I have a MySQL trigger setup on one of my tables, but I actually need end of month. For instance, if I have a test_date of 2015-11-27 the next_due date should be 2016-02-29 and not 2016-02-27. How can I do this? Here's my trigger.

SET NEW.test_date = IFNULL(NEW.test_date,NOW()),
NEW.next_due = TIMESTAMPADD(MONTH,3,NEW.test_date)