feat: add typed tier assurance guardrails

projects/coulomb-pricing/tests/test_governance.py

@@ -1,8 +1,12 @@
 from __future__ import annotations
 
+from dataclasses import replace
 from pathlib import Path
 
+from adaptive_pricing_core.governance import assess_tier_definition_assurance
+from adaptive_pricing_core.pricing_models import AssuranceClaim
 from observatory.api import build_dashboard_payload
+from observatory.load import load_pricing_models
 
 DATA_DIR = Path(__file__).resolve().parent.parent / "data"
 
@@ -46,3 +50,30 @@ def test_recommendations_include_governed_execution_gate() -> None:
     assert execution_gate["confidence"] == "0.88"
     assert execution_gate["risks"]
     assert execution_gate["supporting_observations"]
+
+
+def test_changed_assurance_claim_requires_one_time_definition_approval() -> None:
+    previous = next(
+        item for item in load_pricing_models(DATA_DIR) if item.id == "flat-899-eur-monthly"
+    )
+    current = replace(
+        previous,
+        assurance_claims=(
+            AssuranceClaim(
+                id="availability-tier",
+                kind="availability",
+                customer_wording="Survives a zone loss.",
+                minimum_levels={"V": 3},
+                delivering_service="railiance-platform",
+                evidence_ref="evidence/zone-failover.json",
+            ),
+        ),
+    )
+
+    assessment = assess_tier_definition_assurance(current, previous)
+    unchanged = assess_tier_definition_assurance(current, current)
+
+    assert assessment.decision == "approval_required"
+    assert assessment.approvals[0].evidence_refs == ("evidence/zone-failover.json",)
+    assert unchanged.decision == "proceed"
+    assert unchanged.approvals == ()