Add test for firefox and marionette

t/CanStartBinary.t

@@ -98,6 +98,11 @@ FIREFOX: {
             is($encoded, 0, 'Binary firefox does not encode profile unnecessarily');
         }
 
+        my $firefox_marionette = Selenium::Firefox->new(
+            marionette_enabled => 1
+        );
+        isnt( $firefox->port, 4444, 'firefox can start up its own binary');
+        ok( Selenium::CanStartBinary::probe_port( $firefox_marionette->marionette_port ), 'the firefox binary with marionette enabled is listening on its marionette port');
     }
 }