'Test that the --auth command line creates a dictionary
mapping supported interfaces to the list of credentials
checkers that support it.'

def test_createsDictionary(self):

    options = DummyOptions()
    options.parseOptions(['--auth', 'memory', '--auth', 'anonymous'])
    chd = options['credInterfaces']
    self.assertEqual(len(chd[credentials.IAnonymous]), 1)
    self.assertEqual(len(chd[credentials.IUsernamePassword]), 1)
    chdAnonymous = chd[credentials.IAnonymous][0]
    chdUserPass = chd[credentials.IUsernamePassword][0]
    self.assertTrue(checkers.ICredentialsChecker.providedBy(chdAnonymous))
    self.assertTrue(checkers.ICredentialsChecker.providedBy(chdUserPass))
    self.assertIn(credentials.IAnonymous, chdAnonymous.credentialInterfaces)
    self.assertIn(credentials.IUsernamePassword, chdUserPass.credentialInterfaces)
