diff --git a/core/modules/config/src/Tests/SchemaCheckTestTrait.php b/core/modules/config/src/Tests/SchemaCheckTestTrait.php
index ede1e56..6946157 100644
--- a/core/modules/config/src/Tests/SchemaCheckTestTrait.php
+++ b/core/modules/config/src/Tests/SchemaCheckTestTrait.php
@@ -28,19 +28,19 @@ public function assertConfigSchema(TypedConfigManagerInterface $typed_config, $c
     if ($errors === FALSE) {
       // @todo Since the use of this trait is under TestBase, it works.
       //   Can be fixed as part of https://www.drupal.org/node/2260053.
-      $this->fail(SafeMarkup::format('No schema for @config_name', array('@config_name' => $config_name)));
+      $this->assertTrue(FALSE, SafeMarkup::format('No schema for @config_name', array('@config_name' => $config_name)));
       return;
     }
     elseif ($errors === TRUE) {
       // @todo Since the use of this trait is under TestBase, it works.
       //   Can be fixed as part of https://www.drupal.org/node/2260053.
-      $this->pass(SafeMarkup::format('Schema found for @config_name and values comply with schema.', array('@config_name' => $config_name)));
+      $this->assertTrue(TRUE, SafeMarkup::format('Schema found for @config_name and values comply with schema.', array('@config_name' => $config_name)));
     }
     else {
       foreach ($errors as $key => $error) {
         // @todo Since the use of this trait is under TestBase, it works.
         //   Can be fixed as part of https://www.drupal.org/node/2260053.
-        $this->fail(SafeMarkup::format('Schema key @key failed with: @error', array('@key' => $key, '@error' => $error)));
+        $this->assertTrue(FALSE, SafeMarkup::format('Schema key @key failed with: @error', array('@key' => $key, '@error' => $error)));
       }
     }
   }
@@ -52,7 +52,8 @@ public function assertConfigSchema(TypedConfigManagerInterface $typed_config, $c
    *   The configuration name.
    */
   public function assertConfigSchemaByName($config_name) {
-    $config = $this->config($config_name);
+    $config_factory = \Drupal::configFactory();
+    $config = $config_factory->get($config_name);
     $this->assertConfigSchema(\Drupal::service('config.typed'), $config->getName(), $config->get());
   }
 
diff --git a/core/modules/system/config/schema/system.schema.yml b/core/modules/system/config/schema/system.schema.yml
index e34d375..732798e 100644
--- a/core/modules/system/config/schema/system.schema.yml
+++ b/core/modules/system/config/schema/system.schema.yml
@@ -279,6 +279,9 @@ system.file:
         temporary:
           type: string
           label: 'Temporary directory'
+        private:
+          type: string
+          label: 'Private directory'
     temporary_maximum_age:
       type: integer
       label: 'Maximum age for temporary files'
diff --git a/core/profiles/standard/src/Tests/StandardTest.php b/core/profiles/standard/tests/src/Functional/StandardProfileTest.php
similarity index 64%
rename from core/profiles/standard/src/Tests/StandardTest.php
rename to core/profiles/standard/tests/src/Functional/StandardProfileTest.php
index bff61a9..8f61683 100644
--- a/core/profiles/standard/src/Tests/StandardTest.php
+++ b/core/profiles/standard/tests/src/Functional/StandardProfileTest.php
@@ -1,24 +1,32 @@
 <?php
 
-namespace Drupal\standard\Tests;
+namespace Drupal\Tests\standard\Functional;
 
 use Drupal\config\Tests\SchemaCheckTestTrait;
 use Drupal\contact\Entity\ContactForm;
 use Drupal\Core\Url;
 use Drupal\dynamic_page_cache\EventSubscriber\DynamicPageCacheSubscriber;
 use Drupal\filter\Entity\FilterFormat;
-use Drupal\simpletest\WebTestBase;
+use Drupal\simpletest\NodeCreationTrait;
+use Drupal\Tests\BrowserTestBase;
 use Drupal\user\Entity\Role;
+use Drupal\user\Entity\User;
 
