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

<?php

return [
    [
        'QWERTYUIOP',
        'ERT',
        'DFG',
        'QWDFGYUIOP',
    ],
    [
        'Mark Baker',
        'a',
        'x',
        'Mxrk Bxker',
    ],
    [
        'Mark Baker',
        'a',
        'x',
        1,
        'Mxrk Baker',
    ],
    [
        'Mark Baker',
        'x',
        'a',
        1,
        'Mark Baker',
    ],
];