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6d362b25c5
For smaller datasets, it is not always true the increasing the compression level always results in better compression. Removed the test which made this invalid assumption.
497 lines
18 KiB
Python
497 lines
18 KiB
Python
import unittest
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from test import test_support
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import zlib
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import random
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# print test_support.TESTFN
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def getbuf():
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# This was in the original. Avoid non-repeatable sources.
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# Left here (unused) in case something wants to be done with it.
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import imp
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try:
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t = imp.find_module('test_zlib')
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file = t[0]
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except ImportError:
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file = open(__file__)
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buf = file.read() * 8
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file.close()
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return buf
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class ChecksumTestCase(unittest.TestCase):
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# checksum test cases
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def test_crc32start(self):
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self.assertEqual(zlib.crc32(""), zlib.crc32("", 0))
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def test_crc32empty(self):
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self.assertEqual(zlib.crc32("", 0), 0)
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self.assertEqual(zlib.crc32("", 1), 1)
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self.assertEqual(zlib.crc32("", 432), 432)
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def test_adler32start(self):
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self.assertEqual(zlib.adler32(""), zlib.adler32("", 1))
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def test_adler32empty(self):
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self.assertEqual(zlib.adler32("", 0), 0)
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self.assertEqual(zlib.adler32("", 1), 1)
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self.assertEqual(zlib.adler32("", 432), 432)
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def assertEqual32(self, seen, expected):
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# 32-bit values masked -- checksums on 32- vs 64- bit machines
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# This is important if bit 31 (0x08000000L) is set.
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self.assertEqual(seen & 0x0FFFFFFFFL, expected & 0x0FFFFFFFFL)
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def test_penguins(self):
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self.assertEqual32(zlib.crc32("penguin", 0), 0x0e5c1a120L)
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self.assertEqual32(zlib.crc32("penguin", 1), 0x43b6aa94)
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self.assertEqual32(zlib.adler32("penguin", 0), 0x0bcf02f6)
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self.assertEqual32(zlib.adler32("penguin", 1), 0x0bd602f7)
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self.assertEqual(zlib.crc32("penguin"), zlib.crc32("penguin", 0))
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self.assertEqual(zlib.adler32("penguin"),zlib.adler32("penguin",1))
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class ExceptionTestCase(unittest.TestCase):
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# make sure we generate some expected errors
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def test_bigbits(self):
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# specifying total bits too large causes an error
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self.assertRaises(zlib.error,
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zlib.compress, 'ERROR', zlib.MAX_WBITS + 1)
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def test_badcompressobj(self):
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# verify failure on building compress object with bad params
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self.assertRaises(ValueError, zlib.compressobj, 1, 8, 0)
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def test_baddecompressobj(self):
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# verify failure on building decompress object with bad params
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self.assertRaises(ValueError, zlib.decompressobj, 0)
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class CompressTestCase(unittest.TestCase):
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# Test compression in one go (whole message compression)
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def test_speech(self):
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# decompress(compress(data)) better be data
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x = zlib.compress(hamlet_scene)
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self.assertEqual(zlib.decompress(x), hamlet_scene)
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def test_speech8(self):
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# decompress(compress(data)) better be data -- more compression chances
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data = hamlet_scene * 8
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x = zlib.compress(data)
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self.assertEqual(zlib.decompress(x), data)
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def test_speech16(self):
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# decompress(compress(data)) better be data -- more compression chances
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data = hamlet_scene * 16
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x = zlib.compress(data)
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self.assertEqual(zlib.decompress(x), data)
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def test_speech128(self):
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# decompress(compress(data)) better be data -- more compression chances
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data = hamlet_scene * 8 * 16
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x = zlib.compress(data)
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self.assertEqual(zlib.decompress(x), data)
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class CompressObjectTestCase(unittest.TestCase):
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# Test compression object
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def test_pairsmall(self):
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# use compress object in straightforward manner, decompress w/ object
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data = hamlet_scene
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co = zlib.compressobj(8, 8, -15)
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x1 = co.compress(data)
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x2 = co.flush()
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self.assertRaises(zlib.error, co.flush) # second flush should not work
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dco = zlib.decompressobj(-15)
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y1 = dco.decompress(x1 + x2)
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y2 = dco.flush()
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self.assertEqual(data, y1 + y2)
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def test_pair(self):
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# straightforward compress/decompress objects, more compression
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data = hamlet_scene * 8 * 16
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co = zlib.compressobj(8, 8, -15)
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x1 = co.compress(data)
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x2 = co.flush()
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self.assertRaises(zlib.error, co.flush) # second flush should not work
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dco = zlib.decompressobj(-15)
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y1 = dco.decompress(x1 + x2)
