A test wouldn't work if you're using the default policy unless there is a new bulletin in the last 24 hours. You can clone the policy and then edit the SQL query to be more hours (edit query, paramaters and change 24 to whatever). I changed it to 336 and then the test email went through and I got a link to the new bulletins in the last 2 weeks. I have the policy set to run daily but the last email I got was 12/13 and I know new bulletins came out since then so mine doesn't seem to be working on schedule properly either, even though my test works.
I run "Item Status Changed After PMImport" automation policy. Those emails seem to come through and are my clue to check the remediation center.