Fatal error: Uncaught Error: Class "Tests\TestCase" not found in C:\xampp\htdocs\smsgateway2\tests\Feature\Smpp\SmppInboundEnvelopeRepositoryTest.php:25 Stack trace: #0 {main} thrown in C:\xampp\htdocs\smsgateway2\tests\Feature\Smpp\SmppInboundEnvelopeRepositoryTest.php on line 25