Drupal 8.0.0 beta 12. More info: https://www.drupal.org/node/2514176

core/modules/system/tests/css/system.module.css

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+
+/**
+ * This file is for testing CSS file override in
+ * CascadingStylesheetsTestCase::testRenderOverride().
+ * No contents are necessary.
+ */

core/modules/system/tests/fixtures/broken.info.txt

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+# info.yml for testing broken YAML parsing exception handling.
+name: File
+type: module
+description: 'Defines a file field type.'
+package: Core
+version: VERSION
+core: 8.x
+dependencies::;;
+  - field

core/modules/system/tests/fixtures/common_test.info.txt

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+core: 8.x
+name: common_test
+type: module
+description: 'testing info file parsing'
+simple_string: 'A simple string'
+version: "VERSION"
+double_colon: dummyClassName::

core/modules/system/tests/fixtures/missing_key.info.txt

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+# info.yml for testing missing type key.
+name: File
+description: 'Defines a file field type.'
+package: Core
+version: VERSION
+core: 8.x
+dependencies:
+  - field

core/modules/system/tests/fixtures/missing_keys.info.txt

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+# info.yml for testing missing name, description, and type keys.
+package: Core
+version: VERSION
+dependencies:
+  - field

core/modules/system/tests/http.php

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+<?php
+
+/**
+ * @file
+ * Fake an HTTP request, for use during testing.
+ */
+
+use Drupal\Core\Test\TestKernel;
+use Symfony\Component\HttpFoundation\Request;
+
+chdir('../../../..');
+
+$autoloader = require_once 'autoload.php';
+
+// Change to HTTP.
+$_SERVER['HTTPS'] = NULL;
+ini_set('session.cookie_secure', FALSE);
+foreach ($_SERVER as &$value) {
+  $value = str_replace('core/modules/system/tests/http.php', 'index.php', $value);
+  $value = str_replace('https://', 'http://', $value);
+}
+
+$kernel = new TestKernel('testing', $autoloader, TRUE);
+
+$request = Request::createFromGlobals();
+$response = $kernel->handle($request);
+$response->send();
+
+$kernel->terminate($request, $response);

core/modules/system/tests/https.php

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+<?php
+
+/**
+ * @file
+ * Fake an HTTPS request, for use during testing.
+ *
+ * @todo Fix this to use a new request rather than modifying server variables,
+ *   see http.php.
+ */
+
+use Drupal\Core\Test\TestKernel;
+use Symfony\Component\HttpFoundation\Request;
+
+chdir('../../../..');
+
+$autoloader = require_once 'autoload.php';
+
+// Change to HTTPS.
+$_SERVER['HTTPS'] = 'on';
+foreach ($_SERVER as &$value) {
+  $value = str_replace('core/modules/system/tests/https.php', 'index.php', $value);
+  $value = str_replace('http://', 'https://', $value);
+}
+
+$kernel = new TestKernel('testing', $autoloader, TRUE);
+
+$request = Request::createFromGlobals();
+$response = $kernel->handle($request);
+$response->send();
+
+$kernel->terminate($request, $response);

core/modules/system/tests/modules/accept_header_routing_test/accept_header_routing_test.info.yml

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+name: Accept header based routing test
+core: 8.x
+type: module

core/modules/system/tests/modules/accept_header_routing_test/accept_header_routing_test.services.yml

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+services:
+  accept_header_matcher:
+    class: Drupal\accept_header_routing_test\Routing\AcceptHeaderMatcher
+    tags:
+      - { name: route_filter }

core/modules/system/tests/modules/accept_header_routing_test/src/AcceptHeaderMiddleware.php

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+<?php
+
+/**
+ * @file
+ * Contains \Drupal\accept_header_routing_test\AcceptHeaderMiddleware.
+ */
+
+namespace Drupal\accept_header_routing_test;
+
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpKernel\HttpKernelInterface;
+
+/**
+ * Example implementation of accept header based content negotation.
+ */
+class AcceptHeaderMiddleware implements HttpKernelInterface {
+
+  /**
+   * Constructs a new AcceptHeaderMiddleware instance.
+   *
+   * @param \Symfony\Component\HttpKernel\HttpKernelInterface $app
+   *   The app.
+   */
+  public function __construct(HttpKernelInterface $app) {
+    $this->app = $app;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function handle(Request $request, $type = self::MASTER_REQUEST, $catch = TRUE) {
+    $mapping = [
+      'application/json' => 'json',
+      'application/hal+json' => 'hal_json',
+      'application/xml' => 'xml',
+      'text/html' => 'html',
+    ];
+
+    $accept = $request->headers->get('Accept') ?: ['text/html'];
+    if (isset($mapping[$accept[0]])) {
+      $request->setRequestFormat($mapping[$accept[0]]);
+    }
+
+    return $this->app->handle($request, $type, $catch);
+  }
+
+}

core/modules/system/tests/modules/accept_header_routing_test/src/AcceptHeaderRoutingTestServiceProvider.php

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+<?php
+
+/**
+ * @file
+ * Contains \Drupal\accept_header_routing_test\AcceptHeaderRoutingTestServiceProvider.
+ */
+
+namespace Drupal\accept_header_routing_test;
+
+use Drupal\Core\DependencyInjection\ContainerBuilder;
+use Drupal\Core\DependencyInjection\ServiceModifierInterface;
+
+/**
+ * Service provider for the accept_header_routing_test module.
+ */
+class AcceptHeaderRoutingTestServiceProvider implements ServiceModifierInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function alter(ContainerBuilder $container) {
+    // Remove the basic content negotation middleware and replace it with a
+    // basic header based one.
+    $container->register('http_middleware.negotiation', 'Drupal\accept_header_routing_test\AcceptHeaderMiddleware')
+      ->addTag('http_middleware', ['priority' => 400]);
+  }
+
+}

core/modules/system/tests/modules/accept_header_routing_test/src/Routing/AcceptHeaderMatcher.php

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+<?php
+
+/**
+ * @file
+ * Contains \Drupal\accept_header_routing_test\Routing\AcceptHeaderMatcher.
+ */
+
+namespace Drupal\accept_header_routing_test\Routing;
+
+use Drupal\Component\Utility\SafeMarkup;
+use Drupal\Core\Routing\RouteFilterInterface;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpKernel\Exception\NotAcceptableHttpException;
+use Symfony\Component\Routing\Route;
+use Symfony\Component\Routing\RouteCollection;
+
+/**
+ * Filters routes based on the media type specified in the HTTP Accept headers.
+ */
+class AcceptHeaderMatcher implements RouteFilterInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function filter(RouteCollection $collection, Request $request) {
+    // Generates a list of Symfony formats matching the acceptable MIME types.
+    // @todo replace by proper content negotiation library.
+    $acceptable_mime_types = $request->getAcceptableContentTypes();
+    $acceptable_formats = array_filter(array_map(array($request, 'getFormat'), $acceptable_mime_types));
+    $primary_format = $request->getRequestFormat();
+
+    foreach ($collection as $name => $route) {
+      // _format could be a |-delimited list of supported formats.
+      $supported_formats = array_filter(explode('|', $route->getRequirement('_format')));
+
+      if (empty($supported_formats)) {
+        // No format restriction on the route, so it always matches. Move it to
+        // the end of the collection by re-adding it.
+        $collection->add($name, $route);
+      }
+      elseif (in_array($primary_format, $supported_formats)) {
+        // Perfect match, which will get a higher priority by leaving the route
+        // on top of the list.
+      }
+      // The route partially matches if it doesn't care about format, if it
+      // explicitly allows any format, or if one of its allowed formats is
+      // in the request's list of acceptable formats.
+      elseif (in_array('*/*', $acceptable_mime_types) || array_intersect($acceptable_formats, $supported_formats)) {
+        // Move it to the end of the list.
+        $collection->add($name, $route);
+      }
+      else {
+        // Remove the route if it does not match at all.
+        $collection->remove($name);
+      }
+    }
+
+    if (count($collection)) {
+      return $collection;
+    }
+
+    // We do not throw a
+    // \Symfony\Component\Routing\Exception\ResourceNotFoundException here
+    // because we don't want to return a 404 status code, but rather a 406.
+    throw new NotAcceptableHttpException(SafeMarkup::format('No route found for the specified formats @formats.', array('@formats' => implode(' ', $acceptable_mime_types))));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function applies(Route $route) {
+    return TRUE;
+  }
+
+}

core/modules/system/tests/modules/accept_header_routing_test/tests/Unit/AcceptHeaderMatcherTest.php

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+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\accept_header_routing_teste\Unit\Routing\AcceptHeaderMatcherTest.
+ */
+
+namespace Drupal\Tests\accept_header_routing_teste\Unit\Routing;
+
+use Drupal\accept_header_routing_test\Routing\AcceptHeaderMatcher;
+use Drupal\Tests\Core\Routing\RoutingFixtures;
+use Drupal\Tests\UnitTestCase;
+use Symfony\Component\HttpFoundation\Request;
+
+/**
+ * Confirm that the mime types partial matcher is functioning properly.
+ *
+ * @group Routing
+ */
+class AcceptHeaderMatcherTest extends UnitTestCase {
+
+  /**
+   * A collection of shared fixture data for tests.
+   *
+   * @var \Drupal\Tests\Core\Routing\RoutingFixtures
+   */
+  protected $fixtures;
+
+  /**
+   * The matcher object that is going to be tested.
+   *
+   * @var \Drupal\accept_header_routing_test\Routing\AcceptHeaderMatcher
+   */
+  protected $matcher;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $this->fixtures = new RoutingFixtures();
+    $this->matcher = new AcceptHeaderMatcher();
+  }
+
+  /**
+   * Provides data for the Accept header filtering test.
+   *
+   * @see Drupal\Tests\Core\Routing\AcceptHeaderMatcherTest::testAcceptFiltering()
+   */
+  public function acceptFilterProvider() {
+    return [
+      // Check that JSON routes get filtered and prioritized correctly.
+      ['application/json, text/xml;q=0.9', 'json', 'route_c', 'route_e'],
+      // Tests a JSON request with alternative JSON MIME type Accept header.
+      ['application/x-json, text/xml;q=0.9', 'json', 'route_c', 'route_e'],
+      // Tests a standard HTML request.
+      ['text/html, text/xml;q=0.9', 'html', 'route_e', 'route_c'],
+    ];
+  }
+
+  /**
+   * Tests that requests using Accept headers get filtered correctly.
+   *
+   * @param string $accept_header
+   *   The HTTP Accept header value of the request.
+   * @param string $format
+   *   The request format.
+   * @param string $included_route
+   *   The route name that should survive the filter and be ranked first.
+   * @param string $excluded_route
+   *   The route name that should be filtered out during matching.
+   *
+   * @dataProvider acceptFilterProvider
+   */
+  public function testAcceptFiltering($accept_header, $format, $included_route, $excluded_route) {
+    $collection = $this->fixtures->sampleRouteCollection();
+
+    $request = Request::create('path/two', 'GET');
+    $request->headers->set('Accept', $accept_header);
+    $request->setRequestFormat($format);
+    $routes = $this->matcher->filter($collection, $request);
+    $this->assertEquals(count($routes), 4, 'The correct number of routes was found.');
+    $this->assertNotNull($routes->get($included_route), "Route $included_route was found when matching $accept_header.");
+    $this->assertNull($routes->get($excluded_route), "Route $excluded_route was not found when matching $accept_header.");
+    foreach ($routes as $name => $route) {
+      $this->assertEquals($name, $included_route, "Route $included_route is the first one in the collection when matching $accept_header.");
+      break;
+    }
+  }
+
+  /**
+   * Confirms that the AcceptHeaderMatcher throws an exception for no-route.
+   *
+   * @expectedException \Symfony\Component\HttpKernel\Exception\NotAcceptableHttpException
+   * @expectedExceptionMessage No route found for the specified formats application/json text/xml.
+   */
+  public function testNoRouteFound() {
+    // Remove the sample routes that would match any method.
+    $routes = $this->fixtures->sampleRouteCollection();
+    $routes->remove('route_a');
+    $routes->remove('route_b');
+    $routes->remove('route_c');
+    $routes->remove('route_d');
+
+    $request = Request::create('path/two', 'GET');
+    $request->headers->set('Accept', 'application/json, text/xml;q=0.9');
+    $request->setRequestFormat('json');
+    $this->matcher->filter($routes, $request);
+    $this->matcher->filter($routes, $request);
+    $this->fail('No exception was thrown.');
+  }
+
+}

core/modules/system/tests/modules/action_test/action_test.info.yml

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+name: 'Action test'
+type: module
+description: 'Support module for action testing.'
+package: Testing
+version: VERSION
+core: 8.x

core/modules/system/tests/modules/action_test/src/Plugin/Action/NoType.php

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+<?php
+
+/**
+ * @file
+ * Contains \Drupal\action_test\Plugin\Action\NoType.
+ */
+
+namespace Drupal\action_test\Plugin\Action;
+
+use Drupal\Core\Access\AccessResult;
+use Drupal\Core\Action\ActionBase;
+use Drupal\Core\Session\AccountInterface;
+
+/**
+ * Provides an operation with no type specified.
+ *
+ * @Action(
+ *   id = "action_test_no_type",
+ *   label = @Translation("An operation with no type specified")
+ * )
+ */
+class NoType extends ActionBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function execute($entity = NULL) {
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function access($object, AccountInterface $account = NULL, $return_as_object = FALSE) {
+    $result = AccessResult::allowed();
+    return $return_as_object ? $result : $result->isAllowed();
+  }
+
+}

core/modules/system/tests/modules/action_test/src/Plugin/Action/SaveEntity.php

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+<?php
+
+/**
+ * @file
+ * Contains \Drupal\action_test\Plugin\Action\SaveEntity.
+ */
+
+namespace Drupal\action_test\Plugin\Action;
+
+use Drupal\Core\Action\ActionBase;
+use Drupal\Core\Session\AccountInterface;
+
+/**
+ * Provides an operation to save user entities.
+ *
+ * @Action(
+ *   id = "action_test_save_entity",
+ *   label = @Translation("Saves entities"),
+ *   type = "user"
+ * )
+ */
+class SaveEntity extends ActionBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function execute($entity = NULL) {
+    $entity->save();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function access($object, AccountInterface $account = NULL, $return_as_object = FALSE) {
+    /** @var \Drupal\Core\Entity\EntityInterface $object */
+    return $object->access('update', $account, $return_as_object);
+  }
+
+}

core/modules/system/tests/modules/ajax_forms_test/ajax_forms_test.info.yml

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+name: 'AJAX form test mock module'
+type: module
+description: 'Test for AJAX form calls.'
+core: 8.x
+package: Testing
+version: VERSION

