new_contents: from django.contrib.auth import get_user_model
  from django.core.urlresolvers import reverse
  from django.test import TestCase, override_settings
  
  from buildservice.models import Webhook, Repository
  
  
  @override_settings(BUILDSERVICE_BASE_URL='https://service.com')
  class WebhookTestCase(TestCase):
  
      def setUp(self):
          self.user = get_user_model().objects.create_user('zzz', password='ttt')
          self.repo = Repository.objects.create(name='john-doe/repo')
          self.webhook = Webhook.objects.create(user=self.user, repository=self.repo)
  
      def test_get_push_url(self):
          push_url = reverse('webhooks_push')
          self.assertEqual(self.webhook.get_push_url(), 'https://service.com%s' % push_url)
  
subject: add tests for the Webhook model