diff --git a/core/modules/image/tests/src/Functional/ImageEffectsTest.php b/core/modules/image/tests/src/Functional/ImageEffectsTest.php
index e9cb157..54f3c96 100644
--- a/core/modules/image/tests/src/Functional/ImageEffectsTest.php
+++ b/core/modules/image/tests/src/Functional/ImageEffectsTest.php
@@ -3,7 +3,7 @@
 namespace Drupal\Tests\image\Functional;
 
 use Drupal\image\Entity\ImageStyle;
-use Drupal\system\Tests\Image\ToolkitTestBase;
+use Drupal\Tests\system\Functional\Image\ToolkitTestBase;
 
 /**
  * Tests that the image effects pass parameters to the toolkit correctly.
diff --git a/core/modules/system/tests/modules/image_test/src/Plugin/ImageToolkit/TestToolkit.php b/core/modules/system/tests/modules/image_test/src/Plugin/ImageToolkit/TestToolkit.php
index a28c786..a0f5080 100644
--- a/core/modules/system/tests/modules/image_test/src/Plugin/ImageToolkit/TestToolkit.php
+++ b/core/modules/system/tests/modules/image_test/src/Plugin/ImageToolkit/TestToolkit.php
@@ -161,8 +161,8 @@ public function save($destination) {
    * @param array $args
    *   Values passed to hook.
    *
-   * @see \Drupal\system\Tests\Image\ToolkitTestBase::imageTestReset()
-   * @see \Drupal\system\Tests\Image\ToolkitTestBase::imageTestGetAllCalls()
+   * @see \Drupal\Tests\system\Functional\Image\ToolkitTestBase::imageTestReset()
+   * @see \Drupal\Tests\system\Functional\Image\ToolkitTestBase::imageTestGetAllCalls()
    */
   protected function logCall($op, $args) {
     $results = $this->state->get('image_test.results') ?: [];
diff --git a/core/modules/system/src/Tests/Image/ToolkitSetupFormTest.php b/core/modules/system/tests/src/Functional/Image/ToolkitSetupFormTest.php
similarity index 85%
rename from core/modules/system/src/Tests/Image/ToolkitSetupFormTest.php
rename to core/modules/system/tests/src/Functional/Image/ToolkitSetupFormTest.php
index 7dc9d33..3d1411b 100644
--- a/core/modules/system/src/Tests/Image/ToolkitSetupFormTest.php
+++ b/core/modules/system/tests/src/Functional/Image/ToolkitSetupFormTest.php
@@ -1,15 +1,15 @@
 <?php
 
-namespace Drupal\system\Tests\Image;
+namespace Drupal\Tests\system\Functional\Image;
 
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests image toolkit setup form.
  *
  * @group Image
  */
-class ToolkitSetupFormTest extends WebTestBase {
+class ToolkitSetupFormTest extends BrowserTestBase {
 
   /**
    * Admin user account.
@@ -40,11 +40,13 @@ protected function setUp() {
    * Test Image toolkit setup form.
    */
   public function testToolkitSetupForm() {
+    $assertSession = $this->assertSession();
+
     // Get form.
     $this->drupalGet('admin/config/media/image-toolkit');
 
     // Test that default toolkit is GD.
-    $this->assertFieldByName('image_toolkit', 'gd', 'The default image toolkit is GD.');
+    $assertSession->fieldValueEquals('image_toolkit', 'gd');
 
     // Test changing the jpeg image quality.
     $edit = ['gd[image_jpeg_quality]' => '70'];
@@ -55,7 +57,7 @@ public function testToolkitSetupForm() {
     $edit = ['image_toolkit' => 'test'];
     $this->drupalPostForm(NULL, $edit, 'Save configuration');
     $this->assertEqual($this->config('system.image')->get('toolkit'), 'test');
-    $this->assertFieldByName('test[test_parameter]', '10');
+    $assertSession->fieldValueEquals('test[test_parameter]', '10');
 
     // Test changing the test toolkit parameter.
     $edit = ['test[test_parameter]' => '0'];
diff --git a/core/modules/system/src/Tests/Image/ToolkitTest.php b/core/modules/system/tests/src/Functional/Image/ToolkitTest.php
similarity index 98%
rename from core/modules/system/src/Tests/Image/ToolkitTest.php
rename to core/modules/system/tests/src/Functional/Image/ToolkitTest.php
index f70c261..361b3a8 100644
--- a/core/modules/system/src/Tests/Image/ToolkitTest.php
+++ b/core/modules/system/tests/src/Functional/Image/ToolkitTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\system\Tests\Image;
+namespace Drupal\Tests\system\Functional\Image;
 
 /**
  * Tests image toolkit functions.
diff --git a/core/modules/system/src/Tests/Image/ToolkitTestBase.php b/core/modules/system/tests/src/Functional/Image/ToolkitTestBase.php
similarity index 93%
rename from core/modules/system/src/Tests/Image/ToolkitTestBase.php
rename to core/modules/system/tests/src/Functional/Image/ToolkitTestBase.php
index 0051e94..13d7b66 100644
--- a/core/modules/system/src/Tests/Image/ToolkitTestBase.php
+++ b/core/modules/system/tests/src/Functional/Image/ToolkitTestBase.php
@@ -1,14 +1,19 @@
 <?php
 
-namespace Drupal\system\Tests\Image;
+namespace Drupal\Tests\system\Functional\Image;
 
-use Drupal\simpletest\WebTestBase;
-use Drupal\Component\Utility\SafeMarkup;
+use Drupal\Component\Render\FormattableMarkup;
+use Drupal\Tests\BrowserTestBase;
+use Drupal\Tests\TestFileCreationTrait;
 
 /**
  * Base class for image manipulation testing.
  */
-abstract class ToolkitTestBase extends WebTestBase {
+abstract class ToolkitTestBase extends BrowserTestBase {
+
+  use TestFileCreationTrait {
+    getTestFiles as drupalGetTestFiles;
+  }
 
   /**
    * Modules to enable.