mtt.register("send mail", function(callback) -- create "player2" local auth_handler = minetest.get_auth_handler() auth_handler.set_password("player2", "") -- send a mail mail.send("player1", "player2", "something", "blah") -- check the receivers inbox local list2 = mail.getMessages("player2") assert(list2 ~= nil and #list2 > 0) callback() end)