Harden resource cost evidence contract

tests/test_models.py

@@ -1,5 +1,10 @@
 """Smoke tests for fin-hub model registration."""
 
+from datetime import date
+from decimal import Decimal
+
+import pytest
+
 from fin_hub.models import (
     Budget,
     BurnRate,
@@ -9,6 +14,8 @@ from fin_hub.models import (
     ServiceCost,
     TokenSpend,
 )
+from fin_hub.models.engagement_price import _validate_engagement_price
+from fin_hub.models.service_cost import _normalize_service_cost_attribution
 from hub_core.models.base import Base
 
 
@@ -39,3 +46,41 @@ def test_service_cost_has_external_attribution_seam():
     assert columns["application_id"].nullable is True
     assert columns["app_instance_id"].nullable is True
     assert columns["cost_attribution_key"].nullable is True
+
+
+def test_service_cost_orm_uses_shared_money_and_period_invariants():
+    cost = ServiceCost(
+        service_id="cluster",
+        environment="production",
+        period_month="2026-07",
+        amount=Decimal("10.005"),
+        currency="eur",
+        source=" invoice ",
+    )
+    _normalize_service_cost_attribution(None, None, cost)
+    assert cost.amount == Decimal("10.00")
+    assert cost.currency == "EUR"
+    assert cost.source == "invoice"
+
+    cost.period_month = "2026-13"
+    with pytest.raises(ValueError, match="YYYY-MM"):
+        _normalize_service_cost_attribution(None, None, cost)
+
+
+def test_engagement_price_orm_normalizes_same_basis_as_sqlite():
+    price = EngagementPrice(
+        client_id="acme",
+        application_id="portal",
+        app_instance_id="prod-01",
+        cost_attribution_key=None,
+        period_month="placeholder",
+        effective_from=date(2026, 7, 15),
+        amount=Decimal("100.005"),
+        currency="eur",
+        source=" agreement ",
+    )
+    _validate_engagement_price(None, None, price)
+    assert price.period_month == "2026-07"
+    assert price.amount == Decimal("100.00")
+    assert price.currency == "EUR"
+    assert price.source == "agreement"