How do I test the various subscription status update notification types with sandbox accounts?

Hi,

I am implementing subscriptions and want to test the various "Status Update Notification Types". We are tracking changes using a "Subscription Status URL", but all I seem to be able to get, with a Sandbox account, is:

INITIAL_BUY

RENEWAL

I don't feel comfortable shipping our implementation until I test all cases. Specifically:
CANCEL
INTERACTIVE_RENEWAL

DID_CHANGE_RENEWAL_PREFERENCE

What's the best way to test all cases with a Sandbox account?

Thanks.