test: Verify mailbox delivery in minor dialogs test

The minor dialogs test covers some very specific SMTP exchanges, and
some of those include delivering email.

Today, we don't verify the final mailbox, we just check the SMTP
exchange. However, it can be very useful for some of the tests to do
end-to-end checking of the final mailbox.

This patch implements that ability in the test itself, and on the
(currently only) email delivering dialog.

Subsequent patches that introduce new tests will make use of this
feature.

test/t-12-minor_dialogs/run.sh

@@ -8,7 +8,7 @@ init
 generate_certs_for testserver
 add_user user@testserver secretpassword
 
-mkdir -p .logs
+mkdir -p .logs .mbox
 chasquid -v=2 --logfile=.logs/chasquid.log --config_dir=config &
 wait_until_ready 1025
 
@@ -16,7 +16,28 @@ FAILED=0
 for i in *.cmy; do
 	if ! chamuyero "$i" > ".logs/$i.log" 2>&1 ; then
 		echo "test $i failed, see .logs/$i.log"
+		echo
+		echo "last lines of the log:"
+		tail -n 10 ".logs/$i.log" | sed 's/^/  /g'
+		echo
 		FAILED=1
+		continue
+	fi
+
+	# Some tests do email delivery, this allows us to verify the results.
+	if [ -f "$i.verify" ]; then
+		wait_for_file .mail/user@testserver
+		cp .mail/user@testserver ".mbox/$i.mbox"
+		if ! mail_diff "$i.verify" .mail/user@testserver \
+			> ".mbox/$i.diff" ;
+		then
+			echo "test $i failed, because it had a mail diff"
+			echo
+			echo "mail diff:"
+			sed 's/^/  /g' ".mbox/$i.diff"
+			echo
+			FAILED=1
+		fi
 	fi
 done
 

test/t-12-minor_dialogs/sendmail.cmy.verify

@@ -0,0 +1,6 @@
+From: Mailer daemon <somewhere@horns.com>
+Subject: I've come to haunt you
+
+Muahahahaha
+
+