Lib/test/test_zlib.py

   1 import zlib
   2 import sys
   3 import imp
   4 import string
   5
   6 try:
   7     t = imp.find_module('test_zlib')
   8     file = t[0]
   9 except ImportError:
  10     file = open(__file__)
  11 buf = file.read() * 8
  12 file.close()
  13
  14 # test the chucksums (hex so the test doesn't break on 64-bit machines)
  15 print hex(zlib.crc32('penguin')), hex(zlib.crc32('penguin', 1))
  16 print hex(zlib.adler32('penguin')), hex(zlib.adler32('penguin', 1))
  17
  18 # make sure we generate some expected errors
  19 try:
  20     zlib.compress('ERROR', zlib.MAX_WBITS + 1)
  21 except zlib.error, msg:
  22     print "expecting", msg
  23 try:
  24     zlib.compressobj(1, 8, 0)
  25 except ValueError, msg:
  26     print "expecting", msg
  27 try:
  28     zlib.decompressobj(0)
  29 except ValueError, msg:
  30     print "expecting", msg
  31
  32 x = zlib.compress(buf)
  33 y = zlib.decompress(x)
  34 if buf != y:
  35     print "normal compression/decompression failed"
  36 else:
  37     print "normal compression/decompression succeeded"
  38
  39 buf = buf * 16
  40
  41 co = zlib.compressobj(8, 8, -15)
  42 x1 = co.compress(buf)
  43 x2 = co.flush()
  44 x = x1 + x2
  45
  46 dc = zlib.decompressobj(-15)
  47 y1 = dc.decompress(x)
  48 y2 = dc.flush()
  49 y = y1 + y2
  50 if buf != y:
  51     print "compress/decompression obj failed"
  52 else:
  53     print "compress/decompression obj succeeded"
  54
  55 co = zlib.compressobj(2, 8, -12, 9, 1)
  56 bufs = []
  57 for i in range(0, len(buf), 256):
  58     bufs.append(co.compress(buf[i:i+256]))
  59 bufs.append(co.flush())
  60 combuf = string.join(bufs, '')
  61
  62 decomp1 = zlib.decompress(combuf, -12, -5)
  63 if decomp1 != buf:
  64     print "decompress with init options failed"
  65 else:
  66     print "decompress with init options succeeded"
  67
  68 deco = zlib.decompressobj(-12)
  69 bufs = []
  70 for i in range(0, len(combuf), 128):
  71     bufs.append(deco.decompress(combuf[i:i+128]))
  72 bufs.append(deco.flush())
  73 decomp2 = string.join(buf, '')
  74 if decomp2 != buf:
  75     print "decompressobj with init options failed"
  76 else:
  77     print "decompressobj with init options succeeded"
  78
  79 # Test flush() with the various options, using all the different levels
  80 # in order to provide more variations.
  81 for sync in [zlib.Z_NO_FLUSH, zlib.Z_SYNC_FLUSH, zlib.Z_FULL_FLUSH]:
  82     for level in range(10):
  83         obj = zlib.compressobj( level )
  84         d = obj.compress( buf[:3000] )
  85         d = d + obj.flush( sync )
  86         d = d + obj.compress( buf[3000:] )
  87         d = d + obj.flush()
  88         if zlib.decompress(d) != buf:
  89             print "Decompress failed: flush mode=%i, level=%i" % (sync,level)
  90         del obj
  91
  92 def ignore():
  93     """An empty function with a big string.
  94
  95     Make the compression algorithm work a little harder.
  96     """
  97
  98     """
  99 LAERTES
 100
 101        O, fear me not.
 102        I stay too long: but here my father comes.
 103
 104        Enter POLONIUS
 105
 106        A double blessing is a double grace,
 107        Occasion smiles upon a second leave.
 108
 109 LORD POLONIUS
 110
 111        Yet here, Laertes! aboard, aboard, for shame!
 112        The wind sits in the shoulder of your sail,
 113        And you are stay'd for. There; my blessing with thee!
 114        And these few precepts in thy memory
 115        See thou character. Give thy thoughts no tongue,
 116        Nor any unproportioned thought his act.
 117        Be thou familiar, but by no means vulgar.
 118        Those friends thou hast, and their adoption tried,
 119        Grapple them to thy soul with hoops of steel;
 120        But do not dull thy palm with entertainment
 121        Of each new-hatch'd, unfledged comrade. Beware
 122        Of entrance to a quarrel, but being in,
 123        Bear't that the opposed may beware of thee.
 124        Give every man thy ear, but few thy voice;
 125        Take each man's censure, but reserve thy judgment.
 126        Costly thy habit as thy purse can buy,
 127        But not express'd in fancy; rich, not gaudy;
 128        For the apparel oft proclaims the man,
 129        And they in France of the best rank and station
 130        Are of a most select and generous chief in that.
 131        Neither a borrower nor a lender be;
 132        For loan oft loses both itself and friend,
 133        And borrowing dulls the edge of husbandry.
 134        This above all: to thine ownself be true,
 135        And it must follow, as the night the day,
 136        Thou canst not then be false to any man.
 137        Farewell: my blessing season this in thee!
 138
 139 LAERTES
 140
 141        Most humbly do I take my leave, my lord.
 142
 143 LORD POLONIUS
 144
 145        The time invites you; go; your servants tend.
 146
 147 LAERTES
 148
 149        Farewell, Ophelia; and remember well
 150        What I have said to you.
 151
 152 OPHELIA
 153
 154        'Tis in my memory lock'd,
 155        And you yourself shall keep the key of it.
 156
 157 LAERTES
 158
 159        Farewell.
 160 """
 161