diff --git a/core/modules/file/tests/src/Unit/Plugin/Field/FieldType/FileItemTest.php b/core/modules/file/tests/src/Unit/Plugin/Field/FieldType/FileItemTest.php
index e3fbbd0..03bd156 100644
--- a/core/modules/file/tests/src/Unit/Plugin/Field/FieldType/FileItemTest.php
+++ b/core/modules/file/tests/src/Unit/Plugin/Field/FieldType/FileItemTest.php
@@ -5,7 +5,7 @@
  * Contains \Drupal\Tests\file\Unit\Plugin\Field\FieldType\FileItemTest.
  */
 
-namespace Drupal\Tests\file\Unit\Plugin\Field\FieldType;
+namespace Drupal\Tests\file\Unit\Plugin\Field\FieldType {
 
 use Drupal\Component\Utility\Bytes;
 use Drupal\file\Plugin\Field\FieldType\FileItem;
@@ -50,3 +50,15 @@ public function testValidateMaxFilesize($filesize, $valid) {
   }
 
 }
+
+}
+
+namespace {
+  use Drupal\Component\Utility\String;
+
+  if (!function_exists('t')) {
+    function t($string, array $args = []) {
+      return String::format($string, $args);
+    }
+  }
+}