diff -u b/core/lib/Drupal/Core/Cache/ApcuBackendFactory.php b/core/lib/Drupal/Core/Cache/ApcuBackendFactory.php
--- b/core/lib/Drupal/Core/Cache/ApcuBackendFactory.php
+++ b/core/lib/Drupal/Core/Cache/ApcuBackendFactory.php
@@ -8,7 +8,6 @@
 namespace Drupal\Core\Cache;
 
 use \Drupal\Component\Utility\Crypt;
-use \Drupal\Core\DrupalKernelInterface;
 
 class ApcuBackendFactory implements CacheFactoryInterface {
 
diff -u b/core/modules/simpletest/src/Tests/SimpleTestTest.php b/core/modules/simpletest/src/Tests/SimpleTestTest.php
--- b/core/modules/simpletest/src/Tests/SimpleTestTest.php
+++ b/core/modules/simpletest/src/Tests/SimpleTestTest.php
@@ -161,7 +161,7 @@
     // @see drupal_generate_test_ua();
     $key_file = DRUPAL_ROOT . '/sites/simpletest/' . substr($this->databasePrefix, 10) . '/.htkey';
     $private_key = Crypt::randomBytesBase64(55);
-    $kernel = $this->container->get('kernel');
+    $site_path = $this->container->get('site.path');
     file_put_contents($key_file, $private_key);
 
     // This causes the first of the fifteen passes asserted in
@@ -193,7 +193,7 @@
 
     // These cause the eleventh to fourteenth of the fifteen passes asserted in
     // confirmStubResults().
-    $this->assertTrue(file_exists($kernel->getSitePath() . '/settings.testing.php'));
+    $this->assertTrue(file_exists($site_path . '/settings.testing.php'));
     // Check the settings.testing.php file got included.
     $this->assertTrue(function_exists('simpletest_test_stub_settings_function'));
     // Check that the test-specific service file got loaded.
diff -u b/core/modules/system/src/Tests/File/ReadOnlyStreamWrapperTest.php b/core/modules/system/src/Tests/File/ReadOnlyStreamWrapperTest.php
--- b/core/modules/system/src/Tests/File/ReadOnlyStreamWrapperTest.php
+++ b/core/modules/system/src/Tests/File/ReadOnlyStreamWrapperTest.php
@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Contains \Drupal\system\Tests\File\ReadOnlyStreamWrapperTest.
+ * Definition of Drupal\system\Tests\File\ReadOnlyStreamWrapperTest.
  */
 
 namespace Drupal\system\Tests\File;