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y2 = dco.flush()
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self.assertEqual(data, y1 + y2)
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def test_compressincremental(self):
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# compress object in steps, decompress object as one-shot
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data = hamlet_scene * 8 * 16
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co = zlib.compressobj(2, 8, -12, 9, 1)
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bufs = []
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for i in range(0, len(data), 256):
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bufs.append(co.compress(data[i:i+256]))
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bufs.append(co.flush())
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combuf = ''.join(bufs)
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dco = zlib.decompressobj(-15)
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y1 = dco.decompress(''.join(bufs))
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y2 = dco.flush()
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self.assertEqual(data, y1 + y2)
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def test_decompressincremental(self):
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# compress object in steps, decompress object in steps
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data = hamlet_scene * 8 * 16
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co = zlib.compressobj(2, 8, -12, 9, 1)
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bufs = []
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for i in range(0, len(data), 256):
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bufs.append(co.compress(data[i:i+256]))
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bufs.append(co.flush())
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combuf = ''.join(bufs)
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self.assertEqual(data, zlib.decompress(combuf, -12, -5))
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dco = zlib.decompressobj(-12)
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bufs = []
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for i in range(0, len(combuf), 128):
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bufs.append(dco.decompress(combuf[i:i+128]))
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self.assertEqual('', dco.unconsumed_tail, ########
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"(A) uct should be '': not %d long" %
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len(dco.unconsumed_tail))
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bufs.append(dco.flush())
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self.assertEqual('', dco.unconsumed_tail, ########
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"(B) uct should be '': not %d long" %
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len(dco.unconsumed_tail))
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self.assertEqual(data, ''.join(bufs))
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# Failure means: "decompressobj with init options failed"
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def test_decompinc(self,sizes=[128],flush=True,source=None,cx=256,dcx=64):
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# compress object in steps, decompress object in steps, loop sizes
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source = source or hamlet_scene
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for reps in sizes:
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data = source * reps
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co = zlib.compressobj(2, 8, -12, 9, 1)
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bufs = []
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for i in range(0, len(data), cx):
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bufs.append(co.compress(data[i:i+cx]))
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bufs.append(co.flush())
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combuf = ''.join(bufs)
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self.assertEqual(data, zlib.decompress(combuf, -12, -5))
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dco = zlib.decompressobj(-12)
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bufs = []
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for i in range(0, len(combuf), dcx):
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bufs.append(dco.decompress(combuf[i:i+dcx]))
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self.assertEqual('', dco.unconsumed_tail, ########
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"(A) uct should be '': not %d long" %
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len(dco.unconsumed_tail))
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if flush:
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bufs.append(dco.flush())
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else:
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while True:
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chunk = dco.decompress('')
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if chunk:
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bufs.append(chunk)
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else:
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break
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self.assertEqual('', dco.unconsumed_tail, ########
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"(B) uct should be '': not %d long" %
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len(dco.unconsumed_tail))
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self.assertEqual(data, ''.join(bufs))
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# Failure means: "decompressobj with init options failed"
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def test_decompimax(self,sizes=[128],flush=True,source=None,cx=256,dcx=64):
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# compress in steps, decompress in length-restricted steps, loop sizes
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source = source or hamlet_scene
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for reps in sizes:
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# Check a decompression object with max_length specified
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data = source * reps
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co = zlib.compressobj(2, 8, -12, 9, 1)
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bufs = []
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for i in range(0, len(data), cx):
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bufs.append(co.compress(data[i:i+cx]))
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bufs.append(co.flush())
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combuf = ''.join(bufs)
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self.assertEqual(data, zlib.decompress(combuf, -12, -5),
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'compressed data failure')
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dco = zlib.decompressobj(-12)
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bufs = []
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cb = combuf
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while cb:
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#max_length = 1 + len(cb)//10
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chunk = dco.decompress(cb, dcx)
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self.failIf(len(chunk) > dcx,
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'chunk too big (%d>%d)' % (len(chunk), dcx))
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bufs.append(chunk)
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cb = dco.unconsumed_tail
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if flush:
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bufs.append(dco.flush())
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else:
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while True:
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chunk = dco.decompress('', dcx)
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self.failIf(len(chunk) > dcx,
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'chunk too big in tail (%d>%d)' % (len(chunk), dcx))
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if chunk:
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bufs.append(chunk)
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else:
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break
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self.assertEqual(len(data), len(''.join(bufs)))
