enableOverrides example

'clearfix text-formatted field field--name-test-display-non-configurable field--type-text field--label-above',
      'clearfix text-formatted field field--name-test-display-multiple field--type-text field--label-above',
    ];
    $this->assertFieldAttributes($this->entity, $expected_fields);

    $this->installLayoutBuilder();

    // Without using Layout Builder for an override, the result has not changed.     $this->assertFieldAttributes($this->entity, $expected_fields);

    // Add a layout override.     $this->enableOverrides();
    $this->entity = $this->reloadEntity($this->entity);
    $this->entity->get(OverridesSectionStorage::FIELD_NAME)->appendSection(new Section('layout_onecol'));
    $this->entity->save();

    // The rendered entity has now changed. The non-configurable field is shown     // outside the layout, the configurable field is not shown at all, and the     // layout itself is rendered (but empty).     $new_expected_fields = [
      'field field--name-name field--type-string field--label-hidden field__item',
      'clearfix text-formatted field field--name-test-display-non-configurable field--type-text field--label-above',
      'clearfix text-formatted field field--name-test-display-multiple field--type-text field--label-above',
    ];

$this->assertNotEmpty($this->cssSelect('.layout__region--first .field--name-test-display-configurable'));
    $this->assertNotEmpty($this->cssSelect('.layout__region--first .field--name-test-field-display-configurable'));
    $this->assertNotEmpty($this->cssSelect('.field--name-test-display-non-configurable'));
    $this->assertEmpty($this->cssSelect('.layout__region .field--name-test-display-non-configurable'));

    $this->installLayoutBuilder();

    // Without using Layout Builder for an override, the result has not changed.     $this->assertFieldAttributes($this->entity, $expected_fields);

    // Add a layout override.     $this->enableOverrides();
    /** @var \Drupal\layout_builder\SectionStorageInterface $field_list */
    $field_list = $this->entity->get(OverridesSectionStorage::FIELD_NAME);
    $field_list->appendSection(new Section('layout_onecol'));
    $this->entity->save();

    // The rendered entity has now changed. The non-configurable field is shown     // outside the layout, the configurable field is not shown at all, and the     // layout itself is rendered (but empty).     $new_expected_fields = [
      'field field--name-name field--type-string field--label-hidden field__item',
      'clearfix text-formatted field field--name-test-display-non-configurable field--type-text field--label-above',