Method test_copy_file_range_offset

Lib/test/test_os.py:472–514

(self)

    @unittest.skipUnless(hasattr(os, 'copy_file_range'), 'test needs os.copy_file_range()')
    def test_copy_file_range_offset(self):
        TESTFN4 = os_helper.TESTFN + ".4"
        data = b'0123456789'
        bytes_to_copy = 6
        in_skip = 3
        out_seek = 5

        create_file(os_helper.TESTFN, data)
        self.addCleanup(os_helper.unlink, os_helper.TESTFN)

        in_file = open(os_helper.TESTFN, 'rb')
        self.addCleanup(in_file.close)
        in_fd = in_file.fileno()

        out_file = open(TESTFN4, 'w+b')
        self.addCleanup(os_helper.unlink, TESTFN4)
        self.addCleanup(out_file.close)
        out_fd = out_file.fileno()

        try:
            i = os.copy_file_range(in_fd, out_fd, bytes_to_copy,
                                   offset_src=in_skip,
                                   offset_dst=out_seek)
        except OSError as e:
            # Handle the case in which Python was compiled
            # in a system with the syscall but without support
            # in the kernel.
            if e.errno != errno.ENOSYS:
                raise
            self.skipTest(e)
        else:
            # The number of copied bytes can be less than
            # the number of bytes originally requested.
            self.assertIn(i, range(0, bytes_to_copy+1));

            with open(TESTFN4, 'rb') as in_file:
                read = in_file.read()
            # seeked bytes (5) are zero'ed
            self.assertEqual(read[:out_seek], b'\x00'*out_seek)
            # 012 are skipped (in_skip)
            # 345678 are copied in the file (in_skip + bytes_to_copy)
            self.assertEqual(read[out_seek:],
                             data[in_skip:in_skip+i])

    @unittest.skipUnless(hasattr(os, 'splice'), 'test needs os.splice()')
    def test_splice_invalid_values(self):