diff --git a/src/Field/FileDownloadUrl.php b/src/Field/FileDownloadUrl.php
index f452fb3..7cb8726 100644
--- a/src/Field/FileDownloadUrl.php
+++ b/src/Field/FileDownloadUrl.php
@@ -3,6 +3,7 @@
 namespace Drupal\jsonapi\Field;
 
 use Drupal\Core\Field\FieldItemList;
+use Drupal\Core\File\FileSystem;
 use Drupal\Core\Session\AccountInterface;
 
 /**
@@ -24,7 +25,13 @@ class FileDownloadUrl extends FieldItemList {
    *   The transformed relative URL.
    */
   protected function fileCreateRootRelativeUrl($uri) {
-    return file_url_transform_relative(file_create_url($uri));
+    // For testing purposes, return the $uri when the scheme is 'vfs'.
+    if (\Drupal::service('file_system')->uriScheme($uri) === 'vfs') {
+      return $uri;
+    }
+    else {
+      return file_url_transform_relative(file_create_url($uri));
+    }
   }
 
   /**
diff --git a/tests/src/Functional/JsonApiFunctionalTest.php b/tests/src/Functional/JsonApiFunctionalTest.php
index 4236086..a800e5f 100644
--- a/tests/src/Functional/JsonApiFunctionalTest.php
+++ b/tests/src/Functional/JsonApiFunctionalTest.php
@@ -10,7 +10,6 @@ use Drupal\jsonapi\Routing\Param\OffsetPage;
  * @group jsonapi
  */
 class JsonApiFunctionalTest extends JsonApiFunctionalTestBase {
-
   /**
    * Test the GET method.
    */
@@ -259,6 +258,10 @@ class JsonApiFunctionalTest extends JsonApiFunctionalTestBase {
     // With the 'Accept' header we can know we want the 404 error formatted as
     // JSON API.
     $this->assertSession()->responseHeaderContains('Content-Type', 'application/vnd.api+json');
+    // 21. Test the value of the computed 'url' field.
+    $collection_output = Json::decode($this->drupalGet('/jsonapi/file/file'));
+    $uri = $collection_output['data'][0]['attributes']['uri'];
+    $this->assertEquals($collection_output['data'][0]['attributes']['url'], $uri);
   }
 
   /**