Issue #3180227 by danflanagan8, robertom, xjm, Lendude, quietone: Notice:...

    $id_table = $this->view->storage->get('base_table');

    $this->id_field_alias = $this->view->query->addField($id_table, $id_field);

    $options = $this->getOption('entity_reference_options');

    $options = $this->getOption('entity_reference_options') ?? [];

    // The entity_reference_options are typically set during a call to

    // Drupal\views\Plugin\EntityReferenceSelection\ViewsSelection::initializeView().

    // If any entity_reference_options are not yet set, we apply the same

    // default values that would typically be added by that method.

    $default_options = [

      'match' => NULL,

      'match_operator' => 'CONTAINS',

      'limit' => 0,

      'ids' => NULL,

    ];

    $options += $default_options;

    // Restrict the autocomplete options based on what's been typed already.

    if (isset($options['match'])) {

    $view->setDisplay('entity_reference_1');

    $render = $view->display_handler->render();

    $this->assertSame([], $render, 'Render returned empty array');

    // Execute the View without setting the 'entity_reference_options'.

    // This is equivalent to using the following as entity_reference_options.

    // @code

    // $options = [

    //   'match' => NULL,

    //   'match_operator' => 'CONTAINS',

    //   'limit' => 0,

    //   'ids' => NULL,

    // ];

    // @endcode

    // Assert that this view returns a row for each test entity.

    $view->destroy();

    $view = Views::getView('test_display_entity_reference');

    $view->setDisplay('entity_reference_1');

    $this->executeView($view);

    $this->assertCount(13, $view->result, 'Search returned thirteen rows');

  }

}