make test more clever, refs #20590

tests/test_send_email.sh

 #!/bin/bash
 # Copyright 2017, Florent Thiery
 # envoyer un mail contenant un truc random
-echo "This is a test email" | mail -s "Test email from `cat /etc/hostname`" deployment@ubicast.eu
+RAND="$RANDOM"
+EMAIL="deployment+$RAND@ubicast.eu"
+echo "This is a test email" | mail -s "Test email from `cat /etc/hostname`" $EMAIL
 sleep 10
-tail -n 10 /var/log/mail.log | grep bounced
-if [ $? -na 0 ]; then
+grep $EMAIL /var/log/mail.log | grep bounced
+if [ $? -ne 0 ]; then
     echo "Sending mail failed"
     exit 1
 fi