Proxito middleware: reset to original urlconf after request

This also fixes a flaky test.
We hit this before after proxito too
https://github.com/readthedocs/readthedocs.org/blob/8ebded69160f495c56e2966da90bad3be2dc9f5f/readthedocs/core/middleware.py#L132-L136

Author: stsewd

readthedocs/proxito/middleware.py

@@ -10,6 +10,7 @@
 
 from django.conf import settings
 from django.shortcuts import render
+from django.urls.base import set_urlconf
 from django.utils.deprecation import MiddlewareMixin
 
 from readthedocs.projects.models import Domain, Project
@@ -199,6 +200,10 @@ def process_response(self, request, response):  # noqa
         * For custom domains, check the HSTS values on the Domain object.
           The domain object should be saved already in request.domain.
         """
+        # Reset URLconf for this thread
+        # to the original one.
+        set_urlconf(None)
+
         host = request.get_host().lower().split(':')[0]
         public_domain = settings.PUBLIC_DOMAIN.lower().split(':')[0]
 

readthedocs/proxito/tests/test_middleware.py

@@ -242,8 +242,6 @@ def setUp(self):
         sys.modules['fake_urlconf'] = self.pip.proxito_urlconf
         set_urlconf('fake_urlconf')
 
-    # TODO: Figure out why this is failing in travis
-    @pytest.mark.xfail(strict=True)
     def test_middleware_urlconf_subproject(self):
         resp = self.client.get('/subpath/subproject/testing/en/foodex.html', HTTP_HOST=self.domain)
         self.assertEqual(resp.status_code, 200)