Fatal error: Uncaught Error: Class "Tests\AbstractTestCaseWithOldNow" not found in C:\xampp\htdocs\r10ca\vendor\nesbot\carbon\tests\Carbon\JsonSerializationTest.php:19 Stack trace: #0 {main} thrown in C:\xampp\htdocs\r10ca\vendor\nesbot\carbon\tests\Carbon\JsonSerializationTest.php on line 19