diff -u b/core/modules/system/src/Tests/Entity/EntityChangedConstraintValidatorTest.php b/core/modules/system/src/Tests/Entity/EntityChangedConstraintValidatorTest.php
--- b/core/modules/system/src/Tests/Entity/EntityChangedConstraintValidatorTest.php
+++ b/core/modules/system/src/Tests/Entity/EntityChangedConstraintValidatorTest.php
@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Contains Drupal\system\Tests\Entity\EntityChangedConstraintValidatorTest.
+ * Contains \Drupal\system\Tests\Entity\EntityChangedConstraintValidatorTest.
  */
 
 namespace Drupal\system\Tests\Entity;
@@ -14,6 +14,8 @@
 
 /**
  * Tests validation constraints for EntityChangedConstraintValidator.
+ *
+ * @group Validation
  */
 class EntityChangedConstraintValidatorTest extends EntityUnitTestBase {
 
@@ -24,18 +26,8 @@
    */
   protected $typedData;
 
-  public static function getInfo() {
-    return array(
-      'name' => 'Entity changed constraint',
-      'description' => 'Tests validation constraints for EntityChangedConstraintValidator.',
-      'group' => 'Validation',
-    );
-  }
-
   public function setUp() {
     parent::setUp();
-
-    $this->installEntitySchema('entity_test_changed');
     $this->typedData = $this->container->get('typed_data_manager');
   }
 
@@ -44,12 +36,17 @@
    */
   public function testValidation() {
     // Test the validation.
-    $user1 = $this->createUser();
-    $entity_test = entity_create('entity_test_changed', array('user_id' => $user1->id()));
+    $account = $this->createUser();
+    $entity_test = entity_create('entity_test', array('user_id' => $account->id()));
 
     $entity_test->save();
     $violations = $entity_test->changed->validate();
     $this->assertEqual($violations->count(), 0, 'Validation passed for correct value.');
+    // Set a changed date in the future.
+    $entity_test->set('changed', REQUEST_TIME + 100000);
+    // Run validation on the changed field.
+    $violations = $entity_test->changed->validate();
+    $this->assertEqual($violations->count(), 0, 'Validation passed for correct value.');
 
     // Test the validation when an invalid value is passed.
     // Set a changed date in the past.
reverted:
--- b/core/modules/system/tests/modules/entity_test/entity_test.install
+++ a/core/modules/system/tests/modules/entity_test/entity_test.install
@@ -14,7 +14,6 @@
     'entity_test_rev',
     'entity_test_mul',
     'entity_test_mulrev',
-    'entity_test_changed',
   );
   foreach ($entity_types as $entity_type) {
     // Auto-create fields for testing.
reverted:
--- b/core/modules/system/tests/modules/entity_test/src/Entity/EntityTestChanged.php
+++ /dev/null
@@ -1,66 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\entity_test\Entity\EntityTestChanged.
- */
-
-namespace Drupal\entity_test\Entity;
-
-use Drupal\Core\Entity\EntityTypeInterface;
-use Drupal\Core\Field\BaseFieldDefinition;
-use Drupal\entity_test\Entity\EntityTest;
-use Drupal\Core\Entity\EntityChangedInterface;
-
-/**
- * Defines the test entity class.
- *
- * @ContentEntityType(
- *   id = "entity_test_changed",
- *   label = @Translation("Test entity - data table"),
- *   handlers = {
- *     "access" = "Drupal\entity_test\EntityTestAccessControlHandler",
- *     "form" = {
- *       "default" = "Drupal\entity_test\EntityTestForm",
- *       "delete" = "Drupal\entity_test\EntityTestDeleteForm"
- *     },
- *     "translation" = "Drupal\content_translation\ContentTranslationHandler",
- *     "views_data" = "Drupal\views\EntityViewsData"
- *   },
- *   base_table = "entity_test_changed",
- *   data_table = "entity_test_changed_property_data",
- *   fieldable = TRUE,
- *   entity_keys = {
- *     "id" = "id",
- *     "uuid" = "uuid",
- *     "bundle" = "type"
- *   },
- *   links = {
- *     "canonical" = "entity_test.edit_entity_test_changed",
- *     "edit-form" = "entity_test.edit_entity_test_changed",
- *   }
- * )
- */
-class EntityTestChanged extends EntityTest implements EntityChangedInterface {
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
-    $fields = parent::baseFieldDefinitions($entity_type);
-
-    $fields['changed'] = BaseFieldDefinition::create('changed')
-      ->setLabel(t('Changed'))
-      ->setDescription(t('The time that the entity was last edited.'))
-      ->setRevisionable(TRUE)
-      ->setTranslatable(TRUE);
-    return $fields;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getChangedTime() {
-    return $this->get('changed')->value;
-  }
-}
only in patch2:
unchanged:
--- a/core/modules/system/tests/modules/entity_test/src/Entity/EntityTest.php
+++ b/core/modules/system/tests/modules/entity_test/src/Entity/EntityTest.php
@@ -13,6 +13,7 @@
 use Drupal\Core\Entity\EntityStorageInterface;
 use Drupal\user\EntityOwnerInterface;
 use Drupal\user\UserInterface;
+use Drupal\Core\Entity\EntityChangedInterface;
 
 /**
  * Defines the test entity class.
@@ -48,7 +49,7 @@
  *   field_ui_base_route = "entity.entity_test.admin_form",
  * )
  */
-class EntityTest extends ContentEntityBase implements EntityOwnerInterface {
+class EntityTest extends ContentEntityBase implements EntityOwnerInterface, EntityChangedInterface {
 
   /**
    * {@inheritdoc}
@@ -120,6 +121,11 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
         ),
       ));
 
+    $fields['changed'] = BaseFieldDefinition::create('changed')
+      ->setLabel(t('Changed'))
+      ->setDescription(t('The time that the entity was last edited.'))
+      ->setRevisionable(TRUE)
+      ->setTranslatable(TRUE);
     return $fields;
   }
 
@@ -175,4 +181,10 @@ public function getName() {
     return $this->get('name')->value;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function getChangedTime() {
+    return $this->get('changed')->value;
+  }
 }