class WidgetPluginManagerTest

class WidgetPluginManagerTest extends FieldKernelTestBase {
  
  /**
   * Tests that the widget definitions alter hook works.
   */
  public function testWidgetDefinitionAlter() {
    $widget_definition = \Drupal::service('plugin.manager.field.widget')->getDefinition('test_field_widget_multiple');
    // Test if hook_field_widget_info_alter is being called.
    $this->assertContains('test_field', $widget_definition['field_types'], "The 'test_field_widget_multiple' widget is enabled for the 'test_field' field type in field_test_field_widget_info_alter().");
  }
  
  /**
   * Tests that getInstance falls back on default if current is not applicable.
   *
   * @see \Drupal\field\Tests\FormatterPluginManagerTest::testNotApplicableFallback()
   */
  public function testNotApplicableFallback() {
    /** @var \Drupal\Core\Field\WidgetPluginManager $widget_plugin_manager */
    $widget_plugin_manager = \Drupal::service('plugin.manager.field.widget');
    $base_field_definition = BaseFieldDefinition::create('test_field')->setName('field_multiwidgetfield');
    $widget_options = [
      'field_definition' => $base_field_definition,
      'form_mode' => 'default',
      'configuration' => [
        'type' => 'test_field_widget_multiple',
      ],
    ];
    $instance = $widget_plugin_manager->getInstance($widget_options);
    $this->assertEquals('test_field_widget_multiple', $instance->getPluginId());
    // Now do the same but with machine name field_onewidgetfield, because that
    // makes isApplicable() return FALSE.
    $base_field_definition->setName('field_onewidgetfield');
    $instance = $widget_plugin_manager->getInstance($widget_options);
    // Instance should be default widget.
    $this->assertNotSame('test_field_widget_multiple', $instance->getPluginId());
    $this->assertEquals('test_field_widget', $instance->getPluginId());
  }

}