Test fails without it (spy fails to set its publish intercept):

  1) ascoltatori should delegate to the use ascoltatore for 'pub':
     TypeError: Cannot set property publish of #<EventEmitter> which has only a getter
      at Object.wrapMethod (/home/david/Private/hub/node_modules/mosca/node_modules/ascoltatori/node_modules/sinon/lib/sinon.js:80:30)
      at Object.spy (/home/david/Private/hub/node_modules/mosca/node_modules/ascoltatori/node_modules/sinon/lib/sinon/spy.js:42:22)
      at Object.spy (/home/david/Private/hub/node_modules/mosca/node_modules/ascoltatori/node_modules/sinon/lib/sinon/collection.js:88:39)
      at Context.<anonymous> (/home/david/Private/hub/node_modules/mosca/node_modules/ascoltatori/test/ascoltatori_spec.js:26:28)
      at Test.Runnable.run (/usr/lib/node_modules/mocha/lib/runnable.js:213:32)
      at Runner.runTest (/usr/lib/node_modules/mocha/lib/runner.js:351:10)
      at Runner.runTests.next (/usr/lib/node_modules/mocha/lib/runner.js:397:12)
      at next (/usr/lib/node_modules/mocha/lib/runner.js:277:14)
      at Runner.hooks (/usr/lib/node_modules/mocha/lib/runner.js:286:7)
      at next (/usr/lib/node_modules/mocha/lib/runner.js:234:23)
      at Runner.hook (/usr/lib/node_modules/mocha/lib/runner.js:249:7)
      at Hook.Runnable.run (/usr/lib/node_modules/mocha/lib/runnable.js:215:5)
      at next (/usr/lib/node_modules/mocha/lib/runner.js:243:10)
      at Runner.hook (/usr/lib/node_modules/mocha/lib/runner.js:254:5)
      at process.startup.processNextTick.process._tickCallback (node.js:244:9)