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

<?php

//  Date Value, Result

return [
    [
        19,         // Result for Excel
        19,         // Result for OpenOffice
        22269,
    ],
    [
        1,          // Result for Excel
        1,          // Result for OpenOffice
        30348,
    ],
    [
        10,         // Result for Excel
        10,         // Result for OpenOffice
        30843,
    ],
    [
        11,         // Result for Excel
        11,         // Result for OpenOffice
        '11-Nov-1918',
    ],
    [
        28,         // Result for Excel
        28,         // Result for OpenOffice
        '28-Feb-1904',
    ],
    [
        '#VALUE!',  // Result for Excel
        '#VALUE!',  // Result for OpenOffice
        'Invalid',
    ],
    [
        '#NUM!',  // Result for Excel
        29,       // Result for OpenOffice
        -1,
    ],
    [
        1,         // Result for Excel
        31,        // Result for OpenOffice
        1,
    ],
    [
        0,         // Result for Excel
        30,        // Result for OpenOffice
        0.5,
    ],
    [
        0,         // Result for Excel
        30,        // Result for OpenOffice
        0,
    ],
];