diff --git a/src/_zkapauthorizer/_storage_server.py b/src/_zkapauthorizer/_storage_server.py
index d9c7739b2ebe8f4b9f1fb099e8243a403a5bec28..3f9aec7c698a18913c45c86a1b8924111a3ab110 100644
--- a/src/_zkapauthorizer/_storage_server.py
+++ b/src/_zkapauthorizer/_storage_server.py
@@ -117,7 +117,14 @@ class ZKAPAuthorizerStorageServer(Referenceable):
         """
         return self._original.remote_advise_corrupt_share(*a, **kw)
 
-    def remote_slot_testv_and_readv_and_writev(self, tokens, *a, **kw):
+    def remote_slot_testv_and_readv_and_writev(
+            self,
+            tokens,
+            storage_index,
+            secrets,
+            tw_vectors,
+            r_vector,
+    ):
         """
         Pass through after a token check to ensure clients can only allocate
         storage for mutable shares if they present valid tokens.
@@ -132,8 +139,13 @@ class ZKAPAuthorizerStorageServer(Referenceable):
         # about (and don't expose over the network): renew_leases.  We always
         # pass False for this because we want to manage leases completely
         # separately from writes.
-        kw["renew_leases"] = False
-        return self._original.slot_testv_and_readv_and_writev(*a, **kw)
+        return self._original.slot_testv_and_readv_and_writev(
+            storage_index,
+            secrets,
+            tw_vectors,
+            r_vector,
+            renew_leases=False,
+        )
 
     def remote_slot_readv(self, *a, **kw):
         """
diff --git a/src/_zkapauthorizer/tests/test_storage_protocol.py b/src/_zkapauthorizer/tests/test_storage_protocol.py
index 0eb82e0a56227452e4ff9e42875ed2dcdda41577..51cac393c395cdd3dc520aacc864dc81028e6d3b 100644
--- a/src/_zkapauthorizer/tests/test_storage_protocol.py
+++ b/src/_zkapauthorizer/tests/test_storage_protocol.py
@@ -29,7 +29,8 @@ from testtools import (
 from testtools.matchers import (
     Equals,
     HasLength,
-    Always,
+    IsInstance,
+    AfterPreprocessing,
 )
 from testtools.twistedsupport import (
     succeeded,
@@ -529,11 +530,15 @@ class ShareTests(TestCase):
             True,
         )
 
-        # The operation should fail.  I'm not that concerned with how just
-        # yet.
+        # The operation should fail.
         self.expectThat(
             d,
-            failed(Always()),
+            failed(
+                AfterPreprocessing(
+                    lambda f: f.value,
+                    IsInstance(TypeError),
+                ),
+            ),
         )
 
         # There should be no shares at the given storage index.