text: import re
  
  from django.forms import CharField, Form, Media
  from django.http import HttpRequest, HttpResponse
  from django.middleware.csrf import (
      CsrfViewMiddleware, _compare_salted_tokens as equivalent_tokens, get_token,
  )
  from django.template import TemplateDoesNotExist, TemplateSyntaxError
  from django.template.backends.dummy import TemplateStrings
  from django.test import SimpleTestCase
  
  
  class TemplateStringsTests(SimpleTestCase):
  
      engine_class = TemplateStrings
      backend_name = 'dummy'
      options = {}
  
      @classmethod
      def setUpClass(cls):
          super().setUpClass()
          params = {
              'DIRS': [],
              'APP_DIRS': True,
              'NAME': cls.backend_name,
              'OPTIONS': cls.options,
          }
          cls.engine = cls.engine_class(params)
  
      def test_from_string(self):
          template = self.engine.from_string("Hello!\n")
          content = template.render()
          self.assertEqual(content, "Hello!\n")
  
      def test_get_template(self):
          template = self.engine.get_template('template_backends/hello.html')
          content = template.render({'name': 'world'})
          self.assertEqual(content, "Hello world!\n")
  
      def test_get_template_nonexistent(self):
          with self.assertRaises(TemplateDoesNotExist) as e:
              self.engine.get_template('template_backends/nonexistent.html')
          self.assertEqual(e.exception.backend, self.engine)
  
      def test_get_template_syntax_error(self):
          # There's no way to trigger a syntax error with the dummy backend.
          # The test still lives here to factor it between other backends.
          if self.backend_name == 'dummy':
              self.skipTest("test doesn't apply to dummy backend")
          with self.assertRaises(TemplateSyntaxError):
              self.engine.get_template('template_backends/syntax_error.html')
  
      def test_html_escaping(self):
          template = self.engine.get_template('template_backends/hello.html')
          context = {'name': '<script>alert("XSS!");</script>'}
          content = template.render(context)
  
          self.assertIn('&lt;script&gt;', content)
          self.assertNotIn('<script>', content)
  
      def test_django_html_escaping(self):
          if self.backend_name == 'dummy':
              self.skipTest("test doesn't apply to dummy backend")
  
          class TestForm(Form):
              test_field = CharField()
  
          media = Media(js=['my-script.js'])
          form = TestForm()
          template = self.engine.get_template('template_backends/django_escaping.html')
          content = template.render({'media': media, 'test_form': form})
  
          expected = '{}\n\n{}\n\n{}'.format(media, form, form['test_field'])
  
          self.assertHTMLEqual(content, expected)
  
      def test_csrf_token(self):
          request = HttpRequest()
          CsrfViewMiddleware(lambda req: HttpResponse()).process_view(request, lambda r: None, (), {})
  
          template = self.engine.get_template('template_backends/csrf.html')
          content = template.render(request=request)
  
          expected = '<input type="hidden" name="csrfmiddlewaretoken" value="([^"]+)">'
          match = re.match(expected, content) or re.match(expected.replace('"', "'"), content)
          self.assertTrue(match, "hidden csrftoken field not found in output")
          self.assertTrue(equivalent_tokens(match.group(1), get_token(request)))
  
      def test_no_directory_traversal(self):
          with self.assertRaises(TemplateDoesNotExist):
              self.engine.get_template('../forbidden/template_backends/hello.html')
  
      def test_non_ascii_characters(self):
          template = self.engine.get_template('template_backends/hello.html')
          content = template.render({'name': 'Jérôme'})
          self.assertEqual(content, "Hello Jérôme!\n")
  