Lib/test/test_file.py

   1 # NOTE: this file tests the new `io` library backported from Python 3.x.
   2 # Similar tests for the builtin file object can be found in test_file2k.py.
   3
   4 from __future__ import print_function
   5
   6 import sys
   7 import os
   8 import unittest
   9 from array import array
  10 from weakref import proxy
  11
  12 import io
  13 import _pyio as pyio
  14
  15 from test.test_support import TESTFN, findfile, run_unittest
  16 from UserList import UserList
  17
  18 class AutoFileTests(unittest.TestCase):
  19     # file tests for which a test file is automatically set up
  20
  21     def setUp(self):
  22         self.f = self.open(TESTFN, 'wb')
  23
  24     def tearDown(self):
  25         if self.f:
  26             self.f.close()
  27         os.remove(TESTFN)
  28
  29     def testWeakRefs(self):
  30         # verify weak references
  31         p = proxy(self.f)
  32         p.write(b'teststring')
  33         self.assertEquals(self.f.tell(), p.tell())
  34         self.f.close()
  35         self.f = None
  36         self.assertRaises(ReferenceError, getattr, p, 'tell')
  37
  38     def testAttributes(self):
  39         # verify expected attributes exist
  40         f = self.f
  41         f.name     # merely shouldn't blow up
  42         f.mode     # ditto
  43         f.closed   # ditto
  44
  45     def testReadinto(self):
  46         # verify readinto
  47         self.f.write(b'12')
  48         self.f.close()
  49         a = array('b', b'x'*10)
  50         self.f = self.open(TESTFN, 'rb')
  51         n = self.f.readinto(a)
  52         self.assertEquals(b'12', a.tostring()[:n])
  53
  54     def testReadinto_text(self):
  55         # verify readinto refuses text files
  56         a = array('b', b'x'*10)
  57         self.f.close()
  58         self.f = self.open(TESTFN, 'r')
  59         if hasattr(self.f, "readinto"):
  60             self.assertRaises(TypeError, self.f.readinto, a)
  61
  62     def testWritelinesUserList(self):
  63         # verify writelines with instance sequence
  64         l = UserList([b'1', b'2'])
  65         self.f.writelines(l)
  66         self.f.close()
  67         self.f = self.open(TESTFN, 'rb')
  68         buf = self.f.read()
  69         self.assertEquals(buf, b'12')
  70
  71     def testWritelinesIntegers(self):
  72         # verify writelines with integers
  73         self.assertRaises(TypeError, self.f.writelines, [1, 2, 3])
  74
  75     def testWritelinesIntegersUserList(self):
  76         # verify writelines with integers in UserList
  77         l = UserList([1,2,3])
  78         self.assertRaises(TypeError, self.f.writelines, l)
  79
  80     def testWritelinesNonString(self):
  81         # verify writelines with non-string object
  82         class NonString:
  83             pass
  84
  85         self.assertRaises(TypeError, self.f.writelines,
  86                           [NonString(), NonString()])
  87
  88     def testErrors(self):
  89         f = self.f
  90         self.assertEquals(f.name, TESTFN)
  91         self.assert_(not f.isatty())
  92         self.assert_(not f.closed)
  93
  94         if hasattr(f, "readinto"):
  95             self.assertRaises((IOError, TypeError), f.readinto, "")
  96         f.close()
  97         self.assert_(f.closed)
  98
  99     def testMethods(self):
 100         methods = [('fileno', ()),
 101                    ('flush', ()),
 102                    ('isatty', ()),
 103                    ('next', ()),
 104                    ('read', ()),
 105                    ('write', (b"",)),
 106                    ('readline', ()),
 107                    ('readlines', ()),
 108                    ('seek', (0,)),
 109                    ('tell', ()),
 110                    ('write', (b"",)),
 111                    ('writelines', ([],)),
 112                    ('__iter__', ()),
 113                    ]
 114         if not sys.platform.startswith('atheos'):
 115             methods.append(('truncate', ()))
 116
 117         # __exit__ should close the file
 118         self.f.__exit__(None, None, None)
 119         self.assert_(self.f.closed)
 120
 121         for methodname, args in methods:
 122             method = getattr(self.f, methodname)
 123             # should raise on closed file
 124             self.assertRaises(ValueError, method, *args)
 125
 126         # file is closed, __exit__ shouldn't do anything
 127         self.assertEquals(self.f.__exit__(None, None, None), None)
 128         # it must also return None if an exception was given
 129         try:
 130             1/0
 131         except:
 132             self.assertEquals(self.f.__exit__(*sys.exc_info()), None)
 133
 134     def testReadWhenWriting(self):
 135         self.assertRaises(IOError, self.f.read)
 136
 137 class CAutoFileTests(AutoFileTests):
 138     open = io.open
 139
 140 class PyAutoFileTests(AutoFileTests):
 141     open = staticmethod(pyio.open)
 142
 143
 144 class OtherFileTests(unittest.TestCase):
 145
 146     def testModeStrings(self):
 147         # check invalid mode strings
 148         for mode in ("", "aU", "wU+"):
 149             try:
 150                 f = self.open(TESTFN, mode)
 151             except ValueError:
 152                 pass
 153             else:
 154                 f.close()
 155                 self.fail('%r is an invalid file mode' % mode)
 156
 157     def testStdin(self):
 158         # This causes the interpreter to exit on OSF1 v5.1.
