'CreateDataset fails if no nodes in cluster.'

def test_empty_cluster(self):

    control_service = FakeFlockerClient()
    cluster = BenchmarkCluster(IPAddress('10.0.0.1'), (lambda reactor: control_service), {}, None)
    d = CreateDataset(Clock(), cluster).get_probe()
    self.failureResultOf(d, EmptyClusterError)
