diff --git a/core/modules/system/src/Tests/Routing/RouteNormalizerTest.php b/core/tests/Drupal/FunctionalTests/Routing/RouteNormalizerTest.php
similarity index 63%
rename from core/modules/system/src/Tests/Routing/RouteNormalizerTest.php
rename to core/tests/Drupal/FunctionalTests/Routing/RouteNormalizerTest.php
index 2f70d72..f97619c 100644
--- a/core/modules/system/src/Tests/Routing/RouteNormalizerTest.php
+++ b/core/tests/Drupal/FunctionalTests/Routing/RouteNormalizerTest.php
@@ -5,12 +5,12 @@
  * Contains \Drupal\system\Tests\Routing\RouteNormalizerTest.
  */
 
-namespace Drupal\system\Tests\Routing;
+namespace Drupal\FunctionalTests\Routing;
 
 use Drupal\Component\Utility\UrlHelper;
 use Drupal\Core\Url;
 use Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationUrl;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests the route normalizer functionality.
@@ -19,7 +19,7 @@
  *
  * @see \Drupal\Core\EventSubscriber\RouteNormalizerRequestSubscriber
  */
-class RouteNormalizerTest extends WebTestBase {
+class RouteNormalizerTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
@@ -37,50 +37,55 @@ public function testRedirects() {
 
     // Test front page redirect.
     $front_page_path = '/user/login';
-    $this->config('system.site')->set('page.front', $front_page_path)->save();
+    \Drupal::configFactory()
+      ->getEditable('system.site')
+      ->set('page.front', $front_page_path)
+      ->save();
     $this->drupalGet(Url::fromUri('base:' . $front_page_path));
-    $this->assertNotEqual($this->redirectCount, 0);
-    $this->assertUrl(Url::fromRoute('<front>'));
+    $this->assertSame(Url::fromRoute('<front>')->setAbsolute()->toString(), $this->getSession()->getCurrentUrl());
 
     // Test path alias redirect.
     $this->drupalLogin($this->drupalCreateUser([
       'administer url aliases',
     ]));
+    $this->drupalGet(Url::fromRoute('path.admin_add'));
     $edit = [
       'source' => '/user/password',
       'alias' => '/my-cool/password/recovery/page',
     ];
-    $this->drupalPostForm('admin/config/search/path/add', $edit, t('Save'));
+    $this->submitForm($edit, t('Save'));
     $this->drupalGet(Url::fromUri('base:' . $edit['source']));
-    $this->assertNotEqual($this->redirectCount, 0);
-    $this->assertUrl(Url::fromUri('base:' . $edit['alias']));
+    $this->assertSame(Url::fromUri('base:' . $edit['alias'])->setAbsolute()->toString(), $this->getSession()->getCurrentUrl());
 
     // Test language redirect.
     $this->drupalLogin($this->drupalCreateUser([
       'administer languages',
     ]));
     // We need more than one language to make the redirect work.
+    $this->drupalGet(Url::fromRoute('language.add'));
     $edit = [
       'predefined_langcode' => 'fr',
     ];
-    $this->drupalPostForm('admin/config/regional/language/add', $edit, t('Add language'));
+    $this->submitForm($edit, t('Add language'));
+    $this->drupalGet(Url::fromRoute('language.negotiation'));
     $edit = [
       'language_interface[enabled][language-url]' => 1,
     ];
-    $this->drupalPostForm('admin/config/regional/language/detection', $edit, t('Save settings'));
+    $this->submitForm($edit, t('Save settings'));
+    $this->drupalGet(Url::fromRoute('language.negotiation_url'));
     $edit = [
       'language_negotiation_url_part' => LanguageNegotiationUrl::CONFIG_PATH_PREFIX,
       'prefix[en]' => 'en',
       'prefix[fr]' => 'fr',
     ];
-    $this->drupalPostForm('admin/config/regional/language/detection/url', $edit, t('Save configuration'));
+    $this->submitForm($edit, t('Save configuration'));
     $this->rebuildContainer();
     $url = Url::fromUri('base:/admin/config/regional/language')->setAbsolute()->toString();
     $prefix_count = substr_count($url, '/en/');
     $this->drupalGet($url);
-    $this->assertNotEqual($this->redirectCount, 0);
-    $this->assertTrue(substr_count($this->url, '/en/') == $prefix_count + 1, 'The default language path prefix was added to the final URL.');
-    $this->assertTrue(strpos($this->url, '/admin/config/regional/language') !== FALSE, 'Path preserved.');
+    $current_url = $this->getSession()->getCurrentUrl();
+    $this->assertSame($prefix_count + 1, substr_count($current_url, '/en/'), 'The path prefix of the default language was added to the final URL.');
+    $this->assertContains('/admin/config/regional/language', $current_url, 'Path preserved.');
 
     // Test a redirect having special characters in source/destination paths.
     /** @var \Drupal\Core\Menu\MenuLinkManagerInterface $menu_link_manager */
@@ -91,14 +96,14 @@ public function testRedirects() {
     $this->drupalLogin($this->drupalCreateUser([
       'administer url aliases',
     ]));
+    $this->drupalGet(Url::fromRoute('path.admin_add'));
     $edit = [
       'source' => '/' . $exotic_path,
       'alias' => '/' . $exotic_path . rawurlencode(rawurlencode('#%&+/?')),
     ];
-    $this->drupalPostForm('admin/config/search/path/add', $edit, t('Save'));
+    $this->submitForm($edit, t('Save'));
     $this->drupalGet($exotic_path, ['alias' => TRUE]);
-    $this->assertNotEqual($this->redirectCount, 0);
-    $this->assertTrue(strpos($this->url, UrlHelper::encodePath($edit['alias'])) !== FALSE, 'Redirected to the alias.');
+    $this->assertContains(UrlHelper::encodePath($edit['alias']), $this->getSession()->getCurrentUrl(), 'Redirected to the alias.');
   }
 
 }