A simple local SMTP server

I prefer Fake SMTP for this. It's a desktop app (packed into jar file). Since it is written in Java, you can run it both from Linux/Mac/Windows

For email testing, try Dumbster. From their page:

The Dumbster is a very simple fake SMTP server designed for unit and system testing applications that send email messages. It responds to all standard SMTP commands but does not deliver messages to the user. The messages are stored within the Dumbster for later extraction and verification.

The Dumbster slots itself very easily into your testing strategy. As long as your application talks to an email server using SMTP then the Dumbster can be used to test the application with no code changes.

Various forks exist since the original page is no longer available:

• https://github.com/kirviq/dumbster
• https://github.com/rjo1970/dumbster

More can be found using a Github Search