fix: flaky test by delaying connections

Author: dennis-tra

topology_test.go

@@ -142,6 +142,13 @@ func (t *Topology) Connect(ctx context.Context, a *DHT, b *DHT) {
 	err := a.AddAddresses(ctx, []peer.AddrInfo{bAddr}, time.Hour)
 	require.NoError(t.tb, err)
 
+	// If two peers simultaneously connect they could end up in a state where
+	// one peer is waiting on the connection for the other one although there
+	// already exists a valid connection. This sleep below makes sure that we
+	// don't trigger a "simultaneous" connect. Remove this call to Sleep when
+	// https://github.com/libp2p/go-libp2p/issues/2589 is resolved.
+	time.Sleep(10 * time.Millisecond)
+
 	// Add a's addresses to b
 	err = b.AddAddresses(ctx, []peer.AddrInfo{aAddr}, time.Hour)
 	require.NoError(t.tb, err)