Original function is called instead of stub

Question

I'm having an issue getting Sinon's stub to work correctly for me. When I stub list on retro and the test runs, app.get('/retro', retro.list) is executing the original function retro.list instead of the stub. Since this happens, the test fails because the stub's callCount is 0.

I'm more familiar with coffeescript and I have stubbed things in the same way. Is there something I'm not understanding about Javascript's scoping, or how the require('../routes/retro') works, or is retro is not the same in app.js and test.js.

Much thanks for the help and code below.

test.js:

var request = require('supertest')
  , retro = require('../routes/retro')
  , app = require('../app')
  , sinon = require('sinon');
require('should'); 

describe('GET /retro', function() {
  // less involved, but maybe stupid to test
  it('should call retro.list', function(done) {
    var stub = sinon.stub(retro, 'list');

    request(app)
      .get('/retro')
      .end(function(err, res){
        stub.callCount.should.equal(1);

        if (err) return done(err);
        done();
      })
  })
})

app.js:

var express = require('express')
  , config = require('./config')
  , routes = require('./routes')
  , retro = require('./routes/retro');

var app = express();
config(app);

app.get('/', routes.index);
app.get('/retro', retro.list);

module.exports = app;

retro.js:

var retro = {
  list: function(req, res){
    console.log('actual called');
    res.send("respond with a resource");
  }
}

module.exports = retro;

Answer 1

You'll likely need to create your stubs before requiring/creating the app.

var request = require('supertest')
  , sinon = require('sinon')
  , retro = require('../routes/retro');

var stubRetroList = sinon.stub(retro, 'list');

var app = require('../app');

// ...

    stubRetroList.callCount.should.equal(1);

This allows retro.list to be updated before it's passed to the route:

app.get('/retro', retro.list);

The issue is probably because retro.list isn't being passed-by-reference (pointer), but is rather a reference that's passed-by-value (copied). So, though sinon.stub() is altering retro.list, it wouldn't affect the copy that the '/retro' route already had.