core/modules/system/tests/modules/ajax_forms_test/ajax_forms_test.module

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+<?php
+
+/**
+ * @file
+ * Simpletest mock module for Ajax forms testing.
+ */
+
+use Drupal\Core\Ajax;
+use Drupal\Core\Ajax\AjaxResponse;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Ajax form callback: Selects 'after'.
+ */
+function ajax_forms_test_advanced_commands_after_callback($form, FormStateInterface $form_state) {
+  $selector = '#after_div';
+
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\AfterCommand($selector, "This will be placed after"));
+  return $response;
+}
+
+/**
+ * Ajax form callback: Selects 'alert'.
+ */
+function ajax_forms_test_advanced_commands_alert_callback($form, FormStateInterface $form_state) {
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\AlertCommand('Alert'));
+  return $response;
+}
+
+/**
+ * Ajax form callback: Selects 'append'.
+ */
+function ajax_forms_test_advanced_commands_append_callback($form, FormStateInterface $form_state) {
+  $selector = '#append_div';
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\AppendCommand($selector, "Appended text"));
+  return $response;
+}
+
+/**
+ * Ajax form callback: Selects 'before'.
+ */
+function ajax_forms_test_advanced_commands_before_callback($form, FormStateInterface $form_state) {
+  $selector = '#before_div';
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\BeforeCommand($selector, "Before text"));
+  return $response;
+}
+
+/**
+ * Ajax form callback: Selects 'changed'.
+ */
+function ajax_forms_test_advanced_commands_changed_callback($form, FormStateInterface $form_state) {
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\ChangedCommand('#changed_div'));
+  return $response;
+}
+
+/**
+ * Ajax form callback: Selects 'changed' with asterisk marking inner div.
+ */
+function ajax_forms_test_advanced_commands_changed_asterisk_callback($form, FormStateInterface $form_state) {
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\ChangedCommand('#changed_div', '#changed_div_mark_this'));
+  return $response;
+}
+
+/**
+ * Ajax form callback: Selects 'css'.
+ */
+function ajax_forms_test_advanced_commands_css_callback($form, FormStateInterface $form_state) {
+  $selector = '#css_div';
+  $color = 'blue';
+
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\CssCommand($selector, array('background-color' => $color)));
+  return $response;
+}
+
+/**
+ * Ajax form callback: Selects 'data'.
+ */
+function ajax_forms_test_advanced_commands_data_callback($form, FormStateInterface $form_state) {
+  $selector = '#data_div';
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\DataCommand($selector, 'testkey', 'testvalue'));
+  return $response;
+}
+
+/**
+ * Ajax form callback: Selects 'invoke'.
+ */
+function ajax_forms_test_advanced_commands_invoke_callback($form, FormStateInterface $form_state) {
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\InvokeCommand('#invoke_div', 'addClass', array('error')));
+  return $response;
+}
+
+/**
+ * Ajax form callback: Selects 'html'.
+ */
+function ajax_forms_test_advanced_commands_html_callback($form, FormStateInterface $form_state) {
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\HtmlCommand('#html_div', 'replacement text'));
+  return $response;
+}
+
+/**
+ * Ajax form callback: Selects 'insert'.
+ */
+function ajax_forms_test_advanced_commands_insert_callback($form, FormStateInterface $form_state) {
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\InsertCommand('#insert_div', 'insert replacement text'));
+  return $response;
+}
+
+/**
+ * Ajax form callback: Selects 'prepend'.
+ */
+function ajax_forms_test_advanced_commands_prepend_callback($form, FormStateInterface $form_state) {
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\PrependCommand('#prepend_div', "prepended text"));
+  return $response;
+}
+
+/**
+ * Ajax form callback: Selects 'remove'.
+ */
+function ajax_forms_test_advanced_commands_remove_callback($form, FormStateInterface $form_state) {
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\RemoveCommand('#remove_text'));
+  return $response;
+}
+
+/**
+ * Ajax form callback: Selects 'restripe'.
+ */
+function ajax_forms_test_advanced_commands_restripe_callback($form, FormStateInterface $form_state) {
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\RestripeCommand('#restripe_table'));
+  return $response;
+}
+
+/**
+ * Ajax form callback: Selects 'settings'.
+ */
+function ajax_forms_test_advanced_commands_settings_callback($form, FormStateInterface $form_state) {
+  $setting['ajax_forms_test']['foo'] = 42;
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\SettingsCommand($setting));
+  return $response;
+}
+
+/**
+ * Ajax callback for 'add_css'.
+ */
+function ajax_forms_test_advanced_commands_add_css_callback($form, FormStateInterface $form_state) {
+  $response = new AjaxResponse();
+  $response->addCommand(new Ajax\AddCssCommand('my/file.css'));
+  return $response;
+}
+
+/**
+ * Ajax form callback: Selects the 'drivertext' element of the validation form.
+ */
+function ajax_forms_test_validation_form_callback($form, FormStateInterface $form_state) {
+  drupal_set_message("ajax_forms_test_validation_form_callback invoked");
+  drupal_set_message(t("Callback: drivertext=%drivertext, spare_required_field=%spare_required_field", array('%drivertext' => $form_state->getValue('drivertext'), '%spare_required_field' => $form_state->getValue('spare_required_field'))));
+  return ['#markup' => '<div id="message_area">ajax_forms_test_validation_form_callback at ' . date('c') . '</div>'];
+}
+
+/**
+ * Ajax form callback: Selects the 'drivernumber' element of the validation form.
+ */
+function ajax_forms_test_validation_number_form_callback($form, FormStateInterface $form_state) {
+  drupal_set_message("ajax_forms_test_validation_number_form_callback invoked");
+  drupal_set_message(t("Callback: drivernumber=%drivernumber, spare_required_field=%spare_required_field", array('%drivernumber' => $form_state->getValue('drivernumber'), '%spare_required_field' => $form_state->getValue('spare_required_field'))));
+  return ['#markup' => '<div id="message_area_number">ajax_forms_test_validation_number_form_callback at ' . date('c') . '</div>'];
+}
+
+/**
+ * AJAX form callback: Selects for the ajax_forms_test_lazy_load_form() form.
+ */
+function ajax_forms_test_lazy_load_form_ajax($form, FormStateInterface $form_state) {
+  $build = [
+    '#markup' => 'new content',
+  ];
+
+  if ($form_state->getValue('add_files')) {
+    $build['#attached']['library'][] = 'system/admin';
+    $build['#attached']['library'][] = 'system/drupal.system';
+    $build['#attached']['drupalSettings']['ajax_forms_test_lazy_load_form_submit'] = 'executed';
+  }
+
+  return $build;
+}

core/modules/system/tests/modules/ajax_forms_test/ajax_forms_test.routing.yml

@@ -0,0 +1,39 @@
+ajax_forms_test.get_form:
+  path: '/ajax_forms_test_get_form'
+  defaults:
+    _title: 'AJAX forms simple form test'
+    _form: '\Drupal\ajax_forms_test\Form\AjaxFormsTestSimpleForm'
+  requirements:
+    _access: 'TRUE'
+
+ajax_forms_test.commands_form:
+  path: '/ajax_forms_test_ajax_commands_form'
+  defaults:
+    _title: 'AJAX forms AJAX commands test'
+    _form: '\Drupal\ajax_forms_test\Form\AjaxFormsTestCommandsForm'
+  requirements:
+    _access: 'TRUE'
+
+ajax_forms_test.validation_test:
+  path: '/ajax_validation_test'
+  defaults:
+    _title: 'AJAX Validation Test'
+    _form: '\Drupal\ajax_forms_test\Form\AjaxFormsTestValidationForm'
+  requirements:
+    _access: 'TRUE'
+
+ajax_forms_test.lazy_load_form:
+  path: '/ajax_forms_test_lazy_load_form'
+  defaults:
+    _title: 'AJAX forms lazy load test'
+    _form: '\Drupal\ajax_forms_test\Form\AjaxFormsTestLazyLoadForm'
+  requirements:
+    _access: 'TRUE'
+
+ajax_forms_test.cached_form:
+  path: '/ajax_forms_test_cached_form'
+  defaults:
+    _title: 'AJAX forms cached form test'
+    _form: '\Drupal\ajax_forms_test\Form\AjaxFormsTestCachedForm'
+  requirements:
+    _access: 'TRUE'

core/modules/system/tests/modules/ajax_forms_test/src/Callbacks.php

@@ -0,0 +1,39 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\ajax_forms_test\Callbacks.
+ */
+
+namespace Drupal\ajax_forms_test;
+
+use Drupal\Core\Ajax\AjaxResponse;
+use Drupal\Core\Ajax\DataCommand;
+use Drupal\Core\Ajax\HtmlCommand;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Simple object for testing methods as Ajax callbacks.
+ */
+class Callbacks {
+
+  /**
+   * Ajax callback triggered by select.
+   */
+  function selectCallback($form, FormStateInterface $form_state) {
+    $response = new AjaxResponse();
+    $response->addCommand(new HtmlCommand('#ajax_selected_color', $form_state->getValue('select')));
+    $response->addCommand(new DataCommand('#ajax_selected_color', 'form_state_value_select', $form_state->getValue('select')));
+    return $response;
+  }
+
+  /**
+   * Ajax callback triggered by checkbox.
+   */
+  function checkboxCallback($form, FormStateInterface $form_state) {
+    $response = new AjaxResponse();
+    $response->addCommand(new HtmlCommand('#ajax_checkbox_value', (int) $form_state->getValue('checkbox')));
+    $response->addCommand(new DataCommand('#ajax_checkbox_value', 'form_state_value_select', (int) $form_state->getValue('checkbox')));
+    return $response;
+  }
+}

core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestCachedForm.php

@@ -0,0 +1,50 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\ajax_forms_test\Form\AjaxFormsTestCachedForm.
+ */
+
+namespace Drupal\ajax_forms_test\Form;
+
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Url;
+
+/**
+ * Provides an AJAX form that will be cached.
+ */
+class AjaxFormsTestCachedForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'ajax_form_cache_test_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    $form['test1'] = [
+      '#type' => 'select',
+      '#title' => $this->t('Test 1'),
+      '#options' => [
+        'option1' => $this->t('Option 1'),
+        'option2' => $this->t('Option 2'),
+      ],
+      '#ajax' => [
+        'url' => Url::fromRoute('system.ajax'),
+      ],
+    ];
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+  }
+
+}

core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestCommandsForm.php

@@ -0,0 +1,211 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\ajax_forms_test\Form\AjaxFormsTestCommandsForm.
+ */
+
+namespace Drupal\ajax_forms_test\Form;
+
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Form constructor for the Ajax Command display form.
+ */
+class AjaxFormsTestCommandsForm extends FormBase {
+
+  /**
+   * {@inheritdoc}.
+   */
+  public function getFormId() {
+    return 'ajax_forms_test_ajax_commands_form';
+  }
+
+  /**
+   * {@inheritdoc}.
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    $form = array();
+
+    // Shows the 'after' command with a callback generating commands.
+    $form['after_command_example'] = array(
+      '#value' => $this->t("AJAX 'After': Click to put something after the div"),
+      '#type' => 'submit',
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_after_callback',
+      ),
+      '#suffix' => '<div id="after_div">Something can be inserted after this</div>',
+    );
+
+    // Shows the 'alert' command.
+    $form['alert_command_example'] = array(
+      '#value' => $this->t("AJAX 'Alert': Click to alert"),
+      '#type' => 'submit',
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_alert_callback',
+      ),
+    );
+
+    // Shows the 'append' command.
+    $form['append_command_example'] = array(
+      '#value' => $this->t("AJAX 'Append': Click to append something"),
+      '#type' => 'submit',
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_append_callback',
+      ),
+      '#suffix' => '<div id="append_div">Append inside this div</div>',
+    );
+
+
+    // Shows the 'before' command.
+    $form['before_command_example'] = array(
+      '#value' => $this->t("AJAX 'before': Click to put something before the div"),
+      '#type' => 'submit',
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_before_callback',
+      ),
+      '#suffix' => '<div id="before_div">Insert something before this.</div>',
+    );
+
+    // Shows the 'changed' command without asterisk.
+    $form['changed_command_example'] = array(
+      '#value' => $this->t("AJAX changed: Click to mark div changed."),
+      '#type' => 'submit',
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_changed_callback',
+      ),
+      '#suffix' => '<div id="changed_div"> <div id="changed_div_mark_this">This div can be marked as changed or not.</div></div>',
+    );
+    // Shows the 'changed' command adding the asterisk.
+    $form['changed_command_asterisk_example'] = array(
+      '#value' => $this->t("AJAX changed: Click to mark div changed with asterisk."),
+      '#type' => 'submit',
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_changed_asterisk_callback',
+      ),
+    );
+
+    // Shows the Ajax 'css' command.
+    $form['css_command_example'] = array(
+      '#value' => $this->t("Set the '#box' div to be blue."),
+      '#type' => 'submit',
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_css_callback',
+      ),
+      '#suffix' => '<div id="css_div" style="height: 50px; width: 50px; border: 1px solid black"> box</div>',
+    );
+
+
+    // Shows the Ajax 'data' command. But there is no use of this information,
+    // as this would require a javascript client to use the data.
+    $form['data_command_example'] = array(
+      '#value' => $this->t("AJAX data command: Issue command."),
+      '#type' => 'submit',
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_data_callback',
+      ),
+      '#suffix' => '<div id="data_div">Data attached to this div.</div>',
+    );
+
+    // Shows the Ajax 'invoke' command.
+    $form['invoke_command_example'] = array(
+      '#value' => $this->t("AJAX invoke command: Invoke addClass() method."),
+      '#type' => 'submit',
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_invoke_callback',
+      ),
+      '#suffix' => '<div id="invoke_div">Original contents</div>',
+    );
+
+    // Shows the Ajax 'html' command.
+    $form['html_command_example'] = array(
+      '#value' => $this->t("AJAX html: Replace the HTML in a selector."),
+      '#type' => 'submit',
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_html_callback',
+      ),
+      '#suffix' => '<div id="html_div">Original contents</div>',
+    );
+
+    // Shows the Ajax 'insert' command.
+    $form['insert_command_example'] = array(
+      '#value' => $this->t("AJAX insert: Let client insert based on #ajax['method']."),
+      '#type' => 'submit',
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_insert_callback',
+        'method' => 'prepend',
+      ),
+      '#suffix' => '<div id="insert_div">Original contents</div>',
+    );
+
+    // Shows the Ajax 'prepend' command.
+    $form['prepend_command_example'] = array(
+      '#value' => $this->t("AJAX 'prepend': Click to prepend something"),
+      '#type' => 'submit',
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_prepend_callback',
+      ),
+      '#suffix' => '<div id="prepend_div">Something will be prepended to this div. </div>',
+    );
+
+    // Shows the Ajax 'remove' command.
+    $form['remove_command_example'] = array(
+      '#value' => $this->t("AJAX 'remove': Click to remove text"),
+      '#type' => 'submit',
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_remove_callback',
+      ),
+      '#suffix' => '<div id="remove_div"><div id="remove_text">text to be removed</div></div>',
+    );
+
+    // Shows the Ajax 'restripe' command.
+    $form['restripe_command_example'] = array(
+      '#type' => 'submit',
+      '#value' => $this->t("AJAX 'restripe' command"),
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_restripe_callback',
+      ),
+      '#suffix' => '<div id="restripe_div">
+                    <table id="restripe_table" style="border: 1px solid black" >
+                    <tr id="table-first"><td>first row</td></tr>
+                    <tr ><td>second row</td></tr>
+                    </table>
+                    </div>',
+    );
+
+    // Demonstrates the Ajax 'settings' command. The 'settings' command has
+    // nothing visual to "show", but it can be tested via SimpleTest and via
+    // Firebug.
+    $form['settings_command_example'] = array(
+      '#type' => 'submit',
+      '#value' => $this->t("AJAX 'settings' command"),
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_settings_callback',
+      ),
+    );
+
+    // Shows the Ajax 'add_css' command.
+    $form['add_css_command_example'] = array(
+      '#type' => 'submit',
+      '#value' => $this->t("AJAX 'add_css' command"),
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_advanced_commands_add_css_callback',
+      ),
+    );
+
+    $form['submit'] = array(
+      '#type' => 'submit',
+      '#value' => $this->t('Submit'),
+    );
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}.
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+  }
+
+}

