diff --git a/core/modules/language/src/Tests/EntityTypeWithoutLanguageFormTest.php b/core/modules/language/tests/src/Functional/EntityTypeWithoutLanguageFormTest.php
similarity index 87%
rename from core/modules/language/src/Tests/EntityTypeWithoutLanguageFormTest.php
rename to core/modules/language/tests/src/Functional/EntityTypeWithoutLanguageFormTest.php
index 20a3532..14d5473 100644
--- a/core/modules/language/src/Tests/EntityTypeWithoutLanguageFormTest.php
+++ b/core/modules/language/tests/src/Functional/EntityTypeWithoutLanguageFormTest.php
@@ -1,8 +1,8 @@
 <?php
 
-namespace Drupal\language\Tests;
+namespace Drupal\Tests\language\Functional;
 
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests entity type without language support.
@@ -12,7 +12,7 @@
  *
  * @group language
  */
-class EntityTypeWithoutLanguageFormTest extends WebTestBase {
+class EntityTypeWithoutLanguageFormTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
diff --git a/core/modules/language/src/Tests/LanguageConfigurationElementTest.php b/core/modules/language/tests/src/Functional/LanguageConfigurationElementTest.php
similarity index 98%
rename from core/modules/language/src/Tests/LanguageConfigurationElementTest.php
rename to core/modules/language/tests/src/Functional/LanguageConfigurationElementTest.php
index 93b821d..092de14 100644
--- a/core/modules/language/src/Tests/LanguageConfigurationElementTest.php
+++ b/core/modules/language/tests/src/Functional/LanguageConfigurationElementTest.php
@@ -1,19 +1,19 @@
 <?php
 
-namespace Drupal\language\Tests;
+namespace Drupal\Tests\language\Functional;
 
 use Drupal\Core\Language\LanguageInterface;
 use Drupal\language\Entity\ConfigurableLanguage;
 use Drupal\language\Entity\ContentLanguageSettings;
-use Drupal\simpletest\WebTestBase;
 use Drupal\taxonomy\Entity\Vocabulary;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests the features of the language configuration element field.
  *
  * @group language
  */
-class LanguageConfigurationElementTest extends WebTestBase {
+class LanguageConfigurationElementTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
diff --git a/core/modules/language/src/Tests/LanguageConfigurationTest.php b/core/modules/language/tests/src/Functional/LanguageConfigurationTest.php
similarity index 98%
rename from core/modules/language/src/Tests/LanguageConfigurationTest.php
rename to core/modules/language/tests/src/Functional/LanguageConfigurationTest.php
index cf049f1..97592d2 100644
--- a/core/modules/language/src/Tests/LanguageConfigurationTest.php
+++ b/core/modules/language/tests/src/Functional/LanguageConfigurationTest.php
@@ -1,17 +1,17 @@
 <?php
 
-namespace Drupal\language\Tests;
+namespace Drupal\Tests\language\Functional;
 
 use Drupal\Core\Language\LanguageInterface;
 use Drupal\language\Entity\ConfigurableLanguage;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Adds and configures languages to check negotiation changes.
  *
  * @group language
  */
-class LanguageConfigurationTest extends WebTestBase {
+class LanguageConfigurationTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
diff --git a/core/modules/language/src/Tests/LanguageCustomLanguageConfigurationTest.php b/core/modules/language/tests/src/Functional/LanguageCustomLanguageConfigurationTest.php
similarity index 96%
rename from core/modules/language/src/Tests/LanguageCustomLanguageConfigurationTest.php
rename to core/modules/language/tests/src/Functional/LanguageCustomLanguageConfigurationTest.php
index dbd35cd..f9edc93 100644
--- a/core/modules/language/src/Tests/LanguageCustomLanguageConfigurationTest.php
+++ b/core/modules/language/tests/src/Functional/LanguageCustomLanguageConfigurationTest.php
@@ -1,17 +1,17 @@
 <?php
 
