PhpSpreadsheet/tests/data/Calculation/TextData/LEFT.php

<?php

return [
    [
        null,
        1,
        '',
    ],
    [
        '',
        1,
        '',
    ],
    [
        'QWERTYUIOP',
        -1,
        '#VALUE!',
    ],
    [
        'ABCDEFGHI',
        3,
        'ABC',
    ],
    [
        true,
        2,
        'TR',
    ],
    [
        false,
        2,
        'FA',
    ],
];