Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /var/www/illumine/vendor/sabre/vobject/tests/VObject/Component/VAvailabilityTest.php:15 Stack trace: #0 {main} thrown in /var/www/illumine/vendor/sabre/vobject/tests/VObject/Component/VAvailabilityTest.php on line 15