test: fix build against djangotip

Django recently enabled the cached template loader by default in development.
This was added in:

django/django@bf7c51a

As a result, some tests started failing when the whole test suite was run, but not when they were run individually.

We can fix this by setting the template loaders in our test settings.

Author: browniebroke

django_coverage_plugin/plugin.py

@@ -365,7 +365,7 @@ def lines(self):
                         continue
 
                 if extends and not inblock:
-                    # In an inheriting tempalte, ignore all tags outside of
+                    # In an inheriting template, ignore all tags outside of
                     # blocks.
                     continue
 

tests/plugin_test.py

@@ -45,6 +45,9 @@ def test_settings():
                 'DIRS': ['templates'],      # where the tests put things.
                 'OPTIONS': {
                     'debug': True,
+                    'loaders': [
+                        'django.template.loaders.filesystem.Loader',
+                    ]
                 },
             },
         ],