Fatal error: Uncaught Error: Class "Tests\TestCase" not found in C:\xampp\htdocs\smsgateway2\tests\Feature\Smpp\SmppInboundEnvelopeLifecycleMySqlIntegrationTest.php:28 Stack trace: #0 {main} thrown in C:\xampp\htdocs\smsgateway2\tests\Feature\Smpp\SmppInboundEnvelopeLifecycleMySqlIntegrationTest.php on line 28