old_contents: from django.test import TestCase
  
  from main.api.serializers import DatasetSerializer
  from main.tests.api import helpers
  
  
  class TestDatsetSerializer(helpers.BaseUserTestCase):
  
      def test_name_uniqueness(self):
          """
          Test that the serializer report an error if the dataset name is not unique within a project
          """
          # create a dataset
          dataset = self._create_dataset_from_rows([
              ['What', 'Comment'],
              ['what', 'comments']
          ])
          dataset.name = 'Test'
          dataset.save()
  
          # Trye serializer with a dataset with the same name
          data = {
              'name': dataset.name,
              'project': dataset.project.pk,
              'data_package': dataset.data_package,
              'type': 'generic'
          }
          ser = DatasetSerializer(data=data)
          self.assertFalse(ser.is_valid(()))
          # the errors should be of the form
          # {'non_field_errors': ['The fields project, name must make a unique set.']}
          errors = ser.errors
          self.assertEquals(['non_field_errors'], list(errors.keys()))
          self.assertEquals(1, len(errors.get('non_field_errors')))
          self.assertIn('project, name must make a unique set', errors.get('non_field_errors')[0])
  
new_contents: from django.test import TestCase
  
  from main.api.serializers import DatasetSerializer
  from main.tests.api import helpers
  
  
  class TestDatsetSerializer(helpers.BaseUserTestCase):
  
      def test_name_uniqueness(self):
          """
          Test that the serializer report an error if the dataset name is not unique within a project
          """
          # create a dataset
          dataset = self._create_dataset_from_rows([
              ['What', 'Comment'],
              ['what', 'comments']
          ])
          dataset.name = 'Test'
          dataset.save()
  
          # Trye serializer with a dataset with the same name
          data = {
              'name': dataset.name,
              'project': dataset.project.pk,
              'data_package': dataset.data_package,
              'type': 'generic'
          }
          ser = DatasetSerializer(data=data)
          self.assertFalse(ser.is_valid(()))
          # the errors should be of the form
          # {'non_field_errors': ['The fields project, name must make a unique set.']}
          errors = ser.errors
          self.assertEquals(['non_field_errors'], list(errors.keys()))
          self.assertEquals(1, len(errors.get('non_field_errors')))
          self.assertIn('A dataset with this name already exists in the project.', errors.get('non_field_errors')[0])
  
subject: Fix test to accommodate change of error message.