 /**
  * Tests Standard installation profile expectations.
  *
  * @group standard
  */
-class StandardTest extends WebTestBase {
+class StandardProfileTest extends BrowserTestBase {
 
   use SchemaCheckTestTrait;
+  use NodeCreationTrait {
+    createNode as drupalCreateNode;
+  }
 
+  /**
+   * {@inheritdoc}
+   */
   protected $profile = 'standard';
 
   /**
@@ -32,10 +40,12 @@ class StandardTest extends WebTestBase {
    * Tests Standard installation profile.
    */
   function testStandard() {
-    $this->drupalGet('');
-    $this->assertLink(t('Contact'));
-    $this->clickLink(t('Contact'));
-    $this->assertResponse(200);
+    $assert_session = $this->assertSession();
+    $this->drupalGet('<front>');
+    $page = $this->getSession()->getPage();
+    $contact = $page->findLink('Contact');
+    $contact->click();
+    $assert_session->statusCodeEquals(200);
 
     // Test anonymous user can access 'Main navigation' block.
     $this->adminUser = $this->drupalCreateUser(array(
@@ -48,34 +58,29 @@ function testStandard() {
     $this->drupalLogin($this->adminUser);
     // Configure the block.
     $this->drupalGet('admin/structure/block/add/system_menu_block:main/bartik');
-    $this->drupalPostForm(NULL, array(
+    $this->submitForm(array(
       'region' => 'sidebar_first',
       'id' => 'main_navigation',
     ), t('Save block'));
     // Verify admin user can see the block.
-    $this->drupalGet('');
-    $this->assertText('Main navigation');
+    $this->drupalGet('<front>');
+    $assert_session->pageTextContains('Main navigation');
 
     // Verify we have role = aria on system_powered_by and help_block
     // blocks.
     $this->drupalGet('admin/structure/block');
-    $elements = $this->xpath('//div[@role=:role and @id=:id]', array(
-      ':role' => 'complementary',
-      ':id' => 'block-bartik-help',
-    ));
+    $page = $this->getSession()->getPage();
+    $element = $page->findById('block-bartik-help');
+    $this->assertEquals('complementary', $element->getAttribute('role'), 'Found complementary role on help block.');
 
-    $this->assertEqual(count($elements), 1, 'Found complementary role on help block.');
-
-    $this->drupalGet('');
-    $elements = $this->xpath('//div[@role=:role and @id=:id]', array(
-      ':role' => 'complementary',
-      ':id' => 'block-bartik-powered',
-    ));
-    $this->assertEqual(count($elements), 1, 'Found complementary role on powered by block.');
+    $this->drupalGet('<front>');
+    $page = $this->getSession()->getPage();
+    $element = $page->findById('block-bartik-powered');
+    $this->assertEquals('complementary', $element->getAttribute('role'), 'Found complementary role on powered by block.');
 
     // Verify anonymous user can see the block.
     $this->drupalLogout();
-    $this->assertText('Main navigation');
+    $assert_session->pageTextContains('Main navigation');
 
     // Ensure comments don't show in the front page RSS feed.
     // Create an article.
@@ -90,19 +95,24 @@ function testStandard() {
     // Add a comment.
     $this->drupalLogin($this->adminUser);
     $this->drupalGet('node/1');
-    $this->assertRaw('Then she picked out two somebodies,<br />Sally and me', 'Found a line break.');
-    $this->drupalPostForm(NULL, array(
+    $page = $this->getSession()->getPage();
+    $this->assertContains('Then she picked out two somebodies,<br>Sally and me', $page->getHtml(), 'Found a line break.');
+    $this->submitForm(array(
       'subject[0][value]' => 'Barfoo',
       'comment_body[0][value]' => 'Then she picked out two somebodies, Sally and me',
     ), t('Save'));
     // Fetch the feed.
     $this->drupalGet('rss.xml');
-    $this->assertText('Foobar');
-    $this->assertNoText('Then she picked out two somebodies, Sally and me');
+    // Mink session by default initialized html document so to get xml we use
+    // last response of the driver.
+    $xml = $this->getSession()->getDriver()->getContent();
+    $this->assertContains('Foobar', $xml);
+    $this->assertNotContains('Then she picked out two somebodies, Sally and me', $xml);
 
