new_contents: """
  Tests for Net interface module
  
  It requires requests-mock
  """
  import unittest
  import os
  
  import requests_mock
  
  import net
  requests_mock.Mocker.TEST_PREFIX = 'test_'
  
  
  @requests_mock.Mocker()
  class NetInterfaceTests(unittest.TestCase):
  
      def test_make_get_request(self, mocker):
          mocker.register_uri('GET', 'http://test.com', text='Hello world')
          r = net._make_get_request('http://test.com')
          self.assertEqual('Hello world', r.text)
  
      def test_download(self, mocker):
          mocker.register_uri('GET', 'http://test.com', content=b'Hello world')
          net.download('http://test.com', 'test.file')
          f = open('test.file', 'rb')
          content = f.read()
          f.close()
          os.remove('test.file')
          self.assertEqual(b'Hello world', content)
  
      def test_request_get_content(self, mocker):
          mocker.register_uri('GET', 'http://test.com', content=b'<html></html>')
          content = net.request_get_content('http://test.com')
          self.assertEqual(b'<html></html>', content)
  
      def test_request_get_content_retry_fail(self, mocker):
          mocker.register_uri('GET', 'http://test.com',
                              text='Not found', status_code=404)
          self.assertRaises(RuntimeError,
                            net.request_get_content,
                            'http://test.com', 2, 0.1)
  
subject: add tests?