core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestLazyLoadForm.php

@@ -0,0 +1,59 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\ajax_forms_test\Form\AjaxFormsTestLazyLoadForm.
+ */
+
+namespace Drupal\ajax_forms_test\Form;
+
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Form builder: Builds a form that triggers a simple AJAX callback.
+ */
+class AjaxFormsTestLazyLoadForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'ajax_forms_test_lazy_load_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    // We attach a JavaScript setting, so that one of the generated AJAX
+    // commands will be a settings command. We can then check the settings
+    // command to ensure that the 'currentPath' setting is not part
+    // of the Ajax response.
+    $form['#attached']['drupalSettings']['test'] = 'currentPathUpdate';
+    $form['add_files'] = array(
+      '#title' => $this->t('Add files'),
+      '#type' => 'checkbox',
+      '#default_value' => FALSE,
+    );
+    $form['submit'] = array(
+      '#type' => 'submit',
+      '#value' => $this->t('Submit'),
+      '#ajax' => array(
+        'wrapper' => 'ajax-forms-test-lazy-load-ajax-wrapper',
+        'callback' => 'ajax_forms_test_lazy_load_form_ajax',
+      ),
+      '#prefix' => '<div id="ajax-forms-test-lazy-load-ajax-wrapper"></div>',
+    );
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    $form_state->setRebuild();
+  }
+
+}

core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestSimpleForm.php

@@ -0,0 +1,84 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\ajax_forms_test\Form\AjaxFormsTestSimpleForm.
+ */
+
+namespace Drupal\ajax_forms_test\Form;
+
+use Drupal\Core\Form\FormBase;
+use Drupal\ajax_forms_test\Callbacks;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Form builder: Builds a form that triggers a simple AJAX callback.
+ */
+class AjaxFormsTestSimpleForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'ajax_forms_test_simple_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    $object = new Callbacks();
+
+    $form = array();
+    $form['select'] = array(
+      '#title' => $this->t('Color'),
+      '#type' => 'select',
+      '#options' => array(
+        'red' => 'red',
+        'green' => 'green',
+        'blue' => 'blue'),
+      '#ajax' => array(
+        'callback' => array($object, 'selectCallback'),
+      ),
+      '#suffix' => '<div id="ajax_selected_color">No color yet selected</div>',
+    );
+
+    $form['checkbox'] = array(
+      '#type' => 'checkbox',
+      '#title' => $this->t('Test checkbox'),
+      '#ajax' => array(
+        'callback' => array($object, 'checkboxCallback'),
+      ),
+      '#suffix' => '<div id="ajax_checkbox_value">No action yet</div>',
+    );
+    $form['submit'] = array(
+      '#type' => 'submit',
+      '#value' => $this->t('submit'),
+    );
+
+    // This is for testing invalid callbacks that should return a 500 error in
+    // \Drupal\system\FormAjaxController::content().
+    $invalid_callbacks = array(
+      'null' => NULL,
+      'empty' => '',
+      'nonexistent' => 'some_function_that_does_not_exist',
+    );
+    foreach ($invalid_callbacks as $key => $value) {
+      $form['select_' . $key . '_callback'] = array(
+        '#type' => 'select',
+        '#title' => $this->t('Test %key callbacks', array('%key' => $key)),
+        '#options' => array('red' => 'red'),
+        '#ajax' => array('callback' => $value),
+      );
+    }
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+  }
+
+}

core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestValidationForm.php

@@ -0,0 +1,76 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\ajax_forms_test\Form\AjaxFormsTestValidationForm.
+ */
+
+namespace Drupal\ajax_forms_test\Form;
+
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Form builder: Builds a form that triggers a simple AJAX callback.
+ */
+class AjaxFormsTestValidationForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'ajax_forms_test_validation_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    $form['drivertext'] = array(
+      '#title' => $this->t('AJAX-enabled textfield.'),
+      '#description' => $this->t("When this one AJAX-triggers and the spare required field is empty, you should not get an error."),
+      '#type' => 'textfield',
+      '#default_value' => $form_state->getValue('drivertext', ''),
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_validation_form_callback',
+        'wrapper' => 'message_area',
+        'method' => 'replace',
+      ),
+      '#suffix' => '<div id="message_area"></div>',
+    );
+
+    $form['drivernumber'] = array(
+      '#title' => $this->t('AJAX-enabled number field.'),
+      '#description' => $this->t("When this one AJAX-triggers and the spare required field is empty, you should not get an error."),
+      '#type' => 'number',
+      '#default_value' => $form_state->getValue('drivernumber', ''),
+      '#ajax' => array(
+        'callback' => 'ajax_forms_test_validation_number_form_callback',
+        'wrapper' => 'message_area_number',
+        'method' => 'replace',
+      ),
+      '#suffix' => '<div id="message_area_number"></div>',
+    );
+
+    $form['spare_required_field'] = array(
+      '#title' => $this->t("Spare Required Field"),
+      '#type' => 'textfield',
+      '#required' => TRUE,
+    );
+
+    $form['submit'] = array(
+      '#type' => 'submit',
+      '#value' => $this->t('Submit'),
+    );
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    drupal_set_message($this->t("Validation form submitted"));
+  }
+
+}

core/modules/system/tests/modules/ajax_forms_test/src/Plugin/Block/AjaxFormBlock.php

@@ -0,0 +1,140 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\ajax_forms_test\Plugin\Block\AjaxFormBlock.
+ */
+
+namespace Drupal\ajax_forms_test\Plugin\Block;
+
+use Drupal\Core\Block\BlockBase;
+use Drupal\Core\Form\FormBuilderInterface;
+use Drupal\Core\Form\FormInterface;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Provides an AJAX form block.
+ *
+ * @Block(
+ *   id = "ajax_forms_test_block",
+ *   admin_label = @Translation("AJAX test form"),
+ *   category = @Translation("Forms")
+ * )
+ */
+class AjaxFormBlock extends BlockBase implements FormInterface, ContainerFactoryPluginInterface {
+
+  /**
+   * The form builder.
+   *
+   * @var \Drupal\Core\Form\FormBuilderInterface
+   */
+  protected $formBuilder;
+
+  /**
+   * Constructs a new AjaxFormBlock.
+   *
+   * @param array $configuration
+   *   A configuration array containing information about the plugin instance.
+   * @param string $plugin_id
+   *   The plugin ID for the plugin instance.
+   * @param mixed $plugin_definition
+   *   The plugin implementation definition.
+   * @param \Drupal\Core\Form\FormBuilderInterface $form_builder
+   *   The form builder.
+   */
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, FormBuilderInterface $form_builder) {
+    parent::__construct($configuration, $plugin_id, $plugin_definition);
+    $this->formBuilder = $form_builder;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
+    return new static(
+      $configuration,
+      $plugin_id,
+      $plugin_definition,
+      $container->get('form_builder')
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function build() {
+    return $this->formBuilder->getForm($this);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'ajax_forms_test_block';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    $form['test1'] = [
+      '#type' => 'select',
+      '#title' => $this->t('Test 1'),
+      '#required' => TRUE,
+      '#options' => [
+        'option1' => $this->t('Option 1'),
+        'option2' => $this->t('Option 2'),
+      ],
+      '#ajax' => [
+        'callback' => '::updateOptions',
+        'wrapper' => 'edit-test1-wrapper',
+      ],
+      '#prefix' => '<div id="edit-test1-wrapper">',
+      '#suffix' => '</div>',
+    ];
+    $form['actions'] = [
+      '#type' => 'actions',
+    ];
+    $form['actions']['submit'] = [
+      '#type' => 'submit',
+      '#value' => $this->t('Submit'),
+    ];
+    return $form;
+  }
+
+  /**
+   * Updates the options of a select list.
+   *
+   * @param array $form
+   *   An associative array containing the structure of the form.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The current state of the form.
+   *
+   * @return array
+   *   The updated form element.
+   */
+  public function updateOptions(array $form, FormStateInterface $form_state) {
+    $form['test1']['#options']['option1'] = $this->t('Option 1!!!');
+    $form['test1']['#options'] += [
+      'option3' => $this->t('Option 3'),
+      'option4' => $this->t('Option 4'),
+    ];
+    return $form['test1'];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateForm(array &$form, FormStateInterface $form_state) {
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    drupal_set_message('Submission successful.');
+  }
+
+}

core/modules/system/tests/modules/ajax_test/ajax_test.info.yml

@@ -0,0 +1,8 @@
+name: 'AJAX Test'
+type: module
+description: 'Support module for AJAX framework tests.'
+package: Testing
+version: VERSION
+core: 8.x
+dependencies:
+  - contact

core/modules/system/tests/modules/ajax_test/ajax_test.libraries.yml

@@ -0,0 +1,23 @@
+order:
+ drupalSettings:
+   ajax: test
+ dependencies:
+   - ajax_test/order-css-command
+   - ajax_test/order-footer-js-command
+   - ajax_test/order-header-js-command
+
+order-css-command:
+  css:
+     theme:
+       # Two CSS files (order should remain the same).
+       a.css: {}
+       b.css: {}
+
+order-footer-js-command:
+  js:
+    footer.js: {}
+
+order-header-js-command:
+  header: true
+  js:
+    header.js: {}

core/modules/system/tests/modules/ajax_test/ajax_test.routing.yml

@@ -0,0 +1,52 @@
+ajax_test.dialog_contents:
+  path: '/ajax-test/dialog-contents'
+  defaults:
+    _title: 'AJAX Dialog contents routing'
+    _controller: '\Drupal\ajax_test\Controller\AjaxTestController::dialogContents'
+  requirements:
+    _access: 'TRUE'
+
+ajax_test.dialog_form:
+  path: '/ajax-test/dialog-form'
+  defaults:
+    _title: 'Ajax Form contents'
+    _form: '\Drupal\ajax_test\Form\AjaxTestForm'
+  requirements:
+    _access: 'TRUE'
+
+ajax_test.dialog:
+  path: '/ajax-test/dialog'
+  defaults:
+    _controller: '\Drupal\ajax_test\Controller\AjaxTestController::dialog'
+  requirements:
+    _access: 'TRUE'
+
+ajax_test.dialog_close:
+  path: '/ajax-test/dialog-close'
+  defaults:
+    _controller: '\Drupal\ajax_test\Controller\AjaxTestController::dialogClose'
+  requirements:
+    _access: 'TRUE'
+
+ajax_test.render:
+  path: '/ajax-test/render'
+  defaults:
+    _controller: '\Drupal\ajax_test\Controller\AjaxTestController::render'
+  requirements:
+    _access: 'TRUE'
+
+ajax_test.order:
+  path: '/ajax-test/order'
+  defaults:
+    _controller: '\Drupal\ajax_test\Controller\AjaxTestController::order'
+  options:
+    _theme: ajax_base_page
+  requirements:
+    _access: 'TRUE'
+
+ajax_test.render_error:
+  path: '/ajax-test/render-error'
+  defaults:
+    _controller: '\Drupal\ajax_test\Controller\AjaxTestController::renderError'
+  requirements:
+    _access: 'TRUE'

core/modules/system/tests/modules/ajax_test/src/Controller/AjaxTestController.php

@@ -0,0 +1,211 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\ajax_test\Controller\AjaxTestController.
+ */
+
+namespace Drupal\ajax_test\Controller;
+
+use Drupal\Core\Ajax\AjaxResponse;
+use Drupal\Core\Ajax\AlertCommand;
+use Drupal\Core\Ajax\CloseDialogCommand;
+use Drupal\Core\Ajax\HtmlCommand;
+use Drupal\Core\Url;
+use Symfony\Component\HttpFoundation\Request;
+
+/**
+ * Provides content for dialog tests.
+ */
+class AjaxTestController {
+
+  /**
+   * Example content for dialog testing.
+   *
+   * @return array
+   *   Renderable array of AJAX dialog contents.
+   */
+  public static function dialogContents() {
+    // This is a regular render array; the keys do not have special meaning.
+    $content = array(
+      '#title' => 'AJAX Dialog contents',
+      'content' => array(
+        '#markup' => 'Example message',
+      ),
+      'cancel' => array(
+        '#type' => 'link',
+        '#title' => 'Cancel',
+        '#url' => Url::fromRoute('<front>'),
+        '#attributes' => array(
+          // This is a special class to which JavaScript assigns dialog closing
+          // behavior.
+          'class' => array('dialog-cancel'),
+        ),
+      ),
+    );
+
+    return $content;
+  }
+
+  /**
+   * Returns a render array that will be rendered by AjaxRenderer.
+   *
+   * Ensures that \Drupal\Core\Ajax\AjaxResponse::ajaxRender()
+   * incorporates JavaScript settings generated during the page request by
+   * adding a dummy setting.
+   */
+  public function render() {
+    return [
+      '#attached' => [
+        'library' => [
+          'core/drupalSettings',
+        ],
+        'drupalSettings' => [
+          'ajax' => 'test',
+        ],
+      ],
+    ];
+  }
+
+  /**
+   * Returns an AjaxResponse; settings command set last.
+   *
+   * Helps verifying AjaxResponse reorders commands to ensure correct execution.
+   */
+  public function order() {
+    $response = new AjaxResponse();
+    // HTML insertion command.
+    $response->addCommand(new HtmlCommand('body', 'Hello, world!'));
+    $build['#attached']['library'][] = 'ajax_test/order';
+    $response->setAttachments($build['#attached']);
+
+    return $response;
+  }
+
+  /**
+   * Returns an AjaxResponse with alert command.
+   *
+   * @param \Symfony\Component\HttpFoundation\Request $request
+   *   The current request object.
+   *
+   * @return \Drupal\Core\Ajax\AjaxResponse
+   *   The JSON response object.
+   */
+  public function renderError(Request $request) {
+    $message = '';
+    $query = $request->query;
+    if ($query->has('message')) {
+      $message = $query->get('message');
+    }
+    $response = new AjaxResponse();
+    $response->addCommand(new AlertCommand($message));
+    return $response;
+  }
+
+  /**
+   * Returns a render array of form elements and links for dialog.
+   */
+  public function dialog() {
+    // Add two wrapper elements for testing non-modal dialogs. Modal dialogs use
+    // the global drupal-modal wrapper by default.
+    $build['dialog_wrappers'] = array('#markup' => '<div id="ajax-test-dialog-wrapper-1"></div><div id="ajax-test-dialog-wrapper-2"></div>');
+
+    // Dialog behavior applied to a button.
+    $build['form'] = \Drupal::formBuilder()->getForm('Drupal\ajax_test\Form\AjaxTestDialogForm');
+
+    // Dialog behavior applied to a #type => 'link'.
+    $build['link'] = array(
+      '#type' => 'link',
+      '#title' => 'Link 1 (modal)',
+      '#url' => Url::fromRoute('ajax_test.dialog_contents'),
+      '#attributes' => array(
+        'class' => array('use-ajax'),
+        'data-dialog-type' => 'modal',
+      ),
+    );
+
+    // Dialog behavior applied to links rendered by links.html.twig.
+    $build['links'] = array(
+      '#theme' => 'links',
+      '#links' => array(
+        'link2' => array(
+          'title' => 'Link 2 (modal)',
+          'url' => Url::fromRoute('ajax_test.dialog_contents'),
+          'attributes' => array(
+            'class' => array('use-ajax'),
+            'data-dialog-type' => 'modal',
+            'data-dialog-options' => json_encode(array(
+              'width' => 400,
+            ))
+          ),
+        ),
+        'link3' => array(
+          'title' => 'Link 3 (non-modal)',
+          'url' => Url::fromRoute('ajax_test.dialog_contents'),
+          'attributes' => array(
+            'class' => array('use-ajax'),
+            'data-dialog-type' => 'dialog',
+            'data-dialog-options' => json_encode(array(
+              'target' => 'ajax-test-dialog-wrapper-1',
+              'width' => 800,
+            ))
+          ),
+        ),
+        'link4' => array(
+          'title' => 'Link 4 (close non-modal if open)',
+          'url' => Url::fromRoute('ajax_test.dialog_close'),
+          'attributes' => array(
+            'class' => array('use-ajax'),
+            'data-dialog-type' => 'modal',
+          ),
+        ),
+        'link5' => array(
+          'title' => 'Link 5 (form)',
+          'url' => Url::fromRoute('ajax_test.dialog_form'),
+          'attributes' => array(
+            'class' => array('use-ajax'),
+            'data-dialog-type' => 'modal',
+          ),
+        ),
+        'link6' => array(
+          'title' => 'Link 6 (entity form)',
+          'url' => Url::fromRoute('contact.form_add'),
+          'attributes' => array(
+            'class' => array('use-ajax'),
+            'data-dialog-type' => 'modal',
+            'data-dialog-options' => json_encode(array(
+              'width' => 800,
+              'height' => 500,
+            ))
+          ),
+        ),
+        'link7' => array(
+          'title' => 'Link 7 (non-modal, no target)',
+          'url' => Url::fromRoute('ajax_test.dialog_contents'),
+          'attributes' => array(
+            'class' => array('use-ajax'),
+            'data-dialog-type' => 'dialog',
+            'data-dialog-options' => json_encode(array(
+              'width' => 800,
+            ))
+          ),
+        ),
+      ),
+    );
+
+    return $build;
+  }
+
+  /**
+   * Returns an AjaxResponse with command to close dialog.
+   *
+   * @return \Drupal\Core\Ajax\AjaxResponse
+   *   The JSON response object.
+   */
+  public function dialogClose() {
+    $response = new AjaxResponse();
+    $response->addCommand(new CloseDialogCommand('#ajax-test-dialog-wrapper-1'));
+    return $response;
+  }
+
+}

