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cpython/Lib/test/test_file.py

353 lines
12 KiB
Python

import sys
import os
import unittest
from array import array
from weakref import proxy
import io
import _pyio as pyio
from test.support import gc_collect
from test.support.os_helper import TESTFN
from test.support import os_helper
from test.support import warnings_helper
from collections import UserList
class AutoFileTests:
# file tests for which a test file is automatically set up
def setUp(self):
self.f = self.open(TESTFN, 'wb')
def tearDown(self):
if self.f:
self.f.close()
os_helper.unlink(TESTFN)
def testWeakRefs(self):
# verify weak references
p = proxy(self.f)
p.write(b'teststring')
self.assertEqual(self.f.tell(), p.tell())
self.f.close()
self.f = None
gc_collect() # For PyPy or other GCs.
self.assertRaises(ReferenceError, getattr, p, 'tell')
def testAttributes(self):
# verify expected attributes exist
f = self.f
f.name # merely shouldn't blow up
f.mode # ditto
f.closed # ditto
def testReadinto(self):
# verify readinto
self.f.write(b'12')
self.f.close()
a = array('b', b'x'*10)
self.f = self.open(TESTFN, 'rb')
n = self.f.readinto(a)
self.assertEqual(b'12', a.tobytes()[:n])
def testReadinto_text(self):
# verify readinto refuses text files
a = array('b', b'x'*10)
self.f.close()
self.f = self.open(TESTFN, encoding="utf-8")
if hasattr(self.f, "readinto"):
self.assertRaises(TypeError, self.f.readinto, a)
def testWritelinesUserList(self):
# verify writelines with instance sequence
l = UserList([b'1', b'2'])
self.f.writelines(l)
self.f.close()
self.f = self.open(TESTFN, 'rb')
buf = self.f.read()
self.assertEqual(buf, b'12')
def testWritelinesIntegers(self):
# verify writelines with integers
self.assertRaises(TypeError, self.f.writelines, [1, 2, 3])
def testWritelinesIntegersUserList(self):
# verify writelines with integers in UserList
l = UserList([1,2,3])
self.assertRaises(TypeError, self.f.writelines, l)
def testWritelinesNonString(self):
# verify writelines with non-string object
class NonString:
pass
self.assertRaises(TypeError, self.f.writelines,
[NonString(), NonString()])
def testErrors(self):
f = self.f
self.assertEqual(f.name, TESTFN)
self.assertFalse(f.isatty())
self.assertFalse(f.closed)
if hasattr(f, "readinto"):
self.assertRaises((OSError, TypeError), f.readinto, "")
f.close()
self.assertTrue(f.closed)
def testMethods(self):
methods = [('fileno', ()),
('flush', ()),
('isatty', ()),
('__next__', ()),
('read', ()),
('write', (b"",)),
('readline', ()),
('readlines', ()),
('seek', (0,)),
('tell', ()),
('write', (b"",)),
('writelines', ([],)),
('__iter__', ()),
]
methods.append(('truncate', ()))
# __exit__ should close the file
self.f.__exit__(None, None, None)
self.assertTrue(self.f.closed)
for methodname, args in methods:
method = getattr(self.f, methodname)
# should raise on closed file
self.assertRaises(ValueError, method, *args)
# file is closed, __exit__ shouldn't do anything
self.assertEqual(self.f.__exit__(None, None, None), None)
# it must also return None if an exception was given
try:
1/0
except ZeroDivisionError:
self.assertEqual(self.f.__exit__(*sys.exc_info()), None)
def testReadWhenWriting(self):
self.assertRaises(OSError, self.f.read)
class CAutoFileTests(AutoFileTests, unittest.TestCase):
open = io.open
class PyAutoFileTests(AutoFileTests, unittest.TestCase):
open = staticmethod(pyio.open)
class OtherFileTests:
def tearDown(self):
os_helper.unlink(TESTFN)
def testModeStrings(self):
# check invalid mode strings
self.open(TESTFN, 'wb').close()
for mode in ("", "aU", "wU+", "U+", "+U", "rU+"):
try:
f = self.open(TESTFN, mode)
except ValueError:
pass
else:
f.close()
self.fail('%r is an invalid file mode' % mode)
def testStdin(self):
if sys.platform == 'osf1V5':
# This causes the interpreter to exit on OSF1 v5.1.
self.skipTest(
' sys.stdin.seek(-1) may crash the interpreter on OSF1.'