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self.assertEqual(data, ''.join(bufs), 'Wrong data retrieved')
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def test_decompressmaxlen(self):
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# Check a decompression object with max_length specified
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data = hamlet_scene * 8 * 16
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co = zlib.compressobj(2, 8, -12, 9, 1)
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bufs = []
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for i in range(0, len(data), 256):
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bufs.append(co.compress(data[i:i+256]))
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bufs.append(co.flush())
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combuf = ''.join(bufs)
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self.assertEqual(data, zlib.decompress(combuf, -12, -5),
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'compressed data failure')
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dco = zlib.decompressobj(-12)
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bufs = []
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cb = combuf
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while cb:
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max_length = 1 + len(cb)//10
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chunk = dco.decompress(cb, max_length)
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self.failIf(len(chunk) > max_length,
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'chunk too big (%d>%d)' % (len(chunk),max_length))
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bufs.append(chunk)
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cb = dco.unconsumed_tail
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bufs.append(dco.flush())
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self.assertEqual(len(data), len(''.join(bufs)))
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self.assertEqual(data, ''.join(bufs), 'Wrong data retrieved')
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def test_decompressmaxlenflushless(self):
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# identical to test_decompressmaxlen except flush is replaced
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# with an equivalent. This works and other fails on (eg) 2.2.2
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data = hamlet_scene * 8 * 16
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co = zlib.compressobj(2, 8, -12, 9, 1)
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bufs = []
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for i in range(0, len(data), 256):
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bufs.append(co.compress(data[i:i+256]))
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bufs.append(co.flush())
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combuf = ''.join(bufs)
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self.assertEqual(data, zlib.decompress(combuf, -12, -5),
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'compressed data mismatch')
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dco = zlib.decompressobj(-12)
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bufs = []
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cb = combuf
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while cb:
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max_length = 1 + len(cb)//10
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chunk = dco.decompress(cb, max_length)
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self.failIf(len(chunk) > max_length,
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'chunk too big (%d>%d)' % (len(chunk),max_length))
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bufs.append(chunk)
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cb = dco.unconsumed_tail
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#bufs.append(dco.flush())
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while len(chunk):
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chunk = dco.decompress('', max_length)
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self.failIf(len(chunk) > max_length,
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'chunk too big (%d>%d)' % (len(chunk),max_length))
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bufs.append(chunk)
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self.assertEqual(data, ''.join(bufs), 'Wrong data retrieved')
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def test_maxlenmisc(self):
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# Misc tests of max_length
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dco = zlib.decompressobj(-12)
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self.assertRaises(ValueError, dco.decompress, "", -1)
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self.assertEqual('', dco.unconsumed_tail)
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def test_flushes(self):
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# Test flush() with the various options, using all the
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# different levels in order to provide more variations.
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sync_opt = ['Z_NO_FLUSH', 'Z_SYNC_FLUSH', 'Z_FULL_FLUSH']
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sync_opt = [getattr(zlib, opt) for opt in sync_opt
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if hasattr(zlib, opt)]
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data = hamlet_scene * 8
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for sync in sync_opt:
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for level in range(10):
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obj = zlib.compressobj( level )
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a = obj.compress( data[:3000] )
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b = obj.flush( sync )
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c = obj.compress( data[3000:] )
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d = obj.flush()
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self.assertEqual(zlib.decompress(''.join([a,b,c,d])),
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data, ("Decompress failed: flush "
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"mode=%i, level=%i") % (sync, level))
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del obj
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def test_odd_flush(self):
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# Test for odd flushing bugs noted in 2.0, and hopefully fixed in 2.1
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import random
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if hasattr(zlib, 'Z_SYNC_FLUSH'):
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# Testing on 17K of "random" data
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# Create compressor and decompressor objects
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co = zlib.compressobj(9)
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dco = zlib.decompressobj()
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# Try 17K of data
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# generate random data stream
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try:
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# In 2.3 and later, WichmannHill is the RNG of the bug report
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gen = random.WichmannHill()
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except AttributeError:
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try:
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# 2.2 called it Random
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gen = random.Random()
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except AttributeError:
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# others might simply have a single RNG
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gen = random
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gen.seed(1)
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data = genblock(1, 17 * 1024, generator=gen)
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# compress, sync-flush, and decompress
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first = co.compress(data)
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second = co.flush(zlib.Z_SYNC_FLUSH)
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expanded = dco.decompress(first + second)
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# if decompressed data is different from the input data, choke.
