new_contents: import json
  
  from django.test import TestCase
  from django.core.serializers import serialize
  
  from frontend.models import PCT
  from api.geojson_serializer import as_geojson_stream
  
  
  class GeoJSONSerializerTest(TestCase):
  
      fixtures = ['orgs']
  
      def test_output_is_the_same_as_core_serializer(self):
          fields = ['name', 'org_type', 'ons_code', 'boundary']
          geo_field = 'boundary'
          queryset = PCT.objects.all()
          expected_json = serialize(
              'geojson',
              queryset,
              geometry_field=geo_field,
              fields=fields
          )
          stream = as_geojson_stream(
              queryset.values(*fields),
              geometry_field=geo_field
          )
          expected = json.loads(expected_json)
          actual = json.loads(''.join(stream))
          self.assertEqual(expected, actual)
  
subject: Add test for GeoJSON serializer