code: def test_deployment_config_update(self):
      b = DeploymentConfig(num_replicas=1, max_concurrent_queries=1)
  
      # Test updating a key works.
      b.num_replicas = 2
      assert b.num_replicas == 2
      # Check that not specifying a key doesn't update it.
      assert b.max_concurrent_queries == 1
  
      # Check that input is validated.
      with pytest.raises(ValidationError):
          b.num_replicas = "Hello"
      with pytest.raises(ValidationError):
          b.num_replicas = -1
  
imports: import pytest
  from ray import cloudpickle
  from ray._private.pydantic_compat import ValidationError
  from ray._private.utils import import_attr
  from ray.serve._private.config import DeploymentConfig, ReplicaConfig, _proto_to_dict
  from ray.serve._private.constants import DEFAULT_AUTOSCALING_POLICY, DEFAULT_GRPC_PORT
  from ray.serve._private.utils import DEFAULT
  from ray.serve.autoscaling_policy import default_autoscaling_policy
  from ray.serve.config import AutoscalingConfig, DeploymentMode, HTTPOptions, ProxyLocation, gRPCOptions
  from ray.serve.generated.serve_pb2 import AutoscalingConfig
  from ray.serve.generated.serve_pb2 import DeploymentConfig
  from ray.serve.generated.serve_pb2 import DeploymentLanguage
  from ray.serve.generated.serve_pb2_grpc import add_UserDefinedServiceServicer_to_server
  from ray.serve.schema import DeploymentSchema, HTTPOptionsSchema, ServeApplicationSchema, ServeDeploySchema
label_desc: Use image node_id 2 for calling the TestDeploymentConfig obj's underlying member method code with example usage: obj.test_deployment_config_update() without return types