'The managers on a model are set.'

def test_alter_model_managers_emptying(self):

    project_state = self.set_up_test_model('test_almomae', manager_model=True)
    operation = migrations.AlterModelManagers('Food', managers=[])
    self.assertEqual(operation.describe(), 'Change    managers    on    Food')
    self.assertIn(('test_almomae', 'food'), project_state.models)
    managers = project_state.models[('test_almomae', 'food')].managers
    self.assertEqual(managers[0][0], 'food_qs')
    self.assertIsInstance(managers[0][1], models.Manager)
    self.assertEqual(managers[1][0], 'food_mgr')
    self.assertIsInstance(managers[1][1], FoodManager)
    self.assertEqual(managers[1][1].args, ('a', 'b', 1, 2))
    self.assertEqual(managers[2][0], 'food_mgr_kwargs')
    self.assertIsInstance(managers[2][1], FoodManager)
    self.assertEqual(managers[2][1].args, ('x', 'y', 3, 4))
    new_state = project_state.clone()
    operation.state_forwards('test_almomae', new_state)
    managers = new_state.models[('test_almomae', 'food')].managers
    self.assertEqual(managers, [])
