'If a C{doRead} returns a value indicating disconnection,
C{connectionLost} is called on it.'

def test_connectionLostOnRead(self):

    reactor = Clock()
    poller = _ContinuousPolling(reactor)
    desc = Descriptor()
    desc.doRead = (lambda : ConnectionDone())
    poller.addReader(desc)
    self.assertEqual(desc.events, [])
    reactor.advance(0.001)
    self.assertEqual(desc.events, ['lost'])
