Implements Drupal\field\Plugin\Type\Widget\WidgetInterface::settingsForm().
Overrides WidgetBase::settingsForm
public function settingsForm(array $form, array &$form_state) {
$element['test_widget_setting'] = array(
'#type' => 'textfield',
'#title' => t('Field test field widget setting'),
'#description' => t('A dummy form element to simulate field widget setting.'),
'#default_value' => $this
->getSetting('test_widget_setting'),
'#required' => FALSE,
);
return $element;
}