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self.assertEqual(expanded, data, "17K random source doesn't match")
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def test_manydecompinc(self):
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# Run incremental decompress test for a large range of sizes
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self.test_decompinc(sizes=[1<<n for n in range(8)],
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flush=True, cx=32, dcx=4)
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def test_manydecompimax(self):
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# Run incremental decompress maxlen test for a large range of sizes
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# avoid the flush bug
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self.test_decompimax(sizes=[1<<n for n in range(8)],
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flush=False, cx=32, dcx=4)
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def test_manydecompimaxflush(self):
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# Run incremental decompress maxlen test for a large range of sizes
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# avoid the flush bug
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self.test_decompimax(sizes=[1<<n for n in range(8)],
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flush=True, cx=32, dcx=4)
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def genblock(seed, length, step=1024, generator=random):
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"""length-byte stream of random data from a seed (in step-byte blocks)."""
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if seed is not None:
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generator.seed(seed)
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randint = generator.randint
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if length < step or step < 2:
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step = length
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blocks = []
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for i in range(0, length, step):
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blocks.append(''.join([chr(randint(0,255))
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for x in range(step)]))
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return ''.join(blocks)[:length]
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def choose_lines(source, number, seed=None, generator=random):
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"""Return a list of number lines randomly chosen from the source"""
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if seed is not None:
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generator.seed(seed)
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sources = source.split('\n')
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return [generator.choice(sources) for n in range(number)]
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hamlet_scene = """
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LAERTES
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O, fear me not.
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I stay too long: but here my father comes.
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Enter POLONIUS
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A double blessing is a double grace,
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Occasion smiles upon a second leave.
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LORD POLONIUS
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Yet here, Laertes! aboard, aboard, for shame!
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The wind sits in the shoulder of your sail,
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And you are stay'd for. There; my blessing with thee!
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And these few precepts in thy memory
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See thou character. Give thy thoughts no tongue,
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Nor any unproportioned thought his act.
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Be thou familiar, but by no means vulgar.
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Those friends thou hast, and their adoption tried,
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Grapple them to thy soul with hoops of steel;
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But do not dull thy palm with entertainment
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Of each new-hatch'd, unfledged comrade. Beware
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Of entrance to a quarrel, but being in,
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Bear't that the opposed may beware of thee.
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Give every man thy ear, but few thy voice;
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Take each man's censure, but reserve thy judgment.
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Costly thy habit as thy purse can buy,
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But not express'd in fancy; rich, not gaudy;
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For the apparel oft proclaims the man,
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And they in France of the best rank and station
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Are of a most select and generous chief in that.
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Neither a borrower nor a lender be;
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For loan oft loses both itself and friend,
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And borrowing dulls the edge of husbandry.
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This above all: to thine ownself be true,
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And it must follow, as the night the day,
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Thou canst not then be false to any man.
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Farewell: my blessing season this in thee!
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LAERTES
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Most humbly do I take my leave, my lord.
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LORD POLONIUS
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The time invites you; go; your servants tend.
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LAERTES
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Farewell, Ophelia; and remember well
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What I have said to you.
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OPHELIA
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'Tis in my memory lock'd,
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And you yourself shall keep the key of it.
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LAERTES
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Farewell.
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"""
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def test_main():
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test_support.run_unittest(
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ChecksumTestCase,
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ExceptionTestCase,
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CompressTestCase,
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CompressObjectTestCase
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)
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if __name__ == "__main__":
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test_main()
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def test(tests=''):
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if not tests: tests = 'o'
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testcases = []
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if 'k' in tests: testcases.append(ChecksumTestCase)
|
|
if 'x' in tests: testcases.append(ExceptionTestCase)
|
|
if 'c' in tests: testcases.append(CompressTestCase)
|
|
if 'o' in tests: testcases.append(CompressObjectTestCase)
|
|
test_support.run_unittest(*testcases)
|
|
|
|
if False:
|
|
import sys
|
|
sys.path.insert(1, '/Py23Src/python/dist/src/Lib/test')
|
|
import test_zlib as tz
|
|
ts, ut = tz.test_support, tz.unittest
|
|
su = ut.TestSuite()
|
|
su.addTest(ut.makeSuite(tz.CompressTestCase))
|
|
ts.run_suite(su)
|