'Test observer clean-up after removeObserver for named events.'

def test_cleanUpRemoveEventObserver(self):

    d = EventDispatcher()
    cb = CallbackTracker()
    d.addObserver('//event/test', cb.call)
    d.dispatch(None, '//event/test')
    self.assertEqual(1, cb.called)
    d.removeObserver('//event/test', cb.call)
    self.assertEqual(0, len(d._eventObservers.pop(0)))
