I was suprised to learn on a call with Support yesterday that when we send a test to ourselves within the email tool the URLs that are in the email are not necessarily the same ones served up to the end user. This seems counter-intuitive. We've always used the Test functionality to test everything - images , URLs, etc. and I don't really understand what the Test functionality does if not allow admins and approvers to use these emails for that purpose.
Turns out, we'd been sending out emails with broken links, but everything seemed to work ok on the test versions.
This is CRITICAL for our business, and we shouldn't have to rely on our end users to let us know there's an error.