Having fakeserver available from mozmill tests would really help with imap testing (and to a lesser extent, Pop3). I can imagine it would help with compose/send issues too. On IRC, Standard8 says that runtest.py needs support for this, and it should be possible since it's similar to what firefox does with httpd.

Isn't that what http://mxr.mozilla.org/comm-central/source/mail/test/mozmill/shared-modules/test-nntp-helpers.js does? So this bug is just about extending this to other fakeservers such as imap and pop3?

This bug predates that file. And, from what I recall, we don't actually *use* the fakeserver in that test (as in, spawn the server and use sockets); ISTR there being issues as well with using fakeserver in general from mozmill, but my recollections are two years old at this point. One usability concern about fakeserver is this: when I first wrote mozmill, I didn't know what I was doing, and it predates most of our xpcshell infrastructure, such as asyncTestUtils or messageGenerator. Five years later, there's a clearer idea of what tests actually look like, so the basic high-level API for using fakeserver should look like: let gImapServer = createIMAPServer({ username: "tinderbox", password: "password", ssl: true, port: 1143, configuration: "GMail", profile: "small-inbox" }, on_server_ready); [where all the options have suitable defaults]. In other words, we should have a profile-based system that gives access to a useful suite of messages/folders to specify, and server startup/shutdown should be automatic. [The on_server_ready callback is because the LDAP fakeserver, whenever I get around to that, is definitely not ready immediately, SSL won't be immediately ready, etc.] Migrating to this kind of API in general is useful, and since Mozmill has no preexisting API already, it's a good place to start with it.

I hacked something up for bug 99019. All the bits and pieces are accessible from Mozmill. So this is "only" about providing a nice API?