public void TestAddNoMatchSubsystem()
 {
     using (var udev = new Context())
         using (var e = new Enumerator(udev)) {
             e.AddNoMatchSubsystem("mem");
             e.ScanDevices();
             Assert.NotEmpty(e);
             Assert.DoesNotContain(e, d => d.DevNode == "/dev/null");
         }
 }