diff --git a/core/modules/rdf/src/Tests/CommentAttributesTest.php b/core/modules/rdf/tests/src/Functional/CommentAttributesTest.php
similarity index 99%
rename from core/modules/rdf/src/Tests/CommentAttributesTest.php
rename to core/modules/rdf/tests/src/Functional/CommentAttributesTest.php
index 8ca5798cd5..0c194382ba 100644
--- a/core/modules/rdf/src/Tests/CommentAttributesTest.php
+++ b/core/modules/rdf/tests/src/Functional/CommentAttributesTest.php
@@ -1,10 +1,10 @@
 <?php
 
-namespace Drupal\rdf\Tests;
+namespace Drupal\Tests\rdf\Functional;
 
 use Drupal\comment\CommentInterface;
 use Drupal\comment\CommentManagerInterface;
-use Drupal\comment\Tests\CommentTestBase;
+use Drupal\Tests\comment\Functional\CommentTestBase;
 use Drupal\user\RoleInterface;
 use Drupal\comment\Entity\Comment;
 
diff --git a/core/modules/rdf/src/Tests/GetNamespacesTest.php b/core/modules/rdf/tests/src/Functional/GetNamespacesTest.php
similarity index 61%
rename from core/modules/rdf/src/Tests/GetNamespacesTest.php
rename to core/modules/rdf/tests/src/Functional/GetNamespacesTest.php
index ca46c5cd79..4ced14d337 100644
--- a/core/modules/rdf/src/Tests/GetNamespacesTest.php
+++ b/core/modules/rdf/tests/src/Functional/GetNamespacesTest.php
@@ -1,8 +1,8 @@
 <?php
 
-namespace Drupal\rdf\Tests;
+namespace Drupal\Tests\rdf\Functional;
 
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Confirm that the serialization of RDF namespaces in present in the HTML
@@ -10,7 +10,7 @@
  *
  * @group rdf
  */
-class GetNamespacesTest extends WebTestBase {
+class GetNamespacesTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
@@ -29,22 +29,22 @@ public function testGetRdfNamespaces() {
     $element = $this->xpath('//html[contains(@prefix, :prefix_binding)]', [
       ':prefix_binding' => 'rdfs: http://www.w3.org/2000/01/rdf-schema#',
     ]);
-    $this->assertTrue(!empty($element), 'A prefix declared once is displayed.');
+    $this->assertTrue(!empty($element[0]->getText()), 'A prefix declared once is displayed.');
 
     $element = $this->xpath('//html[contains(@prefix, :prefix_binding)]', [
       ':prefix_binding' => 'foaf: http://xmlns.com/foaf/0.1/',
     ]);
-    $this->assertTrue(!empty($element), 'The same prefix declared in several implementations of hook_rdf_namespaces() is valid as long as all the namespaces are the same.');
+    $this->assertTrue(!empty($element[0]->getText()), 'The same prefix declared in several implementations of hook_rdf_namespaces() is valid as long as all the namespaces are the same.');
 
     $element = $this->xpath('//html[contains(@prefix, :prefix_binding)]', [
       ':prefix_binding' => 'foaf1: http://xmlns.com/foaf/0.1/',
     ]);
-    $this->assertTrue(!empty($element), 'Two prefixes can be assigned the same namespace.');
+    $this->assertTrue(!empty($element[0]->getText()), 'Two prefixes can be assigned the same namespace.');
 
     $element = $this->xpath('//html[contains(@prefix, :prefix_binding)]', [
       ':prefix_binding' => 'dc: http://purl.org/dc/terms/',
     ]);
-    $this->assertTrue(!empty($element), 'When a prefix has conflicting namespaces, the first declared one is used.');
+    $this->assertTrue(!empty($element[0]->getText()), 'When a prefix has conflicting namespaces, the first declared one is used.');
   }
 
 }
diff --git a/core/modules/rdf/src/Tests/ImageFieldAttributesTest.php b/core/modules/rdf/tests/src/Functional/ImageFieldAttributesTest.php
similarity index 93%
rename from core/modules/rdf/src/Tests/ImageFieldAttributesTest.php
rename to core/modules/rdf/tests/src/Functional/ImageFieldAttributesTest.php
index d4d7d35948..e5707591f7 100644
--- a/core/modules/rdf/src/Tests/ImageFieldAttributesTest.php
+++ b/core/modules/rdf/tests/src/Functional/ImageFieldAttributesTest.php
@@ -1,11 +1,12 @@
 <?php
 
-namespace Drupal\rdf\Tests;
+namespace Drupal\Tests\rdf\Functional;
 
 use Drupal\image\Entity\ImageStyle;
-use Drupal\image\Tests\ImageFieldTestBase;
+use Drupal\Tests\image\Functional\ImageFieldTestBase;
 use Drupal\node\Entity\Node;
 use Drupal\file\Entity\File;
+use Drupal\Tests\TestFileCreationTrait;
 
 /**
  * Tests the RDFa markup of imagefields.
@@ -14,6 +15,10 @@
  */
 class ImageFieldAttributesTest extends ImageFieldTestBase {
 
+  use TestFileCreationTrait {
+    getTestFiles as drupalGetTestFiles;
+  }
+
   /**
    * Modules to enable.
    *