Unit test express route calls controller method?

I see some similar questions, but my setup is slightly different and I can't figure out a good way to test this.

I'm trying to test that my express app routes are directed to the correct controller methods.

For example -

//server.js, base application

var express = require("express");
var app = express();
require("./routes.js")(app);
...

//routes.js
var menuController = require("./controllers/menu.js");

module.exports = function(expressApp) {
    expressApp.get('/menu', menuController.getMenu);
};
...

//test file
var express = require('express')
    , menuController = require("../../controllers/menu.js")
    , chai = require('chai')
    , should = chai.should()
    , sinon = require('sinon')
    , sinonChai = require("sinon-chai");
chai.use(sinonChai);

var app = express();
require("../../routes/routes.js")(app);

describe('routes.js', function(){

    it('/menu should call menuController.getMenu route', function(){
        var spy = sinon.spy(menuController, 'getMenu');
        app.get('/menu', spy);

        spy.should.have.been.called;  //fails, never called
    });

});  

How can I check to see that when calling app.get('/menu', ..), the callback from menuController is invoked? Or should I restructure the app somehow (I see a bunch of other ways to configure the routing)?