'Verify that when a L{Deferred} with no references to it is fired,
the logged message includes debug info if debugging on the deferred
is enabled.'

def test_errorLogDebugInfo(self):

    def doit():
        d = defer.Deferred()
        d.debug = True
        d.addCallback((lambda x: (1 // 0)))
        d.callback(1)
    doit()
    gc.collect()
    self._check()
    self.assertEqual(2, len(self.c))
    msg = log.textFromEventDict(self.c[(-1)])
    expected = '(debug:        I'
    self.assertTrue(msg.startswith(expected), 'Expected    message    starting    with:    {0!r}'.format(expected))
