class RelationshipJoinTestBase

abstract class RelationshipJoinTestBase extends PluginKernelTestBase {
  
  /**
   * {@inheritdoc}
   */
  protected static $modules = [
    'system',
    'user',
    'field',
  ];
  
  /**
   * @var \Drupal\user\Entity\User
   */
  protected $rootUser;
  
  /**
   * {@inheritdoc}
   */
  protected function setUpFixtures() {
    $this->installEntitySchema('user');
    $this->installConfig([
      'user',
    ]);
    parent::setUpFixtures();
    // Create a record for uid 1.
    $this->rootUser = User::create([
      'name' => $this->randomMachineName(),
    ]);
    $this->rootUser
      ->save();
    Views::viewsData()->clear();
  }
  
  /**
   * Overrides \Drupal\views\Tests\ViewTestBase::schemaDefinition().
   *
   * Adds a uid column to test the relationships.
   *
   * @internal
   */
  protected function schemaDefinition() {
    $schema = parent::schemaDefinition();
    $schema['views_test_data']['fields']['uid'] = [
      'description' => "The {users_field_data}.uid of the author of the beatle entry.",
      'type' => 'int',
      'unsigned' => TRUE,
      'not null' => TRUE,
      'default' => 0,
    ];
    return $schema;
  }
  
  /**
   * Overrides \Drupal\views\Tests\ViewTestBase::viewsData().
   *
   * Adds a relationship for the uid column.
   */
  protected function viewsData() {
    $data = parent::viewsData();
    $data['views_test_data']['uid'] = [
      'title' => new TranslatableMarkup('UID'),
      'help' => new TranslatableMarkup('The test data UID'),
      'relationship' => [
        'id' => 'standard',
        'base' => 'users_field_data',
        'base field' => 'uid',
      ],
    ];
    return $data;
  }

}