Update to Drupal 8.0.1. For more information, see https://www.drupal.org/node/2627402

core/modules/views/tests/modules/views_test_config/test_views/views.view.test_field_header.yml

@@ -0,0 +1,71 @@
+langcode: en
+status: true
+dependencies: {  }
+id: test_field_header
+label: null
+module: views
+description: ''
+tag: ''
+base_table: views_test_data
+base_field: nid
+core: '8'
+display:
+  default:
+    display_options:
+      fields:
+        name:
+          id: name
+          table: views_test_data
+          field: name
+          plugin_id: string
+          element_label_type: h2
+      style:
+        type: table
+      display_extenders: {  }
+    display_plugin: default
+    display_title: Master
+    id: default
+    position: 0
+    cache_metadata:
+      max-age: 0
+      contexts:
+        - 'languages:language_interface'
+        - url.query_args
+      tags: {  }
+  page_1:
+    display_options:
+      path: test_field_header
+      display_extenders: {  }
+    display_plugin: page
+    display_title: Page
+    id: page_1
+    position: 1
+    cache_metadata:
+      max-age: 0
+      contexts:
+        - 'languages:language_interface'
+        - url.query_args
+      tags: {  }
+  page_2:
+    display_options:
+      path: test_field_header_xss
+      defaults:
+        fields: false
+      fields:
+        name:
+          id: name
+          table: views_test_data
+          field: name
+          plugin_id: string
+          element_label_type: 'script>alert("XSS")</script'
+      display_extenders: {  }
+    display_plugin: page
+    display_title: 'Page 2'
+    id: page_2
+    position: 2
+    cache_metadata:
+      max-age: 0
+      contexts:
+        - 'languages:language_interface'
+        - url.query_args
+      tags: {  }

core/modules/views/tests/src/Unit/Plugin/field/FieldPluginBaseTest.php

@@ -258,6 +258,23 @@ class FieldPluginBaseTest extends UnitTestCase {
     $this->assertEquals($expected_result, $result);
   }
 
+  /**
+   * Tests the "No results text" rendering.
+   *
+   * @covers ::renderText
+   */
+  public function testRenderNoResult() {
+    $this->setupDisplayWithEmptyArgumentsAndFields();
+    $field = $this->setupTestField(['empty' => 'This <strong>should work</strong>.']);
+    $field->field_alias = 'key';
+    $row = new ResultRow(['key' => '']);
+
+    $expected_result = 'This <strong>should work</strong>.';
+    $result = $field->advancedRender($row);
+    $this->assertEquals($expected_result, $result);
+    $this->assertInstanceOf('\Drupal\views\Render\ViewsRenderPipelineMarkup', $result);
+  }
+
   /**
    * Test rendering of a link with a path and options.
    *