 159         if sys.platform != 'osf1V5':
 160             self.assertRaises((IOError, ValueError), sys.stdin.seek, -1)
 161         else:
 162             print((
 163                 '  Skipping sys.stdin.seek(-1), it may crash the interpreter.'
 164                 ' Test manually.'), file=sys.__stdout__)
 165         self.assertRaises((IOError, ValueError), sys.stdin.truncate)
 166
 167     def testBadModeArgument(self):
 168         # verify that we get a sensible error message for bad mode argument
 169         bad_mode = "qwerty"
 170         try:
 171             f = self.open(TESTFN, bad_mode)
 172         except ValueError as msg:
 173             if msg.args[0] != 0:
 174                 s = str(msg)
 175                 if s.find(TESTFN) != -1 or s.find(bad_mode) == -1:
 176                     self.fail("bad error message for invalid mode: %s" % s)
 177             # if msg.args[0] == 0, we're probably on Windows where there may be
 178             # no obvious way to discover why open() failed.
 179         else:
 180             f.close()
 181             self.fail("no error for invalid mode: %s" % bad_mode)
 182
 183     def testSetBufferSize(self):
 184         # make sure that explicitly setting the buffer size doesn't cause
 185         # misbehaviour especially with repeated close() calls
 186         for s in (-1, 0, 1, 512):
 187             try:
 188                 f = self.open(TESTFN, 'wb', s)
 189                 f.write(str(s).encode("ascii"))
 190                 f.close()
 191                 f.close()
 192                 f = self.open(TESTFN, 'rb', s)
 193                 d = int(f.read().decode("ascii"))
 194                 f.close()
 195                 f.close()
 196             except IOError as msg:
 197                 self.fail('error setting buffer size %d: %s' % (s, str(msg)))
 198             self.assertEquals(d, s)
 199
 200     def testTruncateOnWindows(self):
 201         # SF bug <http://www.python.org/sf/801631>
 202         # "file.truncate fault on windows"
 203
 204         os.unlink(TESTFN)
 205         f = self.open(TESTFN, 'wb')
 206
 207         try:
 208             f.write(b'12345678901')   # 11 bytes
 209             f.close()
 210
 211             f = self.open(TESTFN,'rb+')
 212             data = f.read(5)
 213             if data != b'12345':
 214                 self.fail("Read on file opened for update failed %r" % data)
 215             if f.tell() != 5:
 216                 self.fail("File pos after read wrong %d" % f.tell())
 217
 218             f.truncate()
 219             if f.tell() != 5:
 220                 self.fail("File pos after ftruncate wrong %d" % f.tell())
 221
 222             f.close()
 223             size = os.path.getsize(TESTFN)
 224             if size != 5:
 225                 self.fail("File size after ftruncate wrong %d" % size)
 226         finally:
 227             f.close()
 228             os.unlink(TESTFN)
 229
 230     def testIteration(self):
 231         # Test the complex interaction when mixing file-iteration and the
 232         # various read* methods.
