Robin MTA Tester is a development, debug, and testing tool for MTA architects. It is powered by a highly customizable SMTP client designed to emulate the behavior of popular email clients. A rudimentary server is also provided that is mainly used for testing the client.
The primary usage is done via JSON files called test cases. Cases are client configuration files run as Junit tests.
Download Link:- https://github.com/mimecast/robin