diff -u b/core/modules/system/lib/Drupal/system/Tests/Cache/GenericCacheBackendUnitTestBase.php b/core/modules/system/lib/Drupal/system/Tests/Cache/GenericCacheBackendUnitTestBase.php
--- b/core/modules/system/lib/Drupal/system/Tests/Cache/GenericCacheBackendUnitTestBase.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Cache/GenericCacheBackendUnitTestBase.php
@@ -157,10 +157,11 @@
     $test_object->test2 = 100;
     $test_object->test3 = array('drupal1', 'drupal2' => 'drupal3', 'drupal4' => array('drupal5', 'drupal6'));
 
+    $this->checkVariable($test_object);
 
-    cache()->set('test_object', $test_object);
-    $cached = cache()->get('test_object');
-    $this->assertTrue(isset($cached->data) && $cached->data == $test_object, t('Object is saved and restored properly.'));
+//    cache()->set('test_object', $test_object);
+//    $cached = cache()->get('test_object');
+//    $this->assertTrue(isset($cached->data) && $cached->data == $test_object, t('Object is saved and restored properly.'));
   }
 
   /**
@@ -169,24 +170,20 @@
   public function testDelete() {
     $backend = $this->getCacheBackend();
 
-    $this->assertIdentical(FALSE, $backend->get('test1'), "Backend does contain first test key");
+    $this->assertCacheNotExists('test1');
     $backend->set('test1', 7);
-    $cached = $backend->get('test1');
-    $this->assert(is_object($cached), "Backend returned an object");
+    $this->assertCacheExists('test1');
 
-    $this->assertIdentical(FALSE, $backend->get('test2'), "Backend does not contain the second test key");
+    $this->assertCacheNotExists('test2');
     $backend->set('test2', 3);
-    $cached = $backend->get('test2');
-    $this->assert(is_object($cached), "Backend returned an object");
+    $this->assertCacheExists('test2');
 
     $backend->delete('test1');
-    $this->assertIdentical(FALSE, $backend->get('test1'), "Backend deleted the first key");
-
-    $cached = $backend->get('test2');
-    $this->assert(is_object($cached), "Backend still has the second key");
+    $this->assertCacheNotExists('test1');
+    $this->assertCacheExists('test2');
 
     $backend->delete('test2');
-    $this->assertIdentical(FALSE, $backend->get('test2'), "Backend deleted the second key");
+    $this->assertCacheNotExists('test2');
   }
 
   /**
@@ -268,74 +265,6 @@
   }
 
   /**
-   * Test delete multiple feature.
-   */
-  public function testDeleteMultiple() {
-    $backend = $this->getCacheBackend();
-
-    // Set numerous testing keys.
-    $backend->set('test1', 1);
-    $backend->set('test2', 3);
-    $backend->set('test3', 5);
-    $backend->set('test4', 7);
-    $backend->set('test5', 11);
-    $backend->set('test6', 13);
-    $backend->set('test7', 17);
-
-    $backend->deleteMultiple(array(
-      'test1',
-      'test3',
-      'test5',
-      'test7',
-      'test19', // Non existing key should be silent
-      'test21', // Non existing key should be silent
-    ));
-
-    $this->assertIdentical(FALSE, $backend->get('test1'), "Key 1 has been removed");
-    $this->assertNotIdentical(FALSE, $backend->get('test2'), "Key 2 has been kept");
-    $this->assertIdentical(FALSE, $backend->get('test3'), "Key 3 has been removed");
-    $this->assertNotIdentical(FALSE, $backend->get('test4'), "Key 4 has been kept");
-    $this->assertIdentical(FALSE, $backend->get('test5'), "Key 5 has been removed");
-    $this->assertNotIdentical(FALSE, $backend->get('test6'), "Key 6 has been kept");
-    $this->assertIdentical(FALSE, $backend->get('test7'), "Key 1 has been removed");
-    $this->assertIdentical(FALSE, $backend->get('test19'), "Key 19 still does not exists");
-    $this->assertIdentical(FALSE, $backend->get('test21'), "Key 21 still does not exists");
-  }
-
-  /**
-   * Test delete prefix feature.
-   */
-  public function testDeletePrefix() {
-    $backend = $this->getCacheBackend();
-
-    // Set numerous testing keys.
-    $backend->set('banana_test1', 1);
-    $backend->set('monkey_test2', 3);
-    $backend->set('monkey_banana_test3', 5);
-    $backend->set('banana_test_4', 7);
-    $backend->set('poney_monkey_test5_banana', 11);
-    $backend->set('monkey_test6', 13);
-    $backend->set('banana_poney_test7_monkey', 17);
-
-    $backend->deletePrefix('banana');
-
-    $this->assertIdentical(FALSE, $backend->get('banana_test1'), "Key 1 has been removed");
-    $this->assertNotIdentical(FALSE, $backend->get('monkey_test2'), "Key 2 has been kept");
-    $this->assertNotIdentical(FALSE, $backend->get('monkey_banana_test3'), "Key 3 has been kept");
-    $this->assertIdentical(FALSE, $backend->get('banana_test_4'), "Key 4 has been removed");
-    $this->assertNotIdentical(FALSE, $backend->get('poney_monkey_test5_banana'), "Key 5 has been kept");
-    $this->assertNotIdentical(FALSE, $backend->get('monkey_test6'), "Key 6 has been kept");
-    $this->assertIdentical(FALSE, $backend->get('banana_poney_test7_monkey'), "Key 7 has been removed");
-
-    $backend->deletePrefix('monkey');
-
-    $this->assertIdentical(FALSE, $backend->get('monkey_test2'), "Key 2 has been removed");
-    $this->assertIdentical(FALSE, $backend->get('monkey_banana_test3'), "Key 3 has been removed");
-    $this->assertNotIdentical(FALSE, $backend->get('poney_monkey_test5_banana'), "Key 5 has been kept");
-    $this->assertIdentical(FALSE, $backend->get('banana_poney_test7_monkey'), "Key 7 has been removed");
-  }
-
-  /**
    * Test is empty feature.
    */
   public function testIsEmpty() {
@@ -367,13 +296,17 @@
 
     $backend->set('test_cid_clear1', $this->default_value);
     $backend->set('test_cid_clear2', $this->default_value);
+    $backend->set('testkeep_cid_clear3', $this->default_value);
     $this->assertTrue($this->checkCacheExists('test_cid_clear1')
-                      && $this->checkCacheExists('test_cid_clear2'),
-                      t('Two caches were created for checking cid substring with wildcard true.'));
+                      && $this->checkCacheExists('test_cid_clear2')
+                      && $this->checkCacheExists('testkeep_cid_clear3'),
+                      t('Three caches were created for checking cid substring with wildcard true.'));
     $backend->deletePrefix('test_');
     $this->assertFalse($this->checkCacheExists('test_cid_clear1')
                       || $this->checkCacheExists('test_cid_clear2'),
                       t('Two caches removed after clearing cid substring with wildcard true.'));
+    $this->assertTrue($this->checkCacheExists('testkeep_cid_clear3'),
+                      t('One cache exists after clearing cid substring with wildcard true.'));
   }
 
   /**