Fatal error: Uncaught Error: Class "Drupal\serialization\Normalizer\ComplexDataNormalizer" not found in /home/www/drupal8/test/core/modules/serialization/src/Normalizer/EntityNormalizer.php:13
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/core/modules/serialization/src/Normalizer/EntityNormalizer.php on line 13