diff --git a/core/modules/system/src/Tests/RouteProcessor/RouteNoneTest.php b/core/modules/system/tests/src/Kernel/RouteProcessor/RouteNoneTest.php
similarity index 98%
rename from core/modules/system/src/Tests/RouteProcessor/RouteNoneTest.php
rename to core/modules/system/tests/src/Kernel/RouteProcessor/RouteNoneTest.php
index f029156..0511166 100644
--- a/core/modules/system/src/Tests/RouteProcessor/RouteNoneTest.php
+++ b/core/modules/system/tests/src/Kernel/RouteProcessor/RouteNoneTest.php
@@ -5,12 +5,12 @@
  * Contains \Drupal\system\Tests\RouteProcessor\RouteNoneTest.
  */
 
-namespace Drupal\system\Tests\RouteProcessor;
+namespace Drupal\Tests\system\Kernel\RouteProcessor;
 
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\GeneratedUrl;
 use Drupal\Core\Render\BubbleableMetadata;
-use Drupal\simpletest\KernelTestBase;
+use Drupal\KernelTests\KernelTestBase;
 use Symfony\Cmf\Component\Routing\RouteObjectInterface;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\Routing\Route;
diff --git a/core/modules/system/src/Tests/RouteProcessor/RouteProcessorCurrentIntegrationTest.php b/core/modules/system/tests/src/Kernel/RouteProcessor/RouteProcessorCurrentIntegrationTest.php
similarity index 98%
rename from core/modules/system/src/Tests/RouteProcessor/RouteProcessorCurrentIntegrationTest.php
rename to core/modules/system/tests/src/Kernel/RouteProcessor/RouteProcessorCurrentIntegrationTest.php
index 8cdb9c7..39dd77b 100644
--- a/core/modules/system/src/Tests/RouteProcessor/RouteProcessorCurrentIntegrationTest.php
+++ b/core/modules/system/tests/src/Kernel/RouteProcessor/RouteProcessorCurrentIntegrationTest.php
@@ -5,12 +5,12 @@
  * Contains \Drupal\system\Tests\RouteProcessor\RouteProcessorCurrentIntegrationTest.
  */
 
-namespace Drupal\system\Tests\RouteProcessor;
+namespace Drupal\Tests\system\Kernel\RouteProcessor;
 
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\GeneratedUrl;
 use Drupal\Core\Render\BubbleableMetadata;
-use Drupal\simpletest\KernelTestBase;
+use Drupal\KernelTests\KernelTestBase;
 use Symfony\Cmf\Component\Routing\RouteObjectInterface;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\Routing\Route;
diff --git a/core/modules/system/src/Tests/Routing/ContentNegotiationRoutingTest.php b/core/modules/system/tests/src/Kernel/Routing/ContentNegotiationRoutingTest.php
similarity index 96%
rename from core/modules/system/src/Tests/Routing/ContentNegotiationRoutingTest.php
rename to core/modules/system/tests/src/Kernel/Routing/ContentNegotiationRoutingTest.php
index 71d3fe2..0f71607 100644
--- a/core/modules/system/src/Tests/Routing/ContentNegotiationRoutingTest.php
+++ b/core/modules/system/tests/src/Kernel/Routing/ContentNegotiationRoutingTest.php
@@ -5,10 +5,10 @@
  * Contains \Drupal\system\Tests\Routing\ContentNegotiationRoutingTest.
  */
 
-namespace Drupal\system\Tests\Routing;
+namespace Drupal\Tests\system\Kernel\Routing;
 
 use Drupal\Core\DependencyInjection\ContainerBuilder;
-use Drupal\simpletest\KernelTestBase;
+use Drupal\KernelTests\KernelTestBase;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 
@@ -37,8 +37,8 @@ protected function setUp() {
   /**
    * {@inheritdoc}
    */
-  public function containerBuild(ContainerBuilder $container) {
-    parent::containerBuild($container);
+  public function register(ContainerBuilder $container) {
+    parent::register($container);
 
     // \Drupal\simpletest\KernelTestBase::containerBuild() removes the alias path
     // processor.
diff --git a/core/modules/system/src/Tests/Routing/ExceptionHandlingTest.php b/core/modules/system/tests/src/Kernel/Routing/ExceptionHandlingTest.php
similarity index 97%
rename from core/modules/system/src/Tests/Routing/ExceptionHandlingTest.php
rename to core/modules/system/tests/src/Kernel/Routing/ExceptionHandlingTest.php
index a404916..9c28daf 100644
--- a/core/modules/system/src/Tests/Routing/ExceptionHandlingTest.php
+++ b/core/modules/system/tests/src/Kernel/Routing/ExceptionHandlingTest.php
@@ -2,13 +2,13 @@
 
