diff --git a/core/modules/config/src/Tests/CacheabilityMetadataConfigOverrideIntegrationTest.php b/core/modules/config/tests/src/Functional/CacheabilityMetadataConfigOverrideIntegrationTest.php
similarity index 94%
rename from core/modules/config/src/Tests/CacheabilityMetadataConfigOverrideIntegrationTest.php
rename to core/modules/config/tests/src/Functional/CacheabilityMetadataConfigOverrideIntegrationTest.php
index 3ef0754ea6..09aea507a5 100644
--- a/core/modules/config/src/Tests/CacheabilityMetadataConfigOverrideIntegrationTest.php
+++ b/core/modules/config/tests/src/Functional/CacheabilityMetadataConfigOverrideIntegrationTest.php
@@ -1,15 +1,15 @@
 <?php
 
-namespace Drupal\config\Tests;
+namespace Drupal\Tests\config\Functional;
 
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests if configuration overrides correctly affect cacheability metadata.
  *
  * @group config
  */
-class CacheabilityMetadataConfigOverrideIntegrationTest extends WebTestBase {
+class CacheabilityMetadataConfigOverrideIntegrationTest extends BrowserTestBase {
 
   /**
    * {@inheritdoc}
diff --git a/core/modules/config/src/Tests/ConfigEntityFormOverrideTest.php b/core/modules/config/tests/src/Functional/ConfigEntityFormOverrideTest.php
similarity index 94%
rename from core/modules/config/src/Tests/ConfigEntityFormOverrideTest.php
rename to core/modules/config/tests/src/Functional/ConfigEntityFormOverrideTest.php
index 41419b031e..0ba75ac108 100644
--- a/core/modules/config/src/Tests/ConfigEntityFormOverrideTest.php
+++ b/core/modules/config/tests/src/Functional/ConfigEntityFormOverrideTest.php
@@ -1,15 +1,15 @@
 <?php
 
-namespace Drupal\config\Tests;
+namespace Drupal\Tests\config\Functional;
 
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests that config overrides do not bleed through in entity forms and lists.
  *
  * @group config
  */
-class ConfigEntityFormOverrideTest extends WebTestBase {
+class ConfigEntityFormOverrideTest extends BrowserTestBase {
 
   /**
    * {@inheritdoc}
diff --git a/core/modules/config/src/Tests/ConfigEntityListTest.php b/core/modules/config/tests/src/Functional/ConfigEntityListTest.php
similarity index 98%
rename from core/modules/config/src/Tests/ConfigEntityListTest.php
rename to core/modules/config/tests/src/Functional/ConfigEntityListTest.php
index e9950ea424..90392b6329 100644
--- a/core/modules/config/src/Tests/ConfigEntityListTest.php
+++ b/core/modules/config/tests/src/Functional/ConfigEntityListTest.php
@@ -1,17 +1,17 @@
 <?php
 
-namespace Drupal\config\Tests;
+namespace Drupal\Tests\config\Functional;
 
-use Drupal\simpletest\WebTestBase;
 use Drupal\config_test\Entity\ConfigTest;
 use Drupal\Core\Entity\EntityStorageInterface;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests the listing of configuration entities.
  *
  * @group config
  */
-class ConfigEntityListTest extends WebTestBase {
+class ConfigEntityListTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
diff --git a/core/modules/config/src/Tests/ConfigEntityTest.php b/core/modules/config/tests/src/Functional/ConfigEntityTest.php
similarity index 99%
rename from core/modules/config/src/Tests/ConfigEntityTest.php
rename to core/modules/config/tests/src/Functional/ConfigEntityTest.php
index c0dc97bc7b..4d0cd3e06e 100644
--- a/core/modules/config/src/Tests/ConfigEntityTest.php
+++ b/core/modules/config/tests/src/Functional/ConfigEntityTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\config\Tests;
+namespace Drupal\Tests\config\Functional;
 
 use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Core\Entity\EntityMalformedException;
@@ -8,14 +8,14 @@
 use Drupal\Core\Config\Entity\ConfigEntityStorage;
 use Drupal\Core\Config\Entity\Exception\ConfigEntityIdLengthException;
 use Drupal\Core\Url;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests configuration entities.
  *
  * @group config
  */
-class ConfigEntityTest extends WebTestBase {
+class ConfigEntityTest extends BrowserTestBase {
 
   /**
    * The maximum length for the entity storage used in this test.
diff --git a/core/modules/config/src/Tests/ConfigExportImportUITest.php b/core/modules/config/tests/src/Functional/ConfigExportImportUITest.php
similarity index 99%
rename from core/modules/config/src/Tests/ConfigExportImportUITest.php
rename to core/modules/config/tests/src/Functional/ConfigExportImportUITest.php
index 9ba59a85ca..96a80a606f 100644
--- a/core/modules/config/src/Tests/ConfigExportImportUITest.php
+++ b/core/modules/config/tests/src/Functional/ConfigExportImportUITest.php
@@ -1,12 +1,12 @@
 <?php
 
