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#!/usr/bin/env python
#
# Copyright (c) 2011, Andres Moreira <andres@andresmoreira.com>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# * Neither the name of the authors nor the
# names of its contributors may be used to endorse or promote products
# derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL ANDRES MOREIRA BE LIABLE FOR ANY DIRECT,
# INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
import os
import sys
import random
import snappy
import struct
from unittest import TestCase
class SnappyCompressionTest(TestCase):
def test_simple_compress(self):
text = "hello world!".encode('utf-8')
compressed = snappy.compress(text)
self.assertEqual(text, snappy.uncompress(compressed))
def test_moredata_compress(self):
text = "snappy +" * 1000 + " " + "by " * 1000 + " google"
text = text.encode('utf-8')
compressed = snappy.compress(text)
self.assertEqual(text, snappy.uncompress(compressed))
def test_randombytes_compress(self):
_bytes = repr(os.urandom(1000)).encode('utf-8')
compressed = snappy.compress(_bytes)
self.assertEqual(_bytes, snappy.uncompress(compressed))
def test_randombytes2_compress(self):
_bytes = bytes(os.urandom(10000))
compressed = snappy.compress(_bytes)
self.assertEqual(_bytes, snappy.uncompress(compressed))
def test_uncompress_error(self):
self.assertRaises(snappy.UncompressError, snappy.uncompress,
"hoa".encode('utf-8'))
if sys.version_info[0] == 2:
def test_unicode_compress(self):
text = "hello unicode world!".decode('utf-8')
compressed = snappy.compress(text)
self.assertEqual(text, snappy.uncompress(compressed))
def test_decompress(self):
# decompress == uncompress, just to support compatibility with zlib
text = "hello world!".encode('utf-8')
compressed = snappy.compress(text)
self.assertEqual(text, snappy.decompress(compressed))
def test_big_string(self):
text = ('a'*10000000).encode('utf-8')
compressed = snappy.compress(text)
self.assertEqual(text, snappy.decompress(compressed))
class SnappyValidBufferTest(TestCase):
def test_valid_compressed_buffer(self):
text = "hello world!".encode('utf-8')
compressed = snappy.compress(text)
uncompressed = snappy.uncompress(compressed)
self.assertEqual(text == uncompressed,
snappy.isValidCompressed(compressed))
def test_invalid_compressed_buffer(self):
self.assertFalse(snappy.isValidCompressed(
"not compressed".encode('utf-8')))
class SnappyStreaming(TestCase):
def test_random(self):
for _ in range(100):
compressor = snappy.StreamCompressor()
decompressor = snappy.StreamDecompressor()
data = b""
compressed = b""
for _ in range(random.randint(0, 3)):
chunk = os.urandom(random.randint(0, snappy._CHUNK_MAX * 2))
data += chunk
compressed += compressor.add_chunk(
chunk, compress=random.choice([True, False, None]))
upper_bound = random.choice([256, snappy._CHUNK_MAX * 2])
while compressed:
size = random.randint(0, upper_bound)
chunk, compressed = compressed[:size], compressed[size:]
chunk = decompressor.decompress(chunk)
self.assertEqual(data[:len(chunk)], chunk)
data = data[len(chunk):]
decompressor.flush()
self.assertEqual(len(data), 0)
def test_compression(self):
# test that we can add compressed chunks
compressor = snappy.StreamCompressor()
data = b"\0" * 50
compressed_data = snappy.compress(data)
crc = struct.pack("<L", snappy._masked_crc32c(data))
self.assertEqual(crc, b"\x8f)H\xbd")
self.assertEqual(len(compressed_data), 6)
self.assertEqual(compressor.add_chunk(data, compress=True),
b"\xff\x06\x00\x00sNaPpY"
b"\x00\x0a\x00\x00" + crc + compressed_data)
# test that we can add uncompressed chunks
data = b"\x01" * 50
crc = struct.pack("<L", snappy._masked_crc32c(data))
self.assertEqual(crc, b"\xb2\x14)\x8a")
self.assertEqual(compressor.add_chunk(data, compress=False),
b"\x01\x36\x00\x00" + crc + data)
# test that we can add more data than will fit in one chunk
data = b"\x01" * (snappy._CHUNK_MAX * 2 - 5)
crc1 = struct.pack("<L",
snappy._masked_crc32c(data[:snappy._CHUNK_MAX]))
self.assertEqual(crc1, b"h#6\x8e")
crc2 = struct.pack("<L",
snappy._masked_crc32c(data[snappy._CHUNK_MAX:]))
self.assertEqual(crc2, b"q\x8foE")
self.assertEqual(compressor.add_chunk(data, compress=False),
b"\x01\x04\x00\x01" + crc1 + data[:snappy._CHUNK_MAX] +
b"\x01\xff\xff\x00" + crc2 + data[snappy._CHUNK_MAX:])
def test_decompression(self):
# test that we check for the initial stream identifier
data = b"\x01" * 50
self.assertRaises(snappy.UncompressError,
snappy.StreamDecompressor().decompress,
b"\x01\x36\x00\00" +
struct.pack("<L", snappy._masked_crc32c(data)) + data)
self.assertEqual(
snappy.StreamDecompressor().decompress(
b"\xff\x06\x00\x00sNaPpY"
b"\x01\x36\x00\x00" +
struct.pack("<L", snappy._masked_crc32c(data)) + data),
data)
decompressor = snappy.StreamDecompressor()
decompressor.decompress(b"\xff\x06\x00\x00sNaPpY")
self.assertEqual(
decompressor.copy().decompress(
b"\x01\x36\x00\x00" +
struct.pack("<L", snappy._masked_crc32c(data)) + data),
data)
# test that we throw errors for unknown unskippable chunks
self.assertRaises(snappy.UncompressError,
decompressor.copy().decompress, b"\x03\x01\x00\x00")
# test that we skip unknown skippable chunks
self.assertEqual(b"",
decompressor.copy().decompress(b"\xfe\x01\x00\x00"))
# test that we check CRCs
compressed_data = snappy.compress(data)
real_crc = struct.pack("<L", snappy._masked_crc32c(data))
fake_crc = os.urandom(4)
self.assertRaises(snappy.UncompressError,
decompressor.copy().decompress,
b"\x00\x0a\x00\x00" + fake_crc + compressed_data)
self.assertEqual(
decompressor.copy().decompress(
b"\x00\x0a\x00\x00" + real_crc + compressed_data),
data)
# test that we buffer when we don't have enough
uncompressed_data = os.urandom(100)
compressor = snappy.StreamCompressor()
compressed_data = (compressor.compress(uncompressed_data[:50]) +
compressor.compress(uncompressed_data[50:]))
for split1 in range(len(compressed_data) - 1):
for split2 in range(split1, len(compressed_data)):
decompressor = snappy.StreamDecompressor()
self.assertEqual(
(decompressor.decompress(compressed_data[:split1]) +
decompressor.decompress(compressed_data[split1:split2]) +
decompressor.decompress(compressed_data[split2:])),
uncompressed_data)
def test_concatenation(self):
data1 = os.urandom(snappy._CHUNK_MAX * 2)
data2 = os.urandom(4096)
decompressor = snappy.StreamDecompressor()
self.assertEqual(
decompressor.decompress(
snappy.StreamCompressor().compress(data1) +
snappy.StreamCompressor().compress(data2)),
data1 + data2)
if __name__ == "__main__":
import unittest
unittest.main()
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