diff --git a/tests/phpunit/FunctionalGCSTest.php b/tests/phpunit/FunctionalGCSTest.php
index 5ab4b4c..a594e03 100644
--- a/tests/phpunit/FunctionalGCSTest.php
+++ b/tests/phpunit/FunctionalGCSTest.php
@@ -25,6 +25,8 @@ class FunctionalGCSTest extends TestCase
 
     protected StorageApi $sapiClient;
 
+    private StorageClient $storageClient;
+
     private string $testRunId;
 
     public function setUp(): void