diff --git a/src/allmydata/test/test_web.py b/src/allmydata/test/test_web.py
index a4f5c5790..83d73e8ad 100644
--- a/src/allmydata/test/test_web.py
+++ b/src/allmydata/test/test_web.py
@@ -415,7 +415,7 @@ class Web(WebMixin, unittest.TestCase):
                       "files_per_user": 1000,
                       "space_per_user": int(1e9),
                       "sharing_ratio": 1.0,
-                      "encoding_parameters": "3-of-10",
+                      "encoding_parameters": "3-of-10-5",
                       "num_servers": 30,
                       "ownership_mode": "A",
                       "download_rate": 100,