new_contents: 
  from .utils import TemplateTestCase
  
  
  class HelpersTestCase(TemplateTestCase):
  
      def test_escape_html(self):
          self.assertRendered(
              '''{{ _.escape("foo & bar") }}''',
              '''foo &amp; bar''',
              {},
          )
  
      def test_escape_js(self):
          self.assertRendered(
              '''{{ _.escape('=', 'js') }}''',
              '''\\u003D''',
              {},
          )
  
subject: Add helpers tests