     // Ensure block body exists.
     $this->drupalGet('block/add');
-    $this->assertFieldByName('body[0][value]');
+    $page = $this->getSession()->getPage();
+    $this->assertNotNull($page->findField('body[0][value]'), 'Found field with name body[0][value]');
 
     // Now we have all configuration imported, test all of them for schema
     // conformance. Ensures all imported default configuration is valid when
@@ -110,8 +120,9 @@ function testStandard() {
     $names = $this->container->get('config.storage')->listAll();
     /** @var \Drupal\Core\Config\TypedConfigManagerInterface $typed_config */
     $typed_config = $this->container->get('config.typed');
+    $config_factory = \Drupal::configFactory();
     foreach ($names as $name) {
-      $config = $this->config($name);
+      $config = $config_factory->get($name);
       $this->assertConfigSchema($typed_config, $name, $config->get());
     }
 
@@ -137,7 +148,7 @@ function testStandard() {
     /** @var \Drupal\contact\ContactFormInterface $contact_form */
     $contact_form = ContactForm::load('feedback');
     $recipients = $contact_form->getRecipients();
-    $this->assertEqual(['simpletest@example.com'], $recipients);
+    $this->assertEquals(['simpletest@example.com'], $recipients);
 
     $role = Role::create([
       'id' => 'admin_theme',
@@ -148,32 +159,34 @@ function testStandard() {
     $this->adminUser->addRole($role->id());
     $this->adminUser->save();
     $this->drupalGet('node/add');
-    $this->assertResponse(200);
+    $assert_session->statusCodeEquals(200);
+    $this->drupalLogout();
 
     // Ensure that there are no pending updates after installation.
-    $this->drupalLogin($this->rootUser);
+    $root_user = User::load(1);
+    $this->drupalLogin($root_user);
     $this->drupalGet('update.php/selection');
-    $this->assertText('No pending updates.');
+    $assert_session->pageTextContains('No pending updates.');
 
     // Ensure that there are no pending entity updates after installation.
     $this->assertFalse($this->container->get('entity.definition_update_manager')->needsUpdates(), 'After installation, entity schema is up to date.');
 
     // Make sure the optional image styles are not installed.
     $this->drupalGet('admin/config/media/image-styles');
-    $this->assertNoText('Max 325x325');
-    $this->assertNoText('Max 650x650');
-    $this->assertNoText('Max 1300x1300');
-    $this->assertNoText('Max 2600x2600');
+    $assert_session->pageTextNotContains('Max 325x325');
+    $assert_session->pageTextNotContains('Max 650x650');
+    $assert_session->pageTextNotContains('Max 1300x1300');
+    $assert_session->pageTextNotContains('Max 2600x2600');
 
     // Make sure the optional image styles are installed after enabling
     // the responsive_image module.
     \Drupal::service('module_installer')->install(array('responsive_image'));
     $this->rebuildContainer();
     $this->drupalGet('admin/config/media/image-styles');
-    $this->assertText('Max 325x325');
-    $this->assertText('Max 650x650');
-    $this->assertText('Max 1300x1300');
-    $this->assertText('Max 2600x2600');
+    $assert_session->pageTextContains('Max 325x325');
+    $assert_session->pageTextContains('Max 650x650');
+    $assert_session->pageTextContains('Max 1300x1300');
+    $assert_session->pageTextContains('Max 2600x2600');
 
