diff --git a/tests/unit/conftest.py b/tests/unit/conftest.py
index 17224e59..f30a84ae 100644
--- a/tests/unit/conftest.py
+++ b/tests/unit/conftest.py
@@ -16,7 +16,6 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from contextlib import contextmanager
 from unittest.mock import MagicMock, AsyncMock
 from pytest import fixture
 from twisted.internet import defer
@@ -105,3 +104,14 @@ def client():
     client.tor = None
     client.tor_mode = TorMode.DISABLED
     return client
+
+
+@fixture(autouse=True)
+def reset_storage(host):
+    """Replace storage with a fresh mock before each test.
+
+    The host and storage fixtures use session scope, which means any assignments to
+    storage attributes (e.g., storage.method = AsyncMock(...)) persist across tests. This
+    fixture ensures each test starts with a clean slate.
+    """
+    host.memory.storage = AsyncMock()