'L{MaildirDirdbmDomain.requestAvatar} raises L{NotImplementedError}
unless it is supplied with an L{pop3.IMailbox} interface.
When called with an L{pop3.IMailbox}, it returns a 3-tuple
containing L{pop3.IMailbox}, an implementation of that interface
and a NOOP callable.'

def test_requestAvatar(self):

    class ISomething(Interface, ):
        pass
    self.D.addUser('user', 'password')
    self.assertRaises(NotImplementedError, self.D.requestAvatar, 'user', None, ISomething)
    t = self.D.requestAvatar('user', None, pop3.IMailbox)
    self.assertEqual(len(t), 3)
    self.assertTrue((t[0] is pop3.IMailbox))
    self.assertTrue(pop3.IMailbox.providedBy(t[1]))
    t[2]()
