diff --git a/src/allmydata/test/test_storage.py b/src/allmydata/test/test_storage.py
index 06b8d7957..738e218eb 100644
--- a/src/allmydata/test/test_storage.py
+++ b/src/allmydata/test/test_storage.py
@@ -1018,7 +1018,7 @@ class Server(unittest.TestCase):
         ss = StorageServer(workdir, b"\x00" * 20, discard_storage=True)
         ss.setServiceParent(self.sparent)
 
-        upload_immutable(ss, "si0", b"r" * 32, b"c" * 32, {0: b""})
+        upload_immutable(ss, b"si0", b"r" * 32, b"c" * 32, {0: b""})
         ss.remote_advise_corrupt_share(b"immutable", b"si0", 0,
                                        b"This share smells funny.\n")
 
@@ -1033,7 +1033,7 @@ class Server(unittest.TestCase):
         ss.setServiceParent(self.sparent)
 
         si0_s = base32.b2a(b"si0")
-        upload_immutable(ss, "si0", b"r" * 32, b"c" * 32, {0: b""})
+        upload_immutable(ss, b"si0", b"r" * 32, b"c" * 32, {0: b""})
         ss.remote_advise_corrupt_share(b"immutable", b"si0", 0,
                                        b"This share smells funny.\n")
         reportdir = os.path.join(workdir, "corruption-advisories")
@@ -1082,7 +1082,7 @@ class Server(unittest.TestCase):
         ss.setServiceParent(self.sparent)
 
         # Upload one share for this storage index
-        upload_immutable(ss, "si0", b"r" * 32, b"c" * 32, {0: b""})
+        upload_immutable(ss, b"si0", b"r" * 32, b"c" * 32, {0: b""})
 
         # And try to submit a corruption advisory about a different share
         ss.remote_advise_corrupt_share(b"immutable", b"si0", 1,