core/modules/system/tests/modules/ajax_test/src/Form/AjaxTestDialogForm.php

@@ -0,0 +1,117 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\ajax_test\Form\AjaxTestDialogForm.
+ */
+
+namespace Drupal\ajax_test\Form;
+
+use Drupal\ajax_test\Controller\AjaxTestController;
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Ajax\AjaxResponse;
+use Drupal\Core\Ajax\OpenModalDialogCommand;
+use Drupal\Core\Ajax\OpenDialogCommand;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Dummy form for testing DialogRenderer with _form routes.
+ */
+class AjaxTestDialogForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'ajax_test_dialog_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    // In order to use WebTestBase::drupalPostAjaxForm() to POST from a link, we need
+    // to have a dummy field we can set in WebTestBase::drupalPostForm() else it won't
+    // submit anything.
+    $form['textfield'] = array(
+      '#type' => 'hidden'
+    );
+    $form['button1'] = array(
+      '#type' => 'submit',
+      '#name' => 'button1',
+      '#value' => 'Button 1 (modal)',
+      '#ajax' => array(
+        'callback' => '::modal',
+      ),
+    );
+    $form['button2'] = array(
+      '#type' => 'submit',
+      '#name' => 'button2',
+      '#value' => 'Button 2 (non-modal)',
+      '#ajax' => array(
+        'callback' => '::nonModal',
+      ),
+    );
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateForm(array &$form, FormStateInterface $form_state) {
+
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    $form_state->setRedirect('ajax_test.dialog_contents');
+  }
+
+
+  /**
+   * AJAX callback handler for AjaxTestDialogForm.
+   */
+  public function modal(&$form, FormStateInterface $form_state) {
+    return $this->dialog(TRUE);
+  }
+
+  /**
+   * AJAX callback handler for AjaxTestDialogForm.
+   */
+  public function nonModal(&$form, FormStateInterface $form_state) {
+    return $this->dialog(FALSE);
+  }
+
+
+  /**
+   * Util to render dialog in ajax callback.
+   *
+   * @param bool $is_modal
+   *   (optional) TRUE if modal, FALSE if plain dialog. Defaults to FALSE.
+   *
+   * @return \Drupal\Core\Ajax\AjaxResponse
+   *   An ajax response object.
+   */
+  protected function dialog($is_modal = FALSE) {
+    $content = AjaxTestController::dialogContents();
+    $response = new AjaxResponse();
+    $title = $this->t('AJAX Dialog contents');
+
+    // Attach the library necessary for using the Open(Modal)DialogCommand and
+    // set the attachments for this Ajax response.
+    $content['#attached']['library'][] = 'core/drupal.dialog.ajax';
+
+    if ($is_modal) {
+      $response->addCommand(new OpenModalDialogCommand($title, $content));
+    }
+    else {
+      $selector = '#ajax-test-dialog-wrapper-1';
+      $response->addCommand(new OpenDialogCommand($selector, $title, $content));
+    }
+    return $response;
+  }
+
+}

core/modules/system/tests/modules/ajax_test/src/Form/AjaxTestForm.php

@@ -0,0 +1,74 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\ajax_test\Form\AjaxTestForm.
+ */
+
+namespace Drupal\ajax_test\Form;
+
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Dummy form for testing DialogRenderer with _form routes.
+ */
+class AjaxTestForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'ajax_test_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+
+    $form['#action'] = \Drupal::url('ajax_test.dialog');
+
+    $form['description'] = array(
+      '#markup' => '<p>' . $this->t("Ajax Form contents description.") . '</p>',
+    );
+
+    $form['actions'] = array(
+      '#type' => 'actions',
+    );
+    $form['actions']['submit'] = array(
+      '#type' => 'submit',
+      '#value' => $this->t('Do it'),
+    );
+    $form['actions']['preview'] = array(
+      '#type' => 'submit',
+      '#value' => $this->t('Preview'),
+      // No regular submit-handler. This form only works via JavaScript.
+      '#submit' => array(),
+      '#ajax' => array(
+        // This means the ::preview() method on this class would be invoked in
+        // case of a click event. However, since Drupal core's test runner only
+        // is able to execute PHP, not JS, there is no point in actually
+        // implementing this method, because we can never let it be called from
+        // JS; we'd have to manually call it from PHP, at which point we would
+        // not actually be testing it.
+        // Therefore we consciously choose to not implement this method, because
+        // we cannot meaningfully test it anyway.
+        'callback' => '::preview',
+        'event' => 'click',
+      ),
+    );
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {}
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateForm(array &$form, FormStateInterface $form_state) {}
+
+}

core/modules/system/tests/modules/batch_test/batch_test.callbacks.inc

@@ -0,0 +1,160 @@
+<?php
+
+/**
+ * @file
+ * Batch callbacks for the Batch API tests.
+ */
+
+use Drupal\Component\Utility\SafeMarkup;
+
+/**
+ * Implements callback_batch_operation().
+ *
+ * Performs a simple batch operation.
+ */
+function _batch_test_callback_1($id, $sleep, &$context) {
+  // No-op, but ensure the batch take a couple iterations.
+  // Batch needs time to run for the test, so sleep a bit.
+  usleep($sleep);
+  // Track execution, and store some result for post-processing in the
+  // 'finished' callback.
+  batch_test_stack("op 1 id $id");
+  $context['results'][1][] = $id;
+}
+
+/**
+ * Implements callback_batch_operation().
+ *
+ * Performs a multistep batch operation.
+ */
+function _batch_test_callback_2($start, $total, $sleep, &$context) {
+  // Initialize context with progress information.
+  if (!isset($context['sandbox']['current'])) {
+    $context['sandbox']['current'] = $start;
+    $context['sandbox']['count'] = 0;
+  }
+
+  // Process by groups of 5 (arbitrary value).
+  $limit = 5;
+  for ($i = 0; $i < $limit && $context['sandbox']['count'] < $total; $i++) {
+    // No-op, but ensure the batch take a couple iterations.
+    // Batch needs time to run for the test, so sleep a bit.
+    usleep($sleep);
+    // Track execution, and store some result for post-processing in the
+    // 'finished' callback.
+    $id = $context['sandbox']['current'] + $i;
+    batch_test_stack("op 2 id $id");
+    $context['results'][2][] = $id;
+
+    // Update progress information.
+    $context['sandbox']['count']++;
+  }
+  $context['sandbox']['current'] += $i;
+
+  // Inform batch engine about progress.
+  if ($context['sandbox']['count'] != $total) {
+    $context['finished'] = $context['sandbox']['count'] / $total;
+  }
+}
+
+/**
+ * Implements callback_batch_operation().
+ */
+function _batch_test_callback_5($id, $sleep, &$context) {
+  // No-op, but ensure the batch take a couple iterations.
+  // Batch needs time to run for the test, so sleep a bit.
+  usleep($sleep);
+  // Track execution, and store some result for post-processing in the
+  // 'finished' callback.
+  batch_test_stack("op 5 id $id");
+  $context['results'][5][] = $id;
+  // This test is to test finished > 1
+  $context['finished'] = 3.14;
+}
+
+/**
+ * Implements callback_batch_operation().
+ *
+ * Performs a batch operation setting up its own batch.
+ */
+function _batch_test_nested_batch_callback() {
+  batch_test_stack('setting up batch 2');
+  batch_set(_batch_test_batch_2());
+}
+
+/**
+ * Provides a common 'finished' callback for batches 1 to 4.
+ */
+function _batch_test_finished_helper($batch_id, $success, $results, $operations) {
+  $messages = array("results for batch $batch_id");
+  if ($results) {
+    foreach ($results as $op => $op_results) {
+      $messages[] = 'op '. SafeMarkup::escape($op) . ': processed ' . count($op_results) . ' elements';
+    }
+  }
+  else {
+    $messages[] = 'none';
+  }
+
+  if (!$success) {
+    // A fatal error occurred during the processing.
+    $error_operation = reset($operations);
+    $messages[] = t('An error occurred while processing @op with arguments:<br />@args', array('@op' => $error_operation[0], '@args' => print_r($error_operation[1], TRUE)));
+  }
+
+  drupal_set_message(SafeMarkup::set(implode('<br>', $messages)));
+}
+
+/**
+ * Implements callback_batch_finished().
+ *
+ * Triggers 'finished' callback for batch 0.
+ */
+function _batch_test_finished_0($success, $results, $operations) {
+  _batch_test_finished_helper(0, $success, $results, $operations);
+}
+
+/**
+ * Implements callback_batch_finished().
+ *
+ * Triggers 'finished' callback for batch 1.
+ */
+function _batch_test_finished_1($success, $results, $operations) {
+  _batch_test_finished_helper(1, $success, $results, $operations);
+}
+
+/**
+ * Implements callback_batch_finished().
+ *
+ * Triggers 'finished' callback for batch 2.
+ */
+function _batch_test_finished_2($success, $results, $operations) {
+  _batch_test_finished_helper(2, $success, $results, $operations);
+}
+
+/**
+ * Implements callback_batch_finished().
+ *
+ * Triggers 'finished' callback for batch 3.
+ */
+function _batch_test_finished_3($success, $results, $operations) {
+  _batch_test_finished_helper(3, $success, $results, $operations);
+}
+
+/**
+ * Implements callback_batch_finished().
+ *
+ * Triggers 'finished' callback for batch 4.
+ */
+function _batch_test_finished_4($success, $results, $operations) {
+  _batch_test_finished_helper(4, $success, $results, $operations);
+}
+
+/**
+ * Implements callback_batch_finished().
+ *
+ * Triggers 'finished' callback for batch 5.
+ */
+function _batch_test_finished_5($success, $results, $operations) {
+  _batch_test_finished_helper(5, $success, $results, $operations);
+}

core/modules/system/tests/modules/batch_test/batch_test.info.yml

@@ -0,0 +1,6 @@
+name: 'Batch API test'
+type: module
+description: 'Support module for Batch API tests.'
+package: Testing
+version: VERSION
+core: 8.x

core/modules/system/tests/modules/batch_test/batch_test.links.task.yml

@@ -0,0 +1,46 @@
+batch_test.test_form:
+  title: Simple
+  route_name: batch_test.test_form
+  base_route: batch_test.test_form
+
+batch_test.multistep:
+  title: Multistep
+  route_name: batch_test.multistep
+  base_route: batch_test.test_form
+  weight: 1
+
+batch_test.chained:
+  title: Chained
+  route_name: batch_test.chained
+  base_route: batch_test.test_form
+  weight: 2
+
+batch_test.programmatic:
+  title: Chained
+  route_name: batch_test.programmatic
+  base_route: batch_test.test_form
+  weight: 3
+
+batch_test.no_form:
+  title: 'No form'
+  route_name: batch_test.no_form
+  base_route: batch_test.test_form
+  weight: 4
+
+batch_test.large_percentage:
+  title: 'Large percentage'
+  route_name: batch_test.large_percentage
+  base_route: batch_test.test_form
+  weight: 5
+
+batch_test.nested_programmatic:
+  title: 'Nested programmatic'
+  route_name: batch_test.nested_programmatic
+  base_route: batch_test.test_form
+  weight: 6
+
+batch_test.redirect:
+  title: 'Redirect'
+  route_name: batch_test.redirect
+  base_route: batch_test.test_form
+  weight: 7

