This plugin checks what's inside the files.
<?php
// lowercase.php
return [
'lower',
'case',
'lowercase',
];
expect('lowercase.php')->toReturnLowercase();
<?php
// notlowercase.php
return [
'lower',
'caSe',
'lowercase',
];
expect('notlowercase.php')->toReturnLowercase();
You can scan all directory files at once
expect('directory')->toReturnLowercase();