~bzr-pqm/bzr/bzr.dev

2052.3.2 by John Arbash Meinel
Change Copyright .. by Canonical to Copyright ... Canonical
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# Copyright (C) 2006 Canonical Ltd
1666.1.2 by Robert Collins
Fix race condition between end of stream and end of file with tuned_gzip.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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"""Tests for tuned_gzip."""
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# do not use bzrlib test cases here - this should be suitable for sending
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# upstream.
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from cStringIO import StringIO
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from unittest import TestCase
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import zlib
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1773.4.1 by Martin Pool
Add pyflakes makefile target; fix many warnings
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from bzrlib import tuned_gzip
1666.1.2 by Robert Collins
Fix race condition between end of stream and end of file with tuned_gzip.
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class FakeDecompress(object):
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    """A fake decompressor for testing GzipFile."""
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    def __init__(self):
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        self.unused_data=''
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    def decompress(self, buf):
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        """Return an empty string as though we are at eof."""
3943.8.1 by Marius Kruger
remove all trailing whitespace from bzr source
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        # note that the zlib module *overwrites* unused data
1666.1.11 by Robert Collins
Really fix short-read support in tuned_gzip. The python zlib module behaved differently than thought.
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        # on writes after EOF.
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        self.unused_data = buf
1666.1.2 by Robert Collins
Fix race condition between end of stream and end of file with tuned_gzip.
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        return ''
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class TestFakeDecompress(TestCase):
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    """We use a fake decompressor to test GzipFile.
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    This class tests the behaviours we want from it.
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    """
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    def test_decompress(self):
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        # decompressing returns no data.
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        decompress = FakeDecompress()
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        self.assertEqual('', decompress.decompress('0'))
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    def test_unused_data(self):
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        # after decompressing, we have 1 unused byte.
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        # this is normally set by decompressors when they
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        # detect the end of a compressed stream.
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        decompress = FakeDecompress()
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        decompress.decompress('0')
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        self.assertEqual('0', decompress.unused_data)
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        # decompressing again (when the short read is read)
1666.1.11 by Robert Collins
Really fix short-read support in tuned_gzip. The python zlib module behaved differently than thought.
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        # will give us the latest input in the unused_data
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        # this is arguably a bug in zlib but ...
1666.1.2 by Robert Collins
Fix race condition between end of stream and end of file with tuned_gzip.
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        decompress.decompress('1234567')
1666.1.11 by Robert Collins
Really fix short-read support in tuned_gzip. The python zlib module behaved differently than thought.
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        self.assertEqual('1234567', decompress.unused_data)
1666.1.2 by Robert Collins
Fix race condition between end of stream and end of file with tuned_gzip.
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class TestGzip(TestCase):
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    def test__read_short_remainder(self):
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        # a _read call at the end of a compressed hunk should
3943.8.1 by Marius Kruger
remove all trailing whitespace from bzr source
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        # read more bytes if there is less than 8 bytes (the
1666.1.2 by Robert Collins
Fix race condition between end of stream and end of file with tuned_gzip.
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        # gzip trailer) unread.
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        stream = StringIO('\0\0\0\0\0\0\0\0')
1773.4.1 by Martin Pool
Add pyflakes makefile target; fix many warnings
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        myfile = tuned_gzip.GzipFile(fileobj=stream)
1666.1.2 by Robert Collins
Fix race condition between end of stream and end of file with tuned_gzip.
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        # disable the _new_member check, we are microtesting.
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        myfile._new_member = False
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        myfile.crc = zlib.crc32('')
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        myfile.decompress = FakeDecompress()
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        myfile.size = 0
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        myfile._read(1)
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        # all the data should have been read now
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        self.assertEqual('', stream.read())
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        # and it should be new member time in the stream.
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        self.failUnless(myfile._new_member)