Test mailing code should use the same path as real mailing

Since the click-through links were broken at one point ( CRM-1739 ) it was easy to accidentally send a broken mailing even though the test mailing looked good. Would it be possible to have the click-through links and other tokens (such as a the reply-to address) in the test mailing? Ideally the test mailing should look exactly the same as the final mailing. This might help to catch further problems before they get sent out.