new_contents: # Copyright 2020 Mycroft AI Inc.
  #
  # 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.
  #
  from unittest import TestCase, mock
  
  import mycroft.util.plugins as mycroft_plugins
  
  
  def get_plug_mock(name):
      load_mock = mock.Mock(name=name)
      load_mock.name = name
      plug_mock = mock.Mock(name=name)
      plug_mock.name = name
      plug_mock.load.return_value = load_mock
      return plug_mock
  
  
  def mock_iter_entry_points(plug_type):
      """Function to return mocked plugins."""
      plugs = {
          'mycroft.plugins.tts': [get_plug_mock('dummy'),
                                  get_plug_mock('remote')],
          'mycroft.plugins.stt': [get_plug_mock('dummy'),
                                  get_plug_mock('deepspeech')]
      }
      return plugs.get(plug_type, [])
  
  
  @mock.patch('mycroft.util.plugins.pkg_resources')
  class TestPlugins(TestCase):
      def test_load_existing(self, mock_pkg_res):
          """Ensure that plugin objects are returned if found."""
          mock_pkg_res.iter_entry_points.side_effect = mock_iter_entry_points
  
          # Load a couple of existing modules and verify that they're Ok
          plug = mycroft_plugins.load_plugin('mycroft.plugins.tts', 'dummy')
          self.assertEqual(plug.name, 'dummy')
          plug = mycroft_plugins.load_plugin('mycroft.plugins.stt', 'deepspeech')
          self.assertEqual(plug.name, 'deepspeech')
  
      def test_load_nonexisting(self, mock_pkg_res):
          """Ensure that the return value is None when no plugin is found."""
          mock_pkg_res.iter_entry_points.side_effect = mock_iter_entry_points
          plug = mycroft_plugins.load_plugin('mycroft.plugins.tts', 'blah')
          self.assertEqual(plug, None)
  
subject: Add unittests for the plugin util