CatchMe runs a simple SMTP server which catches any message sent to it to display in a web interface. Run CatchMe, set your app to deliver to smtp://127.0.0.1:1025, then check out http://127.0.0.1:1080 to see the emails that arrived so far.
npm install catch-me -g
If you need some specific ports just pass them here
catchme --mailPort 1234 --appPort 4321
npm test will run the unit tests with mocha.