My case auto response is very simple. All the cases are assigned to a queue called "test". In case auto response rule my criteria is "case owner= queue name(test)". rule is active and email template has been assigned(available for use). I don't see any auto response email after case creation in sandbox. Are they any other settings I am missing ?
Sandboxes by default will not deliver emails. You can enable email deliverability in your sandbox or find a non-email way of verifying activity triggering e.g. updating a checkbox field.