core/modules/system/tests/modules/batch_test/batch_test.module

@@ -0,0 +1,199 @@
+<?php
+
+/**
+ * @file
+ * Helper module for the Batch API tests.
+ */
+
+use Drupal\Core\Form\FormState;
+
+/**
+ * Batch operation: Submits form_test_mock_form().
+ */
+function _batch_test_nested_drupal_form_submit_callback($value) {
+  $form_state = (new FormState())
+    ->setValue('test_value', $value);
+  \Drupal::formBuilder()->submitForm('Drupal\batch_test\Form\BatchTestMockForm', $form_state);
+}
+
+/**
+ * Batch 0: Does nothing.
+ */
+function _batch_test_batch_0() {
+  $batch = array(
+    'operations' => array(),
+    'finished' => '_batch_test_finished_0',
+    'file' => drupal_get_path('module', 'batch_test'). '/batch_test.callbacks.inc',
+  );
+  return $batch;
+}
+
+/**
+ * Batch 1: Repeats a simple operation.
+ *
+ * Operations: op 1 from 1 to 10.
+ */
+function _batch_test_batch_1() {
+  // Ensure the batch takes at least two iterations.
+  $total = 10;
+  $sleep = (1000000 / $total) * 2;
+
+  $operations = array();
+  for ($i = 1; $i <= $total; $i++) {
+    $operations[] = array('_batch_test_callback_1', array($i, $sleep));
+  }
+  $batch = array(
+    'operations' => $operations,
+    'finished' => '_batch_test_finished_1',
+    'file' => drupal_get_path('module', 'batch_test'). '/batch_test.callbacks.inc',
+  );
+  return $batch;
+}
+
+/**
+ * Batch 2: Performs a single multistep operation.
+ *
+ * Operations: op 2 from 1 to 10.
+ */
+function _batch_test_batch_2() {
+  // Ensure the batch takes at least two iterations.
+  $total = 10;
+  $sleep = (1000000 / $total) * 2;
+
+  $operations = array(
+    array('_batch_test_callback_2', array(1, $total, $sleep)),
+  );
+  $batch = array(
+    'operations' => $operations,
+    'finished' => '_batch_test_finished_2',
+    'file' => drupal_get_path('module', 'batch_test') . '/batch_test.callbacks.inc',
+  );
+  return $batch;
+}
+
+/**
+ * Batch 3: Performs both single and multistep operations.
+ *
+ * Operations:
+ * - op 1 from 1 to 5,
+ * - op 2 from 1 to 5,
+ * - op 1 from 6 to 10,
+ * - op 2 from 6 to 10.
+ */
+function _batch_test_batch_3() {
+  // Ensure the batch takes at least two iterations.
+  $total = 10;
+  $sleep = (1000000 / $total) * 2;
+
+  $operations = array();
+  for ($i = 1; $i <= round($total / 2); $i++) {
+    $operations[] = array('_batch_test_callback_1', array($i, $sleep));
+  }
+  $operations[] = array('_batch_test_callback_2', array(1, $total / 2, $sleep));
+  for ($i = round($total / 2) + 1; $i <= $total; $i++) {
+    $operations[] = array('_batch_test_callback_1', array($i, $sleep));
+  }
+  $operations[] = array('_batch_test_callback_2', array(6, $total / 2, $sleep));
+  $batch = array(
+    'operations' => $operations,
+    'finished' => '_batch_test_finished_3',
+    'file' => drupal_get_path('module', 'batch_test') . '/batch_test.callbacks.inc',
+  );
+  return $batch;
+}
+
+/**
+ * Batch 4: Performs a batch within a batch.
+ *
+ * Operations:
+ * - op 1 from 1 to 5,
+ * - set batch 2 (op 2 from 1 to 10, should run at the end)
+ * - op 1 from 6 to 10,
+ */
+function _batch_test_batch_4() {
+  // Ensure the batch takes at least two iterations.
+  $total = 10;
+  $sleep = (1000000 / $total) * 2;
+
+  $operations = array();
+  for ($i = 1; $i <= round($total / 2); $i++) {
+    $operations[] = array('_batch_test_callback_1', array($i, $sleep));
+  }
+  $operations[] = array('_batch_test_nested_batch_callback', array());
+  for ($i = round($total / 2) + 1; $i <= $total; $i++) {
+    $operations[] = array('_batch_test_callback_1', array($i, $sleep));
+  }
+  $batch = array(
+    'operations' => $operations,
+    'finished' => '_batch_test_finished_4',
+    'file' => drupal_get_path('module', 'batch_test') . '/batch_test.callbacks.inc',
+  );
+  return $batch;
+}
+
+/**
+ * Batch 5: Repeats a simple operation.
+ *
+ * Operations: op 1 from 1 to 10.
+ */
+function _batch_test_batch_5() {
+  // Ensure the batch takes at least two iterations.
+  $total = 10;
+  $sleep = (1000000 / $total) * 2;
+
+  $operations = array();
+  for ($i = 1; $i <= $total; $i++) {
+    $operations[] = array('_batch_test_callback_5', array($i, $sleep));
+  }
+  $batch = array(
+    'operations' => $operations,
+    'finished' => '_batch_test_finished_5',
+    'file' => drupal_get_path('module', 'batch_test'). '/batch_test.callbacks.inc',
+  );
+  return $batch;
+}
+
+/**
+ * Implements callback_batch_operation().
+ *
+ * Tests the progress page theme.
+ */
+function _batch_test_theme_callback() {
+  // Because drupalGet() steps through the full progressive batch before
+  // returning control to the test function, we cannot test that the correct
+  // theme is being used on the batch processing page by viewing that page
+  // directly. Instead, we save the theme being used in a variable here, so
+  // that it can be loaded and inspected in the thread running the test.
+  $theme = \Drupal::theme()->getActiveTheme()->getName();
+  batch_test_stack($theme);
+}
+
+/**
+ * Tests the title on the progress page by performing a batch callback.
+ */
+function _batch_test_title_callback() {
+  // Because drupalGet() steps through the full progressive batch before
+  // returning control to the test function, we cannot test that the correct
+  // title is being used on the batch processing page by viewing that page
+  // directly. Instead, we save the title being used in a variable here, so
+  // that it can be loaded and inspected in the thread running the test.
+  $request = \Drupal::request();
+  $route_match = \Drupal::routeMatch();
+  $title = \Drupal::service('title_resolver')->getTitle($request, $route_match->getRouteObject());
+  batch_test_stack($title);
+}
+
+/**
+ * Helper function: Stores or retrieves traced execution data.
+ */
+function batch_test_stack($data = NULL, $reset = FALSE) {
+  if ($reset) {
+    \Drupal::state()->delete('batch_test.stack');
+  }
+  if (!isset($data)) {
+    return \Drupal::state()->get('batch_test.stack');
+  }
+  $stack = \Drupal::state()->get('batch_test.stack');
+  $stack[] = $data;
+  \Drupal::state()->set('batch_test.stack', $stack);
+}

core/modules/system/tests/modules/batch_test/batch_test.routing.yml

@@ -0,0 +1,79 @@
+batch_test.redirect:
+  path: '/batch-test/redirect'
+  defaults:
+    _controller: '\Drupal\batch_test\Controller\BatchTestController::testRedirect'
+    _title: 'Redirect'
+  requirements:
+    _access:  'TRUE'
+
+batch_test.large_percentage:
+  path: '/batch-test/large-percentage'
+  defaults:
+    _controller: '\Drupal\batch_test\Controller\BatchTestController::testLargePercentage'
+    _title: 'Simple page with batch over 100% complete'
+  requirements:
+    _access:  'TRUE'
+
+batch_test.nested_programmatic:
+  path: '/batch-test/nested-programmatic/{value}'
+  defaults:
+    _controller: '\Drupal\batch_test\Controller\BatchTestController::testNestedDrupalFormSubmit'
+    _title: 'Nested programmatic'
+    value: '1'
+  requirements:
+    _access: 'TRUE'
+
+batch_test.no_form:
+  path: '/batch-test/no-form'
+  defaults:
+    _controller: '\Drupal\batch_test\Controller\BatchTestController::testNoForm'
+    _title: 'Simple page'
+  requirements:
+    _access: 'TRUE'
+
+batch_test.test_form:
+  path: '/batch-test'
+  defaults:
+    _form: '\Drupal\batch_test\Form\BatchTestSimpleForm'
+    _title: 'Batch test'
+  requirements:
+    _access: 'TRUE'
+
+batch_test.multistep:
+  path: '/batch-test/multistep'
+  defaults:
+    _form: '\Drupal\batch_test\Form\BatchTestMultiStepForm'
+    _title: 'Multistep'
+  requirements:
+    _access: 'TRUE'
+
+batch_test.chained:
+  path: '/batch-test/chained'
+  defaults:
+    _form: '\Drupal\batch_test\Form\BatchTestChainedForm'
+    _title: 'Chained'
+  requirements:
+    _access: 'TRUE'
+
+batch_test.programmatic:
+  path: '/batch-test/programmatic/{value}'
+  defaults:
+    _controller: '\Drupal\batch_test\Controller\BatchTestController::testProgrammatic'
+    _title: 'Programmatic'
+    value: '1'
+  requirements:
+    _access: 'TRUE'
+
+batch_test.test_theme:
+  path: '/admin/batch-test/test-theme'
+  defaults:
+    _controller: '\Drupal\batch_test\Controller\BatchTestController::testThemeBatch'
+  requirements:
+    _access: 'TRUE'
+
+batch_test.test_title:
+  path: '/batch-test/test-title'
+  defaults:
+    _controller: '\Drupal\batch_test\Controller\BatchTestController::testTitleBatch'
+  requirements:
+    _access: 'TRUE'

core/modules/system/tests/modules/batch_test/src/Controller/BatchTestController.php

@@ -0,0 +1,134 @@
+<?php
+/**
+ * @file
+ * Contains \Drupal\batch_test\Controller\BatchTestController.
+ */
+
+namespace Drupal\batch_test\Controller;
+
+use Drupal\Core\Form\FormState;
+
+/**
+ * Controller routines for batch tests.
+ */
+class BatchTestController {
+
+  /**
+   * Redirects successfully.
+   *
+   * @return array
+   *   Render array containing success message.
+   */
+  public function testRedirect() {
+    return array(
+      'success' => array(
+        '#markup' => 'Redirection successful.',
+      )
+    );
+  }
+
+  /**
+   * Fires a batch process without a form submission.
+   *
+   * @return \Symfony\Component\HttpFoundation\RedirectResponse|null
+   *   A redirect response if the batch is progressive. No return value otherwise.
+   */
+  public function testLargePercentage() {
+    batch_test_stack(NULL, TRUE);
+
+    batch_set(_batch_test_batch_5());
+    return batch_process('batch-test/redirect');
+  }
+
+  /**
+   * Submits a form within a batch programmatically.
+   *
+   * @param int $value
+   *   Some value passed to a custom batch callback.
+   *
+   * @return \Symfony\Component\HttpFoundation\RedirectResponse|null
+   *   A redirect response if the batch is progressive. No return value otherwise.
+   */
+  public function testNestedDrupalFormSubmit($value = 1) {
+    // Set the batch and process it.
+    $batch['operations'] = array(
+      array('_batch_test_nested_drupal_form_submit_callback', array($value)),
+    );
+    batch_set($batch);
+    return batch_process('batch-test/redirect');
+  }
+
+  /**
+   * Fires a batch process without a form submission.
+   *
+   * @return \Symfony\Component\HttpFoundation\RedirectResponse|null
+   *   A redirect response if the batch is progressive. No return value otherwise.
+   */
+  public function testNoForm() {
+    batch_test_stack(NULL, TRUE);
+
+    batch_set(_batch_test_batch_1());
+    return batch_process('batch-test/redirect');
+
+  }
+
+  /**
+   * Submits the 'Chained' form programmatically.
+   *
+   * Programmatic form: the page submits the 'Chained' form through
+   * \Drupal::formBuilder()->submitForm().
+   *
+   * @param int $value
+   *   Some value passed to a the chained form.
+   *
+   * @return array
+   *   Render array containing markup.
+   */
+  function testProgrammatic($value = 1) {
+    $form_state = (new FormState())->setValues([
+      'value' => $value,
+    ]);
+    \Drupal::formBuilder()->submitForm('Drupal\batch_test\Form\BatchTestChainedForm', $form_state);
+    return array(
+      'success' => array(
+        '#markup' => 'Got out of a programmatic batched form.',
+      )
+    );
+  }
+
+  /**
+   * Runs a batch for testing theme used on the progress page.
+   *
+   * @return \Symfony\Component\HttpFoundation\RedirectResponse|null
+   *   A redirect response if the batch is progressive. No return value otherwise.
+   */
+  public function testThemeBatch() {
+    batch_test_stack(NULL, TRUE);
+    $batch = array(
+      'operations' => array(
+        array('_batch_test_theme_callback', array()),
+      ),
+    );
+    batch_set($batch);
+    return batch_process('batch-test/redirect');
+  }
+
+  /**
+   * Runs a batch for testing the title shown on the progress page.
+   *
+   * @return \Symfony\Component\HttpFoundation\RedirectResponse|null
+   *   A redirect response if the batch is progressive. No return value otherwise.
+   */
+  public function testTitleBatch() {
+    batch_test_stack(NULL, TRUE);
+    $batch = [
+      'title' => 'Batch Test',
+      'operations' => [
+        ['_batch_test_title_callback', []],
+      ],
+    ];
+    batch_set($batch);
+    return batch_process('batch-test/redirect');
+  }
+
+}

core/modules/system/tests/modules/batch_test/src/Form/BatchTestChainedForm.php

@@ -0,0 +1,112 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\batch_test\Form\BatchTestChainedForm.
+ */
+
+namespace Drupal\batch_test\Form;
+
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Generate form of id batch_test_chained_form.
+ */
+class BatchTestChainedForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'batch_test_chained_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    // This value is used to test that $form_state persists through batched
+    // submit handlers.
+    $form['value'] = array(
+      '#type' => 'textfield',
+      '#title' => 'Value',
+      '#default_value' => 1,
+    );
+    $form['submit'] = array(
+      '#type' => 'submit',
+      '#value' => 'Submit',
+    );
+    $form['#submit'] = array(
+      'Drupal\batch_test\Form\BatchTestChainedForm::batchTestChainedFormSubmit1',
+      'Drupal\batch_test\Form\BatchTestChainedForm::batchTestChainedFormSubmit2',
+      'Drupal\batch_test\Form\BatchTestChainedForm::batchTestChainedFormSubmit3',
+      'Drupal\batch_test\Form\BatchTestChainedForm::batchTestChainedFormSubmit4',
+    );
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+  }
+
+  /**
+   * Form submission handler #1 for batch_test_chained_form
+   */
+  public static function batchTestChainedFormSubmit1($form, FormStateInterface $form_state) {
+    batch_test_stack(NULL, TRUE);
+
+    batch_test_stack('submit handler 1');
+    batch_test_stack('value = ' . $form_state->getValue('value'));
+
+    $value = &$form_state->getValue('value');
+    $value++;
+    batch_set(_batch_test_batch_1());
+
+    $form_state->setRedirect('batch_test.redirect');
+  }
+
+  /**
+   * Form submission handler #2 for batch_test_chained_form
+   */
+  public static function batchTestChainedFormSubmit2($form, FormStateInterface $form_state) {
+    batch_test_stack('submit handler 2');
+    batch_test_stack('value = ' . $form_state->getValue('value'));
+
+    $value = &$form_state->getValue('value');
+    $value++;
+    batch_set(_batch_test_batch_2());
+
+    $form_state->setRedirect('batch_test.redirect');
+  }
+
+  /**
+   * Form submission handler #3 for batch_test_chained_form
+   */
+  public static function batchTestChainedFormSubmit3($form, FormStateInterface $form_state) {
+    batch_test_stack('submit handler 3');
+    batch_test_stack('value = ' . $form_state->getValue('value'));
+
+    $value = &$form_state->getValue('value');
+    $value++;
+
+    $form_state->setRedirect('batch_test.redirect');
+  }
+
+  /**
+   * Form submission handler #4 for batch_test_chained_form
+   */
+  public static function batchTestChainedFormSubmit4($form, FormStateInterface $form_state) {
+    batch_test_stack('submit handler 4');
+    batch_test_stack('value = ' . $form_state->getValue('value'));
+
+    $value = &$form_state->getValue('value');
+    $value++;
+    batch_set(_batch_test_batch_3());
+
+    $form_state->setRedirect('batch_test.redirect');
+  }
+
+}

core/modules/system/tests/modules/batch_test/src/Form/BatchTestMockForm.php

@@ -0,0 +1,48 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\batch_test\Form\BatchTestMockForm.
+ */
+
+namespace Drupal\batch_test\Form;
+
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Generate form of id batch_test_mock_form.
+ */
+class BatchTestMockForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'batch_test_mock_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    $form['test_value'] = array(
+      '#title' => t('Test value'),
+      '#type' => 'textfield',
+    );
+    $form['submit'] = array(
+      '#type' => 'submit',
+      '#value' => t('Submit'),
+    );
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    batch_test_stack('mock form submitted with value = ' . $form_state->getValue('test_value'));
+  }
+
+}

core/modules/system/tests/modules/batch_test/src/Form/BatchTestMultiStepForm.php

@@ -0,0 +1,70 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\batch_test\Form\BatchTestMultiStepForm.
+ */
+
+namespace Drupal\batch_test\Form;
+
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Generate form of id batch_test_multistep_form.
+ */
+class BatchTestMultiStepForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'batch_test_multistep_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    $step = $form_state->get('step');
+    if (empty($step)) {
+      $step = 1;
+      $form_state->set('step', $step);
+    }
+
+    $form['step_display'] = array(
+      '#markup' => 'step ' . $step . '<br/>',
+    );
+    $form['submit'] = array(
+      '#type' => 'submit',
+      '#value' => 'Submit',
+    );
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    batch_test_stack(NULL, TRUE);
+
+    $step = $form_state->get('step');
+    switch ($step) {
+      case 1:
+        batch_set(_batch_test_batch_1());
+        break;
+      case 2:
+        batch_set(_batch_test_batch_2());
+        break;
+    }
+
+    if ($step < 2) {
+      $form_state->set('step', ++$step);
+      $form_state->setRebuild();
+    }
+
+    $form_state->setRedirect('batch_test.redirect');
+  }
+
+}

core/modules/system/tests/modules/batch_test/src/Form/BatchTestSimpleForm.php

@@ -0,0 +1,60 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\batch_test\Form\BatchTestSimpleForm.
+ */
+
+namespace Drupal\batch_test\Form;
+
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Generate form of id batch_test_simple_form.
+ */
+class BatchTestSimpleForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'batch_test_simple_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    $form['batch'] = array(
+      '#type' => 'select',
+      '#title' => 'Choose batch',
+      '#options' => array(
+        'batch_0' => 'batch 0',
+        'batch_1' => 'batch 1',
+        'batch_2' => 'batch 2',
+        'batch_3' => 'batch 3',
+        'batch_4' => 'batch 4',
+      ),
+    );
+    $form['submit'] = array(
+      '#type' => 'submit',
+      '#value' => 'Submit',
+    );
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    batch_test_stack(NULL, TRUE);
+
+    $function = '_batch_test_' . $form_state->getValue('batch');
+    batch_set($function());
+
+    $form_state->setRedirect('batch_test.redirect');
+  }
+
+}

