new_contents: import unittest
  
  from pelican import get_config, parse_arguments
  
  
  class TestParseOverrides(unittest.TestCase):
      def test_flags(self):
          for flag in ['-e', '--extra-settings']:
              args = parse_arguments([flag, 'k=1'])
              self.assertDictEqual(args.overrides, {'k': 1})
  
      def test_parse_multiple_items(self):
          args = parse_arguments('-e k1=1 k2=2'.split())
          self.assertDictEqual(args.overrides, {'k1': 1, 'k2': 2})
  
      def test_parse_valid_json(self):
          json_values_python_values_map = {
              '""': '',
              'null': None,
              '"string"': 'string',
              '["foo", 12, "4", {}]': ['foo', 12, '4', {}]
          }
          for k, v in json_values_python_values_map.items():
              args = parse_arguments(['-e', 'k=' + k])
              self.assertDictEqual(args.overrides, {'k': v})
  
      def test_parse_invalid_syntax(self):
          invalid_items = ['k= 1', 'k =1', 'k', 'k v']
          for item in invalid_items:
              with self.assertRaises(ValueError):
                  parse_arguments(f'-e {item}'.split())
  
      def test_parse_invalid_json(self):
          invalid_json = {
              '', 'False', 'True', 'None', 'some other string',
              '{"foo": bar}', '[foo]'
          }
          for v in invalid_json:
              with self.assertRaises(ValueError):
                  parse_arguments(['-e ', 'k=' + v])
  
  
  class TestGetConfigFromArgs(unittest.TestCase):
      def test_overrides_known_keys(self):
          args = parse_arguments([
              '-e',
              'DELETE_OUTPUT_DIRECTORY=false',
              'OUTPUT_RETENTION=["1.txt"]',
              'SITENAME="Title"'
          ])
          config = get_config(args)
          config_must_contain = {
              'DELETE_OUTPUT_DIRECTORY': False,
              'OUTPUT_RETENTION': ['1.txt'],
              'SITENAME': 'Title'
          }
          self.assertDictEqual(config, {**config, **config_must_contain})
  
      def test_overrides_non_default_type(self):
          args = parse_arguments([
              '-e',
              'DISPLAY_PAGES_ON_MENU=123',
              'PAGE_TRANSLATION_ID=null',
              'TRANSLATION_FEED_RSS_URL="someurl"'
          ])
          config = get_config(args)
          config_must_contain = {
              'DISPLAY_PAGES_ON_MENU': 123,
              'PAGE_TRANSLATION_ID': None,
              'TRANSLATION_FEED_RSS_URL': 'someurl'
          }
          self.assertDictEqual(config, {**config, **config_must_contain})
  
subject: Add failing tests