.../comment/src/Plugin/Action/UnpublishByKeywordComment.php    |  2 +-
 core/modules/node/src/Plugin/Search/NodeSearch.php             |  4 ++--
 core/modules/simpletest/src/AssertContentTrait.php             |  8 +++++++-
 core/modules/system/src/Tests/Render/RenderCacheTest.php       | 10 +++++-----
 4 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/core/modules/comment/src/Plugin/Action/UnpublishByKeywordComment.php b/core/modules/comment/src/Plugin/Action/UnpublishByKeywordComment.php
index 56706ad..6b70450 100644
--- a/core/modules/comment/src/Plugin/Action/UnpublishByKeywordComment.php
+++ b/core/modules/comment/src/Plugin/Action/UnpublishByKeywordComment.php
@@ -28,7 +28,7 @@ class UnpublishByKeywordComment extends ConfigurableActionBase {
    */
   public function execute($comment = NULL) {
     $build = comment_view($comment);
-    $text = drupal_render($build);
+    $text = \Drupal::service('renderer')->renderPlain($build);
     foreach ($this->configuration['keywords'] as $keyword) {
       if (strpos($text, $keyword) !== FALSE) {
         $comment->setPublished(FALSE);
diff --git a/core/modules/node/src/Plugin/Search/NodeSearch.php b/core/modules/node/src/Plugin/Search/NodeSearch.php
index 6bd2e18..9dc4442 100644
--- a/core/modules/node/src/Plugin/Search/NodeSearch.php
+++ b/core/modules/node/src/Plugin/Search/NodeSearch.php
@@ -329,7 +329,7 @@ protected function prepareResults(StatementInterface $found) {
 
       // Fetch comment count for snippet.
       $rendered = SafeMarkup::set(
-        $this->renderer->render($build) . ' ' .
+        $this->renderer->renderPlain($build) . ' ' .
         SafeMarkup::escape($this->moduleHandler->invoke('comment', 'node_update_index', array($node, $item->langcode)))
       );
 
@@ -354,7 +354,7 @@ protected function prepareResults(StatementInterface $found) {
 
       if ($type->displaySubmitted()) {
         $result += array(
-          'user' => $this->renderer->render($username),
+          'user' => $this->renderer->renderPlain($username),
           'date' => $node->getChangedTime(),
         );
       }
diff --git a/core/modules/simpletest/src/AssertContentTrait.php b/core/modules/simpletest/src/AssertContentTrait.php
index b043ea9..3cce705 100644
--- a/core/modules/simpletest/src/AssertContentTrait.php
+++ b/core/modules/simpletest/src/AssertContentTrait.php
@@ -10,6 +10,7 @@
 use Drupal\Component\Serialization\Json;
 use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Component\Utility\Xss;
+use Drupal\Core\Render\RenderContext;
 use Symfony\Component\CssSelector\CssSelector;
 
 /**
@@ -808,7 +809,12 @@ protected function assertNoTitle($title, $message = '', $group = 'Other') {
    *   TRUE on pass, FALSE on fail.
    */
   protected function assertThemeOutput($callback, array $variables = array(), $expected = '', $message = '', $group = 'Other') {
-    $output = \Drupal::theme()->render($callback, $variables);
+    /** @var \Drupal\Core\Render\RendererInterface $renderer */
+    $renderer = \Drupal::service('renderer');
+
+    $output = $renderer->executeInRenderContext(new RenderContext(), function() use ($callback, $variables) {
+      return \Drupal::theme()->render($callback, $variables);
+    });
     $this->verbose(
       '<hr />' . 'Result:' . '<pre>' . SafeMarkup::checkPlain(var_export($output, TRUE)) . '</pre>'
       . '<hr />' . 'Expected:' . '<pre>' . SafeMarkup::checkPlain(var_export($expected, TRUE)) . '</pre>'
diff --git a/core/modules/system/src/Tests/Render/RenderCacheTest.php b/core/modules/system/src/Tests/Render/RenderCacheTest.php
index b4317d1..975358c 100644
--- a/core/modules/system/src/Tests/Render/RenderCacheTest.php
+++ b/core/modules/system/src/Tests/Render/RenderCacheTest.php
@@ -77,14 +77,14 @@ protected function doTestUser1WithContexts($contexts) {
     ];
     $element = $test_element;
     $element['#markup'] = 'content for user 1';
-    $output = \Drupal::service('renderer')->render($element);
+    $output = \Drupal::service('renderer')->renderRoot($element);
     $this->assertEqual($output, 'content for user 1');
 
     // Verify the cache is working by rendering the same element but with
     // different markup passed in; the result should be the same.
     $element = $test_element;
     $element['#markup'] = 'should not be used';
-    $output = \Drupal::service('renderer')->render($element);
+    $output = \Drupal::service('renderer')->renderRoot($element);
     $this->assertEqual($output, 'content for user 1');
     \Drupal::service('account_switcher')->switchBack();
 
@@ -93,7 +93,7 @@ protected function doTestUser1WithContexts($contexts) {
     \Drupal::service('account_switcher')->switchTo($first_authenticated_user);
     $element = $test_element;
     $element['#markup'] = 'content for authenticated users';
-    $output = \Drupal::service('renderer')->render($element);
+    $output = \Drupal::service('renderer')->renderRoot($element);
     $this->assertEqual($output, 'content for authenticated users');
     \Drupal::service('account_switcher')->switchBack();
 
@@ -102,7 +102,7 @@ protected function doTestUser1WithContexts($contexts) {
     \Drupal::service('account_switcher')->switchTo($second_authenticated_user);
     $element = $test_element;
     $element['#markup'] = 'should not be used';
-    $output = \Drupal::service('renderer')->render($element);
+    $output = \Drupal::service('renderer')->renderRoot($element);
     $this->assertEqual($output, 'content for authenticated users');
     \Drupal::service('account_switcher')->switchBack();
 
@@ -111,7 +111,7 @@ protected function doTestUser1WithContexts($contexts) {
     \Drupal::service('account_switcher')->switchTo($admin_user);
     $element = $test_element;
     $element['#markup'] = 'content for admin user';
-    $output = \Drupal::service('renderer')->render($element);
+    $output = \Drupal::service('renderer')->renderRoot($element);
     $this->assertEqual($output, 'content for admin user');
     \Drupal::service('account_switcher')->switchBack();
   }