Fatal error: Uncaught Error: Class "Symfony\Component\String\Tests\AbstractUnicodeTestCase" not found in C:\xampp\htdocs\astra-backoffice\vendor\symfony\string\Tests\UnicodeStringTest.php:17 Stack trace: #0 {main} thrown in C:\xampp\htdocs\astra-backoffice\vendor\symfony\string\Tests\UnicodeStringTest.php on line 17