old_contents: import unittest
  from performance.routine import Tool, Config
  
  
  class ToolTestCase(unittest.TestCase):
      def setUp(self):
          self.host = 'http://www.google.com'
          self.config = Config(host=self.host)
  
      def test_init(self):
          tool = Tool(config=self.config)
          self.assertEqual(self.config, tool.config)
          with self.assertRaises(TypeError) as error:
              tool = Tool(config='invalid_config')
          self.assertEqual('No performance.routine.Config object', error.exception.__str__())
  
new_contents: import unittest
  from performance.routine import Tool, Config
  
  
  class ToolTestCase(unittest.TestCase):
      def setUp(self):
          self.host = 'http://www.google.com'
          self.config = Config(host=self.host)
  
      def test_init(self):
          tool = Tool(config=self.config)
          self.assertEqual(self.config, tool.config)
          with self.assertRaises(TypeError) as error:
              tool = Tool(config='invalid_config')
          self.assertEqual('No performance.routine.Config object', error.exception.__str__())
  
      def test_run(self):
          tool = Tool(config=self.config)
          tool.run()
  
subject: Add test for Tool.run()