PhpSpreadsheet/tests/data/Calculation/DateTime/ISOWEEKNUM.php

<?php

return [
    [
        51,
        '21-Dec-2000',
    ],
    [
        52,
        '2000-01-01',
    ],
    [
        1,
        '2000-01-03',
    ],
    [
        52,
        '1995-01-01',
    ],
    [
        1,
        '1995-01-07',
    ],
    [
        2,
        '1995-01-10',
    ],
    [
        1,
        '2018-01-01',
    ],
    [
        '#VALUE!',
        '1800-01-01',
    ],
];