Some time ago I wrote a blog post describing a way I use to verify MySQL Server bugs. But my job consists not only of bugs which can be verified just by passing SQL queries to the server.
One of such examples is UDF bugs.
MySQL User Reference Manual is good source of information for those who want to write UDF functions, as well as book "MySQL 5.1 Plugin Development" by Sergei Golubchik and Andrew Hutchings. But while the book describes in details how to write UDFs it was created in time when current MySQL version was 5.1 and does not contain information about