fix: return wants from engine.WantlistForPeer()

internal/decision/engine.go

@@ -334,16 +334,17 @@ func (e *Engine) onPeerRemoved(p peer.ID) {
 	e.peerTagger.UntagPeer(p, e.tagQueued)
 }
 
-// WantlistForPeer returns the currently understood want list for a given peer
-func (e *Engine) WantlistForPeer(p peer.ID) (out []wl.Entry) {
+// WantlistForPeer returns the list of keys that the given peer has asked for
+func (e *Engine) WantlistForPeer(p peer.ID) []wl.Entry {
 	partner := e.findOrCreate(p)
 
 	partner.lk.Lock()
 	entries := partner.wantList.Entries()
 	partner.lk.Unlock()
 
 	wl.SortEntries(entries)
-	return
+
+	return entries
 }
 
 // LedgerForPeer returns aggregated data about blocks swapped and communication

internal/decision/engine_test.go

@@ -981,6 +981,40 @@ func TestSendDontHave(t *testing.T) {
 	}
 }
 
+func TestWantlistForPeer(t *testing.T) {
+	bs := blockstore.NewBlockstore(dssync.MutexWrap(ds.NewMapDatastore()))
+	partner := libp2ptest.RandPeerIDFatal(t)
+	otherPeer := libp2ptest.RandPeerIDFatal(t)
+
+	e := newEngine(context.Background(), bs, &fakePeerTagger{}, "localhost", 0, shortTerm, nil)
+	e.StartWorkers(context.Background(), process.WithTeardown(func() error { return nil }))
+
+	blks := testutil.GenerateBlocksOfSize(4, 8*1024)
+	msg := message.New(false)
+	msg.AddEntry(blks[0].Cid(), 2, pb.Message_Wantlist_Have, false)
+	msg.AddEntry(blks[1].Cid(), 3, pb.Message_Wantlist_Have, false)
+	e.MessageReceived(context.Background(), partner, msg)
+
+	msg2 := message.New(false)
+	msg2.AddEntry(blks[2].Cid(), 1, pb.Message_Wantlist_Block, false)
+	msg2.AddEntry(blks[3].Cid(), 4, pb.Message_Wantlist_Block, false)
+	e.MessageReceived(context.Background(), partner, msg2)
+
+	entries := e.WantlistForPeer(otherPeer)
+	if len(entries) != 0 {
+		t.Fatal("expected wantlist to contain no wants for other peer")
+	}
+
+	entries = e.WantlistForPeer(partner)
+	if len(entries) != 4 {
+		t.Fatal("expected wantlist to contain all wants from parter")
+	}
+	if entries[0].Priority != 4 || entries[1].Priority != 3 || entries[2].Priority != 2 || entries[3].Priority != 1 {
+		t.Fatal("expected wantlist to be sorted")
+	}
+
+}
+
 func TestTaggingPeers(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
 	defer cancel()