diff --git a/core/modules/simpletest/src/KernelTestBase.php b/core/modules/simpletest/src/KernelTestBase.php
index 5534d7e..ca83e51 100644
--- a/core/modules/simpletest/src/KernelTestBase.php
+++ b/core/modules/simpletest/src/KernelTestBase.php
@@ -320,7 +320,7 @@ public function containerBuild(ContainerBuilder $container) {
    */
   protected function installConfig(array $modules) {
     foreach ($modules as $module) {
-      if (!$this->container->get('module_handler')->moduleExists($module)) {
+      if ($module != 'core' && !$this->container->get('module_handler')->moduleExists($module)) {
         throw new \RuntimeException(format_string("'@module' module is not enabled.", array(
           '@module' => $module,
         )));
diff --git a/core/modules/system/src/Tests/Token/RouteTokensTest.php b/core/modules/system/src/Tests/Token/RouteTokensTest.php
index c499611..ec19325 100644
--- a/core/modules/system/src/Tests/Token/RouteTokensTest.php
+++ b/core/modules/system/src/Tests/Token/RouteTokensTest.php
@@ -22,7 +22,7 @@ class RouteTokensTest extends KernelTestBase {
    *
    * @var array
    */
-  public static $modules = array('system', 'user', 'core');
+  public static $modules = array('system', 'user');
 
   /**
    * Sets up the test.