'When a port starts, a message including a description of the associated
protocol is logged.'

def test_startedListeningLogMessage(self):

    loggedMessages = self.observe()
    reactor = self.buildReactor()
    @implementer(ILoggingContext)
    class SomeProtocol(DatagramProtocol, ):
        def logPrefix(self):
            return 'Crazy    Protocol'
    protocol = SomeProtocol()
    p = self.getListeningPort(reactor, protocol)
    expectedMessage = ('Crazy    Protocol    starting    on    %d' % (p.getHost().port,))
    self.assertEqual((expectedMessage,), loggedMessages[0]['message'])
