chore(natpmp): more robust tests with longer connection durations

internal/natpmp/helpers_test.go

@@ -4,11 +4,15 @@ import (
 	"errors"
 	"net"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
+// enough for slow machines for local UDP server.
+const initialConnectionDuration = 3 * time.Second
+
 type udpExchange struct {
 	request  []byte
 	response []byte