diff --git a/core/lib/Drupal/Core/Field/FieldModuleUninstallValidator.php b/core/lib/Drupal/Core/Field/FieldModuleUninstallValidator.php
index 4777939..6f8fc20 100644
--- a/core/lib/Drupal/Core/Field/FieldModuleUninstallValidator.php
+++ b/core/lib/Drupal/Core/Field/FieldModuleUninstallValidator.php
@@ -8,7 +8,6 @@
 namespace Drupal\Core\Field;
 
 use Drupal\Core\Entity\EntityManagerInterface;
-use Drupal\Core\Entity\FieldableEntityInterface;
 use Drupal\Core\Entity\FieldableEntityStorageInterface;
 use Drupal\Core\Extension\ModuleUninstallValidatorInterface;
 use Drupal\Core\StringTranslation\StringTranslationTrait;
@@ -47,7 +46,7 @@ public function validate($module_name) {
       // to be able to uninstall them anyway. We also skip the Field module as
       // it implements field purging.
       // See \Drupal\Core\Entity\ContentUninstallValidator.
-      if ($entity_type->getProvider() != $module_name && $entity_type instanceof FieldableEntityInterface) {
+      if ($entity_type->getProvider() != $module_name && $entity_type->isSubclassOf('\Drupal\Core\Entity\FieldableEntityInterface')) {
         foreach ($this->entityManager->getFieldStorageDefinitions($entity_type_id) as $storage_definition) {
           if ($module_name != 'field' && $storage_definition->getProvider() == $module_name) {
             $storage = $this->entityManager->getStorage($entity_type_id);
diff --git a/core/modules/comment/src/Tests/CommentUninstallTest.php b/core/modules/comment/src/Tests/CommentUninstallTest.php
index 419932d..35a532e 100644
--- a/core/modules/comment/src/Tests/CommentUninstallTest.php
+++ b/core/modules/comment/src/Tests/CommentUninstallTest.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\comment\Tests;
 
+use Drupal\Core\Extension\ModuleUninstallValidatorException;
 use Drupal\field\Entity\FieldStorageConfig;
 use Drupal\simpletest\WebTestBase;
 
@@ -41,28 +42,32 @@ function testCommentUninstallWithField() {
     $field_storage = FieldStorageConfig::loadByName('comment', 'comment_body');
     $this->assertNotNull($field_storage, 'The comment_body field exists.');
 
-    // Uninstall the comment module which should trigger field deletion.
-    $this->container->get('module_installer')->uninstall(array('comment'));
-
-    // Check that the field is now deleted.
-    $field_storage = FieldStorageConfig::loadByName('comment', 'comment_body');
-    $this->assertNull($field_storage, 'The comment_body field has been deleted.');
+    // Uninstall the comment module which should not trigger field deletion.
+    $message = 'The comment_body field has not been deleted.';
+    try {
+      $this->container->get('module_installer')->uninstall(array('comment'));
+      $this->fail($message);
+    }
+    catch (ModuleUninstallValidatorException $e) {
+      $this->pass($message);
+    }
   }
 
-
   /**
    * Tests if uninstallation succeeds if the field has been deleted beforehand.
    */
   function testCommentUninstallWithoutField() {
     // Manually delete the comment_body field before module uninstallation.
-    $field_storage = FieldStorageConfig::loadByName('comment', 'comment_body');
+    $field_storage = FieldStorageConfig::loadByName('node', 'comment');
     $this->assertNotNull($field_storage, 'The comment_body field exists.');
     $field_storage->delete();
 
     // Check that the field is now deleted.
-    $field_storage = FieldStorageConfig::loadByName('comment', 'comment_body');
+    $field_storage = FieldStorageConfig::loadByName('node', 'comment');
     $this->assertNull($field_storage, 'The comment_body field has been deleted.');
 
+    field_purge_batch(1);
+
     // Ensure that uninstallation succeeds even if the field has already been
     // deleted manually beforehand.
     $this->container->get('module_installer')->uninstall(array('comment'));
diff --git a/core/modules/field/src/Tests/reEnableModuleFieldTest.php b/core/modules/field/src/Tests/reEnableModuleFieldTest.php
index 2b8f4c1..947ba83 100644
--- a/core/modules/field/src/Tests/reEnableModuleFieldTest.php
+++ b/core/modules/field/src/Tests/reEnableModuleFieldTest.php
@@ -88,10 +88,10 @@ function testReEnabledField() {
     // for it's fields.
     $admin_user = $this->drupalCreateUser(array('access administration pages', 'administer modules'));
     $this->drupalLogin($admin_user);
-    $this->drupalGet('admin/modules');
+    $this->drupalGet('admin/modules/uninstall');
     $this->assertText('Fields type(s) in use');
     $field_storage->delete();
-    $this->drupalGet('admin/modules');
+    $this->drupalGet('admin/modules/uninstall');
     $this->assertText('Fields pending deletion');
     $this->cronRun();
     $this->assertNoText('Fields type(s) in use');