fix(portfolio): tolerate consolidation WAC residue

tests/test_issue34_runtime_blockers.py

@@ -1,4 +1,4 @@
-from datetime import date
+from datetime import UTC, date, datetime
 from decimal import Decimal
 from unittest.mock import MagicMock
 from uuid import UUID
@@ -36,7 +36,7 @@ def test_create_corporate_action_maps_postgres_missing_portfolio_to_404(monkeypa
 
 
 def _action(asset_id="asset-1"):
-    return CorporateAction("ca-1", "pf-1", asset_id, "stock_consolidation", date(2026, 1, 1), Decimal(0), Decimal(1), Decimal(0), Decimal(0), Decimal(0), Decimal(10), Decimal(0), "ev", "idem", "hash", 0)
+    return CorporateAction("ca-1", "pf-1", asset_id, "stock_consolidation", date(2026, 1, 1), Decimal(2), Decimal(1), Decimal(0), Decimal(0), Decimal(0), Decimal(10), Decimal(0), "ev", "idem", "hash", 0)
 
 
 def _repo_for_row(asset_id):
@@ -47,8 +47,8 @@ def _repo_for_row(asset_id):
     conn.__enter__.return_value = conn
     conn.cursor.return_value.__enter__.return_value = cur
     repo._connect = MagicMock(return_value=conn)
-    cur.fetchone.side_effect = [(Decimal(0), Decimal(10), Decimal(0), asset_id, "enabled"), None, None, None, (7, date(2026, 1, 1))]
-    cur.fetchall.return_value = []
+    cur.fetchone.side_effect = [(Decimal(2), Decimal(10), Decimal(0), asset_id, "enabled"), None, None, None, (7, date(2026, 1, 1))]
+    cur.fetchall.return_value = [("buy", Decimal(2), Decimal(0), Decimal(0), Decimal(0), datetime(2025, 12, 31, tzinfo=UTC))]
     return repo
 
 
@@ -63,3 +63,60 @@ def test_record_corporate_action_rejects_different_asset_id():
     repo = _repo_for_row(UUID("12345678-1234-5678-1234-567812345678"))
     with pytest.raises(ValueError, match="CORPORATE_ACTION_ASSET_MISMATCH"):
         repo.record_corporate_action("pf-1", action=_action("87654321-4321-8765-4321-876543218765"), idempotency_key="idem", payload_hash="hash")
+
+
+def test_record_corporate_action_accepts_daekyo_rounding_residue():
+    repo = object.__new__(PostgresPortfolioRepository)
+    repo.ensure_schema = MagicMock()
+    conn = MagicMock()
+    cur = MagicMock()
+    conn.__enter__.return_value = conn
+    conn.cursor.return_value.__enter__.return_value = cur
+    repo._connect = MagicMock(return_value=conn)
+    cur.fetchone.side_effect = [
+        (Decimal(1452), Decimal(10), Decimal(0), "asset-1", "enabled"),
+        None,
+        None,
+        None,
+        (7, datetime(2026, 9, 13, tzinfo=UTC)),
+    ]
+    cur.fetchall.return_value = [
+        (
+            "buy",
+            Decimal(1452),
+            Decimal("1086.234145936639256198347107438016528926"),
+            Decimal(0),
+            Decimal(0),
+            datetime(2026, 9, 9, tzinfo=UTC),
+        )
+    ]
+    action = CorporateAction(
+        "ca-1",
+        "pf-1",
+        "asset-1",
+        "stock_consolidation",
+        date(2026, 9, 10),
+        Decimal(1452),
+        Decimal(726),
+        Decimal(0),
+        Decimal(0),
+        Decimal(0),
+        Decimal(10),
+        Decimal(0),
+        "KIS 019685 2026-09-10",
+        "idem-daekyo",
+        "hash-daekyo",
+        0,
+    )
+
+    saved = repo.record_corporate_action(
+        "pf-1",
+        action=action,
+        idempotency_key="idem-daekyo",
+        payload_hash="hash-daekyo",
+    )
+
+    assert saved.quantity_after == Decimal(726)
+    assert saved.average_price_after == Decimal("2172.46829187")
+    assert saved.total_cost_basis == Decimal("1577211.97990000")
+    assert saved.ledger_entry_id == 7