diff --git a/core/modules/menu_ui/src/Tests/MenuLanguageTest.php b/core/modules/menu_ui/tests/src/Functional/MenuLanguageTest.php
similarity index 99%
rename from core/modules/menu_ui/src/Tests/MenuLanguageTest.php
rename to core/modules/menu_ui/tests/src/Functional/MenuLanguageTest.php
index 4c48f05da7..efdf3a988d 100644
--- a/core/modules/menu_ui/src/Tests/MenuLanguageTest.php
+++ b/core/modules/menu_ui/tests/src/Functional/MenuLanguageTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\menu_ui\Tests;
+namespace Drupal\Tests\menu_ui\Functional;
 
 use Drupal\Component\Utility\Unicode;
 use Drupal\language\Entity\ConfigurableLanguage;
diff --git a/core/modules/menu_ui/src/Tests/MenuNodeTest.php b/core/modules/menu_ui/tests/src/Functional/MenuNodeTest.php
similarity index 98%
rename from core/modules/menu_ui/src/Tests/MenuNodeTest.php
rename to core/modules/menu_ui/tests/src/Functional/MenuNodeTest.php
index 3f1bba06ee..87b39ad8ca 100644
--- a/core/modules/menu_ui/src/Tests/MenuNodeTest.php
+++ b/core/modules/menu_ui/tests/src/Functional/MenuNodeTest.php
@@ -1,18 +1,18 @@
 <?php
 
-namespace Drupal\menu_ui\Tests;
+namespace Drupal\Tests\menu_ui\Functional;
 
-use Drupal\simpletest\WebTestBase;
 use Drupal\language\Entity\ConfigurableLanguage;
 use Drupal\menu_link_content\Entity\MenuLinkContent;
 use Drupal\node\Entity\Node;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Add, edit, and delete a node with menu link.
  *
  * @group menu_ui
  */
-class MenuNodeTest extends WebTestBase {
+class MenuNodeTest extends BrowserTestBase {
 
   /**
    * An editor user.
@@ -60,7 +60,7 @@ public function testMenuNodeFormWidget() {
     // item" options in menu_ui_form_node_type_form_alter(). The "log out" link
     // adds the "user.roles:authenticated" cache context.
     $this->drupalGet('admin/structure/types/manage/page');
-    $this->assertCacheContext('user.roles:authenticated');
+    $this->assertSession()->responseHeaderContains('X-Drupal-Cache-Contexts', 'user.roles:authenticated');
 
     // Verify that the menu link title has the correct maxlength.
     $max_length = \Drupal::entityManager()->getBaseFieldDefinitions('menu_link_content')['title']->getSetting('max_length');
diff --git a/core/modules/menu_ui/src/Tests/MenuTest.php b/core/modules/menu_ui/tests/src/Functional/MenuTest.php
similarity index 97%
rename from core/modules/menu_ui/src/Tests/MenuTest.php
rename to core/modules/menu_ui/tests/src/Functional/MenuTest.php
index dde95027bd..c40e4710d2 100644
--- a/core/modules/menu_ui/src/Tests/MenuTest.php
+++ b/core/modules/menu_ui/tests/src/Functional/MenuTest.php
@@ -1,10 +1,11 @@
 <?php
 
-namespace Drupal\menu_ui\Tests;
+namespace Drupal\Tests\menu_ui\Functional;
 
 use Drupal\block\Entity\Block;
 use Drupal\Component\Serialization\Json;
 use Drupal\Component\Utility\Unicode;
+use Drupal\Core\EventSubscriber\MainContentViewSubscriber;
 use Drupal\Core\Menu\MenuLinkInterface;
 use Drupal\Core\Url;
 use Drupal\menu_link_content\Entity\MenuLinkContent;
@@ -216,7 +217,7 @@ public function addCustomMenu() {
 
     // Confirm that the custom menu block is available.
     $this->drupalGet('admin/structure/block/list/' . $this->config('system.theme')->get('default'));
-    $this->clickLinkPartialName('Place block');
+    $this->clickLink('Place block');
     $this->assertText($label);
 
