Fatal error: Uncaught Error: Class "Drupal\Core\Block\BlockBase" not found in /home/qcsvlel/www/core/modules/navigation/tests/navigation_test_block/src/Plugin/Block/NavigationTestBlock.php:21 Stack trace: #0 {main} thrown in /home/qcsvlel/www/core/modules/navigation/tests/navigation_test_block/src/Plugin/Block/NavigationTestBlock.php on line 21