A truncate table command is not caught by a delete trigger.
Although a truncate table statement is, in effect, like a delete without a where clause (it removes all rows), changes to the data rows are not logged, and so cannot fire a trigger.
Since permission for the truncate tablecommand defaults to the table owner and is not transferable, only the table owner need worry about inadvertently circumventing a delete trigger with a truncate table statement.
The writetext command, whether logged or unlogged, does not cause a trigger to fire.