core/modules/system/tests/modules/cache_test/cache_test.info.yml

@@ -0,0 +1,6 @@
+name: 'Cache test'
+type: module
+description: 'Support module for cache system testing.'
+package: Testing
+version: VERSION
+core: 8.x

core/modules/system/tests/modules/common_test/common_test.css

@@ -0,0 +1,2 @@
+
+/* This file is for testing CSS file inclusion, no contents are necessary. */

core/modules/system/tests/modules/common_test/common_test.info.yml

@@ -0,0 +1,6 @@
+name: 'Common Test'
+type: module
+description: 'Support module for Common tests.'
+package: Testing
+version: VERSION
+core: 8.x

core/modules/system/tests/modules/common_test/common_test.libraries.yml

@@ -0,0 +1,115 @@
+jquery.farbtastic:
+  version: 0.1
+  js:
+    assets/vendor/farbtastic/farbtastic.js: {}
+  css:
+    component:
+      assets/vendor/farbtastic/farbtastic.css: {}
+  dependencies:
+    - core/jquery
+
+# Library to test CSS and JS file assets.
+files:
+  js:
+    foo.js: {}
+  css:
+    theme:
+      bar.css: {}
+
+# Library to test external CSS and JS file assets.
+external:
+  version: 1
+  js:
+    http://example.com/script.js: { type: external }
+  css:
+    theme:
+      http://example.com/stylesheet.css: { type: external }
+
+# Library to test JS file asset attributes (both internal and external).
+js-attributes:
+  version: 1
+  js:
+    deferred-internal.js: { attributes: { defer: true, bar: foo } }
+    http://example.com/deferred-external.js:
+      type: external
+      attributes:
+        foo: bar
+        defer: true
+
+js-header:
+  header: true
+  js:
+    header.js: {}
+  dependencies:
+    - core/drupal
+
+# Library to test setting cache = FALSE, to prevent aggregation.
+no-cache:
+  js:
+    nocache.js: { cache: false }
+
+order:
+  js:
+    weight_-3_1.js: { weight: -3 }
+    weight_0_1.js: {}
+    weight_0_2.js: {}
+    weight_-8_1.js: { weight: -8 }
+    weight_-8_2.js: { weight: -8 }
+    weight_-8_3.js: { weight: -8 }
+    http://example.com/weight_-5_1.js: { type: external, weight: -5 }
+    weight_-8_4.js: { weight: -8 }
+    weight_-3_2.js: { weight: -3 }
+    weight_0_3.js: {}
+  css:
+    base:
+      base_weight_0_1.js: {}
+      base_weight_0_2.js: {}
+      base_weight_-8_1.js: { weight: -8 }
+      base_weight_-101_1.js: { weight: -101 }
+    layout:
+      layout_weight_0_1.js: {}
+      layout_weight_0_2.js: {}
+      layout_weight_-8_1.js: { weight: -8 }
+      layout_weight_-101_1.js: { weight: -101 }
+    component:
+      component_weight_0_1.js: {}
+      component_weight_0_2.js: {}
+      component_weight_-8_1.js: { weight: -8}
+      component_weight_-101_1.js: { weight: -101}
+    state:
+      state_weight_0_1.js: {}
+      state_weight_0_2.js: {}
+      state_weight_-8_1.js: { weight: -8}
+      state_weight_-101_1.js: { weight: -101}
+    theme:
+      theme_weight_0_1.js: {}
+      theme_weight_0_2.js: {}
+      theme_weight_-8_1.js: { weight: -8}
+      theme_weight_-101_1.js: { weight: -101}
+
+weight:
+  css:
+    theme:
+      first.css: {}
+      lighter.js: { weight: -1 }
+  js:
+    first.js: {}
+    lighter.js: { weight: -1 }
+    before-jquery.js: { weight: -21 }
+
+browsers:
+  js:
+    old-ie.js:
+      browsers:
+        'IE': 'lte IE 8'
+        '!IE': false
+    no-ie.js:
+      browsers:
+        IE: false
+
+querystring:
+  js:
+    querystring.js?arg1=value1&arg2=value2: {}
+  css:
+    theme:
+      querystring.css?arg1=value1&arg2=value2: {}

core/modules/system/tests/modules/common_test/common_test.module

@@ -0,0 +1,280 @@
+<?php
+
+/**
+ * @file
+ * Helper module for the Common tests.
+ */
+
+use \Drupal\Core\Asset\AttachedAssetsInterface;
+
+/**
+ * Applies #printed to an element to help test #pre_render.
+ */
+function common_test_drupal_render_printing_pre_render($elements) {
+  $elements['#printed'] = TRUE;
+  return $elements;
+}
+
+/**
+ * Implements hook_TYPE_alter().
+ */
+function common_test_drupal_alter_alter(&$data, &$arg2 = NULL, &$arg3 = NULL) {
+  // Alter first argument.
+  if (is_array($data)) {
+    $data['foo'] = 'Drupal';
+  }
+  elseif (is_object($data)) {
+    $data->foo = 'Drupal';
+  }
+  // Alter second argument, if present.
+  if (isset($arg2)) {
+    if (is_array($arg2)) {
+      $arg2['foo'] = 'Drupal';
+    }
+    elseif (is_object($arg2)) {
+      $arg2->foo = 'Drupal';
+    }
+  }
+  // Try to alter third argument, if present.
+  if (isset($arg3)) {
+    if (is_array($arg3)) {
+      $arg3['foo'] = 'Drupal';
+    }
+    elseif (is_object($arg3)) {
+      $arg3->foo = 'Drupal';
+    }
+  }
+}
+
+/**
+ * Implements hook_TYPE_alter() on behalf of Bartik theme.
+ *
+ * Same as common_test_drupal_alter_alter(), but here, we verify that themes
+ * can also alter and come last.
+ */
+function bartik_drupal_alter_alter(&$data, &$arg2 = NULL, &$arg3 = NULL) {
+  // Alter first argument.
+  if (is_array($data)) {
+    $data['foo'] .= ' theme';
+  }
+  elseif (is_object($data)) {
+    $data->foo .= ' theme';
+  }
+  // Alter second argument, if present.
+  if (isset($arg2)) {
+    if (is_array($arg2)) {
+      $arg2['foo'] .= ' theme';
+    }
+    elseif (is_object($arg2)) {
+      $arg2->foo .= ' theme';
+    }
+  }
+  // Try to alter third argument, if present.
+  if (isset($arg3)) {
+    if (is_array($arg3)) {
+      $arg3['foo'] .= ' theme';
+    }
+    elseif (is_object($arg3)) {
+      $arg3->foo .= ' theme';
+    }
+  }
+}
+
+/**
+ * Implements hook_TYPE_alter() on behalf of block module.
+ *
+ * This is to verify that
+ * \Drupal::moduleHandler()->alter(array(TYPE1, TYPE2), ...) allows
+ * hook_module_implements_alter() to affect the order in which module
+ * implementations are executed.
+ */
+function block_drupal_alter_foo_alter(&$data, &$arg2 = NULL, &$arg3 = NULL) {
+  $data['foo'] .= ' block';
+}
+
+/**
+ * Implements hook_module_implements_alter().
+ *
+ * @see block_drupal_alter_foo_alter()
+ */
+function common_test_module_implements_alter(&$implementations, $hook) {
+  // For
+  // \Drupal::moduleHandler()->alter(array('drupal_alter', 'drupal_alter_foo'), ...),
+  // make the block module implementations run after all the other modules. Note
+  // that when \Drupal::moduleHandler->alter() is called with an array of types,
+  // the first type is considered primary and controls the module order.
+  if ($hook == 'drupal_alter_alter' && isset($implementations['block'])) {
+    $group = $implementations['block'];
+    unset($implementations['block']);
+    $implementations['block'] = $group;
+  }
+}
+
+/**
+ * Implements hook_theme().
+ */
+function common_test_theme() {
+  return array(
+    'common_test_foo' => array(
+      'variables' => array('foo' => 'foo', 'bar' => 'bar'),
+    ),
+    'common_test_render_element' => array(
+      'render element' => 'foo',
+    ),
+    'common_test_empty' => array(
+      'variables' => array('foo' => 'foo'),
+      'function' => 'theme_common_test_empty',
+    ),
+  );
+}
+
+/**
+ * Provides a theme function for drupal_render().
+ */
+function theme_common_test_foo($variables) {
+  return $variables['foo'] . $variables['bar'];
+}
+
+/**
+ * Always returns an empty string.
+ */
+function theme_common_test_empty($variables) {
+  return '';
+}
+
+/**
+ * Implements MODULE_preprocess().
+ *
+ * @see RenderTest::testDrupalRenderThemePreprocessAttached()
+ */
+function common_test_preprocess(&$variables, $hook) {
+  if (!\Drupal::state()->get('theme_preprocess_attached_test', FALSE)) {
+    return;
+  }
+  $variables['#attached']['library'][] = 'test/generic_preprocess';
+}
+
+/**
+ * Implements MODULE_preprocess_HOOK().
+ *
+ * @see RenderTest::testDrupalRenderThemePreprocessAttached()
+ */
+function common_test_preprocess_common_test_render_element(&$variables) {
+  if (!\Drupal::state()->get('theme_preprocess_attached_test', FALSE)) {
+    return;
+  }
+  $variables['#attached']['library'][] = 'test/specific_preprocess';
+}
+
+/**
+ * Implements hook_library_info_build().
+ */
+function common_test_library_info_build() {
+  $libraries = [];
+  if (\Drupal::state()->get('common_test.library_info_build_test')) {
+    $libraries['dynamic_library'] = [
+      'version' => '1.0',
+      'css' => [
+        'base' => [
+          'common_test.css' => [],
+        ],
+      ],
+    ];
+  }
+  return $libraries;
+}
+
+/**
+ * Implements hook_library_info_alter().
+ */
+function common_test_library_info_alter(&$libraries, $module) {
+  if ($module == 'core' && isset($libraries['jquery.farbtastic'])) {
+    // Change the version of Farbtastic to 0.0.
+    $libraries['jquery.farbtastic']['version'] = '0.0';
+    // Make Farbtastic depend on jQuery Form to test library dependencies.
+    $libraries['jquery.farbtastic']['dependencies'][] = 'core/jquery.form';
+  }
+
+  // Alter the dynamically registered library definition.
+  if ($module == 'common_test' && isset($libraries['dynamic_library'])) {
+    $libraries['dynamic_library']['dependencies'] = [
+      'core/jquery',
+    ];
+  }
+}
+
+/**
+ * Implements hook_cron().
+ *
+ * System module should handle if a module does not catch an exception and keep
+ * cron going.
+ *
+ * @see common_test_cron_helper()
+ *
+ */
+function common_test_cron() {
+  throw new Exception(t('Uncaught exception'));
+}
+
+/**
+ * Implements hook_page_attachments().
+ *
+ * @see \Drupal\system\Tests\Common\PageRenderTest::assertPageRenderHookExceptions()
+ */
+function common_test_page_attachments(array &$page) {
+  $page['#attached']['library'][] = 'core/foo';
+  $page['#attached']['library'][] = 'core/bar';
+  $page['#cache']['tags'] = ['example'];
+  $page['#cache']['contexts'] = ['user.permissions'];
+
+  if (\Drupal::state()->get('common_test.hook_page_attachments.descendant_attached', FALSE)) {
+    $page['content']['#attached']['library'][] = 'core/jquery';
+  }
+
+  if (\Drupal::state()->get('common_test.hook_page_attachments.render_array', FALSE)) {
+    $page['something'] = [
+      '#markup' => 'test',
+    ];
+  }
+}
+
+/**
+ * Implements hook_page_attachments_alter().
+ *
+ * @see \Drupal\system\Tests\Common\PageRenderTest::assertPageRenderHookExceptions()
+ */
+function common_test_page_attachments_alter(array &$page) {
+  // Remove a library that was added in common_test_page_attachments(), to test
+  // that this hook can do what it claims to do.
+  if (isset($page['#attached']['library']) && ($index = array_search('core/bar', $page['#attached']['library'])) && $index !== FALSE) {
+    unset($page['#attached']['library'][$index]);
+  }
+  $page['#attached']['library'][] = 'core/baz';
+  $page['#cache']['tags'] = ['example'];
+  $page['#cache']['contexts'] = ['user.permissions'];
+
+  if (\Drupal::state()->get('common_test.hook_page_attachments_alter.descendant_attached', FALSE)) {
+    $page['content']['#attached']['library'][] = 'core/jquery';
+  }
+
+  if (\Drupal::state()->get('common_test.hook_page_attachments_alter.render_array', FALSE)) {
+    $page['something'] = [
+      '#markup' => 'test',
+    ];
+  }
+}
+
+/**
+ * Implements hook_js_settings_alter().
+ *
+ * @see \Drupal\system\Tests\Common\JavaScriptTest::testHeaderSetting()
+ */
+function common_test_js_settings_alter(&$settings, AttachedAssetsInterface $assets) {
+  // Modify an existing setting.
+  if (array_key_exists('pluralDelimiter', $settings)) {
+    $settings['pluralDelimiter'] = '☃';
+  }
+
+  // Add a setting.
+  $settings['foo'] = 'bar';
+}

core/modules/system/tests/modules/common_test/common_test.print.css

@@ -0,0 +1,2 @@
+
+/* This file is for testing CSS file inclusion, no contents are necessary. */

core/modules/system/tests/modules/common_test/common_test.routing.yml

@@ -0,0 +1,21 @@
+common_test.l_active_class:
+  path: '/common-test/type-link-active-class'
+  defaults:
+    _controller: '\Drupal\common_test\Controller\CommonTestController::typeLinkActiveClass'
+  requirements:
+    _access: 'TRUE'
+
+common_test.destination:
+  path: '/common-test/destination'
+  defaults:
+    _controller: '\Drupal\common_test\Controller\CommonTestController::destination'
+  requirements:
+    _access: 'TRUE'
+
+common_test.js_and_css_querystring:
+  path: '/common-test/query-string'
+  defaults:
+    _title: 'Test querystring'
+    _controller: '\Drupal\common_test\Controller\CommonTestController::jsAndCssQuerystring'
+  requirements:
+    _access: 'TRUE'

core/modules/system/tests/modules/common_test/src/Controller/CommonTestController.php

