text: import datetime
  
  from django.core.exceptions import ValidationError
  from django.forms import DurationField
  from django.test import SimpleTestCase
  from django.utils import translation
  from django.utils.duration import duration_string
  
  from . import FormFieldAssertionsMixin
  
  
  class DurationFieldTest(FormFieldAssertionsMixin, SimpleTestCase):
  
      def test_durationfield_clean(self):
          f = DurationField()
          self.assertEqual(datetime.timedelta(seconds=30), f.clean('30'))
          self.assertEqual(datetime.timedelta(minutes=15, seconds=30), f.clean('15:30'))
          self.assertEqual(datetime.timedelta(hours=1, minutes=15, seconds=30), f.clean('1:15:30'))
          self.assertEqual(
              datetime.timedelta(days=1, hours=1, minutes=15, seconds=30, milliseconds=300),
              f.clean('1 1:15:30.3')
          )
  
      def test_overflow(self):
          msg = "The number of days must be between {min_days} and {max_days}.".format(
              min_days=datetime.timedelta.min.days,
              max_days=datetime.timedelta.max.days,
          )
          f = DurationField()
          with self.assertRaisesMessage(ValidationError, msg):
              f.clean('1000000000 00:00:00')
          with self.assertRaisesMessage(ValidationError, msg):
              f.clean('-1000000000 00:00:00')
  
      def test_overflow_translation(self):
          msg = "Le nombre de jours doit être entre {min_days} et {max_days}.".format(
              min_days=datetime.timedelta.min.days,
              max_days=datetime.timedelta.max.days,
          )
          with translation.override('fr'):
              with self.assertRaisesMessage(ValidationError, msg):
                  DurationField().clean('1000000000 00:00:00')
  
      def test_durationfield_render(self):
          self.assertWidgetRendersTo(
              DurationField(initial=datetime.timedelta(hours=1)),
              '<input id="id_f" type="text" name="f" value="01:00:00" required>',
          )
  
      def test_durationfield_integer_value(self):
          f = DurationField()
          self.assertEqual(datetime.timedelta(0, 10800), f.clean(10800))
  
      def test_durationfield_prepare_value(self):
          field = DurationField()
          td = datetime.timedelta(minutes=15, seconds=30)
          self.assertEqual(field.prepare_value(td), duration_string(td))
          self.assertEqual(field.prepare_value('arbitrary'), 'arbitrary')
          self.assertIsNone(field.prepare_value(None))
  