Method test_copy_file_range

Lib/test/test_os/test_os.py:440–471

(self)

    @unittest.skipUnless(hasattr(os, 'copy_file_range'), 'test needs os.copy_file_range()')
    def test_copy_file_range(self):
        TESTFN2 = os_helper.TESTFN + ".3"
        data = b'0123456789'

        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(TESTFN2, 'w+b')
        self.addCleanup(os_helper.unlink, TESTFN2)
        self.addCleanup(out_file.close)
        out_fd = out_file.fileno()

        try:
            i = os.copy_file_range(in_fd, out_fd, 5)
        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, 6));

            with open(TESTFN2, 'rb') as in_file:
                self.assertEqual(in_file.read(), data[:i])

    @unittest.skipUnless(hasattr(os, 'copy_file_range'), 'test needs os.copy_file_range()')
    def test_copy_file_range_offset(self):