new_contents: from django.test import TestCase
  
  from revproxy import connection
  
  
  class TestOutput(TestCase):
  
      def setUp(self):
          self.connection = connection.HTTPConnectionPool.ConnectionCls('example.com')
  
      def test_byte_url(self):
          """Output strings are always byte strings, even using Python 3"""
          mock_output = b'mock output'
          connection._output(self.connection, mock_output)
          self.assertEqual(self.connection._buffer, [mock_output])
  
      def test_host_is_first(self):
          """Make sure the host line is second in the request"""
          mock_host_output = b'host: example.com'
          for output in [b'GET / HTTP/1.1', b'before', mock_host_output, b'after']:
              connection._output(self.connection, output)
          self.assertEqual(self.connection._buffer[1], mock_host_output)
  
subject: Add tests for output as bytes and testing that the host line is second