diff --git a/core/modules/file/src/Plugin/migrate/source/d7/File.php b/core/modules/file/src/Plugin/migrate/source/d7/File.php
index a4a500b..6752575 100644
--- a/core/modules/file/src/Plugin/migrate/source/d7/File.php
+++ b/core/modules/file/src/Plugin/migrate/source/d7/File.php
@@ -84,7 +84,7 @@ public function prepareRow(Row $row) {
     // At this point, $path could be an absolute path or a relative path,
     // depending on how the scheme's variable was set. So we need to shear out
     if (isset($this->configuration['constants']['source_file_private_path'])) {
-      $path = str_replace($this->configuration['constants']['source_file_private_path'], NULL, $path);
+      $path = str_replace($this->configuration['constants']['source_file_private_path'], NULL, realpath($path));
     }
     else {
       $path = str_replace($this->configuration['constants']['source_base_path'], NULL, $path);
diff --git a/core/modules/file/tests/src/Kernel/Migrate/d7/MigratePrivateFileTest.php b/core/modules/file/tests/src/Kernel/Migrate/d7/MigratePrivateFileTest.php
index 848ade4..076c1fa 100644
--- a/core/modules/file/tests/src/Kernel/Migrate/d7/MigratePrivateFileTest.php
+++ b/core/modules/file/tests/src/Kernel/Migrate/d7/MigratePrivateFileTest.php
@@ -2,7 +2,7 @@
 
 namespace Drupal\Tests\file\Kernel\Migrate\d7;
 
-use Drupal\Core\StreamWrapper\StreamWrapperInterface;
+use Drupal\Core\DependencyInjection\ContainerBuilder;
 use Drupal\file\Entity\File;
 use Drupal\file\FileInterface;
 use Drupal\Tests\migrate_drupal\Kernel\d7\MigrateDrupal7TestBase;
@@ -23,11 +23,10 @@ protected function setUp() {
     parent::setUp();
     $this->setSetting('file_private_path', 'sites/default/private');
     $this->installEntitySchema('file');
-    $this->container->get('stream_wrapper_manager')->registerWrapper('private', 'Drupal\Core\StreamWrapper\PrivateStream', StreamWrapperInterface::NORMAL);
-    $fs = \Drupal::service('file_system');
+    $fs = $this->container->get('file_system');
 
     // Put test file in the source directory.
-    file_put_contents('private://sites/default/private/Babylon5.txt', str_repeat('*', 3));
+    file_put_contents('private://Babylon5.txt', str_repeat('*', 3));
 
     /** @var \Drupal\migrate\Plugin\Migration $migration */
     $migration = $this->getMigration('d7_file_private');
@@ -40,6 +39,15 @@ protected function setUp() {
   }
 
   /**
+   * {@inheritdoc}
+   */
+  public function register(ContainerBuilder $container) {
+    parent::register($container);
+    $container->register('stream_wrapper.private', 'Drupal\Core\StreamWrapper\PrivateStream')
+      ->addTag('stream_wrapper', ['scheme' => 'private']);
+  }
+
+  /**
    * Tests a single file entity.
    *
    * @param int $id