M41: harden trust boundaries and delivery

backend/tests/test_knowledge.py

@@ -7,6 +7,7 @@ import httpx
 
 from app.api.routers import knowledge as knowledge_router
 from app.core.config import get_settings
+from app.core.ratelimit import SlidingWindowLimiter
 from app.services.knowledge import KnowledgeHealth
 from app.services.knowledge.demo import DemoKnowledgeProvider
 from app.services.knowledge.procedures import iter_procedure_documents
@@ -140,6 +141,16 @@ def test_ask_question_requires_authentication(client):
     assert response.status_code == 401
 
 
+def test_knowledge_questions_are_bounded_per_session_and_client(ops_client, monkeypatch):
+    limiter = SlidingWindowLimiter(max_requests=1, window_seconds=60)
+    monkeypatch.setattr(knowledge_router, "_question_limiter", limiter)
+    body = {"question": "What is the vehicle return procedure?"}
+    assert ops_client.post("/api/v1/knowledge/questions", json=body).status_code == 200
+    blocked = ops_client.post("/api/v1/knowledge/questions", json=body)
+    assert blocked.status_code == 429
+    assert int(blocked.headers["retry-after"]) >= 1
+
+
 def test_ask_question_is_audited_without_leaking_full_text(ops_client):
     ops_client.post(
         "/api/v1/knowledge/questions",
@@ -695,5 +706,38 @@ def test_ragcore_search_fallback_prefers_damage_procedure(monkeypatch):
         ),
     )
     answer = provider.ask("Wat moet ik doen bij schade?", "test-correlation-damage", "nl-BE")
+    assert answer.evidence_state == "insufficient"
+    assert answer.answer == ""
+    assert any(source.document_id == "damage-procedure" for source in answer.sources)
+
+
+def test_ragcore_search_fallback_accepts_relevant_damage_evidence_above_threshold(monkeypatch):
+    provider = RAGcoreKnowledgeProvider()
+    monkeypatch.setattr(provider._settings, "ragcore_space_id", "space-1")
+    search = _search_body()
+    search["results"].append(
+        {
+            "citation": {
+                "document_id": "damage-procedure",
+                "document_version_id": "version-2",
+                "title": "damage-procedure.md",
+                "section": "Damage",
+                "excerpt": "Record damage and keep the vehicle blocked.",
+            },
+            "rank": 1,
+            "scores": {"fused": 0.5},
+        }
+    )
+    monkeypatch.setattr(
+        provider,
+        "_client",
+        lambda: _FakeClient(
+            post_responses={
+                "/v1/answers": _FakeResponse(503, {}),
+                "/v1/search": _FakeResponse(200, search),
+            }
+        ),
+    )
+    answer = provider.ask("Wat moet ik doen bij schade?", "strong-damage", "nl-BE")
     assert answer.evidence_state == "grounded"
     assert answer.sources[0].document_id == "damage-procedure"