'If a dictionary key contains a circular reference (which is probably a
bad practice anyway) it will be resolved by a
L{crefutil._DictKeyAndValue}, not by placing a L{crefutil.NotKnown}
into a dictionary key.'

def test_dontPutCircularReferencesInDictionaryKeys(self):

    self.assertRaises(AssertionError, dict().__setitem__, crefutil.NotKnown(), 'value')
