diff --git a/Tests/Fixtures/TranslatableTextAlign.php b/Tests/Fixtures/TranslatableTextAlign.php
index 7a5d5cdff..4464088c7 100644
--- a/Tests/Fixtures/TranslatableTextAlign.php
+++ b/Tests/Fixtures/TranslatableTextAlign.php
@@ -20,7 +20,7 @@ enum TranslatableTextAlign implements TranslatableInterface
     case Center;
     case Right;
 
-    public function trans(TranslatorInterface $translator, string $locale = null): string
+    public function trans(TranslatorInterface $translator, ?string $locale = null): string
     {
         return $translator->trans($this->name, locale: $locale);
     }