'``FlockerConfiguration.is_valid_format`` returns ``False`` if the
supplied configuration for a single application does not contain the
required "image" key.'

def test_not_valid_on_application_missing_image(self):

    config = {u'version': 1, u'applications': {u'postgres': {u'build': u'.'}}}
    parser = FlockerConfiguration(config)
    self.assertFalse(parser.is_valid_format())
