new_contents: #!/usr/bin/env python3
  # -*- coding: utf-8 -*-
  import io
  from logging import StreamHandler
  from unittest import TestCase
  
  from logger import log
  
  
  class TestLog(TestCase):
      def test_set_level(self):
          out = io.StringIO()
          log.logger.addHandler(StreamHandler(stream=out))
          log.set_level(log.Level.WARN)
          log.i("message")
          self.assertEqual(out.getvalue(), "")
          log.set_level(log.Level.INFO)
          log.i("message")
          self.assertEqual(out.getvalue(), "message\n")
  
      def test_d(self):
          out = io.StringIO()
          log.logger.addHandler(StreamHandler(stream=out))
          log.set_level(log.Level.DEBUG)
  
          log.d("message")
          self.assertEqual(out.getvalue(), "message\n")
  
      def test_d__byte(self):
          out = io.StringIO()
          log.logger.addHandler(StreamHandler(stream=out))
          log.set_level(log.Level.DEBUG)
  
          log.d(b'message')
          self.assertEqual(out.getvalue(), "message\n")
  
      def test_i(self):
          out = io.StringIO()
          log.logger.addHandler(StreamHandler(stream=out))
  
          log.i("message")
          self.assertEqual(out.getvalue(), "message\n")
  
      def test_w(self):
          out = io.StringIO()
          log.logger.addHandler(StreamHandler(stream=out))
  
          log.w("message")
          self.assertEqual(out.getvalue(), "message\n")
  
      def test_e(self):
          out = io.StringIO()
          log.logger.addHandler(StreamHandler(stream=out))
  
          log.e("message")
          self.assertEqual(out.getvalue(), "message\n")
  
subject: Add test case for log.py.