class DatabaseTestController

class DatabaseTestController extends ControllerBase {
  
  /**
   * The database connection.
   *
   * @var \Drupal\Core\Database\Connection
   */
  protected $connection;
  
  /**
   * Constructs a DatabaseTestController object.
   *
   * @param \Drupal\Core\Database\Connection $connection
   *   A database connection.
   */
  public function __construct(Connection $connection) {
    $this->connection = $connection;
  }
  
  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container) {
    return new static($container->get('database'));
  }
  
  /**
   * Runs a pager query and returns the results.
   *
   * This function does care about the page GET parameter, as set by the
   * test HTTP call.
   *
   * @return \Symfony\Component\HttpFoundation\JsonResponse
   */
  public function pagerQueryEven($limit) {
    $query = $this->connection
      ->select('test', 't');
    $query->fields('t', [
      'name',
    ])
      ->orderBy('age');
    // This should result in 2 pages of results.
    $query = $query->extend(PagerSelectExtender::class)
      ->limit($limit);
    $names = $query->execute()
      ->fetchCol();
    return new JsonResponse([
      'names' => $names,
    ]);
  }
  
  /**
   * Runs a pager query and returns the results.
   *
   * This function does care about the page GET parameter, as set by the
   * test HTTP call.
   *
   * @return \Symfony\Component\HttpFoundation\JsonResponse
   */
  public function pagerQueryOdd($limit) {
    $query = $this->connection
      ->select('test_task', 't');
    $query->fields('t', [
      'task',
    ])
      ->orderBy('pid');
    // This should result in 4 pages of results.
    $query = $query->extend(PagerSelectExtender::class)
      ->limit($limit);
    $names = $query->execute()
      ->fetchCol();
    return new JsonResponse([
      'names' => $names,
    ]);
  }
  
  /**
   * Runs a tablesort query and returns the results.
   *
   * This function does care about the page GET parameter, as set by the
   * test HTTP call.
   *
   * @return \Symfony\Component\HttpFoundation\JsonResponse
   */
  public function testTablesort() {
    $header = [
      'tid' => [
        'data' => t('Task ID'),
        'field' => 'tid',
        'sort' => 'desc',
      ],
      'pid' => [
        'data' => t('Person ID'),
        'field' => 'pid',
      ],
      'task' => [
        'data' => t('Task'),
        'field' => 'task',
      ],
      'priority' => [
        'data' => t('Priority'),
        'field' => 'priority',
      ],
    ];
    $query = $this->connection
      ->select('test_task', 't');
    $query->fields('t', [
      'tid',
      'pid',
      'task',
      'priority',
    ]);
    $query = $query->extend(TableSortExtender::class)
      ->orderByHeader($header);
    // We need all the results at once to check the sort.
    $tasks = $query->execute()
      ->fetchAll();
    return new JsonResponse([
      'tasks' => $tasks,
    ]);
  }
  
  /**
   * Runs a tablesort query with a second order_by after and returns the results.
   *
   * This function does care about the page GET parameter, as set by the
   * test HTTP call.
   *
   * @return \Symfony\Component\HttpFoundation\JsonResponse
   */
  public function testTablesortFirst() {
    $header = [
      'tid' => [
        'data' => t('Task ID'),
        'field' => 'tid',
        'sort' => 'desc',
      ],
      'pid' => [
        'data' => t('Person ID'),
        'field' => 'pid',
      ],
      'task' => [
        'data' => t('Task'),
        'field' => 'task',
      ],
      'priority' => [
        'data' => t('Priority'),
        'field' => 'priority',
      ],
    ];
    $query = $this->connection
      ->select('test_task', 't');
    $query->fields('t', [
      'tid',
      'pid',
      'task',
      'priority',
    ]);
    $query = $query->extend(TableSortExtender::class)
      ->orderByHeader($header)
      ->orderBy('priority');
    // We need all the results at once to check the sort.
    $tasks = $query->execute()
      ->fetchAll();
    return new JsonResponse([
      'tasks' => $tasks,
    ]);
  }

}