     // Enable the block.
@@ -531,7 +532,7 @@ public function testSystemMenuRename() {
     // Make sure menu shows up with new name in block addition.
     $default_theme = $this->config('system.theme')->get('default');
     $this->drupalget('admin/structure/block/list/' . $default_theme);
-    $this->clickLinkPartialName('Place block');
+    $this->clickLink('Place block');
     $this->assertText($edit['label']);
   }
 
@@ -557,7 +558,7 @@ public function testUnpublishedNodeMenuItem() {
     $this->assertNoText($item->getTitle(), "Menu link pointing to unpublished node is only visible to users with 'bypass node access' permission");
     // The cache contexts associated with the (in)accessible menu links are
     // bubbled. See DefaultMenuLinkTreeManipulators::menuLinkCheckAccess().
-    $this->assertCacheContext('user.permissions');
+    $this->assertSession()->responseHeaderContains('X-Drupal-Cache-Contexts', 'user.permissions');
   }
 
   /**
@@ -577,9 +578,16 @@ public function testBlockContextualLinks() {
     // Get server-rendered contextual links.
     // @see \Drupal\contextual\Tests\ContextualDynamicContextTest:renderContextualLinks()
     $post = ['ids[0]' => $id];
-    $response = $this->drupalPost('contextual/render', 'application/json', $post, ['query' => ['destination' => 'test-page']]);
-    $this->assertResponse(200);
-    $json = Json::decode($response);
+    $client = \Drupal::httpClient();
+    $url = $this->buildUrl('contextual/render', ['query' => ['destination' => 'test-page']]);
+    $response = $client->post($url, [
+      'form_params' => $post,
+      'headers' => [
+        'Accept' => 'application/json',
+      ],
+    ]);
+    $this->assertEquals(200, $response->getStatusCode());
+    $json = Json::decode((string) $response);
     $this->assertIdentical($json[$id], '<ul class="contextual-links"><li class="block-configure"><a href="' . base_path() . 'admin/structure/block/manage/' . $block->id() . '">Configure block</a></li><li class="entitymenuedit-form"><a href="' . base_path() . 'admin/structure/menu/manage/' . $custom_menu->id() . '">Edit menu</a></li></ul>');
   }
 
@@ -867,13 +875,13 @@ public function testMenuParentsJsAccess() {
     $admin = $this->drupalCreateUser(['administer menu']);
     $this->drupalLogin($admin);
     // Just check access to the callback overall, the POST data is irrelevant.
-    $this->drupalGetAjax('admin/structure/menu/parents');
+    $this->drupalGet('admin/structure/menu/parents', ['query' => [MainContentViewSubscriber::WRAPPER_FORMAT => 'drupal_ajax']], ['X-Requested-With: XMLHttpRequest']);
     $this->assertResponse(200);
 
     // Do standard user tests.
     // Log in the user.
     $this->drupalLogin($this->authenticatedUser);
-    $this->drupalGetAjax('admin/structure/menu/parents');
+    $this->drupalGet('admin/structure/menu/parents', ['query' => [MainContentViewSubscriber::WRAPPER_FORMAT => 'drupal_ajax']], ['X-Requested-With: XMLHttpRequest']);
     $this->assertResponse(403);
   }
 
diff --git a/core/modules/menu_ui/src/Tests/MenuWebTestBase.php b/core/modules/menu_ui/tests/src/Functional/MenuWebTestBase.php
similarity index 94%
rename from core/modules/menu_ui/src/Tests/MenuWebTestBase.php
rename to core/modules/menu_ui/tests/src/Functional/MenuWebTestBase.php
index e0ee98fbf0..b8dfb242d4 100644
--- a/core/modules/menu_ui/src/Tests/MenuWebTestBase.php
+++ b/core/modules/menu_ui/tests/src/Functional/MenuWebTestBase.php
@@ -1,13 +1,13 @@
 <?php
 
-namespace Drupal\menu_ui\Tests;
+namespace Drupal\Tests\menu_ui\Functional;
 
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Base class for menu web tests.
  */
-abstract class MenuWebTestBase extends WebTestBase {
+abstract class MenuWebTestBase extends BrowserTestBase {
 
   /**
    * Modules to enable.