'If the X_FRAME_OPTIONS setting is not set then it defaults to
SAMEORIGIN.'

def test_defaults_sameorigin(self):

    with override_settings(X_FRAME_OPTIONS=None):
        del settings.X_FRAME_OPTIONS
        r = XFrameOptionsMiddleware().process_response(HttpRequest(), HttpResponse())
        self.assertEqual(r['X-Frame-Options'], 'SAMEORIGIN')
