new_contents: import uuid
  from unittest import mock
  
  from django.test import TestCase
  
  from casexml.apps.case.mock import CaseBlock
  
  from corehq.apps.hqcase.bulk import CaseBulkDB
  from corehq.form_processor.interfaces.dbaccessors import CaseAccessors
  from corehq.form_processor.models import XFormInstance
  from corehq.form_processor.tests.utils import FormProcessorTestUtils
  
  
  @mock.patch('corehq.apps.hqcase.bulk.CASEBLOCK_CHUNKSIZE', new=5)
  class TestUpdateCases(TestCase):
      domain = 'test_bulk_update_cases'
  
      def tearDown(self):
          FormProcessorTestUtils.delete_all_xforms()
          FormProcessorTestUtils.delete_all_cases()
          super().tearDown()
  
      def test(self):
          with CaseBulkDB(self.domain, 'my_user_id', 'my_device_id') as bulk_db:
              for i in range(1, 18):
                  bulk_db.save(CaseBlock(
                      create=True,
                      case_id=str(uuid.uuid4()),
                      case_type='patient',
                      case_name=f"case_{i}",
                      update={'phase': '1'},
                  ))
  
          self.assertEqual(len(XFormInstance.objects.get_form_ids_in_domain(self.domain)), 4)
          case_accessor = CaseAccessors(self.domain)
          self.assertEqual(len(case_accessor.get_case_ids_in_domain()), 17)
  
subject: Add basic test for CaseBulkDB