def _get_cluster(timeout=None):
    """Gets cluster for the default project.

    Creates a client with the inferred credentials and project ID from
    the local environment. Then uses :meth:`.Client.list_clusters` to
    get the unique cluster owned by the project.

    If the request fails for any reason, or if there isn't exactly one cluster
    owned by the project, then this function will fail.

    :type timeout: int
    :param timeout: (Optional) The socket timeout in milliseconds.

    :rtype: :class:`gcloud_bigtable.cluster.Cluster`
    :returns: The unique cluster owned by the project inferred from
              the environment.
    :raises: :class:`ValueError <exceptions.ValueError>` if any of the unused
    """
    client_kwargs = {'admin': True}
    if timeout is not None:
        client_kwargs['timeout_seconds'] = timeout / 1000.0
    client = Client(**client_kwargs)
    client.start()
    clusters, failed_zones = client.list_clusters()
    client.stop()

    if len(failed_zones) != 0:
        raise ValueError('Determining cluster via ListClusters encountered '
                         'failed zones.')
    if len(clusters) == 0:
        raise ValueError('This client doesn\'t have access to any clusters.')
    if len(clusters) > 1:
        raise ValueError('This client has access to more than one cluster. '
                         'Please directly pass the cluster you\'d '
                         'like to use.')
    return clusters[0]
COL_NAME3 = b'col-name3-but-other-fam'
CELL_VAL1 = b'cell-val'
CELL_VAL2 = b'cell-val-newer'
CELL_VAL3 = b'altcol-cell-val'
CELL_VAL4 = b'foo'
ROW_KEY = b'row-key'
ROW_KEY_ALT = b'row-key-alt'
EXPECTED_ZONES = (
    'asia-east1-b',
    'europe-west1-c',
    'us-central1-b',
    CENTRAL_1C_ZONE,
)
EXISTING_CLUSTERS = []
CREDENTIALS = GoogleCredentials.get_application_default()
CLIENT = Client(CREDENTIALS, project_id=PROJECT_ID, admin=True)
CLUSTER = CLIENT.cluster(CENTRAL_1C_ZONE, CLUSTER_ID,
                         display_name=CLUSTER_ID)


def setUpModule():
    CLIENT.start()
    clusters, failed_zones = CLIENT.list_clusters()

    if len(failed_zones) != 0:
        raise ValueError('List clusters failed in module set up.')

    EXISTING_CLUSTERS[:] = clusters

    # After listing, create the test cluster.
    CLUSTER.create()