def METHOD_NAME(self):
    self.populateMaildir()
    mds = mail.MaildirSource(self.maildir)
    yield self.attachChangeSource(mds)
    # monkey-patch in a parse method
    def parse(message, prefix):
        assert 'this is a test' in message.get_payload()
        return ('svn', {"author": 'jimmy'})
    mds.parse = parse
    yield mds.messageReceived('newmsg')
    self.assertMailProcessed()
    self.assertEqual(self.master.data.updates.changesAdded, [{
        'author': 'jimmy',
        'committer': None,
        'branch': None,
        'category': None,
        'codebase': None,
        'comments': None,
        'files': None,
        'project': '',
        'properties': {},
        'repository': '',
        'revision': None,
        'revlink': '',
        'src': 'svn',
        'when_timestamp': None,
    }])