'It can be very confusing if you write some code which responds to a
command, but gets the return value wrong.  Most commonly you end up
returning None instead of a dictionary.
Verify that if that happens, the framework logs a useful error.'

def test_brokenReturnValue(self):

    L = []
    SimpleSymmetricCommandProtocol().dispatchCommand(amp.AmpBox(_command=BrokenReturn.commandName)).addErrback(L.append)
    L[0].trap(amp.BadLocalReturn)
    self.failUnlessIn('None', repr(L[0].value))
