--- a/Allura/allura/tests/unit/test_app.py
+++ b/Allura/allura/tests/unit/test_app.py
@@ -33,6 +33,18 @@
         self.assertIsNone(app.validate_mount_point(mount_point))
         app.relaxed_mount_points = True
         self.assertIsNotNone(app.validate_mount_point(mount_point))
+
+    def test_describe_permission(self):
+        class DummyApp(Application):
+            permissions_desc = {
+                'foo': 'bar',
+                'post': 'overridden',
+            }
+        f = DummyApp.describe_permission
+        self.assertEqual(f('foo'), 'bar')
+        self.assertEqual(f('post'), 'overridden')
+        self.assertEqual(f('admin'), 'Set permissions.')
+        self.assertEqual(f('does_not_exist'), '')
 
 
 class TestInstall(WithDatabase):