 /**
  * @file
- * Contains \Drupal\system\Tests\Routing\ExceptionHandlingTest.
+ * Contains \Drupal\Tests\system\Kernel\Routing\ExceptionHandlingTest.
  */
 
-namespace Drupal\system\Tests\Routing;
+namespace Drupal\Tests\system\Kernel\Routing;
 
 use Drupal\Component\Utility\Html;
-use Drupal\simpletest\KernelTestBase;
+use Drupal\KernelTests\KernelTestBase;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 
diff --git a/core/modules/system/src/Tests/Routing/RouteProviderTest.php b/core/modules/system/tests/src/Kernel/Routing/RouteProviderTest.php
similarity index 93%
rename from core/modules/system/src/Tests/Routing/RouteProviderTest.php
rename to core/modules/system/tests/src/Kernel/Routing/RouteProviderTest.php
index 056a37a..151946a 100644
--- a/core/modules/system/src/Tests/Routing/RouteProviderTest.php
+++ b/core/modules/system/tests/src/Kernel/Routing/RouteProviderTest.php
@@ -2,10 +2,10 @@
 
 /**
  * @file
- * Contains \Drupal\system\Tests\Routing\RouteProviderTest.
+ * Contains \Drupal\Tests\system\Kernel\Routing\RouteProviderTest.
  */
 
-namespace Drupal\system\Tests\Routing;
+namespace Drupal\Tests\system\Kernel\Routing;
 
 use Drupal\Core\Cache\MemoryBackend;
 use Drupal\Core\Database\Database;
@@ -15,14 +15,14 @@
 use Drupal\Core\Routing\MatcherDumper;
 use Drupal\Core\Routing\RouteProvider;
 use Drupal\Core\State\State;
+use Drupal\KernelTests\KernelTestBase;
 use Drupal\Tests\Core\Routing\RoutingFixtures;
-use Drupal\simpletest\KernelTestBase;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\RequestStack;
+use Symfony\Component\Routing\Exception\ResourceNotFoundException;
 use Symfony\Component\Routing\Exception\RouteNotFoundException;
 use Symfony\Component\Routing\Route;
 use Symfony\Component\Routing\RouteCollection;
-use Symfony\Component\Routing\Exception\ResourceNotFoundException;
 
 /**
  * Confirm that the default route provider is working correctly.
@@ -91,8 +91,8 @@ protected function setUp() {
   /**
    * {@inheritdoc}
    */
-  public function containerBuild(ContainerBuilder $container) {
-    parent::containerBuild($container); // TODO: Change the autogenerated stub
+  public function register(ContainerBuilder $container) {
+    parent::register($container); // TODO: Change the autogenerated stub
 
     // Readd the incoming path alias for these tests.
     if ($container->hasDefinition('path_processor_alias')) {
@@ -185,7 +185,8 @@ function testOutlinePathMatch() {
 
     // All of the matching paths have the correct pattern.
     foreach ($routes as $route) {
-      $this->assertEqual($route->compile()->getPatternOutline(), '/path/%/one', 'Found path has correct pattern');
+      $this->assertEqual($route->compile()
+        ->getPatternOutline(), '/path/%/one', 'Found path has correct pattern');
     }
 
     $this->assertEqual(count($routes), 2, 'The correct number of routes was found.');
@@ -214,7 +215,8 @@ function testOutlinePathMatchTrailingSlash() {
 
     // All of the matching paths have the correct pattern.
     foreach ($routes as $route) {
-      $this->assertEqual($route->compile()->getPatternOutline(), '/path/%/one', 'Found path has correct pattern');
+      $this->assertEqual($route->compile()
+        ->getPatternOutline(), '/path/%/one', 'Found path has correct pattern');
     }
 
     $this->assertEqual(count($routes), 2, 'The correct number of routes was found.');
@@ -249,13 +251,13 @@ function testOutlinePathMatchDefaults() {
 
       // All of the matching paths have the correct pattern.
       foreach ($routes as $route) {
-        $this->assertEqual($route->compile()->getPatternOutline(), '/some/path', 'Found path has correct pattern');
+        $this->assertEqual($route->compile()
+          ->getPatternOutline(), '/some/path', 'Found path has correct pattern');
       }
 
       $this->assertEqual(count($routes), 1, 'The correct number of routes was found.');
       $this->assertNotNull($routes->get('poink'), 'The first matching route was found.');
-    }
-    catch (ResourceNotFoundException $e) {
+    } catch (ResourceNotFoundException $e) {
       $this->fail('No matching route found with default argument value.');
     }
   }
@@ -288,13 +290,13 @@ function testOutlinePathMatchDefaultsCollision() {
 
