diff --git a/core/modules/datetime/src/Tests/WrapperDemoTest.php b/core/modules/datetime/src/Tests/WrapperDemoTest.php
new file mode 100644
index 0000000..2b3234e
--- /dev/null
+++ b/core/modules/datetime/src/Tests/WrapperDemoTest.php
@@ -0,0 +1,127 @@
+<?php
+
+namespace Drupal\datetime\Tests;
+
+use Drupal\Component\Utility\SafeMarkup;
+use Drupal\Component\Utility\Unicode;
+use Drupal\Core\Datetime\DrupalDateTime;
+use Drupal\Core\Datetime\Entity\DateFormat;
+use Drupal\Core\Entity\Entity\EntityViewDisplay;
+use Drupal\entity_test\Entity\EntityTest;
+use Drupal\field\Entity\FieldConfig;
+use Drupal\field\Entity\FieldStorageConfig;
+use Drupal\node\Entity\Node;
+use Drupal\simpletest\WebTestBase;
+
+/**
+ * Tests Datetime field functionality.
+ *
+ * @group datetime
+ */
+class WrapperDemoTest extends WebTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('node', 'entity_test', 'datetime', 'field_ui');
+
+  /**
+   * The default display settings to use for the formatters.
+   */
+  protected $defaultSettings;
+
+  /**
+   * An array of display options to pass to entity_get_display()
+   *
+   * @var array
+   */
+  protected $displayOptions;
+
+  /**
+   * A field storage to use in this test class.
+   *
+   * @var \Drupal\field\Entity\FieldStorageConfig
+   */
+  protected $fieldStorage;
+
+  /**
+   * The field used in this test class.
+   *
+   * @var \Drupal\field\Entity\FieldConfig
+   */
+  protected $field;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $web_user = $this->drupalCreateUser(array(
+      'access content',
+      'view test entity',
+      'administer entity_test content',
+      'administer entity_test form display',
+      'administer content types',
+      'administer node fields',
+    ));
+    $this->drupalLogin($web_user);
+
+    // Create a field with settings to validate.
+    $field_name = Unicode::strtolower($this->randomMachineName());
+    $this->fieldStorage = FieldStorageConfig::create(array(
+      'field_name' => $field_name,
+      'entity_type' => 'entity_test',
+      'type' => 'datetime',
+      'settings' => array('datetime_type' => 'date'),
+    ));
+    $this->fieldStorage->save();
+    $this->field = FieldConfig::create([
+      'field_storage' => $this->fieldStorage,
+      'bundle' => 'entity_test',
+      'required' => TRUE,
+    ]);
+    $this->field->save();
+
+    entity_get_form_display($this->field->getTargetEntityTypeId(), $this->field->getTargetBundle(), 'default')
+      ->setComponent($field_name, array(
+        'type' => 'datetime_default',
+      ))
+      ->save();
+
+    $this->defaultSettings = array(
+      'timezone_override' => '',
+    );
+
+    $this->displayOptions = array(
+      'type' => 'datetime_default',
+      'label' => 'hidden',
+      'settings' => array('format_type' => 'medium') + $this->defaultSettings,
+    );
+    entity_get_display($this->field->getTargetEntityTypeId(), $this->field->getTargetBundle(), 'full')
+      ->setComponent($field_name, $this->displayOptions)
+      ->save();
+  }
+
+  /**
+   * Demonstrate this wrapper bug.
+   */
+  function testDatetimeField() {
+    $field_name = $this->fieldStorage->getName();
+    // Change the field to a datetime field.
+    $this->fieldStorage->setSetting('datetime_type', 'datetime');
+    $this->fieldStorage->save();
+
+    // Display creation form.
+    $this->drupalGet('entity_test/add');
+
+    $elements = $this->xpath('//div[@class="test-classy"]');
+
+    debug($elements);
+
+    $this->assertEqual(count($elements), 1, 'Fount one classy datetime_wrapper');
+  }
+
+}
\ No newline at end of file
diff --git a/core/themes/classy/templates/form/datetime-wrapper.html.twig b/core/themes/classy/templates/form/datetime-wrapper.html.twig
index 3f6aa59..89bfa91 100644
--- a/core/themes/classy/templates/form/datetime-wrapper.html.twig
+++ b/core/themes/classy/templates/form/datetime-wrapper.html.twig
@@ -13,6 +13,7 @@
  * @see template_preprocess_datetime_wrapper()
  */
 #}
+<div class="test-classy">CLASSY</div>
 {%
   set title_classes = [
     'label',