new_contents: import pytest
  
  from shadho.backend.json.domain import Domain
  from shadho.backend.json.model import Model
  from shadho.backend.json.value import Value
  from shadho.backend.utils import InvalidObjectError
  from shadho.backend.base.tests.test_base_domain import TestBaseDomain
  
  import uuid
  
  import numpy as np
  import scipy.stats
  
  
  class TestJsonDomain(TestBaseDomain):
      """Unit tests for the JSON backend Domain class"""
  
      __model_class__ = Model
      __domain_class__ = Domain
      __value_class__ = Value
  
      def test_init(self):
          # Test the default initialization
          d = self.__domain_class__()
          assert hasattr(d, 'id')
          assert d.id is not None
          assert d.domain is None
          assert d.strategy == 'random'
          assert d.scaling == 'linear'
          assert d.model is None
          assert d.values == []
          assert d.exhaustive is False
          assert d.exhaustive_idx is None
  
          # Test setting id, constant domain, strategy, scaling, model, and values
          m = self.__model_class__()
          v = self.__value_class__()
          did = str(uuid.uuid4())
          d = self.__domain_class__(id=did, domain=1, strategy='tpe', scaling='ln', model=m,
                    values=[v])
          assert d.id == did
          assert d.domain == 1
          assert d.strategy == 'tpe'
          assert d.scaling == 'ln'
          assert d.model == m.id
          assert d.values == [v.id]
          assert d.exhaustive is False
          assert d.exhaustive_idx is None
  
          # Test setting discrete domain, model by id, and value by id
          d = self.__domain_class__(id=did, domain=[1, 2, 3, 4], model=m.id, values=[v.id])
          assert d.domain == [1, 2, 3, 4]
          assert d.model == m.id
          assert d.values == [v.id]
          assert d.exhaustive is False
          assert d.exhaustive_idx is None
  
          # Test setting a discrete domain with exhaustive search
          d = self.__domain_class__(domain=[1, 2, 3, 4], exhaustive=True)
          assert d.domain == [1, 2, 3, 4]
          assert d.exhaustive
          assert d.exhaustive_idx == 0
  
          # Test setting continuous domain from `scipy.stats.rv_continuous`
          dist = scipy.stats.uniform(loc=-7, scale=42)
          d = self.__domain_class__(domain=dist)
          assert d.domain is dist
  
          # Test setting continuous domain from dictionary
          rng = np.random.RandomState().get_state()
          domain = {
              'distribution': 'uniform',
              'args': [],
              'kwargs': {
                  'loc': -7,
                  'scale': 42,
              },
              'rng': [rng[0], list(rng[1]), rng[2], rng[3], rng[4]]
          }
          d = self.__domain_class__(domain=domain)
          assert d.domain.dist.name == 'uniform'
          assert d.domain.args == ()
          assert d.domain.kwds == {'loc': -7, 'scale': 42}
          state = d.domain.random_state.get_state()
          assert state[0] == rng[0]
          assert np.all(state[1] == np.array(rng[1]))
          assert state[2] == rng[2]
          assert state[3] == rng[3]
          assert state[4] == rng[4]
  
      def test_add_value(self):
          d = self.__domain_class__()
  
          # Test adding a Value object
          v = self.__value_class__()
          d.add_value(v)
          assert d.values == [v.id]
  
          # Test adding an id
          vid = str(uuid.uuid4())
          d.add_value(vid)
          assert d.values == [v.id, vid]
  
          with pytest.raises(InvalidObjectError):
              d.add_value((1, 2, 3))
  
          assert d.values == [v.id, vid]
  
subject: add tests fro JSON domain