fix race in simconn_test

p2p/net/simconn/router.go

@@ -11,11 +11,14 @@ import (
 // PerfectRouter is a router that has no latency or jitter and can route to
 // every node
 type PerfectRouter struct {
+	mu    sync.Mutex
 	nodes map[net.Addr]*SimConn
 }
 
 // SendPacket implements Router.
 func (r *PerfectRouter) SendPacket(deadline time.Time, p Packet) error {
+	r.mu.Lock()
+	defer r.mu.Unlock()
 	conn, ok := r.nodes[p.To]
 	if !ok {
 		return errors.New("unknown destination")

p2p/net/simconn/simconn_test.go

@@ -228,6 +228,7 @@ func TestSimConnDeadlinesWithLatency(t *testing.T) {
 	})
 
 	t.Run("read fails after deadline", func(t *testing.T) {
+		defer reset()
 		// Set a short deadline
 		deadline := time.Now().Add(50 * time.Millisecond) // Less than router latency
 		err := conn2.SetReadDeadline(deadline)
@@ -239,15 +240,14 @@ func TestSimConnDeadlinesWithLatency(t *testing.T) {
 		go func() {
 			defer wg.Done()
 			// Send data after setting deadline
-			_, err = conn1.WriteTo([]byte("test"), addr2)
+			_, err := conn1.WriteTo([]byte("test"), addr2)
 			require.NoError(t, err)
 		}()
 
 		// Read should fail due to deadline
 		buf := make([]byte, 1024)
 		_, _, err = conn2.ReadFrom(buf)
 		require.ErrorIs(t, err, ErrDeadlineExceeded)
-		reset()
 	})
 }