-namespace Drupal\config\Tests;
+namespace Drupal\Tests\config\Functional;
 
 use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Archiver\ArchiveTar;
 use Drupal\field\Entity\FieldConfig;
 use Drupal\field\Entity\FieldStorageConfig;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests the user interface for importing/exporting configuration.
@@ -17,7 +17,7 @@
  *
  * @group config
  */
-class ConfigExportImportUITest extends WebTestBase {
+class ConfigExportImportUITest extends BrowserTestBase {
 
   /**
    * The contents of the config export tarball, held between test methods.
diff --git a/core/modules/config/src/Tests/ConfigExportUITest.php b/core/modules/config/tests/src/Functional/ConfigExportUITest.php
similarity index 96%
rename from core/modules/config/src/Tests/ConfigExportUITest.php
rename to core/modules/config/tests/src/Functional/ConfigExportUITest.php
index c9f53b36fd..d9bdbc42b2 100644
--- a/core/modules/config/src/Tests/ConfigExportUITest.php
+++ b/core/modules/config/tests/src/Functional/ConfigExportUITest.php
@@ -1,17 +1,17 @@
 <?php
 
-namespace Drupal\config\Tests;
+namespace Drupal\Tests\config\Functional;
 
 use Drupal\Core\Archiver\Tar;
 use Drupal\Core\Serialization\Yaml;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests the user interface for exporting configuration.
  *
  * @group config
  */
-class ConfigExportUITest extends WebTestBase {
+class ConfigExportUITest extends BrowserTestBase {
 
   /**
    * Modules to enable.
diff --git a/core/modules/config/src/Tests/ConfigFormOverrideTest.php b/core/modules/config/tests/src/Functional/ConfigFormOverrideTest.php
similarity index 91%
rename from core/modules/config/src/Tests/ConfigFormOverrideTest.php
rename to core/modules/config/tests/src/Functional/ConfigFormOverrideTest.php
index f721eeba74..f267561d2a 100644
--- a/core/modules/config/src/Tests/ConfigFormOverrideTest.php
+++ b/core/modules/config/tests/src/Functional/ConfigFormOverrideTest.php
@@ -1,8 +1,8 @@
 <?php
 
-namespace Drupal\config\Tests;
+namespace Drupal\Tests\config\Functional;
 
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests config overrides do not appear on forms that extend ConfigFormBase.
@@ -10,7 +10,7 @@
  * @group config
  * @see \Drupal\Core\Form\ConfigFormBase
  */
-class ConfigFormOverrideTest extends WebTestBase {
+class ConfigFormOverrideTest extends BrowserTestBase {
 
   /**
    * Tests that overrides do not affect forms.
diff --git a/core/modules/config/src/Tests/ConfigImportAllTest.php b/core/modules/config/tests/src/Functional/ConfigImportAllTest.php
similarity index 97%
rename from core/modules/config/src/Tests/ConfigImportAllTest.php
rename to core/modules/config/tests/src/Functional/ConfigImportAllTest.php
index 459be7a24f..0608681dd7 100644
--- a/core/modules/config/src/Tests/ConfigImportAllTest.php
+++ b/core/modules/config/tests/src/Functional/ConfigImportAllTest.php
@@ -1,12 +1,13 @@
 <?php
 
-namespace Drupal\config\Tests;
+namespace Drupal\Tests\config\Functional;
 
 use Drupal\Core\Config\StorageComparer;
 use Drupal\filter\Entity\FilterFormat;
-use Drupal\system\Tests\Module\ModuleTestBase;
 use Drupal\shortcut\Entity\Shortcut;
 use Drupal\taxonomy\Entity\Term;
+use Drupal\Tests\SchemaCheckTestTrait;
+use Drupal\Tests\system\Functional\Module\ModuleTestBase;
 
 /**
  * Tests the largest configuration import possible with all available modules.
diff --git a/core/modules/config/src/Tests/ConfigImportInstallProfileTest.php b/core/modules/config/tests/src/Functional/ConfigImportInstallProfileTest.php
similarity index 94%
rename from core/modules/config/src/Tests/ConfigImportInstallProfileTest.php
rename to core/modules/config/tests/src/Functional/ConfigImportInstallProfileTest.php
index eaece36db3..8b0787d6ee 100644
--- a/core/modules/config/src/Tests/ConfigImportInstallProfileTest.php
+++ b/core/modules/config/tests/src/Functional/ConfigImportInstallProfileTest.php
@@ -1,15 +1,15 @@
 <?php
 
-namespace Drupal\config\Tests;
+namespace Drupal\Tests\config\Functional;
 
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests the importing/exporting configuration based on the install profile.
  *
  * @group config
  */
-class ConfigImportInstallProfileTest extends WebTestBase {
+class ConfigImportInstallProfileTest extends BrowserTestBase {
 
