diff --git a/src/ServiceContainer/SymfonyExtension.php b/src/ServiceContainer/SymfonyExtension.php
index 1a5f165..fc61b20 100644
--- a/src/ServiceContainer/SymfonyExtension.php
+++ b/src/ServiceContainer/SymfonyExtension.php
@@ -175,7 +175,7 @@ final class SymfonyExtension implements Extension
     private function fallbackToTestEnvironment(): void
     {
         // If there's no defined server / environment variable with an environment, default to test
-        if (($_SERVER['APP_ENV'] ?? $_ENV['APP_ENV']) === null) {
+        if (($_SERVER['APP_ENV'] ?? $_ENV['APP_ENV'] ?? null) === null) {
             putenv('APP_ENV=' . $_SERVER['APP_ENV'] = $_ENV['APP_ENV'] = 'test');
         }
     }