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Code Issues Projects Releases Packages Wiki Activity Actions 9

- Issue #6939: Fix file I/O objects in the io module to keep the original

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file position when calling `truncate()`.  It would previously change the
  file position to the given argument, which goes against the tradition of
  ftruncate() and other truncation APIs.  Patch by Pascal Chambon.
This commit is contained in:
Antoine Pitrou 2010-01-31 22:26:04 +00:00
parent e70c72c06b
commit f3fa074703
12 changed files with 97 additions and 47 deletions
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20
Lib/test/test_io.py
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@ -233,6 +233,11 @@ class IOTest(unittest.TestCase):
support.unlink(support.TESTFN)
def write_ops(self, f):
self.assertEqual(f.write(b"blah."), 5)
f.truncate(0)
self.assertEqual(f.tell(), 5)
f.seek(0)
self.assertEqual(f.write(b"blah."), 5)
self.assertEqual(f.seek(0), 0)
self.assertEqual(f.write(b"Hello."), 6)
@ -244,8 +249,9 @@ class IOTest(unittest.TestCase):
self.assertEqual(f.write(b"h"), 1)
self.assertEqual(f.seek(-1, 2), 13)
self.assertEqual(f.tell(), 13)
self.assertEqual(f.truncate(12), 12)
self.assertEqual(f.tell(), 12)
self.assertEqual(f.tell(), 13)
self.assertRaises(TypeError, f.seek, 0.0)
def read_ops(self, f, buffered=False):
@ -290,7 +296,7 @@ class IOTest(unittest.TestCase):
self.assertEqual(f.tell(), self.LARGE + 2)
self.assertEqual(f.seek(0, 2), self.LARGE + 2)
self.assertEqual(f.truncate(self.LARGE + 1), self.LARGE + 1)
self.assertEqual(f.tell(), self.LARGE + 1)
self.assertEqual(f.tell(), self.LARGE + 2)
self.assertEqual(f.seek(0, 2), self.LARGE + 1)
self.assertEqual(f.seek(-1, 2), self.LARGE)
self.assertEqual(f.read(2), b"x")
@ -988,7 +994,7 @@ class BufferedWriterTest(unittest.TestCase, CommonBufferedTests):
bufio = self.tp(raw, 8)
bufio.write(b"abcdef")
self.assertEqual(bufio.truncate(3), 3)
self.assertEqual(bufio.tell(), 3)
self.assertEqual(bufio.tell(), 6)
with self.open(support.TESTFN, "rb", buffering=0) as f:
self.assertEqual(f.read(), b"abc")
@ -1374,6 +1380,14 @@ class BufferedRandomTest(BufferedReaderTest, BufferedWriterTest):
self.assertEqual(s,
b"A" + b"B" * overwrite_size + b"A" * (9 - overwrite_size))
def test_truncate_after_read_or_write(self):
raw = self.BytesIO(b"A" * 10)
bufio = self.tp(raw, 100)
self.assertEqual(bufio.read(2), b"AA") # the read buffer gets filled
self.assertEqual(bufio.truncate(), 2)
self.assertEqual(bufio.write(b"BB"), 2) # the write buffer increases
self.assertEqual(bufio.truncate(), 4)
def test_misbehaved_io(self):
BufferedReaderTest.test_misbehaved_io(self)
BufferedWriterTest.test_misbehaved_io(self)