diff --git a/core/modules/config_translation/src/Tests/ConfigTranslationFormTest.php b/core/modules/config_translation/tests/src/Functional/ConfigTranslationFormTest.php
similarity index 92%
rename from core/modules/config_translation/src/Tests/ConfigTranslationFormTest.php
rename to core/modules/config_translation/tests/src/Functional/ConfigTranslationFormTest.php
index 387d686460..4698b05a8e 100644
--- a/core/modules/config_translation/src/Tests/ConfigTranslationFormTest.php
+++ b/core/modules/config_translation/tests/src/Functional/ConfigTranslationFormTest.php
@@ -1,16 +1,16 @@
 <?php
 
-namespace Drupal\config_translation\Tests;
+namespace Drupal\Tests\config_translation\Functional;
 
 use Drupal\language\Entity\ConfigurableLanguage;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests for altering configuration translation forms.
  *
  * @group config_translation
  */
-class ConfigTranslationFormTest extends WebTestBase {
+class ConfigTranslationFormTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
diff --git a/core/modules/config_translation/src/Tests/ConfigTranslationInstallTest.php b/core/modules/config_translation/tests/src/Functional/ConfigTranslationInstallTest.php
similarity index 97%
rename from core/modules/config_translation/src/Tests/ConfigTranslationInstallTest.php
rename to core/modules/config_translation/tests/src/Functional/ConfigTranslationInstallTest.php
index 2c8aabcab4..633d100414 100644
--- a/core/modules/config_translation/src/Tests/ConfigTranslationInstallTest.php
+++ b/core/modules/config_translation/tests/src/Functional/ConfigTranslationInstallTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\config_translation\Tests;
+namespace Drupal\Tests\config_translation\Functional;
 
 use Drupal\simpletest\InstallerTestBase;
 
diff --git a/core/modules/config_translation/src/Tests/ConfigTranslationOverviewTest.php b/core/modules/config_translation/tests/src/Functional/ConfigTranslationOverviewTest.php
similarity index 89%
rename from core/modules/config_translation/src/Tests/ConfigTranslationOverviewTest.php
rename to core/modules/config_translation/tests/src/Functional/ConfigTranslationOverviewTest.php
index d593a69d38..c8d9d8e401 100644
--- a/core/modules/config_translation/src/Tests/ConfigTranslationOverviewTest.php
+++ b/core/modules/config_translation/tests/src/Functional/ConfigTranslationOverviewTest.php
@@ -1,17 +1,17 @@
 <?php
 
-namespace Drupal\config_translation\Tests;
+namespace Drupal\Tests\config_translation\Functional;
 
 use Drupal\Component\Utility\Html;
 use Drupal\language\Entity\ConfigurableLanguage;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Translate settings and entities to various languages.
  *
  * @group config_translation
  */
-class ConfigTranslationOverviewTest extends WebTestBase {
+class ConfigTranslationOverviewTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
@@ -77,9 +77,9 @@ public function testMapperListPage() {
     // Make sure there is only a single operation for each dropbutton, either
     // 'List' or 'Translate'.
     foreach ($this->cssSelect('ul.dropbutton') as $i => $dropbutton) {
-      $this->assertIdentical(1, $dropbutton->count());
-      foreach ($dropbutton->li as $link) {
-        $this->assertTrue(((string) $link->a === 'Translate') || ((string) $link->a === 'List'));
+      $this->assertIdentical(1, count($dropbutton->findAll('xpath', '/*')));
+      foreach ($dropbutton->findAll('xpath', '/li/a') as $link) {
+        $this->assertTrue(($link->getText() === 'Translate') || ($link->getText() === 'List'));
       }
     }
 
