def METHOD_NAME(self, mock_blob_service_factory):
    connection_timeout = 3
    read_timeout = 11
    self.app.conf.update(
        {
            'azureblockblob_connection_timeout': connection_timeout,
            'azureblockblob_read_timeout': read_timeout,
        }
    )
    mock_blob_service_client_instance = Mock()
    mock_blob_service_factory.from_connection_string.return_value = (
        mock_blob_service_client_instance
    )
    base_url = "azureblockblob://"
    connection_string = "connection_string"
    backend = AzureBlockBlobBackend(
        app=self.app, url=f'{base_url}{connection_string}'
    )
    client = backend._blob_service_client
    assert client is mock_blob_service_client_instance
    (
        mock_blob_service_factory
        .from_connection_string
        .assert_called_once_with(
            connection_string,
            connection_timeout=connection_timeout,
            read_timeout=read_timeout
        )
    )