-namespace Drupal\language\Tests;
+namespace Drupal\Tests\language\Functional;
 
-use Drupal\simpletest\WebTestBase;
 use Drupal\Core\Language\Language;
 use Drupal\Core\Language\LanguageInterface;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Adds and configures custom languages.
  *
  * @group language
  */
-class LanguageCustomLanguageConfigurationTest extends WebTestBase {
+class LanguageCustomLanguageConfigurationTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
diff --git a/core/modules/language/src/Tests/LanguageListTest.php b/core/modules/language/tests/src/Functional/LanguageListTest.php
similarity index 98%
rename from core/modules/language/src/Tests/LanguageListTest.php
rename to core/modules/language/tests/src/Functional/LanguageListTest.php
index d407530..ccb036a 100644
--- a/core/modules/language/src/Tests/LanguageListTest.php
+++ b/core/modules/language/tests/src/Functional/LanguageListTest.php
@@ -1,18 +1,18 @@
 <?php
 
-namespace Drupal\language\Tests;
+namespace Drupal\Tests\language\Functional;
 
 use Drupal\language\Entity\ConfigurableLanguage;
-use Drupal\simpletest\WebTestBase;
 use Drupal\Core\Language\Language;
 use Drupal\Core\Language\LanguageInterface;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Adds a new language and tests changing its status and the default language.
  *
  * @group language
  */
-class LanguageListTest extends WebTestBase {
+class LanguageListTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
diff --git a/core/modules/language/src/Tests/LanguageLocaleListTest.php b/core/modules/language/tests/src/Functional/LanguageLocaleListTest.php
similarity index 93%
rename from core/modules/language/src/Tests/LanguageLocaleListTest.php
rename to core/modules/language/tests/src/Functional/LanguageLocaleListTest.php
index dd3e02a..6919c26 100644
--- a/core/modules/language/src/Tests/LanguageLocaleListTest.php
+++ b/core/modules/language/tests/src/Functional/LanguageLocaleListTest.php
@@ -1,15 +1,15 @@
 <?php
 
-namespace Drupal\language\Tests;
+namespace Drupal\Tests\language\Functional;
 
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Adds a new language with translations and tests language list order.
  *
  * @group language
  */
-class LanguageLocaleListTest extends WebTestBase {
+class LanguageLocaleListTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
diff --git a/core/modules/language/src/Tests/LanguageSelectorTranslatableTest.php b/core/modules/language/tests/src/Functional/LanguageSelectorTranslatableTest.php
similarity index 93%
rename from core/modules/language/src/Tests/LanguageSelectorTranslatableTest.php
rename to core/modules/language/tests/src/Functional/LanguageSelectorTranslatableTest.php
index 84d6779..dd8894e 100644
--- a/core/modules/language/src/Tests/LanguageSelectorTranslatableTest.php
+++ b/core/modules/language/tests/src/Functional/LanguageSelectorTranslatableTest.php
@@ -1,15 +1,15 @@
 <?php
 
-namespace Drupal\language\Tests;
+namespace Drupal\Tests\language\Functional;
 
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests the content translation settings language selector options.
  *
  * @group language
  */
-class LanguageSelectorTranslatableTest extends WebTestBase {
+class LanguageSelectorTranslatableTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
diff --git a/core/modules/language/src/Tests/LanguageSwitchingTest.php b/core/modules/language/tests/src/Functional/LanguageSwitchingTest.php
similarity index 99%
rename from core/modules/language/src/Tests/LanguageSwitchingTest.php
rename to core/modules/language/tests/src/Functional/LanguageSwitchingTest.php
index 5d4469d..6149893 100644
--- a/core/modules/language/src/Tests/LanguageSwitchingTest.php
+++ b/core/modules/language/tests/src/Functional/LanguageSwitchingTest.php
@@ -1,19 +1,19 @@
 <?php
 
