'L{MaildirDirdbmDomain.userDirectory} is supplied with a user name
and returns the path to that user\'s maildir subdirectory.
Calling L{MaildirDirdbmDomain.userDirectory} with a
non-existent user returns the \'postmaster\' directory if there
is a postmaster or returns L{None} if there is no postmaster.'

def test_userDirectory(self):

    self.D.addUser('user', 'password')
    self.assertEqual(self.D.userDirectory('user'), os.path.join(self.D.root, 'user'))
    self.D.postmaster = False
    self.assertIdentical(self.D.userDirectory('nouser'), None)
    self.D.postmaster = True
    self.assertEqual(self.D.userDirectory('nouser'), os.path.join(self.D.root, 'postmaster'))
