Fixed & reduced version of https://gist.github.com/dazld/6493549

index.js

'use strict';

var assert       = require('assert')
  , director     = require('director')
  , EventEmitter = require('events').EventEmitter
  , ns           = require('continuation-local-storage').createNamespace('testing')
  ;

/*
 * CONSTANTS
 */
var NUM_TESTS = 1000;

function createRouter() {
  var emitter = new EventEmitter()
    , router  = new director.http.Router()
    ;

  var createHandler = function () {
    return function () {
      assert(ns.get('req'), "req propagated to Router handler");
      emitter.emit('routeMatched', ns.get('req').someId);
    };
  };

  var ret = {
    _createHandler : createHandler,
    initialize : function () {
      router.on('get','/page/:id', ret._createHandler(/* route, routeFunction */));
    },
    on : emitter.on.bind(emitter),
    once : emitter.once.bind(emitter),
    dispatch : function (req, res) {
      assert(ns.get('req'), "req propagated to Router dispatch");
      router.dispatch(req, res, function (err) {
        console.log(err);
      });
    }
  };
  
  return ret;
}

var router = createRouter();
router.initialize();

function spawnAsync(i) {
  var req = {
    url     : '/page/' + i,
    method  : 'get',
    someId  : Math.floor(Math.random() * Date.now()),
    headers : {
      'content-type' : 'text/html'
    }
  };

  ns.set('req', req);

  process.nextTick(router.dispatch.bind(router, req));
}

router.on('routeMatched', function (id) {
  assert(id,                             "id passed to routeMatched listener");
  assert(ns.get('req'),                  "req propagated to routeMatched listener");
  assert.equal(id, ns.get('req').someId, "passed id and req.someId match");
});

// actually do the thing
for (var i = 0; i < NUM_TESTS; i++) ns.run(spawnAsync.bind(null, i));

package.json

{
  "name": "clsbughunt",
  "dependencies": {
    "continuation-local-storage": "~2.1.2",
    "director": "~1.2.0"
  }
}