diff --git a/core/lib/Drupal/Core/Cache/NullBackend.php b/core/lib/Drupal/Core/Cache/NullBackend.php
index c3da5d7..0408fc3 100644
--- a/core/lib/Drupal/Core/Cache/NullBackend.php
+++ b/core/lib/Drupal/Core/Cache/NullBackend.php
@@ -42,7 +42,7 @@ class NullBackend implements CacheBackendInterface {
   /**
    * Implements Drupal\Core\Cache\CacheBackendInterface::set().
    */
-  function set($cid, $data, $expire = CACHE_PERMANENT) {}
+  function set($cid, $data, $expire = CACHE_PERMANENT, array $tags = array()) {}
 
   /**
    * Implements Drupal\Core\Cache\CacheBackendInterface::delete().
@@ -75,6 +75,11 @@ class NullBackend implements CacheBackendInterface {
   function garbageCollection() {}
 
   /**
+   * Implements Drupal\Core\Cache\CacheBackendInterface::invalidateTags().
+   */
+  public function invalidateTags(array $tags) {}
+
+  /**
    * Implements Drupal\Core\Cache\CacheBackendInterface::isEmpty().
    */
   function isEmpty() {
diff --git a/core/modules/system/tests/cache.test b/core/modules/system/tests/cache.test
index 8a5d9ff..1b129c1 100644
--- a/core/modules/system/tests/cache.test
+++ b/core/modules/system/tests/cache.test
@@ -2,6 +2,8 @@
 
 use Drupal\Core\Cache\DatabaseBackend;
 use Drupal\Core\Cache\InstallBackend;
+use Drupal\Core\Cache\NullBackend;
+use Drupal\simpletest\UnitTestBase;
 use Drupal\simpletest\WebTestBase;
 
 class CacheTestCase extends WebTestBase {
@@ -600,3 +602,30 @@ class CacheInstallTestCase extends CacheTestCase {
     }
   }
 }
+
+/**
+ * Tests the cache NullBackend.
+ */
+class NullBackendTestCase extends UnitTestBase {
+  public static function getInfo() {
+    return array(
+      'name' => 'Cache NullBackend test',
+      'description' => 'Tests the cache NullBackend.',
+      'group' => 'Cache',
+    );
+  }
+
+  /**
+   * Tests that the NullBackend does not actually store variables.
+   */
+  function testNullBackend() {
+    $null_cache = new NullBackend('test');
+
+    $key = $this->randomName();
+    $value = $this->randomName();
+
+    $null_cache->set($key, $value);
+    $this->assertTrue($null_cache->isEmpty());
+    $this->assertFalse($null_cache->get($key));
+  }
+}