Fix unbound event

Validation is raised from dispatch_event_from_json so
event is unbound.

src/ert/ensemble_evaluator/evaluator.py

@@ -263,7 +263,7 @@ async def handle_dispatch(self, websocket: WebSocketServerProtocol) -> None:
                             f"closing connection to dispatcher: {ex}"
                         )
                         await websocket.close(
-                            code=1011, reason=f"failed handling {event}"
+                            code=1011, reason=f"failed handling message {raw_msg!r}"
                         )
                         return
 

tests/ert/unit_tests/ensemble_evaluator/test_ensemble_evaluator.py

@@ -2,10 +2,12 @@
 import datetime
 from functools import partial
 from typing import cast
+from unittest.mock import MagicMock
 
 import pytest
 from hypothesis import given
 from hypothesis import strategies as st
+from websockets.server import WebSocketServerProtocol
 
 from _ert.events import (
     EESnapshot,
@@ -63,6 +65,19 @@ async def mock_failure(message, *args, **kwargs):
         await evaluator.run_and_get_successful_realizations()
 
 
+async def test_when_dispatch_is_given_invalid_event_the_socket_is_closed(
+    make_ee_config,
+):
+    evaluator = EnsembleEvaluator(TestEnsemble(0, 2, 2, id_="0"), make_ee_config())
+
+    socket = MagicMock(spec=WebSocketServerProtocol)
+    socket.__aiter__.return_value = ["invalid_json"]
+    await evaluator.handle_dispatch(socket)
+    socket.close.assert_called_once_with(
+        code=1011, reason="failed handling message 'invalid_json'"
+    )
+
+
 async def test_no_config_raises_valueerror_when_running():
     evaluator = EnsembleEvaluator(TestEnsemble(0, 2, 2, id_="0"), None)
     with pytest.raises(ValueError, match="no config for evaluator"):