new_contents: # Copyright 2016 Red Hat
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  import contextlib
  
  import mock
  
  from nova.cmd import compute
  from nova.cmd import network
  from nova import db
  from nova import exception
  from nova import test
  
  
  @contextlib.contextmanager
  def restore_db():
      orig = db.api.IMPL
      try:
          yield
      finally:
          db.api.IMPL = orig
  
  
  class ComputeMainTest(test.NoDBTestCase):
      @mock.patch('nova.utils.monkey_patch')
      @mock.patch('nova.conductor.api.API.wait_until_ready')
      @mock.patch('oslo_reports.guru_meditation_report')
      def _call_main(self, mod, gmr, cond, patch):
          @mock.patch.object(mod, 'config')
          @mock.patch.object(mod, 'service')
          def run_main(serv, conf):
              mod.main()
  
          run_main()
  
      def test_compute_main_blocks_db(self):
          with restore_db():
              self._call_main(compute)
              self.assertRaises(exception.DBNotAllowed,
                                db.api.instance_get, 1, 2)
  
      def test_network_main_blocks_db(self):
          with restore_db():
              self._call_main(network)
              self.assertRaises(exception.DBNotAllowed,
                                db.api.instance_get, 1, 2)
  
subject: Add test for nova-compute and nova-network main database blocks