Fixed #24168 -- Allowed selecting a template engine in a few APIs.

Specifically in rendering shortcuts, template responses, and class-based
views that return template responses.

Also added a test for render_to_response(status=...) which was missing
from fdbfc980.

Thanks Tim and Carl for the review.

tests/generic_views/test_base.py

@@ -7,6 +7,7 @@ from django.core.exceptions import ImproperlyConfigured
 from django.core.urlresolvers import resolve
 from django.http import HttpResponse
 from django.test import TestCase, RequestFactory, override_settings
+from django.test.utils import require_jinja2
 from django.views.generic import View, TemplateView, RedirectView
 
 from . import views
@@ -278,10 +279,23 @@ class TemplateViewTest(TestCase):
 
     def test_template_name_required(self):
         """
-        A template view must provide a template name
+        A template view must provide a template name.
         """
         self.assertRaises(ImproperlyConfigured, self.client.get, '/template/no_template/')
 
+    @require_jinja2
+    def test_template_engine(self):
+        """
+        A template view may provide a template engine.
+        """
+        request = self.rf.get('/using/')
+        view = TemplateView.as_view(template_name='generic_views/using.html')
+        self.assertEqual(view(request).render().content, b'DTL\n')
+        view = TemplateView.as_view(template_name='generic_views/using.html', template_engine='django')
+        self.assertEqual(view(request).render().content, b'DTL\n')
+        view = TemplateView.as_view(template_name='generic_views/using.html', template_engine='jinja2')
+        self.assertEqual(view(request).render().content, b'Jinja2\n')
+
     def test_template_params(self):
         """
         A generic template view passes kwargs as context.