diff --git a/t/db_dependent/Koha/AdditionalField.t b/t/db_dependent/Koha/AdditionalField.t
index db2d50d8fa..b369dc7ce2 100755
--- a/t/db_dependent/Koha/AdditionalField.t
+++ b/t/db_dependent/Koha/AdditionalField.t
@@ -30,7 +30,7 @@ subtest 'effective_authorised_value_category' => sub {
     );
     $field->store()->discard_changes();
 
-    is($field->effective_authorised_value_category, '', 'no default category');
+    is($field->effective_authorised_value_category, undef, 'no default category');
 
     $field = Koha::AdditionalField->new(
         {