     // Verify certain routes' responses are cacheable by Dynamic Page Cache, to
     // ensure these responses are very fast for authenticated users.
@@ -181,22 +194,22 @@ function testStandard() {
     $this->drupalLogin($this->adminUser);
     $url = Url::fromRoute('contact.site_page');
     $this->drupalGet($url);
-    $this->assertEqual('UNCACHEABLE', $this->drupalGetHeader(DynamicPageCacheSubscriber::HEADER), 'Site-wide contact page cannot be cached by Dynamic Page Cache.');
+    $assert_session->responseHeaderContains(DynamicPageCacheSubscriber::HEADER, 'UNCACHEABLE');
 
     $url = Url::fromRoute('<front>');
     $this->drupalGet($url);
     $this->drupalGet($url);
-    $this->assertEqual('HIT', $this->drupalGetHeader(DynamicPageCacheSubscriber::HEADER), 'Frontpage is cached by Dynamic Page Cache.');
+    $assert_session->responseHeaderContains(DynamicPageCacheSubscriber::HEADER, 'HIT');
 
     $url = Url::fromRoute('entity.node.canonical', ['node' => 1]);
     $this->drupalGet($url);
     $this->drupalGet($url);
-    $this->assertEqual('HIT', $this->drupalGetHeader(DynamicPageCacheSubscriber::HEADER), 'Full node page is cached by Dynamic Page Cache.');
+    $assert_session->responseHeaderContains(DynamicPageCacheSubscriber::HEADER, 'HIT');
 
     $url = Url::fromRoute('entity.user.canonical', ['user' => 1]);
     $this->drupalGet($url);
     $this->drupalGet($url);
-    $this->assertEqual('HIT', $this->drupalGetHeader(DynamicPageCacheSubscriber::HEADER), 'User profile page is cached by Dynamic Page Cache.');
+    $assert_session->responseHeaderContains(DynamicPageCacheSubscriber::HEADER, 'HIT');
   }
 
 }
diff --git a/core/tests/Drupal/Tests/BrowserTestBase.php b/core/tests/Drupal/Tests/BrowserTestBase.php
index a8700b4..acdce5d 100644
--- a/core/tests/Drupal/Tests/BrowserTestBase.php
+++ b/core/tests/Drupal/Tests/BrowserTestBase.php
@@ -274,6 +274,13 @@
   protected $baseUrl;
 
   /**
+   * The original array of shutdown function callbacks.
+   *
+   * @var array
+   */
+  protected $originalShutdownCallbacks = [];
+
+  /**
    * Initializes Mink sessions.
    */
   protected function initMink() {
@@ -505,6 +512,10 @@ protected function tearDown() {
     if ($this->mink) {
       $this->mink->stopSessions();
     }
+
+    // Restore original shutdown callbacks.
+    $callbacks = &drupal_register_shutdown_function();
+    $callbacks = $this->originalShutdownCallbacks;
   }
 
   /**
@@ -806,7 +817,7 @@ protected function drupalLogin(AccountInterface $account) {
 
     // @see BrowserTestBase::drupalUserIsLoggedIn()
     $account->sessionId = $this->getSession()->getCookie($this->getSessionName());
-    $this->assertTrue($this->drupalUserIsLoggedIn($account), SafeMarkup::format('User %name successfully logged in.', array('name' => $account->getUsername())));
+    $this->assertTrue($this->drupalUserIsLoggedIn($account), SafeMarkup::format('User %name successfully logged in.', array('%name' => $account->getUsername())));
 
     $this->loggedInUser = $account;
     $this->container->get('current_user')->setAccount($account);
@@ -1241,6 +1252,14 @@ protected function prepareEnvironment() {
     ));
 
     drupal_set_time_limit($this->timeLimit);
+
+    // Save and clean the shutdown callbacks array because it is static cached
+    // and will be changed by the test run. Otherwise it will contain callbacks
+    // from both environments and the testing environment will try to call the
+    // handlers defined by the original one.
+    $callbacks = &drupal_register_shutdown_function();
+    $this->originalShutdownCallbacks = $callbacks;
+    $callbacks = [];
   }
 
   /**