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# Copyright (C) 2006, 2009, 2010 Canonical Ltd
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
"""Tests for tuned_gzip."""
# do not use bzrlib test cases here - this should be suitable for sending
# upstream.
from cStringIO import StringIO
from unittest import TestCase
import zlib
from bzrlib import tuned_gzip
class FakeDecompress(object):
"""A fake decompressor for testing GzipFile."""
def __init__(self):
self.unused_data=''
def decompress(self, buf):
"""Return an empty string as though we are at eof."""
# note that the zlib module *overwrites* unused data
# on writes after EOF.
self.unused_data = buf
return ''
class TestFakeDecompress(TestCase):
"""We use a fake decompressor to test GzipFile.
This class tests the behaviours we want from it.
"""
def test_decompress(self):
# decompressing returns no data.
decompress = FakeDecompress()
self.assertEqual('', decompress.decompress('0'))
def test_unused_data(self):
# after decompressing, we have 1 unused byte.
# this is normally set by decompressors when they
# detect the end of a compressed stream.
decompress = FakeDecompress()
decompress.decompress('0')
self.assertEqual('0', decompress.unused_data)
# decompressing again (when the short read is read)
# will give us the latest input in the unused_data
# this is arguably a bug in zlib but ...
decompress.decompress('1234567')
self.assertEqual('1234567', decompress.unused_data)
class TestGzip(TestCase):
def test__read_short_remainder(self):
# a _read call at the end of a compressed hunk should
# read more bytes if there is less than 8 bytes (the
# gzip trailer) unread.
stream = StringIO('\0\0\0\0\0\0\0\0')
myfile = tuned_gzip.GzipFile(fileobj=stream)
# disable the _new_member check, we are microtesting.
myfile._new_member = False
myfile.crc = zlib.crc32('')
myfile.decompress = FakeDecompress()
myfile.size = 0
myfile._read(1)
# all the data should have been read now
self.assertEqual('', stream.read())
# and it should be new member time in the stream.
self.failUnless(myfile._new_member)
def test_negative_crc(self):
"""Content with a negative crc should not break when written"""
sio = StringIO()
gfile = tuned_gzip.GzipFile(mode="w", fileobj=sio)
gfile.write("\xFF")
gfile.close()
self.assertEqual(gfile.crc & 0xFFFFFFFFL, 0xFF000000L)
self.assertEqual(sio.getvalue()[-8:-4], "\x00\x00\x00\xFF")
class TestToGzip(TestCase):
def assertToGzip(self, chunks):
bytes = ''.join(chunks)
gzfromchunks = tuned_gzip.chunks_to_gzip(chunks)
gzfrombytes = tuned_gzip.bytes_to_gzip(bytes)
self.assertEqual(gzfrombytes, gzfromchunks)
decoded = tuned_gzip.GzipFile(fileobj=StringIO(gzfromchunks)).read()
self.assertEqual(bytes, decoded)
def test_single_chunk(self):
self.assertToGzip(['a modest chunk\nwith some various\nbits\n'])
def test_simple_text(self):
self.assertToGzip(['some\n', 'strings\n', 'to\n', 'process\n'])
def test_large_chunks(self):
self.assertToGzip(['a large string\n'*1024])
self.assertToGzip(['a large string\n']*1024)
def test_enormous_chunks(self):
self.assertToGzip(['a large string\n'*1024*256])
self.assertToGzip(['a large string\n']*1024*256)
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