If your script or app sends mail and you’ve got no time or don’t feel like configuring a real SMTP server, use a mailsink. A debugging method that in it’s simplest form just displays the result of the SMTP conversation, namely the message.
Fire up a terminal an run this code:
python -m smtpd -n -c DebuggingServer localhost:3000
This listens on port 3000 on your localhost (127.0.0.1). If you need port 25 (the SMTP default port), just run the line with sudo and enter your password:
sudo python -m smtpd -n -c DebuggingServer localhost:25
That’s it. Enjoy.