diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index 979cdd1f..6cb5bb89 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -5,6 +5,6 @@
 require_once __DIR__.'/../vendor/autoload.php';
 
 // Unsafe is needed because google/auth uses getenv/putenv to determine the Application Credentials
-$dotenv = Dotenv\Dotenv::createUnsafeImmutable(__DIR__);
+$dotenv = Dotenv\Dotenv::createUnsafeMutable(__DIR__);
 $dotenv->safeLoad();
 $dotenv->required('GOOGLE_APPLICATION_CREDENTIALS');