Fatal error: Uncaught Error: Class "JMS\Serializer\Tests\Fixtures\SimpleObject" not found in /home/kiwakim/stock/vendor/jms/serializer/tests/Fixtures/ObjectWithNullProperty.php:7 Stack trace: #0 {main} thrown in /home/kiwakim/stock/vendor/jms/serializer/tests/Fixtures/ObjectWithNullProperty.php on line 7