@@ -0,0 +1,96 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\common_test\Controller\CommonTestController.
+ */
+
+namespace Drupal\common_test\Controller;
+
+use Drupal\Component\Utility\SafeMarkup;
+use Drupal\Core\Url;
+use Symfony\Component\HttpFoundation\Response;
+
+/**
+ * Controller routines for common_test routes.
+ */
+class CommonTestController {
+
+  /**
+   * Returns links to the current page, with and without query strings.
+   *
+   * Using #type 'link' causes these links to be rendered with _l().
+   */
+  public function typeLinkActiveClass() {
+    return array(
+      'no_query' => array(
+        '#type' => 'link',
+        '#title' => t('Link with no query string'),
+        '#url' => Url::fromRoute('<current>'),
+        '#options' => array(
+          'set_active_class' => TRUE,
+        ),
+      ),
+      'with_query' => array(
+        '#type' => 'link',
+        '#title' => t('Link with a query string'),
+        '#url' => Url::fromRoute('<current>'),
+        '#options' => array(
+          'query' => array(
+            'foo' => 'bar',
+            'one' => 'two',
+          ),
+          'set_active_class' => TRUE,
+        ),
+      ),
+      'with_query_reversed' => array(
+        '#type' => 'link',
+        '#title' => t('Link with the same query string in reverse order'),
+        '#url' => Url::fromRoute('<current>'),
+        '#options' => array(
+          'query' => array(
+            'one' => 'two',
+            'foo' => 'bar',
+          ),
+          'set_active_class' => TRUE,
+        ),
+      ),
+    );
+  }
+
+  /**
+   * Adds a JavaScript file and a CSS file with a query string appended.
+   *
+   * @return string
+   *   An empty string.
+   */
+  public function jsAndCssQuerystring() {
+    $attached = array(
+      '#attached' => array(
+        'library' => array(
+          'node/drupal.node',
+        ),
+        'css' => array(
+          drupal_get_path('module', 'node') . '/css/node.admin.css' => array(),
+          // A relative URI may have a query string.
+          '/' . drupal_get_path('module', 'node') . '/node-fake.css?arg1=value1&arg2=value2' => array(),
+        ),
+      ),
+    );
+    return \Drupal::service('renderer')->renderRoot($attached);
+  }
+
+  /**
+   * Prints a destination query parameter.
+   *
+   * @return \Symfony\Component\HttpFoundation\Response
+   *   A new Response object containing a string with the destination query
+   *   parameter.
+   */
+  public function destination() {
+    $destination = \Drupal::destination()->getAsArray();
+    $output = "The destination: " . SafeMarkup::checkPlain($destination['destination']);
+    return new Response($output);
+  }
+
+}

core/modules/system/tests/modules/common_test/templates/common-test-foo.html.twig

@@ -0,0 +1,13 @@
+{#
+/**
+ * @file
+ * Default theme implementation for the common test foo.
+ *
+ * Available variables:
+ * - foo: foo.
+ * - bar: bar.
+ *
+ * @ingroup themeable
+ */
+#}
+{{ foo }}{{ bar -}}

core/modules/system/tests/modules/common_test/templates/common-test-render-element.html.twig

@@ -0,0 +1,12 @@
+{#
+/**
+ * @file
+ * Default theme implementation for the common test render element.
+ *
+ * Available variables:
+ * - foo: A render array.
+ *
+ * @ingroup themeable
+ */
+#}
+{{ foo }}

core/modules/system/tests/modules/common_test_cron_helper/common_test_cron_helper.info.yml

@@ -0,0 +1,6 @@
+name: 'Common Test Cron Helper'
+type: module
+description: 'Helper module for CronRunTestCase::testCronExceptions().'
+package: Testing
+version: VERSION
+core: 8.x

core/modules/system/tests/modules/common_test_cron_helper/common_test_cron_helper.module

@@ -0,0 +1,18 @@
+<?php
+
+/**
+ * @file
+ * Helper module for the testCronExceptions in addition to common_test module.
+ */
+
+/**
+ * Implements hook_cron().
+ *
+ * common_test_cron() throws an exception, but the execution should reach this
+ * function as well.
+ *
+ * @see common_test_cron()
+ */
+function common_test_cron_helper_cron() {
+  \Drupal::state()->set('common_test.cron', 'success');
+}

core/modules/system/tests/modules/condition_test/condition_test.info.yml

@@ -0,0 +1,6 @@
+name: "Condition Test Support"
+type: module
+description: "Test general form component for condition plugins."
+package: Testing
+version: VERSION
+core: 8.x

core/modules/system/tests/modules/condition_test/condition_test.routing.yml

@@ -0,0 +1,6 @@
+condition_test.1:
+  path: '/condition_test'
+  defaults:
+    _form: '\Drupal\condition_test\FormController'
+  requirements:
+    _access: 'TRUE'

core/modules/system/tests/modules/condition_test/src/FormController.php

@@ -0,0 +1,78 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\condition_test\FormController.
+ */
+
+namespace Drupal\condition_test;
+
+use Drupal\Core\Form\FormInterface;
+use Drupal\Core\Condition\ConditionManager;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\node\Entity\Node;
+
+/**
+ * Routing controller class for condition_test testing of condition forms.
+ */
+class FormController implements FormInterface {
+
+  /**
+   * The condition plugin we will be working with.
+   *
+   * @var \Drupal\Core\Condition\ConditionInterface
+   */
+  protected $condition;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'condition_node_type_test_form';
+  }
+
+  /**
+   * Constructs a \Drupal\condition_test\FormController object.
+   */
+  public function __construct() {
+    $manager = new ConditionManager(\Drupal::service('container.namespaces'), \Drupal::cache('discovery'), \Drupal::moduleHandler());
+    $this->condition = $manager->createInstance('node_type');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    $form = $this->condition->buildConfigurationForm($form, $form_state);
+    $form['actions']['submit'] = array(
+      '#type' => 'submit',
+      '#value' => t('Submit'),
+    );
+    return $form;
+  }
+
+  /**
+   * Implements \Drupal\Core\Form\FormInterface::validateForm().
+   *
+   */
+  public function validateForm(array &$form, FormStateInterface $form_state) {
+    $this->condition->validateConfigurationForm($form, $form_state);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    $this->condition->submitConfigurationForm($form, $form_state);
+    $config = $this->condition->getConfig();
+    foreach ($config['bundles'] as $bundle) {
+      drupal_set_message('Bundle: ' . $bundle);
+    }
+
+    $article = Node::load(1);
+    $this->condition->setContextValue('node', $article);
+    if ($this->condition->execute()) {
+      drupal_set_message(t('Executed successfully.'));
+    }
+  }
+}

core/modules/system/tests/modules/condition_test/src/Plugin/Condition/ConditionTestDualUser.php

@@ -0,0 +1,42 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\condition_test\Plugin\Condition\ConditionTestDualUser.
+ */
+
+namespace Drupal\condition_test\Plugin\Condition;
+
+use Drupal\Core\Condition\ConditionPluginBase;
+
+/**
+ * Provides a condition that requires two users.
+ *
+ * @Condition(
+ *   id = "condition_test_dual_user",
+ *   label = @Translation("Dual user"),
+ *   context = {
+ *     "user1" = @ContextDefinition("entity:user", label = @Translation("User 1")),
+ *     "user2" = @ContextDefinition("entity:user", label = @Translation("User 2"))
+ *   }
+ * )
+ */
+class ConditionTestDualUser extends ConditionPluginBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function evaluate() {
+    $user1 = $this->getContextValue('user1');
+    $user2 = $this->getContextValue('user2');
+    return $user1->id() === $user2->id();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function summary() {
+    return $this->t('This condition has two users.');
+  }
+
+}

core/modules/system/tests/modules/condition_test/src/Tests/ConditionTestDualUserTest.php

@@ -0,0 +1,98 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\condition_test\Tests\ConditionTestDualUserTest.
+ */
+
+namespace Drupal\condition_test\Tests;
+
+use Drupal\Core\Plugin\Context\Context;
+use Drupal\Core\Plugin\Context\ContextDefinition;
+use Drupal\simpletest\KernelTestBase;
+use Drupal\user\Entity\User;
+
+/**
+ * Tests a condition that requires two users.
+ *
+ * @group condition_test
+ */
+class ConditionTestDualUserTest extends KernelTestBase {
+
+  /**
+   * An anonymous user for testing purposes.
+   *
+   * @var \Drupal\user\Entity\User
+   */
+  protected $anonymous;
+
+  /**
+   * An authenticated user for testing purposes.
+   *
+   * @var \Drupal\user\Entity\User
+   */
+  protected $authenticated;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['system', 'user', 'condition_test'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $this->installSchema('system', 'sequences');
+    $this->installEntitySchema('user');
+
+    $this->anonymous = User::create(['uid' => 0]);
+    $this->authenticated = User::create(['uid' => 1]);
+  }
+
+  /**
+   * Tests the dual user condition.
+   */
+  public function testConditions() {
+    $this->doTestIdenticalUser();
+    $this->doTestDifferentUser();
+  }
+
+  /**
+   * Tests with both contexts mapped to the same user.
+   */
+  protected function doTestIdenticalUser() {
+    /** @var \Drupal\Core\Condition\ConditionPluginBase $condition */
+    $condition = \Drupal::service('plugin.manager.condition')
+      ->createInstance('condition_test_dual_user')
+      // Map the anonymous user to both contexts.
+      ->setContextMapping([
+        'user1' => 'anonymous',
+        'user2' => 'anonymous',
+      ]);
+    $definition = new ContextDefinition('entity:user');
+    $contexts['anonymous'] = (new Context($definition))->setContextValue($this->anonymous);
+    \Drupal::service('context.handler')->applyContextMapping($condition, $contexts);
+    $this->assertTrue($condition->execute());
+  }
+
+  /**
+   * Tests with each context mapped to different users.
+   */
+  protected function doTestDifferentUser() {
+    /** @var \Drupal\Core\Condition\ConditionPluginBase $condition */
+    $condition = \Drupal::service('plugin.manager.condition')
+      ->createInstance('condition_test_dual_user')
+      ->setContextMapping([
+        'user1' => 'anonymous',
+        'user2' => 'authenticated',
+      ]);
+    $definition = new ContextDefinition('entity:user');
+    $contexts['anonymous'] = (new Context($definition))->setContextValue($this->anonymous);
+    $contexts['authenticated'] = (new Context($definition))->setContextValue($this->authenticated);
+    \Drupal::service('context.handler')->applyContextMapping($condition, $contexts);
+    $this->assertFalse($condition->execute());
+  }
+
+}

core/modules/system/tests/modules/conneg_test/conneg_test.info.yml

@@ -0,0 +1,6 @@
+name: Content negotiation test
+type: module
+description: 'Support testing content negotiation variations.'
+package: Core
+version: VERSION
+core: 8.x

core/modules/system/tests/modules/conneg_test/conneg_test.routing.yml

@@ -0,0 +1,32 @@
+# Tests
+conneg.simpletest:
+  path: conneg/simple.json
+  defaults:
+    _controller: '\Drupal\conneg_test\Controller\TestController::simple'
+  requirements:
+    _access: 'TRUE'
+conneg.html:
+  path: conneg/html
+  defaults:
+    _controller: '\Drupal\conneg_test\Controller\TestController::html'
+  requirements:
+    _access: 'TRUE'
+conneg.simple_conneg:
+  path: conneg/html
+  defaults:
+    _controller: '\Drupal\conneg_test\Controller\TestController::format'
+  requirements:
+    _access: 'TRUE'
+    _format: 'json|xml'
+conneg.variable_with_period:
+  path: conneg/plugin/{plugin_id}
+  defaults:
+    _controller: '\Drupal\conneg_test\Controller\TestController::variable'
+  requirements:
+    _access: 'TRUE'
+conneg.full_content_negotiation:
+  path: conneg/negotiate
+  defaults:
+    _controller: '\Drupal\conneg_test\Controller\TestController::format'
+  requirements:
+    _access: 'TRUE'

core/modules/system/tests/modules/conneg_test/src/Controller/TestController.php

@@ -0,0 +1,76 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\conneg_test\Controller\TestController.
+ */
+
+namespace Drupal\conneg_test\Controller;
+
+use Symfony\Component\HttpFoundation\JsonResponse;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+/**
+ * Test controller for content negotation tests.
+ */
+class TestController {
+
+  /**
+   * Returns a json response.
+   *
+   * @return \Symfony\Component\HttpFoundation\JsonResponse
+   */
+  public function simple() {
+    return new JsonResponse(['some' => 'data']);
+  }
+
+  /**
+   * Returns a simple render array.
+   *
+   * @return array
+   */
+  public function html() {
+    return [
+      '#markup' => 'here',
+    ];
+  }
+
+  /**
+   * Returns different responses dependening on the request format.
+   *
+   * @param \Symfony\Component\HttpFoundation\Request $request
+   *   The request
+   *
+   * @return \Symfony\Component\HttpFoundation\Response
+   *   The response.
+   */
+  public function format(Request $request) {
+    switch ($request->getRequestFormat()) {
+      case 'json':
+        return new JsonResponse(['some' => 'data']);
+
+      case 'xml':
+        return new Response('<xml></xml>', Response::HTTP_OK, ['Content-Type' => 'application/xml']);
+
+      default:
+        return new Response($request->getRequestFormat());
+    }
+  }
+
+  /**
+   * Returns a render array depending on some passed in value.
+   *
+   * @param string $plugin_id
+   *   The plugin ID.
+   *
+   * @return array
+   *   The render array
+   */
+  public function variable($plugin_id) {
+    return [
+      '#markup' => $plugin_id,
+    ];
+  }
+
+}

core/modules/system/tests/modules/cron_queue_test/cron_queue_test.info.yml

@@ -0,0 +1,6 @@
+name: 'Cron Queue test'
+type: module
+description: 'Support module for the cron queue runner.'
+package: Testing
+version: VERSION
+core: 8.x

core/modules/system/tests/modules/cron_queue_test/src/Plugin/QueueWorker/CronQueueTestBrokenQueue.php

@@ -0,0 +1,32 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\cron_queue_test\Plugin\QueueWorker\CronQueueTestBrokenQueue.
+ */
+
+namespace Drupal\cron_queue_test\Plugin\QueueWorker;
+
+use Drupal\Core\Queue\QueueWorkerBase;
+use Drupal\Core\Queue\SuspendQueueException;
+
+/**
+ * @QueueWorker(
+ *   id = "cron_queue_test_broken_queue",
+ *   title = @Translation("Broken queue test"),
+ *   cron = {"time" = 60}
+ * )
+ */
+class CronQueueTestBrokenQueue extends QueueWorkerBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function processItem($data) {
+    if ($data == 'crash') {
+      throw new SuspendQueueException('The queue is broken.');
+    }
+    // Do nothing otherwise.
+  }
+
+}

core/modules/system/tests/modules/cron_queue_test/src/Plugin/QueueWorker/CronQueueTestException.php

