'Assert that when a single manifestation exists on the cluster a ``GET``
request to the ``/configuration/datasets`` returns a list of one object
that represents that manifestation.
:param kwargs: Additional arguments to use when creating the
manifestation.  See ``_manifestation``.
:return: A ``Deferred`` that fires when the assertion has been made.'

def _one_dataset_test(self, **kwargs):

    manifestation = _manifestation(**kwargs)
    deployment = Deployment(nodes={Node(uuid=self.NODE_A_UUID, manifestations={manifestation.dataset_id: manifestation})})
    expected = [api_dataset_from_dataset_and_node(manifestation.dataset, self.NODE_A)]
    return self._dataset_test(deployment, expected)
