diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockHiddenRegionTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockHiddenRegionTest.php
index 1232420..710c53f 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockHiddenRegionTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockHiddenRegionTest.php
@@ -64,6 +64,7 @@ public function testBlockNotInHiddenRegion() {
     config('system.theme')
       ->set('default', $theme)
       ->save();
+    \Drupal::service('router.builder')->rebuild();
     menu_router_rebuild();
 
     // Ensure that "block_test_theme" is set as the default theme.
diff --git a/core/modules/color/lib/Drupal/color/Tests/ColorTest.php b/core/modules/color/lib/Drupal/color/Tests/ColorTest.php
index 1a02f25..577a3be 100644
--- a/core/modules/color/lib/Drupal/color/Tests/ColorTest.php
+++ b/core/modules/color/lib/Drupal/color/Tests/ColorTest.php
@@ -48,7 +48,8 @@ function setUp() {
       ),
     );
     theme_enable(array_keys($this->themes));
-    drupal_flush_all_caches();
+    \Drupal::service('router.builder')->rebuild();
+    menu_router_rebuild();
 
     // Array filled with valid and not valid color values
     $this->colorTests = array(
diff --git a/core/modules/system/lib/Drupal/system/Tests/Menu/MenuRouterTest.php b/core/modules/system/lib/Drupal/system/Tests/Menu/MenuRouterTest.php
index 3b666a0..e9bb6e5 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Menu/MenuRouterTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Menu/MenuRouterTest.php
@@ -338,6 +338,7 @@ function testMenuName() {
     // Change the menu_name parameter in menu_test.module, then force a menu
     // rebuild.
     menu_test_menu_name('changed');
+    \Drupal::service('router.builder')->rebuild();
     menu_router_rebuild();
 
     $menu_links = entity_load_multiple_by_properties('menu_link', array('router_path' => 'menu_name_test'));