 233         dataoffset = 16384
 234         filler = b"ham\n"
 235         assert not dataoffset % len(filler), \
 236             "dataoffset must be multiple of len(filler)"
 237         nchunks = dataoffset // len(filler)
 238         testlines = [
 239             b"spam, spam and eggs\n",
 240             b"eggs, spam, ham and spam\n",
 241             b"saussages, spam, spam and eggs\n",
 242             b"spam, ham, spam and eggs\n",
 243             b"spam, spam, spam, spam, spam, ham, spam\n",
 244             b"wonderful spaaaaaam.\n"
 245         ]
 246         methods = [("readline", ()), ("read", ()), ("readlines", ()),
 247                    ("readinto", (array("b", b" "*100),))]
 248
 249         try:
 250             # Prepare the testfile
 251             bag = self.open(TESTFN, "wb")
 252             bag.write(filler * nchunks)
 253             bag.writelines(testlines)
 254             bag.close()
 255             # Test for appropriate errors mixing read* and iteration
 256             for methodname, args in methods:
 257                 f = self.open(TESTFN, 'rb')
 258                 if next(f) != filler:
 259                     self.fail, "Broken testfile"
 260                 meth = getattr(f, methodname)
 261                 meth(*args)  # This simply shouldn't fail
 262                 f.close()
 263
 264             # Test to see if harmless (by accident) mixing of read* and
 265             # iteration still works. This depends on the size of the internal
 266             # iteration buffer (currently 8192,) but we can test it in a
 267             # flexible manner.  Each line in the bag o' ham is 4 bytes
 268             # ("h", "a", "m", "\n"), so 4096 lines of that should get us
 269             # exactly on the buffer boundary for any power-of-2 buffersize
 270             # between 4 and 16384 (inclusive).
 271             f = self.open(TESTFN, 'rb')
 272             for i in range(nchunks):
 273                 next(f)
 274             testline = testlines.pop(0)
 275             try:
 276                 line = f.readline()
 277             except ValueError:
 278                 self.fail("readline() after next() with supposedly empty "
 279                           "iteration-buffer failed anyway")
 280             if line != testline:
 281                 self.fail("readline() after next() with empty buffer "
 282                           "failed. Got %r, expected %r" % (line, testline))
 283             testline = testlines.pop(0)
 284             buf = array("b", b"\x00" * len(testline))
 285             try:
 286                 f.readinto(buf)
 287             except ValueError:
 288                 self.fail("readinto() after next() with supposedly empty "
 289                           "iteration-buffer failed anyway")
 290             line = buf.tostring()
 291             if line != testline:
 292                 self.fail("readinto() after next() with empty buffer "
 293                           "failed. Got %r, expected %r" % (line, testline))
 294
 295             testline = testlines.pop(0)
 296             try:
 297                 line = f.read(len(testline))
 298             except ValueError:
 299                 self.fail("read() after next() with supposedly empty "
 300                           "iteration-buffer failed anyway")
 301             if line != testline:
 302                 self.fail("read() after next() with empty buffer "
 303                           "failed. Got %r, expected %r" % (line, testline))
 304             try:
 305                 lines = f.readlines()
 306             except ValueError:
 307                 self.fail("readlines() after next() with supposedly empty "
 308                           "iteration-buffer failed anyway")
 309             if lines != testlines:
 310                 self.fail("readlines() after next() with empty buffer "
 311                           "failed. Got %r, expected %r" % (line, testline))
 312             # Reading after iteration hit EOF shouldn't hurt either
 313             f = self.open(TESTFN, 'rb')
 314             try:
 315                 for line in f:
 316                     pass
 317                 try:
 318                     f.readline()
 319                     f.readinto(buf)
 320                     f.read()
 321                     f.readlines()
 322                 except ValueError:
 323                     self.fail("read* failed after next() consumed file")
 324             finally:
 325                 f.close()
 326         finally:
 327             os.unlink(TESTFN)
 328
 329 class COtherFileTests(OtherFileTests):
 330     open = io.open
 331
 332 class PyOtherFileTests(OtherFileTests):
 333     open = staticmethod(pyio.open)
 334
 335
 336 def test_main():
 337     # Historically, these tests have been sloppy about removing TESTFN.
 338     # So get rid of it no matter what.
 339     try:
 340         run_unittest(CAutoFileTests, PyAutoFileTests,
 341                      COtherFileTests, PyOtherFileTests)
 342     finally:
 343         if os.path.exists(TESTFN):
 344             os.unlink(TESTFN)
 345
 346 if __name__ == '__main__':
 347     test_main()