@@ -104,9 +104,9 @@ public function testMapperListPage() {
       // Make sure there is only a single 'Translate' operation for each
       // dropbutton.
       foreach ($this->cssSelect('ul.dropbutton') as $i => $dropbutton) {
-        $this->assertIdentical(1, $dropbutton->count());
-        foreach ($dropbutton->li as $link) {
-          $this->assertIdentical('Translate', (string) $link->a);
+        $this->assertIdentical(1, count($dropbutton->findAll('xpath', '/*')));
+        foreach ($dropbutton->findAll('xpath', '/li/a') as $link) {
+          $this->assertIdentical('Translate', $link->getText());
         }
       }
 
diff --git a/core/modules/config_translation/src/Tests/ConfigTranslationUiTest.php b/core/modules/config_translation/tests/src/Functional/ConfigTranslationUiTest.php
similarity index 99%
rename from core/modules/config_translation/src/Tests/ConfigTranslationUiTest.php
rename to core/modules/config_translation/tests/src/Functional/ConfigTranslationUiTest.php
index 0a867e57d9..dc8c8a749a 100644
--- a/core/modules/config_translation/src/Tests/ConfigTranslationUiTest.php
+++ b/core/modules/config_translation/tests/src/Functional/ConfigTranslationUiTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\config_translation\Tests;
+namespace Drupal\Tests\config_translation\Functional;
 
 use Drupal\Component\Serialization\Json;
 use Drupal\Component\Utility\Html;
@@ -8,19 +8,24 @@
 use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Language\Language;
 use Drupal\Core\Language\LanguageInterface;
+use Drupal\Core\Test\AssertMailTrait;
 use Drupal\field\Entity\FieldConfig;
 use Drupal\field\Entity\FieldStorageConfig;
 use Drupal\filter\Entity\FilterFormat;
 use Drupal\language\Entity\ConfigurableLanguage;
 use Drupal\node\Entity\NodeType;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Translate settings and entities to various languages.
  *
  * @group config_translation
  */
-class ConfigTranslationUiTest extends WebTestBase {
+class ConfigTranslationUiTest extends BrowserTestBase {
+
+  use AssertMailTrait {
+    getMails as drupalGetMails;
+  }
 
   /**
    * Modules to enable.
@@ -198,7 +203,7 @@ public function testSiteInformationTranslationUi() {
     $this->drupalPostForm('admin/config/regional/translate', $search, t('Filter'));
 
     $textarea = current($this->xpath('//textarea'));
-    $lid = (string) $textarea[0]['name'];
+    $lid = (string) $textarea->getAttribute('name');
     $edit = [
       $lid => $fr_site_name_label,
     ];
diff --git a/core/modules/config_translation/src/Tests/ConfigTranslationUiThemeTest.php b/core/modules/config_translation/tests/src/Functional/ConfigTranslationUiThemeTest.php
similarity index 86%
rename from core/modules/config_translation/src/Tests/ConfigTranslationUiThemeTest.php
rename to core/modules/config_translation/tests/src/Functional/ConfigTranslationUiThemeTest.php
index 53713a9238..dcfb7916fe 100644
--- a/core/modules/config_translation/src/Tests/ConfigTranslationUiThemeTest.php
+++ b/core/modules/config_translation/tests/src/Functional/ConfigTranslationUiThemeTest.php
@@ -1,16 +1,16 @@
 <?php
 
-namespace Drupal\config_translation\Tests;
+namespace Drupal\Tests\config_translation\Functional;
 
 use Drupal\language\Entity\ConfigurableLanguage;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Verifies theme configuration translation settings.
  *
  * @group config_translation
  */
-class ConfigTranslationUiThemeTest extends WebTestBase {
+class ConfigTranslationUiThemeTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
@@ -65,7 +65,7 @@ public function testThemeDiscovery() {
       ':label' => 'Install and set as default',
       ':theme' => $theme,
     ]);
-    $this->drupalGet($GLOBALS['base_root'] . $elements[0]['href'], ['external' => TRUE]);
+    $this->drupalGet($GLOBALS['base_root'] . $elements[0]->getAttribute('href'), ['external' => TRUE]);
 
     $translation_base_url = 'admin/config/development/performance/translate';
     $this->drupalGet($translation_base_url);