https://api.drupal.org/api/drupal/core%21modules%21serialization%21tests%21src%21Kernel%21EntitySerializationTest.php/property/EntitySerializationTest%3A%3Aserializer/8.9.x
EntitySerializationTest::$serializer | Drupal API
serializerdrupalapi
https://api.drupal.org/api/drupal/core%21modules%21serialization%21tests%21src%21Kernel%21EntitySerializationTest.php/function/EntitySerializationTest%3A%3AsetUp/9
function EntitySerializationTest::setUp | Drupal API
functionsetupdrupalapi