'POST ``/configuration/leases`` can acquire a lease without expiration.'

def test_acquire_no_expiration(self):

    d = self.acquire_lease(None)
    def acquired(_):
        self.assertEqual(self.persistence_service.get().leases[self.dataset3], Lease(dataset_id=self.dataset3, node_id=self.node3, expiration=None))
    d.addCallback(acquired)
    return d
