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# coding: utf-8
# -------------------------------------------------------------------------
# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License. See License.txt in the project root for
# license information.
# --------------------------------------------------------------------------
import os
from azure.storage.blob._upload_chunking import _SubStream
from threading import Lock
from io import (BytesIO, SEEK_SET)
from tests.testcase import (
StorageTestCase,
)
# ------------------------------------------------------------------------------
class StorageBlobUploadChunkingTest(StorageTestCase):
# this is a white box test that's designed to make sure _Substream behaves properly
# when the buffer needs to be swapped out at least once
def test_sub_stream_with_length_larger_than_buffer(self):
data = os.urandom(12 * 1024 * 1024)
# assuming the max size of the buffer is 4MB, this test needs to be updated if that has changed
# the block size is 6MB for this test
expected_data = data[0: 6 * 1024 * 1024]
wrapped_stream = BytesIO(data) # simulate stream given by user
lockObj = Lock() # simulate multi-threaded environment
substream = _SubStream(wrapped_stream, stream_begin_index=0, length=6 * 1024 * 1024, lockObj=lockObj)
try:
# substream should start with position at 0
self.assertEqual(substream.tell(), 0)
# reading a chunk that is smaller than the buffer
data_chunk_1 = substream.read(2 * 1024 * 1024)
self.assertEqual(len(data_chunk_1), 2 * 1024 * 1024)
# reading a chunk that is bigger than the data remaining in buffer, force a buffer swap
data_chunk_2 = substream.read(4 * 1024 * 1024)
self.assertEqual(len(data_chunk_2), 4 * 1024 * 1024)
# assert data is consistent
self.assertEqual(data_chunk_1 + data_chunk_2, expected_data)
self.assertEqual(6 * 1024 * 1024, substream.tell())
# attempt to read more than what the sub stream contains should return nothing
empty_data = substream.read(1 * 1024 * 1024)
self.assertEqual(0, len(empty_data))
self.assertEqual(6 * 1024 * 1024, substream.tell())
# test seek outside of current buffer, which is at the moment the last 2MB of data
substream.seek(0, SEEK_SET)
data_chunk_1 = substream.read(4 * 1024 * 1024)
data_chunk_2 = substream.read(2 * 1024 * 1024)
# assert data is consistent
self.assertEqual(data_chunk_1 + data_chunk_2, expected_data)
# test seek inside of buffer, which is at the moment the last 2MB of data
substream.seek(4 * 1024 * 1024, SEEK_SET)
data_chunk_2 = substream.read(2 * 1024 * 1024)
# assert data is consistent
self.assertEqual(data_chunk_1 + data_chunk_2, expected_data)
finally:
wrapped_stream.close()
substream.close()
# this is a white box test that's designed to make sure _Substream behaves properly
# when block size is smaller than 4MB, thus there's no need for buffer swap
def test_sub_stream_with_length_equal_to_buffer(self):
data = os.urandom(6 * 1024 * 1024)
# assuming the max size of the buffer is 4MB, this test needs to be updated if that has changed
# the block size is 2MB for this test
expected_data = data[0: 2 * 1024 * 1024]
wrapped_stream = BytesIO(expected_data) # simulate stream given by user
lockObj = Lock() # simulate multi-threaded environment
substream = _SubStream(wrapped_stream, stream_begin_index=0, length=2 * 1024 * 1024, lockObj=lockObj)
try:
# substream should start with position at 0
self.assertEqual(substream.tell(), 0)
# reading a chunk that is smaller than the buffer
data_chunk_1 = substream.read(1 * 1024 * 1024)
self.assertEqual(len(data_chunk_1), 1 * 1024 * 1024)
# reading a chunk that is bigger than the buffer, should not read anything beyond
data_chunk_2 = substream.read(4 * 1024 * 1024)
self.assertEqual(len(data_chunk_2), 1 * 1024 * 1024)
# assert data is consistent
self.assertEqual(data_chunk_1 + data_chunk_2, expected_data)
# test seek
substream.seek(1 * 1024 * 1024, SEEK_SET)
data_chunk_2 = substream.read(1 * 1024 * 1024)
# assert data is consistent
self.assertEqual(data_chunk_1 + data_chunk_2, expected_data)
finally:
wrapped_stream.close()
substream.close()
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