diff --git a/src/_zkapauthorizer/tests/fixtures.py b/src/_zkapauthorizer/tests/fixtures.py
new file mode 100644
index 0000000000000000000000000000000000000000..20b05922495aefce85e12a69941276836840950a
--- /dev/null
+++ b/src/_zkapauthorizer/tests/fixtures.py
@@ -0,0 +1,34 @@
+from __future__ import (
+    absolute_import,
+)
+
+from fixtures import (
+    Fixture,
+    TempDir,
+)
+
+from twisted.python.filepath import (
+    FilePath,
+)
+
+from allmydata.storage.server import (
+    StorageServer,
+)
+
+class AnonymousStorageServer(Fixture):
+    """
+    Supply an instance of allmydata.storage.server.StorageServer which
+    implements anonymous access to Tahoe-LAFS storage server functionality.
+
+    :ivar FilePath tempdir: The path to the server's storage on the
+        filesystem.
+
+    :ivar allmydata.storage.server.StorageServer storage_server: The storage
+        server.
+    """
+    def _setUp(self):
+        self.tempdir = FilePath(self.useFixture(TempDir()).join(b"storage"))
+        self.storage_server = StorageServer(
+            self.tempdir.asBytesMode().path,
+            b"x" * 20,
+        )
diff --git a/src/_zkapauthorizer/tests/test_base64.py b/src/_zkapauthorizer/tests/test_base64.py
index 05501c6caae6d185a413a9d5876d78c0c5df9322..4a988b6beae887138a8379210f2e76cae0aaab53 100644
--- a/src/_zkapauthorizer/tests/test_base64.py
+++ b/src/_zkapauthorizer/tests/test_base64.py
@@ -16,6 +16,10 @@
 Tests for ``_zkapauthorizer._base64``.
 """
 
+from __future__ import (
+    absolute_import,
+)
+
 from base64 import (
     urlsafe_b64encode,
 )
diff --git a/src/_zkapauthorizer/tests/test_client_resource.py b/src/_zkapauthorizer/tests/test_client_resource.py
index 77b5bb38228a73044f7c08f98d460a024138c8b2..20047d3cf2b986112c386dd99e1cf782d87cb573 100644
--- a/src/_zkapauthorizer/tests/test_client_resource.py
+++ b/src/_zkapauthorizer/tests/test_client_resource.py
@@ -17,6 +17,10 @@ Tests for the web resource provided by the client part of the Tahoe-LAFS
 plugin.
 """
 
+from __future__ import (
+    absolute_import,
+)
+
 import attr
 
 from .._base64 import (
diff --git a/src/_zkapauthorizer/tests/test_controller.py b/src/_zkapauthorizer/tests/test_controller.py
index 4e3f264ce22a05d32535c87888d19d2af93d0147..6001b29a5d0f824d655c6f24d9fa039e70645577 100644
--- a/src/_zkapauthorizer/tests/test_controller.py
+++ b/src/_zkapauthorizer/tests/test_controller.py
@@ -16,6 +16,10 @@
 Tests for ``_zkapauthorizer.controller``.
 """
 
+from __future__ import (
+    absolute_import,
+)
+
 from json import (
     loads,
     dumps,
diff --git a/src/_zkapauthorizer/tests/test_matchers.py b/src/_zkapauthorizer/tests/test_matchers.py
index 7ff71c0fd360daefab6a0485dd62abbf4bc4d187..868a1e998bec4a54c093f24637a5a3f8ecee6261 100644
--- a/src/_zkapauthorizer/tests/test_matchers.py
+++ b/src/_zkapauthorizer/tests/test_matchers.py
@@ -16,6 +16,10 @@
 Tests for ``_zkapauthorizer.tests.matchers``.
 """
 