       // All of the matching paths have the correct pattern.
       foreach ($routes as $route) {
-        $this->assertEqual($route->compile()->getPatternOutline(), '/some/path', 'Found path has correct pattern');
+        $this->assertEqual($route->compile()
+          ->getPatternOutline(), '/some/path', 'Found path has correct pattern');
       }
 
       $this->assertEqual(count($routes), 1, 'The correct number of routes was found.');
       $this->assertNotNull($routes->get('poink'), 'The first matching route was found.');
-    }
-    catch (ResourceNotFoundException $e) {
+    } catch (ResourceNotFoundException $e) {
       $this->fail('No matching route found with default argument value.');
     }
   }
@@ -328,12 +330,14 @@ function testOutlinePathMatchDefaultsCollision2() {
       $routes_array = $routes->all();
 
       $this->assertEqual(count($routes), 2, 'The correct number of routes was found.');
-      $this->assertEqual(array('narf', 'poink'), array_keys($routes_array), 'Ensure the fitness was taken into account.');
+      $this->assertEqual(array(
+        'narf',
+        'poink'
+      ), array_keys($routes_array), 'Ensure the fitness was taken into account.');
       $this->assertNotNull($routes->get('narf'), 'The first matching route was found.');
       $this->assertNotNull($routes->get('poink'), 'The second matching route was found.');
       $this->assertNull($routes->get('eep'), 'Non-matching route was not found.');
-    }
-    catch (ResourceNotFoundException $e) {
+    } catch (ResourceNotFoundException $e) {
       $this->fail('No matching route found with default argument value.');
     }
   }
@@ -367,12 +371,14 @@ function testOutlinePathMatchDefaultsCollision3() {
       $routes_array = $routes->all();
 
       $this->assertEqual(count($routes), 2, 'The correct number of routes was found.');
-      $this->assertEqual(array('poink', 'poink2'), array_keys($routes_array), 'Ensure the fitness and name were taken into account in the sort.');
+      $this->assertEqual(array(
+        'poink',
+        'poink2'
+      ), array_keys($routes_array), 'Ensure the fitness and name were taken into account in the sort.');
       $this->assertNotNull($routes->get('poink'), 'The first matching route was found.');
       $this->assertNotNull($routes->get('poink2'), 'The second matching route was found.');
       $this->assertNull($routes->get('eep'), 'Non-matching route was not found.');
-    }
-    catch (ResourceNotFoundException $e) {
+    } catch (ResourceNotFoundException $e) {
       $this->fail('No matching route found with default argument value.');
     }
   }
@@ -402,12 +408,12 @@ public function testOutlinePathMatchZero() {
 
       // All of the matching paths have the correct pattern.
       foreach ($routes as $route) {
-        $this->assertEqual($route->compile()->getPatternOutline(), '/some/path/%', 'Found path has correct pattern');
+        $this->assertEqual($route->compile()
+          ->getPatternOutline(), '/some/path/%', 'Found path has correct pattern');
       }
 
       $this->assertEqual(count($routes), 1, 'The correct number of routes was found.');
-    }
-    catch (ResourceNotFoundException $e) {
+    } catch (ResourceNotFoundException $e) {
       $this->fail('No matchout route found with 0 as argument value');
     }
   }
@@ -522,13 +528,16 @@ public function testRouteByName() {
     $exception_thrown = FALSE;
     try {
       $provider->getRouteByName('invalid_name');
-    }
-    catch (RouteNotFoundException $e) {
+    } catch (RouteNotFoundException $e) {
       $exception_thrown = TRUE;
     }
     $this->assertTrue($exception_thrown, 'Random route was not found.');
 
-    $routes = $provider->getRoutesByNames(array('route_c', 'route_d', $this->randomMachineName()));
+    $routes = $provider->getRoutesByNames(array(
+      'route_c',
+      'route_d',
+      $this->randomMachineName()
+    ));
     $this->assertEqual(count($routes), 2, 'Only two valid routes found.');
     $this->assertEqual($routes['route_c']->getPath(), '/path/two');
     $this->assertEqual($routes['route_d']->getPath(), '/path/three');
diff --git a/core/modules/system/src/Tests/Routing/UrlIntegrationTest.php b/core/modules/system/tests/src/Kernel/Routing/UrlIntegrationTest.php
similarity index 91%
rename from core/modules/system/src/Tests/Routing/UrlIntegrationTest.php
rename to core/modules/system/tests/src/Kernel/Routing/UrlIntegrationTest.php
index 1d3f934..83b805e 100644
--- a/core/modules/system/src/Tests/Routing/UrlIntegrationTest.php
+++ b/core/modules/system/tests/src/Kernel/Routing/UrlIntegrationTest.php
@@ -2,13 +2,13 @@
 
