mirror of https://github.com/python/cpython
184 lines
6.4 KiB
Python
184 lines
6.4 KiB
Python
"""Test largefile support on system where this makes sense.
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"""
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import os
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import stat
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import sys
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import unittest
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from test.test_support import run_unittest, TESTFN, verbose, requires, \
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TestSkipped, unlink
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try:
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import signal
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# The default handler for SIGXFSZ is to abort the process.
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# By ignoring it, system calls exceeding the file size resource
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# limit will raise IOError instead of crashing the interpreter.
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oldhandler = signal.signal(signal.SIGXFSZ, signal.SIG_IGN)
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except (ImportError, AttributeError):
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pass
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# create >2GB file (2GB = 2147483648 bytes)
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size = 2500000000L
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class TestCase(unittest.TestCase):
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"""Test that each file function works as expected for a large
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(i.e. > 2GB, do we have to check > 4GB) files.
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"""
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def test_seek(self):
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if verbose:
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print 'create large file via seek (may be sparse file) ...'
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f = open(TESTFN, 'wb')
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try:
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f.write('z')
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f.seek(0)
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f.seek(size)
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f.write('a')
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f.flush()
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if verbose:
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print 'check file size with os.fstat'
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self.assertEqual(os.fstat(f.fileno())[stat.ST_SIZE], size+1)
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finally:
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f.close()
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def test_osstat(self):
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if verbose:
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print 'check file size with os.stat'
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self.assertEqual(os.stat(TESTFN)[stat.ST_SIZE], size+1)
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def test_seek_read(self):
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if verbose:
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print 'play around with seek() and read() with the built largefile'
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f = open(TESTFN, 'rb')
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try:
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self.assertEqual(f.tell(), 0)
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self.assertEqual(f.read(1), 'z')
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self.assertEqual(f.tell(), 1)
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f.seek(0)
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self.assertEqual(f.tell(), 0)
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f.seek(0, 0)
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self.assertEqual(f.tell(), 0)
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f.seek(42)
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self.assertEqual(f.tell(), 42)
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f.seek(42, 0)
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self.assertEqual(f.tell(), 42)
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f.seek(42, 1)
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self.assertEqual(f.tell(), 84)
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f.seek(0, 1)
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self.assertEqual(f.tell(), 84)
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f.seek(0, 2) # seek from the end
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self.assertEqual(f.tell(), size + 1 + 0)
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f.seek(-10, 2)
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self.assertEqual(f.tell(), size + 1 - 10)
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f.seek(-size-1, 2)
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self.assertEqual(f.tell(), 0)
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f.seek(size)
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self.assertEqual(f.tell(), size)
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# the 'a' that was written at the end of file above
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self.assertEqual(f.read(1), 'a')
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f.seek(-size-1, 1)
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self.assertEqual(f.read(1), 'z')
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self.assertEqual(f.tell(), 1)
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finally:
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f.close()
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def test_lseek(self):
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if verbose:
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print 'play around with os.lseek() with the built largefile'
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f = open(TESTFN, 'rb')
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try:
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self.assertEqual(os.lseek(f.fileno(), 0, 0), 0)
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self.assertEqual(os.lseek(f.fileno(), 42, 0), 42)
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self.assertEqual(os.lseek(f.fileno(), 42, 1), 84)
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self.assertEqual(os.lseek(f.fileno(), 0, 1), 84)
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self.assertEqual(os.lseek(f.fileno(), 0, 2), size+1+0)
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self.assertEqual(os.lseek(f.fileno(), -10, 2), size+1-10)
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self.assertEqual(os.lseek(f.fileno(), -size-1, 2), 0)
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self.assertEqual(os.lseek(f.fileno(), size, 0), size)
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# the 'a' that was written at the end of file above
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self.assertEqual(f.read(1), 'a')
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finally:
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f.close()
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def test_truncate(self):
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if verbose:
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print 'try truncate'
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f = open(TESTFN, 'r+b')
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# this is already decided before start running the test suite
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# but we do it anyway for extra protection
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if not hasattr(f, 'truncate'):
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raise TestSkipped, "open().truncate() not available on this system"
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try:
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f.seek(0, 2)
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# else we've lost track of the true size
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self.assertEqual(f.tell(), size+1)
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# Cut it back via seek + truncate with no argument.
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newsize = size - 10
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f.seek(newsize)
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f.truncate()
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self.assertEqual(f.tell(), newsize) # else pointer moved
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f.seek(0, 2)
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self.assertEqual(f.tell(), newsize) # else wasn't truncated
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# Ensure that truncate(smaller than true size) shrinks
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# the file.
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newsize -= 1
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f.seek(42)
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f.truncate(newsize)
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self.assertEqual(f.tell(), 42) # else pointer moved
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f.seek(0, 2)
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self.assertEqual(f.tell(), newsize) # else wasn't truncated
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# XXX truncate(larger than true size) is ill-defined
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# across platform; cut it waaaaay back
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f.seek(0)
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f.truncate(1)
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self.assertEqual(f.tell(), 0) # else pointer moved
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self.assertEqual(len(f.read()), 1) # else wasn't truncated
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finally:
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f.close()
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def main_test():
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# On Windows and Mac OSX this test comsumes large resources; It
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# takes a long time to build the >2GB file and takes >2GB of disk
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# space therefore the resource must be enabled to run this test.
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# If not, nothing after this line stanza will be executed.
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if sys.platform[:3] == 'win' or sys.platform == 'darwin':
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requires('largefile',
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'test requires %s bytes and a long time to run' % str(size))
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else:
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# Only run if the current filesystem supports large files.
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# (Skip this test on Windows, since we now always support
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# large files.)
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f = open(TESTFN, 'wb')
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try:
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# 2**31 == 2147483648
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f.seek(2147483649L)
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# Seeking is not enough of a test: you must write and
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# flush, too!
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f.write("x")
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f.flush()
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except (IOError, OverflowError):
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f.close()
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unlink(TESTFN)
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raise TestSkipped, "filesystem does not have largefile support"
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else:
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f.close()
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suite = unittest.TestSuite()
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suite.addTest(TestCase('test_seek'))
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suite.addTest(TestCase('test_osstat'))
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suite.addTest(TestCase('test_seek_read'))
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suite.addTest(TestCase('test_lseek'))
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f = open(TESTFN, 'w')
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if hasattr(f, 'truncate'):
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suite.addTest(TestCase('test_truncate'))
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f.close()
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unlink(TESTFN)
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run_unittest(suite)
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unlink(TESTFN)
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if __name__ == '__main__':
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main_test()
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