
-	ps.eval <- func() {
-		gs := ps.rt.(*GossipSubRouter)
-		topic := "test1"
-		gs.mesh[topic] = make(map[peer.ID]struct{})
-		gs.mesh[topic][blah] = struct{}{}
-
-		rpc := &RPC{RPC: pb.RPC{}, from: h.ID()}
-		msgs := make([]*pb.Message, 10)
-		for i := 0; i < 10; i++ {
-			msgs[i] = makeTestMessage(i)
-			msgs[i].Data = make([]byte, 100)
-			rand.Read(msgs[i].Data)
-		}
-		rpc.Publish = msgs
-
-		gs.sendRPC(blah, rpc)
-		close(msgch)
-		delete(ps.peers, blah)
-	}
-
-	rpcs := make([]*RPC, 0, 10)
-	for rpc := range msgch {
-		rpcs = append(rpcs, rpc)
-	}
-	if len(rpcs) < 2 {
-		t.Fatalf("expected large rpc message to be fragmented before sending on output channel, got %d rpcs", len(rpcs))
-	}
-}
-
 func TestGossipsubOpportunisticGrafting(t *testing.T) {
 	originalGossipSubPruneBackoff := GossipSubPruneBackoff
 	GossipSubPruneBackoff = 500 * time.Millisecond
@@ -1757,3 +1717,140 @@ func (ps *mockPeerScoreInspector) score(p peer.ID) float64 {
 	defer ps.mx.Unlock()
 	return ps.scores[p]
 }
+
+func TestGossipsubRPCFragmentation(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	hosts := getNetHosts(t, ctx, 2)
+	ps := getGossipsub(ctx, hosts[0])
+
+	// make a fake peer that requests everything through IWANT gossip
+	iwe := iwantEverything{h: hosts[1]}
+	iwe.h.SetStreamHandler(GossipSubID_v10, iwe.handleStream)
+
+	connect(t, hosts[0], hosts[1])
+
+	// have the real pubsub join the test topic
+	_, err := ps.Subscribe("test")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// wait for the real pubsub to connect and try to graft to the faker
+	time.Sleep(time.Second)
+
+	// publish a bunch of fairly large messages from the real host
+	nMessages := 1000
+	msgSize := 20000
+	for i := 0; i < nMessages; i++ {
+		msg := make([]byte, msgSize)
+		rand.Read(msg)
+		ps.Publish("test", msg)
+		time.Sleep(20 * time.Millisecond)
+	}
+
+	// wait a bit for them to be received via gossip by the fake peer
+	time.Sleep(5 * time.Second)
+
+	// we should have received all the messages
+	if iwe.msgsReceived != nMessages {
+		t.Fatalf("expected fake gossipsub peer to receive all messages, got %d / %d", iwe.msgsReceived, nMessages)
+	}
+
+	// and we should have seen an IHAVE message for each of them
+	if iwe.ihavesReceived != nMessages {
+		t.Fatalf("expected to get IHAVEs for every message, got %d / %d", iwe.ihavesReceived, nMessages)
+	}
+
+	// If everything were fragmented with maximum efficiency, we would expect to get
+	// (nMessages * msgSize) / ps.maxMessageSize total RPCs containing the messages we sent IWANTs for.
+	// The actual number will probably be larger, since there's some overhead for the RPC itself, and
+	// we probably aren't packing each RPC to it's maximum size
+	minExpectedRPCS := (nMessages * msgSize) / ps.maxMessageSize
+	if iwe.rpcsWithMessages < minExpectedRPCS {
+		t.Fatalf("expected to receive at least %d RPCs containing messages, got %d", minExpectedRPCS, iwe.rpcsWithMessages)
+	}
+}
+
+// iwantEverything is a simple gossipsub client that never grafts onto a mesh,
+// instead requesting everything through IWANT gossip messages. It is used to
+// test that large responses to IWANT requests are fragmented into multiple RPCs.
+type iwantEverything struct {
+	h                host.Host
+	rpcsWithMessages int
+	msgsReceived     int
+	ihavesReceived   int
+}
+
+func (iwe *iwantEverything) handleStream(s network.Stream) {
+	os, err := iwe.h.NewStream(context.Background(), s.Conn().RemotePeer(), GossipSubID_v10)
+	if err != nil {
+		panic(err)
+	}
+
+	msgIdsReceived := make(map[string]struct{})
+	gossipMsgIdsReceived := make(map[string]struct{})
+
+	// send a subscription for test in the output stream to become candidate for gossip
+	r := ggio.NewDelimitedReader(s, 1<<20)
+	w := ggio.NewDelimitedWriter(os)
+	truth := true
+	topic := "test"
+	err = w.WriteMsg(&pb.RPC{Subscriptions: []*pb.RPC_SubOpts{&pb.RPC_SubOpts{Subscribe: &truth, Topicid: &topic}}})
+
+	remotePidBytes, err := s.Conn().RemotePeer().MarshalBinary()
+	if err != nil {
+		panic(err)
+	}
+	toPrune := []*pb.PeerInfo{{PeerID: remotePidBytes}}
+
+	var rpc pb.RPC
+	for {
+		rpc.Reset()
+		err = r.ReadMsg(&rpc)
+		if err != nil {
+			if err != io.EOF {
+				s.Reset()
+			}
+			return
+		}
+
+		if len(rpc.Publish) != 0 {
+			iwe.rpcsWithMessages++
+		}
+		// keep track of unique message ids received
+		for _, msg := range rpc.Publish {
+			id := string(msg.Seqno)
+			if _, seen := msgIdsReceived[id]; !seen {
+				iwe.msgsReceived++
+			}
+			msgIdsReceived[id] = struct{}{}
+		}
+
+		if rpc.Control != nil {
+			// send a PRUNE for all grafts, so we don't get direct message deliveries
+			var prunes []*pb.ControlPrune
+			for _, graft := range rpc.Control.Graft {
+				prunes = append(prunes, &pb.ControlPrune{TopicID: graft.TopicID, Peers: toPrune})
+			}
+
+			var iwants []*pb.ControlIWant
+			for _, ihave := range rpc.Control.Ihave {
+				iwants = append(iwants, &pb.ControlIWant{MessageIDs: ihave.MessageIDs})
+				for _, msgId := range ihave.MessageIDs {
+					if _, seen := gossipMsgIdsReceived[msgId]; !seen {
+						iwe.ihavesReceived++
+					}
+					gossipMsgIdsReceived[msgId] = struct{}{}
+				}
+			}
+
+			out := rpcWithControl(nil, nil, iwants, nil, prunes)
+			err = w.WriteMsg(out)
+			if err != nil {
+				panic(err)
+			}
+		}
+	}
+}