Question

To use a specific url-config in your Django tests all you have to do is specify it:

class MyTests(TestCase):
    urls = 'myproj.myapp.urls'

    def test_myurl(self):
        r = self.client.get('/foo/')  # looks up /foo/ in myproj/myapp/urls.py

it doesn’t look like the implementation is thread-safe however:

def _urlconf_setup(self):
    if hasattr(self, 'urls'):
        self._old_root_urlconf = settings.ROOT_URLCONF
        settings.ROOT_URLCONF = self.urls
        clear_url_caches()

and I’m seeing 404 errors in my test-log after I run the test-suite with py.test -n8 (using all 8 cpus).

Has anyone else seen/solved this problem?

Answer 1

The short answer: setting urls on your TestCase subclass is not thread safe when called from py.test -n, presumably because the different threads are clobbering settings.ROOT_URLCONF.

There is code in django/core/handlers/base.py:get_response() (I just checked the latest revision too) which will fetch urlconf from the request object if present, instead of using settings.ROOT_URLCONF.

The solution then, is to attach the value of self.urls to the request object that Client.py passes to the view function. We haven’t seen any problems after implementing this fix, running 1100+ tests with -n8.

(If you already have your own copies of client.py and testcases.py, it is relatively easy (~14 loc) to remove the current urlconf machinery from _pre_setup and instead pass self.urls through Client so ClientHandler can attach it to request before calling self.get_response().)