[management, client] Add IPv6 overlay support (#5631)

client/internal/rosenpass/manager_test.go

@@ -0,0 +1,14 @@
+package rosenpass
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestFindRandomAvailableUDPPort(t *testing.T) {
+	port, err := findRandomAvailableUDPPort()
+	require.NoError(t, err)
+	require.Greater(t, port, 0)
+	require.LessOrEqual(t, port, 65535)
+}