diff --git a/src/_zkapauthorizer/tests/fixtures.py b/src/_zkapauthorizer/tests/fixtures.py
index a01dc6ff430eef143a73c0b0242767514b136dbb..8803180f62410c0f62e7032563ef6af7ae142a3c 100644
--- a/src/_zkapauthorizer/tests/fixtures.py
+++ b/src/_zkapauthorizer/tests/fixtures.py
@@ -36,7 +36,7 @@ class AnonymousStorageServer(Fixture):
 
     :ivar tempdir: The path to the server's storage on the filesystem.
 
-    :ivar backend: The protocol-agnostic storage server backend.
+    :ivar storage_server: The protocol-agnostic storage server backend.
 
     :ivar clock: The ``IReactorTime`` provider to supply to ``StorageServer``
         for its time-checking needs.
@@ -45,11 +45,11 @@ class AnonymousStorageServer(Fixture):
     clock: Clock = attr.ib()
 
     tempdir: FilePath = attr.ib(default=None)
-    backend: StorageServer = attr.ib(default=None)
+    storage_server: StorageServer = attr.ib(default=None)
 
     def _setUp(self):
         self.tempdir = FilePath(self.useFixture(TempDir()).join(u"storage"))
-        self.backend = StorageServer(
+        self.storage_server = StorageServer(
             self.tempdir.path,
             b"x" * 20,
             clock=self.clock,
diff --git a/src/_zkapauthorizer/tests/test_storage_protocol.py b/src/_zkapauthorizer/tests/test_storage_protocol.py
index 2ee75aaae77a34dadf1c239c2397ceddcd852fc7..ed54432b9d36907a4baa826d91331b089306e8db 100644
--- a/src/_zkapauthorizer/tests/test_storage_protocol.py
+++ b/src/_zkapauthorizer/tests/test_storage_protocol.py
@@ -154,13 +154,13 @@ class ShareTests(TestCase):
         )
 
         self.clock = Clock()
-        self.storage = self.useFixture(
+        self.anonymous_storage_server = self.useFixture(
             AnonymousStorageServer(self.clock),
-        )
+        ).storage_server
 
         self.spending_recorder, spender = RecordingSpender.make()
         self.server = ZKAPAuthorizerStorageServer(
-            self.storage.backend,
+            self.anonymous_storage_server,
             self.pass_value,
             self.signing_key,
             spender,
@@ -191,7 +191,7 @@ class ShareTests(TestCase):
         self.spending_recorder.reset()
 
         # And clean out any shares that might confuse things.
-        cleanup_storage_server(self.storage.backend)
+        cleanup_storage_server(self.anonymous_storage_server)
 
     def test_get_version(self):
         """
@@ -410,7 +410,7 @@ class ShareTests(TestCase):
         # Create some shares to alter the behavior of the next
         # allocate_buckets.
         write_toy_shares(
-            self.storage.backend,
+            self.anonymous_storage_server,
             storage_index,
             renew_secret,
             cancel_secret,
@@ -479,7 +479,7 @@ class ShareTests(TestCase):
         )
 
         self.assertThat(
-            dict(get_lease_grant_times(self.storage.backend, storage_index)),
+            dict(get_lease_grant_times(self.anonymous_storage_server, storage_index)),
             Equals(expected_leases),
         )
 
@@ -503,7 +503,7 @@ class ShareTests(TestCase):
 
         # Create a share we can toy with.
         write_toy_shares(
-            self.storage.backend,
+            self.anonymous_storage_server,
             storage_index,
             add_lease_secret,
             cancel_secret,
@@ -526,7 +526,7 @@ class ShareTests(TestCase):
             matches_spent_passes(self.public_key_hash, self.pass_factory.spent),
         )
 
-        leases = list(self.storage.backend.get_leases(storage_index))
+        leases = list(self.anonymous_storage_server.get_leases(storage_index))
         self.assertThat(leases, HasLength(2))
 
     def _stat_shares_immutable_test(
@@ -539,7 +539,7 @@ class ShareTests(TestCase):
 
         # Create a share we can toy with.
         write_shares(
-            self.storage,
+            self.anonymous_storage_server,
             storage_index,
             {sharenum},
             size,
@@ -548,7 +548,7 @@ class ShareTests(TestCase):
         # Perhaps put some more leases on it.  Leases might impact our
         # ability to determine share data size.
         for renew_secret in leases:
-            self.storage.backend.add_lease(
+            self.anonymous_storage_server.add_lease(
                 storage_index,
                 renew_secret,
                 cancel_secret,
@@ -589,8 +589,8 @@ class ShareTests(TestCase):
             size,
             when,
             leases,
-            lambda storage, storage_index, sharenums, size, canary: write_toy_shares(
-                storage.backend,
+            lambda storage_server, storage_index, sharenums, size, canary: write_toy_shares(
+                storage_server,
                 storage_index,
                 renew_secret,
                 cancel_secret,
@@ -616,7 +616,7 @@ class ShareTests(TestCase):
         """
         assume(version not in (1, 2))
 