   /**
    * The profile to install as a basis for testing.
diff --git a/core/modules/config/src/Tests/ConfigImportUITest.php b/core/modules/config/tests/src/Functional/ConfigImportUITest.php
similarity index 99%
rename from core/modules/config/src/Tests/ConfigImportUITest.php
rename to core/modules/config/tests/src/Functional/ConfigImportUITest.php
index 772dadadd2..4094af6290 100644
--- a/core/modules/config/src/Tests/ConfigImportUITest.php
+++ b/core/modules/config/tests/src/Functional/ConfigImportUITest.php
@@ -1,18 +1,18 @@
 <?php
 
-namespace Drupal\config\Tests;
+namespace Drupal\Tests\config\Functional;
 
 use Drupal\Component\Utility\Html;
 use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Core\Config\InstallStorage;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests the user interface for importing/exporting configuration.
  *
  * @group config
  */
-class ConfigImportUITest extends WebTestBase {
+class ConfigImportUITest extends BrowserTestBase {
 
   /**
    * Modules to install.
diff --git a/core/modules/config/src/Tests/ConfigImportUploadTest.php b/core/modules/config/tests/src/Functional/ConfigImportUploadTest.php
similarity index 92%
rename from core/modules/config/src/Tests/ConfigImportUploadTest.php
rename to core/modules/config/tests/src/Functional/ConfigImportUploadTest.php
index 5e2129513c..8271a049f5 100644
--- a/core/modules/config/src/Tests/ConfigImportUploadTest.php
+++ b/core/modules/config/tests/src/Functional/ConfigImportUploadTest.php
@@ -1,15 +1,15 @@
 <?php
 
-namespace Drupal\config\Tests;
+namespace Drupal\Tests\config\Functional;
 
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests importing configuration from an uploaded file.
  *
  * @group config
  */
-class ConfigImportUploadTest extends WebTestBase {
+class ConfigImportUploadTest extends BrowserTestBase {
 
   /**
    * A user with the 'import configuration' permission.
diff --git a/core/modules/config/src/Tests/ConfigInstallWebTest.php b/core/modules/config/tests/src/Functional/ConfigInstallWebTest.php
similarity index 98%
rename from core/modules/config/src/Tests/ConfigInstallWebTest.php
rename to core/modules/config/tests/src/Functional/ConfigInstallWebTest.php
index 63ecb5bb68..a28a5b4fd7 100644
--- a/core/modules/config/src/Tests/ConfigInstallWebTest.php
+++ b/core/modules/config/tests/src/Functional/ConfigInstallWebTest.php
@@ -1,11 +1,11 @@
 <?php
 
-namespace Drupal\config\Tests;
+namespace Drupal\Tests\config\Functional;
 
 use Drupal\Core\Config\PreExistingConfigException;
 use Drupal\Core\Config\StorageInterface;
 use Drupal\language\Entity\ConfigurableLanguage;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests installation and removal of configuration objects in install, disable
@@ -13,7 +13,7 @@
  *
  * @group config
  */
-class ConfigInstallWebTest extends WebTestBase {
+class ConfigInstallWebTest extends BrowserTestBase {
 
   /**
    * The admin user used in this test.
diff --git a/core/modules/config/src/Tests/ConfigSingleImportExportTest.php b/core/modules/config/tests/src/Functional/ConfigSingleImportExportTest.php
similarity index 98%
rename from core/modules/config/src/Tests/ConfigSingleImportExportTest.php
rename to core/modules/config/tests/src/Functional/ConfigSingleImportExportTest.php
index 16cff0aa8a..0619a60245 100644
--- a/core/modules/config/src/Tests/ConfigSingleImportExportTest.php
+++ b/core/modules/config/tests/src/Functional/ConfigSingleImportExportTest.php
@@ -1,16 +1,16 @@
 <?php
 
-namespace Drupal\config\Tests;
+namespace Drupal\Tests\config\Functional;
 
 use Drupal\Core\Serialization\Yaml;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests the user interface for importing/exporting a single configuration.
  *
  * @group config
  */
-class ConfigSingleImportExportTest extends WebTestBase {
+class ConfigSingleImportExportTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
diff --git a/core/modules/config/src/Tests/LanguageNegotiationFormOverrideTest.php b/core/modules/config/tests/src/Functional/LanguageNegotiationFormOverrideTest.php
similarity index 93%
rename from core/modules/config/src/Tests/LanguageNegotiationFormOverrideTest.php
rename to core/modules/config/tests/src/Functional/LanguageNegotiationFormOverrideTest.php
index ba67960650..6c4e1bb311 100644
--- a/core/modules/config/src/Tests/LanguageNegotiationFormOverrideTest.php
+++ b/core/modules/config/tests/src/Functional/LanguageNegotiationFormOverrideTest.php
@@ -1,8 +1,8 @@
 <?php
 
-namespace Drupal\config\Tests;
+namespace Drupal\Tests\config\Functional;
 
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests language-negotiation overrides are not on language-negotiation form.
@@ -10,7 +10,7 @@
  * @group config
  * @see \Drupal\Core\Form\ConfigFormBase
  */
-class LanguageNegotiationFormOverrideTest extends WebTestBase {
+class LanguageNegotiationFormOverrideTest extends BrowserTestBase {
 
   public static $modules = ['language', 'locale', 'locale_test'];