old_contents: import asyncio
  import uuid
  from sanic.response import text
  from sanic import Sanic
  from io import StringIO
  import logging
  
  logging_format = '''module: %(module)s; \
  function: %(funcName)s(); \
  message: %(message)s'''
  
  
  def test_log():
      log_stream = StringIO()
      for handler in logging.root.handlers[:]:
          logging.root.removeHandler(handler)
      logging.basicConfig(
          format=logging_format,
          level=logging.DEBUG,
          stream=log_stream
      )
      log = logging.getLogger()
      app = Sanic('test_logging')
      rand_string = str(uuid.uuid4())
  
      @app.route('/')
      def handler(request):
          log.info(rand_string)
          return text('hello')
  
      request, response = app.test_client.get('/')
      log_text = log_stream.getvalue()
      assert rand_string in log_text
  
  if __name__ == "__main__":
      test_log()
  
new_contents: import uuid
  from importlib import reload
  
  from sanic.config import LOGGING
  from sanic.response import text
  from sanic import Sanic
  from io import StringIO
  import logging
  
  logging_format = '''module: %(module)s; \
  function: %(funcName)s(); \
  message: %(message)s'''
  
  
  def reset_logging():
      logging.shutdown()
      reload(logging)
  
  
  def test_log():
      log_stream = StringIO()
      for handler in logging.root.handlers[:]:
          logging.root.removeHandler(handler)
      logging.basicConfig(
          format=logging_format,
          level=logging.DEBUG,
          stream=log_stream
      )
      log = logging.getLogger()
      app = Sanic('test_logging')
      rand_string = str(uuid.uuid4())
  
      @app.route('/')
      def handler(request):
          log.info(rand_string)
          return text('hello')
  
      request, response = app.test_client.get('/')
      log_text = log_stream.getvalue()
      assert rand_string in log_text
  
  
  def test_default_log_fmt():
  
      reset_logging()
      Sanic()
      for fmt in [h.formatter for h in logging.getLogger('sanic').handlers]:
          assert fmt._fmt == LOGGING['formatters']['simple']['format']
  
      reset_logging()
      Sanic(log_config=None)
      for fmt in [h.formatter for h in logging.getLogger('sanic').handlers]:
          assert fmt._fmt == "%(asctime)s: %(levelname)s: %(message)s"
  
  
  if __name__ == "__main__":
      test_log()
  
subject: add tests