-        sharedir = FilePath(self.storage.backend.sharedir).preauthChild(
+        sharedir = FilePath(self.anonymous_storage_server.sharedir).preauthChild(
             # storage_index_to_dir likes to return multiple segments
             # joined by pathsep
             storage_index_to_dir(storage_index),
@@ -658,7 +658,7 @@ class ShareTests(TestCase):
         ``stat_shares`` declines to offer a result (by raising
         ``ValueError``).
         """
-        sharedir = FilePath(self.storage.backend.sharedir).preauthChild(
+        sharedir = FilePath(self.anonymous_storage_server.sharedir).preauthChild(
             # storage_index_to_dir likes to return multiple segments
             # joined by pathsep
             storage_index_to_dir(storage_index),
@@ -710,8 +710,8 @@ class ShareTests(TestCase):
         write real multi-gigabyte files to exercise the behavior.
         """
 
-        def write_shares(storage, storage_index, sharenums, size, canary):
-            sharedir = FilePath(storage.backend.sharedir).preauthChild(
+        def write_shares(storage_server, storage_index, sharenums, size, canary):
+            sharedir = FilePath(storage_server.sharedir).preauthChild(
                 # storage_index_to_dir likes to return multiple segments
                 # joined by pathsep
                 storage_index_to_dir(storage_index),
@@ -816,7 +816,7 @@ class ShareTests(TestCase):
         """
         # Create a share we can toy with.
         write_toy_shares(
-            self.storage.backend,
+            self.anonymous_storage_server,
             storage_index,
             renew_secret,
             cancel_secret,
@@ -834,7 +834,7 @@ class ShareTests(TestCase):
             succeeded(Always()),
         )
         self.assertThat(
-            FilePath(self.storage.backend.corruption_advisory_dir).children(),
+            FilePath(self.anonymous_storage_server.corruption_advisory_dir).children(),
             HasLength(1),
         )
 
@@ -924,7 +924,7 @@ class ShareTests(TestCase):
         self.assertThat(
             dict(
                 get_lease_grant_times(
-                    self.storage.backend,
+                    self.anonymous_storage_server,
                     storage_index,
                 )
             ),
@@ -952,7 +952,9 @@ class ShareTests(TestCase):
         def leases():
             return list(
                 lease.to_mutable_data()
-                for lease in self.storage.backend.get_slot_leases(storage_index)
+                for lease in self.anonymous_storage_server.get_slot_leases(
+                    storage_index
+                )
             )
 
         def write():
diff --git a/src/_zkapauthorizer/tests/test_storage_server.py b/src/_zkapauthorizer/tests/test_storage_server.py
index defab2b6842a34ffc513cc9a444a61a6ea0dd890..a085bc5f8003f218250383ba8474917c3668ef8f 100644
--- a/src/_zkapauthorizer/tests/test_storage_server.py
+++ b/src/_zkapauthorizer/tests/test_storage_server.py
@@ -194,15 +194,15 @@ class PassValidationTests(TestCase):
         # the same time so we can do lease expiration calculations more
         # easily.
         self.clock.advance(time())
-        self.storage = self.useFixture(
+        self.anonymous_storage_server = self.useFixture(
             AnonymousStorageServer(self.clock),
-        )
+        ).storage_server
         self.signing_key = random_signing_key()
         self.public_key_hash = PublicKey.from_signing_key(
             self.signing_key
         ).encode_base64()
         self.storage_server = ZKAPAuthorizerStorageServer(
-            self.storage.backend,
+            self.anonymous_storage_server,
             self.pass_value,
             self.signing_key,
             spender,
@@ -222,10 +222,10 @@ class PassValidationTests(TestCase):
         # Hypothesis and testtools fixtures don't play nicely together in a
         # way that allows us to just move everything from `setUp` into this
         # method.
-        cleanup_storage_server(self.storage.backend)
+        cleanup_storage_server(self.anonymous_storage_server)
         # One of the tests makes the server read-only partway through.  Make
         # sure that doesn't leak into other examples.
-        self.storage.backend.readonly_storage = False
+        self.anonymous_storage_server.readonly_storage = False
 
         self.spending_recorder.reset()
 
@@ -532,7 +532,7 @@ class PassValidationTests(TestCase):
         )
         # Create some shares at a slot which will require lease renewal.
         write_toy_shares(
-            self.storage.backend,
+            self.anonymous_storage_server,
             storage_index,
             renew_secret,
             cancel_secret,
@@ -805,7 +805,7 @@ class PassValidationTests(TestCase):
         # the subsequent `allocate_buckets` operation - but of which the
         # client is unaware.
         write_toy_shares(
-            self.storage.backend,
+            self.anonymous_storage_server,
             storage_index,
             renew_secret,
             cancel_secret,
@@ -875,7 +875,7 @@ class PassValidationTests(TestCase):
     ):
         # Create some shares at a slot which will require lease renewal.
         write_toy_shares(
-            self.storage.backend,
+            self.anonymous_storage_server,
             storage_index,
             renew_secret,
             cancel_secret,
@@ -938,7 +938,7 @@ class PassValidationTests(TestCase):
 
         # Put some shares up there to target with the add_lease operation.
         write_toy_shares(
-            self.storage.backend,
+            self.anonymous_storage_server,
             storage_index,
             renew_secret,
             cancel_secret,
@@ -957,7 +957,7 @@ class PassValidationTests(TestCase):
 
         # Turn off space-allocating operations entirely.  Since there will be
         # no space for a new lease, the operation will fail.
-        self.storage.backend.readonly_storage = True
+        self.anonymous_storage_server.readonly_storage = True
 
         try:
             self.storage_server.doRemoteCall(