diff --git a/core/modules/toolbar/src/Tests/ToolbarCacheContextsTest.php b/core/modules/toolbar/src/Tests/ToolbarCacheContextsTest.php
index 84fdf58..be47b08 100644
--- a/core/modules/toolbar/src/Tests/ToolbarCacheContextsTest.php
+++ b/core/modules/toolbar/src/Tests/ToolbarCacheContextsTest.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\toolbar\Tests;
 
+use Drupal\Core\Cache\Cache;
 use Drupal\simpletest\WebTestBase;
 use Drupal\system\Tests\Cache\AssertPageCacheContextsAndTagsTrait;
 
@@ -95,11 +96,11 @@ public function testToolbarCacheContextsCaller() {
   /**
    * Tests that cache contexts are applied for both users.
    *
-   * @param array $cache_contexts
+   * @param string[] $cache_contexts
    *   Expected cache contexts for both users.
    */
   private function testToolbarCacheContexts(array $cache_contexts) {
-    // Caches has to be rebuilt since modules might have added some routes.
+    // Caches have to be rebuilt since modules might have added some routes.
     drupal_flush_all_caches();
 
     // Default cache contexts that should exist on all test cases.
@@ -107,7 +108,7 @@ private function testToolbarCacheContexts(array $cache_contexts) {
       'languages:language_interface',
       'theme',
     ];
-    $cache_contexts = array_merge($default_cache_contexts, $cache_contexts);
+    $cache_contexts = Cache::mergeContexts($default_cache_contexts, $cache_contexts);
 
     // Assert contexts for user1 which has only default permissions.
     $this->drupalLogin($this->adminUser);