 /**
  * @file
- * Contains \Drupal\system\Tests\Routing\UrlIntegrationTest.
+ * Contains \Drupal\Tests\system\Kernel\Routing\UrlIntegrationTest.
  */
 
-namespace Drupal\system\Tests\Routing;
+namespace Drupal\Tests\system\Kernel\Routing;
 
 use Drupal\Core\Url;
-use Drupal\simpletest\KernelTestBase;
+use Drupal\KernelTests\KernelTestBase;
 use Drupal\user\Entity\Role;
 use Drupal\user\Entity\User;
 
diff --git a/core/modules/system/src/Tests/ServiceProvider/ServiceProviderTest.php b/core/modules/system/tests/src/Kernel/ServiceProvider/ServiceProviderTest.php
similarity index 89%
rename from core/modules/system/src/Tests/ServiceProvider/ServiceProviderTest.php
rename to core/modules/system/tests/src/Kernel/ServiceProvider/ServiceProviderTest.php
index ef2fb79..863b9c2 100644
--- a/core/modules/system/src/Tests/ServiceProvider/ServiceProviderTest.php
+++ b/core/modules/system/tests/src/Kernel/ServiceProvider/ServiceProviderTest.php
@@ -2,12 +2,12 @@
 
 /**
  * @file
- * Contains \Drupal\system\Tests\ServiceProvider\ServiceProviderTest.
+ * Contains \Drupal\Tests\system\Kernel\ServiceProvider\ServiceProviderTest.
  */
 
-namespace Drupal\system\Tests\ServiceProvider;
+namespace Drupal\Tests\system\Kernel\ServiceProvider;
 
-use Drupal\simpletest\KernelTestBase;
+use Drupal\KernelTests\KernelTestBase;
 
 /**
  * Tests service provider registration to the DIC.
@@ -21,7 +21,7 @@ class ServiceProviderTest extends KernelTestBase {
    *
    * @var array
    */
-  public static $modules = array('file', 'service_provider_test');
+  public static $modules = array('file', 'service_provider_test', 'system');
 
   /**
    * Tests that services provided by module service providers get registered to the DIC.
diff --git a/core/modules/system/src/Tests/Routing/MatcherDumperTest.php b/core/tests/Drupal/KernelTests/Core/Routing/MatcherDumperTest.php
similarity index 97%
rename from core/modules/system/src/Tests/Routing/MatcherDumperTest.php
rename to core/tests/Drupal/KernelTests/Core/Routing/MatcherDumperTest.php
index f98d294..bfc042d 100644
--- a/core/modules/system/src/Tests/Routing/MatcherDumperTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Routing/MatcherDumperTest.php
@@ -2,14 +2,14 @@
 
 /**
  * @file
- * Contains \Drupal\system\Tests\Routing\MatcherDumperTest.
+ * Contains \Drupal\KernelTests\Core\Routing\MatcherDumperTest.
  */
 
-namespace Drupal\system\Tests\Routing;
+namespace Drupal\KernelTests\Core\Routing;
 
 use Drupal\Core\KeyValueStore\KeyValueMemoryFactory;
 use Drupal\Core\State\State;
-use Drupal\simpletest\KernelTestBase;
+use Drupal\KernelTests\KernelTestBase;
 use Symfony\Component\Routing\Route;
 use Symfony\Component\Routing\RouteCollection;
 use Drupal\Core\Database\Database;
diff --git a/core/modules/system/src/Tests/Session/AccountSwitcherTest.php b/core/tests/Drupal/KernelTests/Core/Session/AccountSwitcherTest.php
similarity index 94%
rename from core/modules/system/src/Tests/Session/AccountSwitcherTest.php
rename to core/tests/Drupal/KernelTests/Core/Session/AccountSwitcherTest.php
index edbf6b2..db6997a 100644
--- a/core/modules/system/src/Tests/Session/AccountSwitcherTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Session/AccountSwitcherTest.php
@@ -2,13 +2,13 @@
 
 /**
  * @file
- * Contains \Drupal\system\Tests\Session\AccountSwitcherTest.
+ * Contains \Drupal\KernelTests\Core\Session\AccountSwitcherTest.
  */
 
-namespace Drupal\system\Tests\Session;
+namespace Drupal\KernelTests\Core\Session;
 
 use Drupal\Core\Session\UserSession;
-use Drupal\simpletest\KernelTestBase;
+use Drupal\KernelTests\KernelTestBase;
 
 /**
  * Test case for account switching.