+from __future__ import (
+    absolute_import,
+)
+
 from zope.interface import (
     Interface,
     implementer,
diff --git a/src/_zkapauthorizer/tests/test_model.py b/src/_zkapauthorizer/tests/test_model.py
index f614c1c912823cec16cf9db27a546c46d27a7b9b..14fd2f0a7339fd264ff6ba5e492f55adad6a8b20 100644
--- a/src/_zkapauthorizer/tests/test_model.py
+++ b/src/_zkapauthorizer/tests/test_model.py
@@ -17,6 +17,10 @@
 Tests for ``_zkapauthorizer.model``.
 """
 
+from __future__ import (
+    absolute_import,
+)
+
 from os import (
     mkdir,
 )
diff --git a/src/_zkapauthorizer/tests/test_plugin.py b/src/_zkapauthorizer/tests/test_plugin.py
index d497c724877505caf6ae95cbc451e429fbb2d384..b8acfc58a6c463198f1210d859d72d344d03bc5c 100644
--- a/src/_zkapauthorizer/tests/test_plugin.py
+++ b/src/_zkapauthorizer/tests/test_plugin.py
@@ -16,6 +16,10 @@
 Tests for the Tahoe-LAFS plugin.
 """
 
+from __future__ import (
+    absolute_import,
+)
+
 from io import (
     BytesIO,
 )
diff --git a/src/_zkapauthorizer/tests/test_storage_protocol.py b/src/_zkapauthorizer/tests/test_storage_protocol.py
index 0bd6cb80835986f16bee3f4eacfa72f635608bec..0b3743db1ec1d642e9ef83148fb06fbf0eee1742 100644
--- a/src/_zkapauthorizer/tests/test_storage_protocol.py
+++ b/src/_zkapauthorizer/tests/test_storage_protocol.py
@@ -16,11 +16,13 @@
 Tests for communication between the client and server components.
 """
 
+from __future__ import (
+    absolute_import,
+)
+
 import attr
 
 from fixtures import (
-    Fixture,
-    TempDir,
     MonkeyPatch,
 )
 from testtools import (
@@ -62,10 +64,6 @@ from foolscap.referenceable import (
     LocalReferenceable,
 )
 
-from allmydata.storage.server import (
-    StorageServer,
-)
-
 from .strategies import (
     storage_indexes,
     lease_renew_secrets,
@@ -81,6 +79,9 @@ from .strategies import (
 from .matchers import (
     matches_version_dictionary,
 )
+from .fixtures import (
+    AnonymousStorageServer,
+)
 from ..api import (
     ZKAPAuthorizerStorageServer,
     ZKAPAuthorizerStorageClient,
@@ -92,25 +93,6 @@ from ..model import (
     Pass,
 )
 
-class AnonymousStorageServer(Fixture):
-    """
-    Supply an instance of allmydata.storage.server.StorageServer which
-    implements anonymous access to Tahoe-LAFS storage server functionality.
-
-    :ivar FilePath tempdir: The path to the server's storage on the
-        filesystem.
-
-    :ivar allmydata.storage.server.StorageServer storage_server: The storage
-        server.
-    """
-    def _setUp(self):
-        self.tempdir = FilePath(self.useFixture(TempDir()).join(b"storage"))
-        self.storage_server = StorageServer(
-            self.tempdir.asBytesMode().path,
-            b"x" * 20,
-        )
-
-
 @attr.s
 class LocalRemote(object):
     """
diff --git a/src/_zkapauthorizer/tests/test_strategies.py b/src/_zkapauthorizer/tests/test_strategies.py
index 22f5aacfa67f0a06f886122f4d30856b718b8eac..6a0307ea4b799204dba2c4f297473a0d52619215 100644
--- a/src/_zkapauthorizer/tests/test_strategies.py
+++ b/src/_zkapauthorizer/tests/test_strategies.py
@@ -16,6 +16,10 @@
 Tests for our custom Hypothesis strategies.
 """
 
+from __future__ import (
+    absolute_import,
+)
+
 from testtools import (
     TestCase,
 )