def METHOD_NAME(self):
    plan = PlanFactory()
    plan_dest_1 = PlanFactory()
    plan_dest_2 = PlanFactory()
    plan_dest_1.migrate_plan = plan
    plan_dest_1.save()
    plan_dest_2.migrate_plan = plan
    plan_dest_2.save()
    migrate_to = plan.migrate_to.all()
    self.assertEqual(len(migrate_to), 2)
    self.assertIn(plan_dest_1, migrate_to)
    self.assertIn(plan_dest_2, migrate_to)