diff --git a/core/modules/views/src/Plugin/views/field/FieldPluginBase.php b/core/modules/views/src/Plugin/views/field/FieldPluginBase.php
index a45cdf2..10fc04a 100644
--- a/core/modules/views/src/Plugin/views/field/FieldPluginBase.php
+++ b/core/modules/views/src/Plugin/views/field/FieldPluginBase.php
@@ -875,10 +875,12 @@ public function buildOptionsForm(&$form, FormStateInterface $form_state) {
       $this->documentSelfTokens($options[t('Fields')]);
 
       // Default text.
-      $output = '<p>' . $this->t('You must add some additional fields to this display before using this field. These fields may be marked as <em>Exclude from display</em> if you prefer. Note that due to rendering order, you cannot use fields that come after this field; if you need a field not listed here, rearrange your fields.') . '</p>';
+
+      $output = [];
+      $output[][ '#markup'] = '<p>' . $this->t('You must add some additional fields to this display before using this field. These fields may be marked as <em>Exclude from display</em> if you prefer. Note that due to rendering order, you cannot use fields that come after this field; if you need a field not listed here, rearrange your fields.') . '</p>';
       // We have some options, so make a list.
       if (!empty($options)) {
-        $output = '<p>' . $this->t("The following replacement tokens are available for this field. Note that due to rendering order, you cannot use fields that come after this field; if you need a field not listed here, rearrange your fields.") . '</p>';
+        $output[]['#markup'] = '<p>' . $this->t("The following replacement tokens are available for this field. Note that due to rendering order, you cannot use fields that come after this field; if you need a field not listed here, rearrange your fields.") . '</p>';
         foreach (array_keys($options) as $type) {
           if (!empty($options[$type])) {
             $items = array();
@@ -890,7 +892,7 @@ public function buildOptionsForm(&$form, FormStateInterface $form_state) {
               '#items' => $items,
               '#list_type' => $type,
             );
-            $output .= $this->getRenderer()->renderPlain($item_list);
+            $output[] = $item_list;
           }
         }
       }
@@ -901,7 +903,7 @@ public function buildOptionsForm(&$form, FormStateInterface $form_state) {
       $form['alter']['help'] = array(
         '#type' => 'details',
         '#title' => $this->t('Replacement patterns'),
-        '#value' => SafeMarkup::set($output),
+        '#value' => $output,
         '#states' => array(
           'visible' => array(
             array(
diff --git a/core/modules/views_ui/src/Tests/FieldUITest.php b/core/modules/views_ui/src/Tests/FieldUITest.php
index 3b66c21..34d4215 100644
--- a/core/modules/views_ui/src/Tests/FieldUITest.php
+++ b/core/modules/views_ui/src/Tests/FieldUITest.php
@@ -67,7 +67,7 @@ public function testFieldUI() {
   /**
    * Tests the field labels.
    */
-  public function atestFieldLabel() {
+  public function testFieldLabel() {
     // Create a view with unformatted style and make sure the fields have no
     // labels by default.
     $view = array();
diff --git a/core/modules/views_ui/src/Tests/PreviewTest.php b/core/modules/views_ui/src/Tests/PreviewTest.php
index 01816af..ff10213 100644
--- a/core/modules/views_ui/src/Tests/PreviewTest.php
+++ b/core/modules/views_ui/src/Tests/PreviewTest.php
@@ -26,7 +26,7 @@ class PreviewTest extends UITestBase {
   /**
    * Tests contextual links in the preview form.
    */
-  public function atestPreviewContextual() {
+  public function testPreviewContextual() {
     \Drupal::service('module_installer')->install(array('contextual'));
     $this->resetAll();
 
@@ -49,7 +49,7 @@ public function atestPreviewContextual() {
   /**
    * Tests arguments in the preview form.
    */
-  function atestPreviewUI() {
+  function testPreviewUI() {
     $this->drupalGet('admin/structure/views/view/test_preview/edit');
     $this->assertResponse(200);
 
@@ -99,7 +99,7 @@ function atestPreviewUI() {
    *
    * @see https://www.drupal.org/node/2452659
    */
-  public function atestTaxonomyAJAX() {
+  public function testTaxonomyAJAX() {
     \Drupal::service('module_installer')->install(array('taxonomy'));
     $this->getPreviewAJAX('taxonomy_term', 'page_1', 0);
   }
@@ -212,7 +212,7 @@ public function testPreviewWithPagersUI() {
   /**
    * Tests the additional information query info area.
    */
-  public function atestPreviewAdditionalInfo() {
+  public function testPreviewAdditionalInfo() {
     \Drupal::service('module_installer')->install(array('views_ui_test'));
     $this->resetAll();