Router instance mounted explicitly at '//' exposes routes when path begins only with a single /:

const TestRoutes = express.Router();

TestRoutes.get('/drop/table/:table', (req, res) => { 
  // drop table
  res.send(`Dropped table '${req.params.table}'`);
})

TestRoutes.get('/', sendListOfTestRoutes);

if (TEST) app.use('//', TestRoutes);

app.listen();

Expected behavior is that navigating to http://hostname/ would bypass this Router and go to the main app, but instead Express serves the list of test routes mounted within the router at //.