class NodeFieldOverridesTest

class NodeFieldOverridesTest extends EntityKernelTestBase {
  
  /**
   * Current logged in user.
   *
   * @var \Drupal\user\UserInterface
   */
  protected $user;
  
  /**
   * Modules to enable.
   *
   * @var array
   */
  protected static $modules = [
    'user',
    'system',
    'field',
    'node',
  ];
  
  /**
   * {@inheritdoc}
   */
  protected function setUp() : void {
    parent::setUp();
    $this->installConfig([
      'user',
    ]);
    $this->user = $this->createUser();
    \Drupal::service('current_user')->setAccount($this->user);
  }
  
  /**
   * Tests that field overrides work as expected.
   */
  public function testFieldOverrides() {
    if (!NodeType::load('ponies')) {
      NodeType::create([
        'name' => 'Ponies',
        'type' => 'ponies',
      ])->save();
    }
    $override = BaseFieldOverride::loadByName('node', 'ponies', 'uid');
    if ($override) {
      $override->delete();
    }
    $uid_field = \Drupal::service('entity_field.manager')->getBaseFieldDefinitions('node')['uid'];
    $config = $uid_field->getConfig('ponies');
    $config->save();
    $this->assertEquals('Drupal\\node\\Entity\\Node::getDefaultEntityOwner', $config->get('default_value_callback'));
    /** @var \Drupal\node\NodeInterface $node */
    $node = Node::create([
      'type' => 'ponies',
    ]);
    $owner = $node->getOwner();
    $this->assertInstanceOf(UserInterface::class, $owner);
    $this->assertEquals($this->user
      ->id(), $owner->id());
  }

}