def METHOD_NAME(self):
    # "OK case"
    DefDescriptor(name='a_name', base_definition=None, jobs={'foo': 42})
    # error cases
    with self.assertRaises(ValueError):
        DefDescriptor(name=None, base_definition=None, jobs={'foo': 42})
    with self.assertRaises(ModelValidationError):
        DefDescriptor(name='a_name', base_definition=None, jobs={})