-namespace Drupal\language\Tests;
+namespace Drupal\Tests\language\Functional;
 
 use Drupal\language\Entity\ConfigurableLanguage;
 use Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationUrl;
 use Drupal\menu_link_content\Entity\MenuLinkContent;
 use Drupal\Core\Language\LanguageInterface;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Functional tests for the language switching feature.
  *
  * @group language
  */
-class LanguageSwitchingTest extends WebTestBase {
+class LanguageSwitchingTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
diff --git a/core/modules/language/src/Tests/LanguageTourTest.php b/core/modules/language/tests/src/Functional/LanguageTourTest.php
similarity index 96%
rename from core/modules/language/src/Tests/LanguageTourTest.php
rename to core/modules/language/tests/src/Functional/LanguageTourTest.php
index 7778367..31c1ce2 100644
--- a/core/modules/language/src/Tests/LanguageTourTest.php
+++ b/core/modules/language/tests/src/Functional/LanguageTourTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\language\Tests;
+namespace Drupal\Tests\language\Functional;
 
 use Drupal\tour\Tests\TourTestBase;
 
diff --git a/core/modules/language/src/Tests/LanguageUILanguageNegotiationTest.php b/core/modules/language/tests/src/Functional/LanguageUILanguageNegotiationTest.php
similarity index 99%
rename from core/modules/language/src/Tests/LanguageUILanguageNegotiationTest.php
rename to core/modules/language/tests/src/Functional/LanguageUILanguageNegotiationTest.php
index 03dd8cb..d73dceb 100644
--- a/core/modules/language/src/Tests/LanguageUILanguageNegotiationTest.php
+++ b/core/modules/language/tests/src/Functional/LanguageUILanguageNegotiationTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\language\Tests;
+namespace Drupal\Tests\language\Functional;
 
 use Drupal\Core\Url;
 use Drupal\language\Entity\ConfigurableLanguage;
@@ -8,9 +8,9 @@
 use Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationSelected;
 use Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationSession;
 use Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationUrl;
+use Drupal\Tests\BrowserTestBase;
 use Drupal\user\Plugin\LanguageNegotiation\LanguageNegotiationUser;
 use Drupal\user\Plugin\LanguageNegotiation\LanguageNegotiationUserAdmin;
-use Drupal\simpletest\WebTestBase;
 use Drupal\Core\Language\Language;
 use Drupal\Core\Language\LanguageInterface;
 use Symfony\Component\HttpFoundation\Request;
@@ -37,7 +37,7 @@
  *
  * @group language
  */
-class LanguageUILanguageNegotiationTest extends WebTestBase {
+class LanguageUILanguageNegotiationTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
diff --git a/core/modules/language/src/Tests/LanguageUrlRewritingTest.php b/core/modules/language/tests/src/Functional/LanguageUrlRewritingTest.php
similarity index 97%
rename from core/modules/language/src/Tests/LanguageUrlRewritingTest.php
rename to core/modules/language/tests/src/Functional/LanguageUrlRewritingTest.php
index 5cd80dc..9cd6a60 100644
--- a/core/modules/language/src/Tests/LanguageUrlRewritingTest.php
+++ b/core/modules/language/tests/src/Functional/LanguageUrlRewritingTest.php
@@ -1,12 +1,12 @@
 <?php
 
-namespace Drupal\language\Tests;
+namespace Drupal\Tests\language\Functional;
 
 use Drupal\Core\Language\Language;
 use Drupal\Core\Language\LanguageInterface;
 use Drupal\Core\Url;
 use Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationUrl;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 use Symfony\Component\HttpFoundation\Request;
 
 /**
@@ -14,7 +14,7 @@
  *
  * @group language
  */
-class LanguageUrlRewritingTest extends WebTestBase {
+class LanguageUrlRewritingTest extends BrowserTestBase {
 
   /**
    * Modules to enable.