def testChunkedDownload(self):
    bytes_http = object()
    http = object()
    download_stream = six.StringIO()
    download = transfer.Download.FromStream(
        download_stream, chunksize=26, total_size=52)
    download.bytes_http = bytes_http

    # Setting autospec on a mock with an iterable side_effect is
    # currently broken (http://bugs.python.org/issue17826), so
    # instead we write a little function.