test_fileio.py 文件源码

def testTruncateOnWindows(self):
        def bug801631():
            # SF bug <http://www.python.org/sf/801631>
            # "file.truncate fault on windows"
            f = _FileIO(TESTFN, 'w')
            f.write(bytes(range(11)))
            f.close()

            f = _FileIO(TESTFN,'r+')
            data = f.read(5)
            if data != bytes(range(5)):
                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)

        try:
            bug801631()
        finally:
            os.unlink(TESTFN)