The Mock-JavaMail project
I came across it when developing a plugin for Jenkins, and it's been a dream to use!
Just drop the dependency into your project, and you're ready to go (I'll let Kohsuke explain how to set it up and use it).
If you're impatient, here's a quick example of how it's used:
Example:
// Setup test: add mail to inbox
Mailbox tmp = Mailbox.get("foo@bar.com");
tmp.add(/* your javax.mail.Message */)
assertEquals 1, tmp.size()
// Connect to the inmemory mailbox using "imap"
Session session = Session.getInstance(System.getProperties(), null);
Store store = session.getStore('imap');
store.connect("bar.com","foo","anything");
// Check the mail exists!
Folder inbox = store.getFolder("INBOX");
inbox.open(Folder.READ_ONLY);
assertEquals 1, inbox.getMessageCount()
store.close();
