'If a dataset with the given name already exists,
``/VolumeDriver.Create`` succeeds without create a new volume.'

def test_create_duplicate_name(self):

    name = u'thename'
    d = self.flocker_client.create_dataset(self.NODE_A, int(DEFAULT_SIZE.to_Byte()), metadata={NAME_FIELD: name})
    d.addCallback((lambda _: self.create(name)))
    d.addCallback((lambda _: self.flocker_client.list_datasets_configuration()))
    d.addCallback((lambda results: self.assertEqual(len(list(results)), 1)))
    return d
