Fixed #17529 -- get_template_from_string default arguments break

``get_template_from_string`` default arguments were breaking
``assertTemplateUsed``. The solution has been to return only the names of the
templates with a ``name`` attribute distinct of ``None``. The default ``name``
kwarg of ``Template`` has been changed to ``None``, more pythonic than ``'<Unknown
Template>'``.

1 files changed, 7 insertions, 0 deletions

diff --git a/tests/test_utils/tests.py b/tests/test_utils/tests.py
index 666fde2fa6..9f7831d2b7 100644
--- a/tests/test_utils/tests.py
+++ b/tests/test_utils/tests.py
@@ -214,6 +214,8 @@ class AssertNumQueriesContextManagerTests(TestCase):
 
 
 class AssertTemplateUsedContextManagerTests(TestCase):
+    urls = 'test_utils.urls'
+
     def test_usage(self):
         with self.assertTemplateUsed('template_used/base.html'):
             render_to_string('template_used/base.html')
@@ -270,6 +272,11 @@ class AssertTemplateUsedContextManagerTests(TestCase):
             with self.assertTemplateUsed('template_used/base.html'):
                 render_to_string('template_used/alternative.html')
 
+        with self.assertRaises(AssertionError) as cm:
+            response = self.client.get('/test_utils/no_template_used/')
+            self.assertTemplateUsed(response, 'template_used/base.html')
+        self.assertEqual(cm.exception.args[0], "No templates used to render the response")
+
     def test_failure(self):
         with self.assertRaises(TypeError):
             with self.assertTemplateUsed():