' Test manually.')
if not sys.stdin.isatty():
# Issue 14853: stdin becomes seekable when redirected to a file
self.skipTest('stdin must be a TTY in this test')
with self.assertRaises((IOError, ValueError)):
sys.stdin.seek(-1)
with self.assertRaises((IOError, ValueError)):
sys.stdin.truncate()
def testBadModeArgument(self):
# verify that we get a sensible error message for bad mode argument
bad_mode = "qwerty"
try:
f = self.open(TESTFN, bad_mode)
except ValueError as msg:
if msg.args[0] != 0:
s = str(msg)
if TESTFN in s or bad_mode not in s:
self.fail("bad error message for invalid mode: %s" % s)
# if msg.args[0] == 0, we're probably on Windows where there may be
# no obvious way to discover why open() failed.
else:
f.close()
self.fail("no error for invalid mode: %s" % bad_mode)
def _checkBufferSize(self, s):
try:
f = self.open(TESTFN, 'wb', s)
f.write(str(s).encode("ascii"))
f.close()
f.close()
f = self.open(TESTFN, 'rb', s)
d = int(f.read().decode("ascii"))
f.close()
f.close()
except OSError as msg:
self.fail('error setting buffer size %d: %s' % (s, str(msg)))
self.assertEqual(d, s)
def testSetBufferSize(self):
# make sure that explicitly setting the buffer size doesn't cause
# misbehaviour especially with repeated close() calls
for s in (-1, 0, 512):
with warnings_helper.check_no_warnings(self,
message='line buffering',
category=RuntimeWarning):
self._checkBufferSize(s)
# test that attempts to use line buffering in binary mode cause
# a warning
with self.assertWarnsRegex(RuntimeWarning, 'line buffering'):
self._checkBufferSize(1)
def testTruncateOnWindows(self):
# SF bug <https://bugs.python.org/issue801631>
# "file.truncate fault on windows"
f = self.open(TESTFN, 'wb')
try:
f.write(b'12345678901') # 11 bytes
f.close()
f = self.open(TESTFN,'rb+')
data = f.read(5)
if data != b'12345':
self.fail("Read on file opened for update failed %r" % data)
if f.tell() != 5:
self.fail("File pos after read wrong %d" % f.tell())
f.truncate()
if f.tell() != 5:
self.fail("File pos after ftruncate wrong %d" % f.tell())
f.close()
size = os.path.getsize(TESTFN)
if size != 5:
self.fail("File size after ftruncate wrong %d" % size)
finally:
f.close()
def testIteration(self):
# Test the complex interaction when mixing file-iteration and the
# various read* methods.
dataoffset = 16384
filler = b"ham\n"
assert not dataoffset % len(filler), \
"dataoffset must be multiple of len(filler)"
nchunks = dataoffset // len(filler)
testlines = [
b"spam, spam and eggs\n",
b"eggs, spam, ham and spam\n",
b"saussages, spam, spam and eggs\n",
b"spam, ham, spam and eggs\n",
b"spam, spam, spam, spam, spam, ham, spam\n",
b"wonderful spaaaaaam.\n"
]
methods = [("readline", ()), ("read", ()), ("readlines", ()),
("readinto", (array("b", b" "*100),))]
# Prepare the testfile
bag = self.open(TESTFN, "wb")
bag.write(filler * nchunks)
bag.writelines(testlines)
bag.close()
# Test for appropriate errors mixing read* and iteration
for methodname, args in methods:
f = self.open(TESTFN, 'rb')
self.assertEqual(next(f), filler)
meth = getattr(f, methodname)
meth(*args) # This simply shouldn't fail
f.close()
# Test to see if harmless (by accident) mixing of read* and
# iteration still works. This depends on the size of the internal
# iteration buffer (currently 8192,) but we can test it in a
# flexible manner. Each line in the bag o' ham is 4 bytes
# ("h", "a", "m", "\n"), so 4096 lines of that should get us
# exactly on the buffer boundary for any power-of-2 buffersize
# between 4 and 16384 (inclusive).
f = self.open(TESTFN, 'rb')
for i in range(nchunks):
next(f)
testline = testlines.pop(0)
try:
line = f.readline()
except ValueError:
self.fail("readline() after next() with supposedly empty "
"iteration-buffer failed anyway")
if line != testline:
self.fail("readline() after next() with empty buffer "
"failed. Got %r, expected %r" % (line, testline))
testline = testlines.pop(0)
buf = array("b", b"\x00" * len(testline))
try:
f.readinto(buf)
except ValueError:
self.fail("readinto() after next() with supposedly empty "
"iteration-buffer failed anyway")
line = buf.tobytes()
if line != testline:
self.fail("readinto() after next() with empty buffer "
"failed. Got %r, expected %r" % (line, testline))
testline = testlines.pop(0)
try:
line = f.read(len(testline))
except ValueError:
self.fail("read() after next() with supposedly empty "
"iteration-buffer failed anyway")
if line != testline:
self.fail("read() after next() with empty buffer "
"failed. Got %r, expected %r" % (line, testline))
try:
lines = f.readlines()
except ValueError:
self.fail("readlines() after next() with supposedly empty "
"iteration-buffer failed anyway")
if lines != testlines:
self.fail("readlines() after next() with empty buffer "
"failed. Got %r, expected %r" % (line, testline))
f.close()
# Reading after iteration hit EOF shouldn't hurt either
f = self.open(TESTFN, 'rb')
try:
for line in f:
pass
try:
f.readline()
f.readinto(buf)
f.read()
f.readlines()
except ValueError:
self.fail("read* failed after next() consumed file")
finally:
f.close()
class COtherFileTests(OtherFileTests, unittest.TestCase):
open = io.open
class PyOtherFileTests(OtherFileTests, unittest.TestCase):
open = staticmethod(pyio.open)
if __name__ == '__main__':
unittest.main()