@@ -0,0 +1,28 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\cron_queue_test\Plugin\QueueWorker\CronQueueTestException.
+ */
+
+namespace Drupal\cron_queue_test\Plugin\QueueWorker;
+
+use Drupal\Core\Queue\QueueWorkerBase;
+
+/**
+ * @QueueWorker(
+ *   id = "cron_queue_test_exception",
+ *   title = @Translation("Exception test"),
+ *   cron = {"time" = 60}
+ * )
+ */
+class CronQueueTestException extends QueueWorkerBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function processItem($data) {
+    throw new \Exception('That is not supposed to happen.');
+  }
+
+}

core/modules/system/tests/modules/database_test/database_test.info.yml

@@ -0,0 +1,6 @@
+name: 'Database Test'
+type: module
+description: 'Support module for Database layer tests.'
+core: 8.x
+package: Testing
+version: VERSION

core/modules/system/tests/modules/database_test/database_test.install

@@ -0,0 +1,278 @@
+<?php
+
+/**
+ * @file
+ * Install, update and uninstall functions for the database_test module.
+ */
+
+/**
+ * Implements hook_schema().
+ *
+ * The database tests use the database API which depends on schema
+ * information for certain operations on certain databases.
+ * Therefore, the schema must actually be declared in a normal module
+ * like any other, not directly in the test file.
+ */
+function database_test_schema() {
+  $schema['test'] = array(
+    'description' => 'Basic test table for the database unit tests.',
+    'fields' => array(
+      'id' => array(
+        'type' => 'serial',
+        'unsigned' => TRUE,
+        'not null' => TRUE,
+      ),
+      'name' => array(
+        'description' => "A person's name",
+        'type' => 'varchar_ascii',
+        'length' => 255,
+        'not null' => TRUE,
+        'default' => '',
+        'binary' => TRUE,
+      ),
+      'age' => array(
+        'description' => "The person's age",
+        'type' => 'int',
+        'unsigned' => TRUE,
+        'not null' => TRUE,
+        'default' => 0,
+      ),
+      'job' => array(
+        'description' => "The person's job",
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => TRUE,
+        'default' => 'Undefined',
+      ),
+    ),
+    'primary key' => array('id'),
+    'unique keys' => array(
+      'name' => array('name')
+    ),
+    'indexes' => array(
+      'ages' => array('age'),
+    ),
+  );
+
+  // This is an alternate version of the same table that is structured the same
+  // but has a non-serial Primary Key.
+  $schema['test_people'] = array(
+    'description' => 'A duplicate version of the test table, used for additional tests.',
+    'fields' => array(
+      'name' => array(
+        'description' => "A person's name",
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => TRUE,
+        'default' => '',
+      ),
+      'age' => array(
+        'description' => "The person's age",
+        'type' => 'int',
+        'unsigned' => TRUE,
+        'not null' => TRUE,
+        'default' => 0,
+      ),
+      'job' => array(
+        'description' => "The person's job",
+        'type' => 'varchar_ascii',
+        'length' => 255,
+        'not null' => TRUE,
+        'default' => '',
+      ),
+    ),
+    'primary key' => array('job'),
+    'indexes' => array(
+      'ages' => array('age'),
+    ),
+  );
+
+  $schema['test_people_copy'] = array(
+    'description' => 'A duplicate version of the test_people table, used for additional tests.',
+    'fields' => array(
+      'name' => array(
+        'description' => "A person's name",
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => TRUE,
+        'default' => '',
+      ),
+      'age' => array(
+        'description' => "The person's age",
+        'type' => 'int',
+        'unsigned' => TRUE,
+        'not null' => TRUE,
+        'default' => 0,
+      ),
+      'job' => array(
+        'description' => "The person's job",
+        'type' => 'varchar_ascii',
+        'length' => 255,
+        'not null' => TRUE,
+        'default' => '',
+      ),
+    ),
+    'primary key' => array('job'),
+    'indexes' => array(
+      'ages' => array('age'),
+    ),
+  );
+
+  $schema['test_one_blob'] = array(
+    'description' => 'A simple table including a BLOB field for testing BLOB behavior.',
+    'fields' => array(
+      'id' => array(
+        'description' => 'Simple unique ID.',
+        'type' => 'serial',
+        'not null' => TRUE,
+      ),
+      'blob1' => array(
+        'description' => 'A BLOB field.',
+        'type' => 'blob',
+      ),
+    ),
+    'primary key' => array('id'),
+    );
+
+  $schema['test_two_blobs'] = array(
+    'description' => 'A simple test table with two BLOB fields.',
+    'fields' => array(
+      'id' => array(
+        'description' => 'Simple unique ID.',
+        'type' => 'serial',
+        'not null' => TRUE,
+      ),
+      'blob1' => array(
+        'description' => 'A dummy BLOB field.',
+        'type' => 'blob',
+      ),
+      'blob2' => array(
+        'description' => 'A second BLOB field.',
+        'type' => 'blob'
+      ),
+    ),
+    'primary key' => array('id'),
+    );
+
+  $schema['test_task'] = array(
+    'description' => 'A task list for people in the test table.',
+    'fields' => array(
+      'tid' => array(
+        'description' => 'Task ID, primary key.',
+        'type' => 'serial',
+        'not null' => TRUE,
+      ),
+      'pid' => array(
+        'description' => 'The {test_people}.pid, foreign key for the test table.',
+        'type' => 'int',
+        'unsigned' => TRUE,
+        'not null' => TRUE,
+        'default' => 0,
+      ),
+      'task' => array(
+        'description' => 'The task to be completed.',
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => TRUE,
+        'default' => '',
+      ),
+      'priority' => array(
+        'description' => 'The priority of the task.',
+        'type' => 'int',
+        'unsigned' => TRUE,
+        'not null' => TRUE,
+        'default' => 0,
+      ),
+    ),
+    'primary key' => array('tid'),
+  );
+
+  $schema['test_null'] = array(
+    'description' => 'Basic test table for NULL value handling.',
+    'fields' => array(
+      'id' => array(
+        'type' => 'serial',
+        'unsigned' => TRUE,
+        'not null' => TRUE,
+      ),
+      'name' => array(
+        'description' => "A person's name.",
+        'type' => 'varchar_ascii',
+        'length' => 255,
+        'not null' => FALSE,
+        'default' => '',
+      ),
+      'age' => array(
+        'description' => "The person's age.",
+        'type' => 'int',
+        'unsigned' => TRUE,
+        'not null' => FALSE,
+        'default' => 0),
+    ),
+    'primary key' => array('id'),
+    'unique keys' => array(
+      'name' => array('name')
+    ),
+    'indexes' => array(
+      'ages' => array('age'),
+    ),
+  );
+
+  $schema['test_serialized'] = array(
+    'description' => 'Basic test table for NULL value handling.',
+    'fields' => array(
+      'id' => array(
+        'type' => 'serial',
+        'unsigned' => TRUE,
+        'not null' => TRUE,
+      ),
+      'name' => array(
+        'description' => "A person's name.",
+        'type' => 'varchar_ascii',
+        'length' => 255,
+        'not null' => FALSE,
+        'default' => '',
+      ),
+      'info' => array(
+        'description' => "The person's data in serialized form.",
+        'type' => 'blob',
+        'serialize' => TRUE,
+      ),
+    ),
+    'primary key' => array('id'),
+    'unique keys' => array(
+      'name' => array('name')
+    ),
+  );
+
+  $schema['test_composite_primary'] = array(
+    'description' => 'Basic test table with a composite primary key',
+    'fields' => array(
+      'name' => array(
+        'description' => "A person's name",
+        'type' => 'varchar',
+        'length' => 50,
+        'not null' => TRUE,
+        'default' => '',
+        'binary' => TRUE,
+      ),
+      'age' => array(
+        'description' => "The person's age",
+        'type' => 'int',
+        'unsigned' => TRUE,
+        'not null' => TRUE,
+        'default' => 0,
+      ),
+      'job' => array(
+        'description' => "The person's job",
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => TRUE,
+        'default' => 'Undefined',
+      ),
+    ),
+    'primary key' => array('name', 'age'),
+  );
+
+  return $schema;
+}

core/modules/system/tests/modules/database_test/database_test.module

@@ -0,0 +1,46 @@
+<?php
+
+use Drupal\Core\Database\Query\AlterableInterface;
+use Symfony\Component\HttpFoundation\JsonResponse;
+
+/**
+ * Implements hook_query_alter().
+ */
+function database_test_query_alter(AlterableInterface $query) {
+
+  if ($query->hasTag('database_test_alter_add_range')) {
+    $query->range(0, 2);
+  }
+
+  if ($query->hasTag('database_test_alter_add_join')) {
+    $people_alias = $query->join('test', 'people', "test_task.pid = %alias.id");
+    $query->addField($people_alias, 'name', 'name');
+    $query->condition($people_alias . '.id', 2);
+  }
+
+  if ($query->hasTag('database_test_alter_change_conditional')) {
+    $conditions =& $query->conditions();
+    $conditions[0]['value'] = 2;
+  }
+
+  if ($query->hasTag('database_test_alter_change_fields')) {
+    $fields =& $query->getFields();
+    unset($fields['age']);
+  }
+
+  if ($query->hasTag('database_test_alter_change_expressions')) {
+    $expressions =& $query->getExpressions();
+    $expressions['double_age']['expression'] = 'age*3';
+  }
+}
+
+
+/**
+ * Implements hook_query_TAG_alter().
+ *
+ * Called by DatabaseTestCase::testAlterRemoveRange.
+ */
+function database_test_query_database_test_alter_remove_range_alter(AlterableInterface $query) {
+  $query->range();
+}
+

core/modules/system/tests/modules/database_test/database_test.routing.yml

@@ -0,0 +1,41 @@
+database_test.db_query_temporary:
+  path: '/database_test/db_query_temporary'
+  defaults:
+    _controller: '\Drupal\database_test\Controller\DatabaseTestController::dbQueryTemporary'
+  requirements:
+    _access: 'TRUE'
+
+database_test.pager_query_even:
+  path: '/database_test/pager_query_even/{limit}'
+  defaults:
+    _controller: '\Drupal\database_test\Controller\DatabaseTestController::pagerQueryEven'
+  requirements:
+    _access: 'TRUE'
+
+database_test.pager_query_odd:
+  path: '/database_test/pager_query_odd/{limit}'
+  defaults:
+    _controller: '\Drupal\database_test\Controller\DatabaseTestController::pagerQueryOdd'
+  requirements:
+    _access: 'TRUE'
+
+database_test.tablesort:
+  path: '/database_test/tablesort'
+  defaults:
+    _controller: '\Drupal\database_test\Controller\DatabaseTestController::testTablesort'
+  requirements:
+    _access: 'TRUE'
+
+database_test.tablesort_first:
+  path: '/database_test/tablesort_first'
+  defaults:
+    _controller: '\Drupal\database_test\Controller\DatabaseTestController::testTablesortFirst'
+  requirements:
+    _access: 'TRUE'
+
+database_test.tablesort_default_sort:
+  path: '/database_test/tablesort_default_sort'
+  defaults:
+    _form: '\Drupal\database_test\Form\DatabaseTestForm'
+  requirements:
+    _access: 'TRUE'

core/modules/system/tests/modules/database_test/src/Controller/DatabaseTestController.php

@@ -0,0 +1,150 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\database_test\Controller\DatabaseTestController.
+ */
+
+namespace Drupal\database_test\Controller;
+
+use Symfony\Component\HttpFoundation\JsonResponse;
+
+/**
+ * Controller routines for database_test routes.
+ */
+class DatabaseTestController {
+
+  /**
+   * Runs db_query_temporary() and outputs the table name and its number of rows.
+   *
+   * We need to test that the table created is temporary, so we run it here, in a
+   * separate menu callback request; After this request is done, the temporary
+   * table should automatically dropped.
+   *
+   * @return \Symfony\Component\HttpFoundation\JsonResponse
+   */
+  public function dbQueryTemporary() {
+    $table_name = db_query_temporary('SELECT age FROM {test}', array());
+    return new JsonResponse(array(
+      'table_name' => $table_name,
+      'row_count' => db_select($table_name)->countQuery()->execute()->fetchField(),
+    ));
+  }
+
+  /**
+   * Runs a pager query and returns the results.
+   *
+   * This function does care about the page GET parameter, as set by the
+   * simpletest HTTP call.
+   *
+   * @return \Symfony\Component\HttpFoundation\JsonResponse
+   */
+  public function pagerQueryEven($limit) {
+    $query = db_select('test', 't');
+    $query
+      ->fields('t', array('name'))
+      ->orderBy('age');
+
+    // This should result in 2 pages of results.
+    $query = $query
+      ->extend('Drupal\Core\Database\Query\PagerSelectExtender')
+      ->limit($limit);
+
+    $names = $query->execute()->fetchCol();
+
+    return new JsonResponse(array(
+      'names' => $names,
+    ));
+  }
+
+  /**
+   * Runs a pager query and returns the results.
+   *
+   * This function does care about the page GET parameter, as set by the
+   * simpletest HTTP call.
+   *
+   * @return \Symfony\Component\HttpFoundation\JsonResponse
+   */
+  public function pagerQueryOdd($limit) {
+    $query = db_select('test_task', 't');
+    $query
+      ->fields('t', array('task'))
+      ->orderBy('pid');
+
+    // This should result in 4 pages of results.
+    $query = $query
+      ->extend('Drupal\Core\Database\Query\PagerSelectExtender')
+      ->limit($limit);
+
+    $names = $query->execute()->fetchCol();
+
+    return new JsonResponse(array(
+      'names' => $names,
+    ));
+  }
+
+  /**
+   * Runs a tablesort query and returns the results.
+   *
+   * This function does care about the page GET parameter, as set by the
+   * simpletest HTTP call.
+   *
+   * @return \Symfony\Component\HttpFoundation\JsonResponse
+   */
+  public function testTablesort() {
+    $header = array(
+      'tid' => array('data' => t('Task ID'), 'field' => 'tid', 'sort' => 'desc'),
+      'pid' => array('data' => t('Person ID'), 'field' => 'pid'),
+      'task' => array('data' => t('Task'), 'field' => 'task'),
+      'priority' => array('data' => t('Priority'), 'field' => 'priority', ),
+    );
+
+    $query = db_select('test_task', 't');
+    $query
+      ->fields('t', array('tid', 'pid', 'task', 'priority'));
+
+    $query = $query
+      ->extend('Drupal\Core\Database\Query\TableSortExtender')
+      ->orderByHeader($header);
+
+    // We need all the results at once to check the sort.
+    $tasks = $query->execute()->fetchAll();
+
+    return new JsonResponse(array(
+      'tasks' => $tasks,
+    ));
+  }
+
+  /**
+   * Runs a tablesort query with a second order_by after and returns the results.
+   *
+   * This function does care about the page GET parameter, as set by the
+   * simpletest HTTP call.
+   *
+   * @return \Symfony\Component\HttpFoundation\JsonResponse
+   */
+  public function testTablesortFirst() {
+    $header = array(
+      'tid' => array('data' => t('Task ID'), 'field' => 'tid', 'sort' => 'desc'),
+      'pid' => array('data' => t('Person ID'), 'field' => 'pid'),
+      'task' => array('data' => t('Task'), 'field' => 'task'),
+      'priority' => array('data' => t('Priority'), 'field' => 'priority', ),
+    );
+
+    $query = db_select('test_task', 't');
+    $query
+      ->fields('t', array('tid', 'pid', 'task', 'priority'));
+
+    $query = $query
+      ->extend('Drupal\Core\Database\Query\TableSortExtender')
+      ->orderByHeader($header)
+      ->orderBy('priority');
+
+    // We need all the results at once to check the sort.
+    $tasks = $query->execute()->fetchAll();
+
+    return new JsonResponse(array(
+      'tasks' => $tasks,
+    ));
+  }
+}

core/modules/system/tests/modules/database_test/src/Form/DatabaseTestForm.php

@@ -0,0 +1,81 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\database_test\Form\DatabaseTestForm.
+ */
+
+namespace Drupal\database_test\Form;
+
+use Drupal\Component\Utility\SafeMarkup;
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\user\Entity\User;
+
+/**
+ * Form controller for database_test module.
+ */
+class DatabaseTestForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'database_test_theme_tablesort';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    $header = array(
+      'username' => array('data' => t('Username'), 'field' => 'u.name'),
+      'status' => array('data' => t('Status'), 'field' => 'u.status'),
+    );
+
+    $query = db_select('users_field_data', 'u');
+    $query->condition('u.uid', 0, '<>');
+    $query->condition('u.default_langcode', 1);
+
+    $count_query = clone $query;
+    $count_query->addExpression('COUNT(u.uid)');
+
+    $query = $query
+      ->extend('Drupal\Core\Database\Query\PagerSelectExtender')
+      ->extend('Drupal\Core\Database\Query\TableSortExtender');
+    $query
+      ->fields('u', array('uid'))
+      ->limit(50)
+      ->orderByHeader($header)
+      ->setCountQuery($count_query);
+    $uids = $query
+      ->execute()
+      ->fetchCol();
+
+    $options = array();
+
+    foreach (User::loadMultiple($uids) as $account) {
+      $options[$account->id()] = array(
+        'title' => array('data' => array('#title' => SafeMarkup::checkPlain($account->getUsername()))),
+        'username' => SafeMarkup::checkPlain($account->getUsername()),
+        'status' =>  $account->isActive() ? t('active') : t('blocked'),
+      );
+    }
+
+    $form['accounts'] = array(
+      '#type' => 'tableselect',
+      '#header' => $header,
+      '#options' => $options,
+      '#empty' => t('No people available.'),
+    );
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+  }
+
+}