(find-file "/tmp/sent")
(insert "empty")
(kill-region (point-min) (point-max))
(write-file "/tmp/sent")
(kill-buffer)

(find-file "/tmp/result")
(kill-region (point-min) (point-max))
(write-file "/tmp/result")
(kill-buffer)

(find-file "/tmp/show-sendmail-args.sh")
(kill-region (point-min) (point-max))
(insert "#!/bin/sh
echo $* >> /tmp/result")
(write-file "/tmp/show-sendmail-args.sh")
(chmod "/tmp/show-sendmail-args.sh" 448)

(setq sendmail-program "/tmp/show-sendmail-args.sh")
(setq mail-specify-envelope-from t)
(setq mail-envelope-from 'header)
(setq send-mail-function 'sendmail-send-it)

(compose-mail "Echo Mail Server <echo@univie.ac.at>" "test"
               '((From: . "example@example.org")))
(message-send-and-exit)

(notmuch-mua-mail "Echo Mail Server <echo@univie.ac.at>" "test"
               '((From: . "example@example.org")))
(notmuch-mua-send-and-exit)

(save-buffers-kill-terminal)