diff --git a/tests/unit/conftest.py b/tests/unit/conftest.py
index 4205230b..c1c56fcd 100644
--- a/tests/unit/conftest.py
+++ b/tests/unit/conftest.py
@@ -274,7 +274,7 @@ def get(self, *_args, **_kwargs):
     http_session = MockHttpSession()
 
     client = AlephHttpClient(api_server="http://localhost")
-    client.http_session = http_session
+    client._http_session = http_session
 
     return client