From 3cf44d64099d587e06ad2a9c50c20847191853b9 Mon Sep 17 00:00:00 2001
From: Khalim Conn-Kowlessar <kconnkowlessar@gmail.com>
Date: Tue, 7 Jul 2026 11:55:49 +0000
Subject: [PATCH] =?UTF-8?q?An=20attach-mode=20partial=20failure=20persists?=
 =?UTF-8?q?=20successes=20then=20records=20the=20failure=20=F0=9F=9F=A5?=
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Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 .../modelling_e2e/test_handler.py             | 73 +++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/tests/applications/modelling_e2e/test_handler.py b/tests/applications/modelling_e2e/test_handler.py
index fe7ef7815..f2e33187b 100644
--- a/tests/applications/modelling_e2e/test_handler.py
+++ b/tests/applications/modelling_e2e/test_handler.py
@@ -438,6 +438,79 @@ def test_attach_mode_models_the_batch_without_child_subtasks() -> None:
     assert [r.property_id for r in plan_requests] == [pid1, pid2]
 
 
+def test_attach_mode_partial_failure_persists_successes_then_records_failure() -> None:
+    """In attach mode a failing property doesn't stop its siblings: the batch
+    flushes the successes, then raises SubTaskFailure carrying
+    {succeeded, failed} so the sub_task record holds the outcome (ADR-0055)."""
+    # Arrange — property 222's EPC fetch blows up; 111 models fine
+    pid_ok, pid_bad = 111, 222
+    mock_engine = _engine_mock([pid_ok, pid_bad], [1001, 1002], [POSTCODE, POSTCODE])
+    mock_orch = _mock_orchestrator()
+    task_id = uuid4()
+
+    with ExitStack() as stack:
+        stack.enter_context(patch("applications.modelling_e2e.handler.os.environ", _ENV))
+        stack.enter_context(
+            patch("applications.modelling_e2e.handler._get_engine", return_value=mock_engine)
+        )
+        epc_client = stack.enter_context(
+            patch("applications.modelling_e2e.handler.EpcClientService")
+        ).return_value
+        epc_client.get_by_uprn.side_effect = [
+            MagicMock(),
+            RuntimeError("gov API exploded"),
+        ]
+        stack.enter_context(patch("applications.modelling_e2e.handler.GeospatialS3Repository"))
+        stack.enter_context(patch("applications.modelling_e2e.handler.GoogleSolarApiClient"))
+        stack.enter_context(
+            patch("applications.modelling_e2e.handler._spatial_for", return_value=None)
+        )
+        stack.enter_context(
+            patch("applications.modelling_e2e.handler._solar_insights_for", return_value=None)
+        )
+        stack.enter_context(
+            patch("applications.modelling_e2e.handler.overlays_from", return_value=[])
+        )
+        stack.enter_context(
+            patch("applications.modelling_e2e.handler.PropertyOverridesPostgresReader")
+        ).return_value.overrides_for_many.return_value = {}
+        stack.enter_context(
+            patch("applications.modelling_e2e.handler.ScenarioPostgresRepository")
+        ).return_value.get_many.return_value = [MagicMock()]
+        stack.enter_context(patch("applications.modelling_e2e.handler.catalogue_snapshot_with_off_catalogue_overrides"))
+        stack.enter_context(patch("applications.modelling_e2e.handler.Session"))
+        stack.enter_context(
+            patch("applications.modelling_e2e.handler.run_modelling", return_value=_plan_mock())
+        )
+        MockUoW = stack.enter_context(patch("applications.modelling_e2e.handler.PostgresUnitOfWork"))
+        mock_uow = MagicMock()
+        MockUoW.return_value.__enter__.return_value = mock_uow
+        MockUoW.return_value.__exit__.return_value = False
+
+        # Act
+        from applications.modelling_e2e.handler import handler
+        from domain.tasks.subtasks import SubTaskFailure
+
+        with pytest.raises(SubTaskFailure) as raised:
+            handler.__wrapped__(  # type: ignore[attr-defined]
+                {"task_id": str(task_id), "subtask_id": str(uuid4()),
+                 "property_ids": [pid_ok, pid_bad], "portfolio_id": PORTFOLIO_ID,
+                 "scenario_id": SCENARIO_ID, "refetch_solar": False,
+                 "dry_run": False},
+                None, mock_orch, task_id,
+            )
+
+    # Assert — the success flushed before the failure was recorded
+    plan_requests = mock_uow.plan.save_batch.call_args.args[0]
+    assert [r.property_id for r in plan_requests] == [pid_ok]
+    details = raised.value.details
+    assert details is not None
+    assert details["succeeded"] == 1
+    assert details["failed"] == [
+        {"property_id": pid_bad, "error": "gov API exploded"}
+    ]
+
+
 # ---------------------------------------------------------------------------
 # Lodged EPC path
 # ---------------------------------------------------------------------------