[eluser]Dam1an[/eluser]
Although its not built in (which I think it should), there's a very easy and clean way to do it
Create an email library extending the default one
Replace the send function by creating your own
Have an optional parapemter for success (default to true)
The reason for the optional paramter is so you can test what happens if it would fail
Check if a config item for test mode exists
If in test mode, return true or false for success
If not in test mode, call the real send method
I'll mock some code up later and post it back (unless my description was so clear and easy you don't need it)
EDIT: Fuzzy beat me