diff --git a/tests/ert/conftest.py b/tests/ert/conftest.py
index 1f25cbfa176..1d240be2671 100644
--- a/tests/ert/conftest.py
+++ b/tests/ert/conftest.py
@@ -475,6 +475,7 @@ class MockESConfig(EvaluatorServerConfig):
         def __init__(self, *args, **kwargs):
             if "use_token" not in kwargs:
                 kwargs["use_token"] = False
+            kwargs["use_ipc_protocol"] = True
             super().__init__(*args, **kwargs)
 
     monkeypatch.setattr("ert.cli.main.EvaluatorServerConfig", MockESConfig)