feat(obligation): obligation-level aggregation engine

Erste Ausführung des Legal Obligation Layer v1: aggregiert Bewertungen auf
Kriterium-/Control-Ebene zu Findings auf Obligation-Ebene
(Regulation → Legal Obligation → Control → Criterion).

- regulierungs-agnostisch (obligation_id/tier/met/legal_basis/conditional)
- fail-safe: LM applicable=false→NA · keine erfüllt→FAILED · alle→MET · Teil→PARTIAL;
  BP/OPT covered→MET sonst OPEN (nie FAILED); LM unbewertbar→UNDETERMINED (Legacy behalten)
- Redundanz-Kollaps per OR pro legal_basis-Anforderung → kein künstliches PARTIAL
- Applicability als Hook (Prädikat-Engine folgt separat)

Shadow-Benchmark (Opus-GT, 3 Firmen): 38 Control-Findings → 13 Obligation-Findings
(2,9×); ~23 redundante Falsch-Positive strukturell korrigiert, echte Lücken erhalten,
PARTIAL=0. 16/16 Unit-Tests grün.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend-compliance/tests/test_obligation_aggregation.py

@@ -0,0 +1,153 @@
+"""Unit-Tests Obligation Aggregation Engine (Legal Obligation Layer v1).
+
+Deckt die fail-safe Regeln + den Redundanz-Kollaps ab (echte DSE-Szenarien:
+recipients 9×, objection LM+BP, portability OPTIONAL-Format)."""
+from compliance.services.obligation_aggregation import (
+    BP, LM, OPT, CriterionEval, aggregate_obligation, aggregate_obligations,
+    evals_from_tiered, summarize,
+)
+
+
+def _ce(oid, tier, met, cid, basis="", crit="", cond=None):
+    return CriterionEval(oid, tier, met, cid, basis, crit, cond)
+
+
+class TestRedundancyCollapse:
+    def test_nine_controls_one_confirms_collapses_to_one_met(self):
+        # recipients_disclosed: 9 Controls, gleiche Anforderung (Art 13(1)(e))
+        evals = [_ce("recipients_disclosed", LM, i == 4, f"DATA-{i}", "Art. 13(1)(e)")
+                 for i in range(9)]
+        res = aggregate_obligation("recipients_disclosed", evals)
+        assert res.status == "MET"
+        assert res.lm_met == 1 and res.lm_total == 1   # 9 → 1 Anforderung
+        assert len(res.evidence) == 9
+
+    def test_all_nine_absent_fails_once(self):
+        evals = [_ce("recipients_disclosed", LM, False, f"DATA-{i}", "Art. 13(1)(e)")
+                 for i in range(9)]
+        res = aggregate_obligation("recipients_disclosed", evals)
+        assert res.status == "FAILED"
+        assert res.bucket == "PFLICHT"
+
+
+class TestPartialMultiFacet:
+    def test_two_distinct_lm_requirements_one_met_is_partial(self):
+        evals = [
+            _ce("transfer", LM, True, "C1", "Art. 13(1)(f)"),    # erfüllt
+            _ce("transfer", LM, False, "C2", "Art. 46"),         # fehlt → distinkt
+        ]
+        res = aggregate_obligation("transfer", evals)
+        assert res.status == "PARTIAL"
+        assert res.lm_met == 1 and res.lm_total == 2
+
+    def test_both_distinct_requirements_met(self):
+        evals = [
+            _ce("transfer", LM, True, "C1", "Art. 13(1)(f)"),
+            _ce("transfer", LM, True, "C2", "Art. 46"),
+        ]
+        assert aggregate_obligation("transfer", evals).status == "MET"
+
+
+class TestApplicability:
+    def test_conditional_false_is_na(self):
+        evals = [_ce("transfer", LM, False, "C1", "Art. 44", cond="has_third_country_transfer")]
+        res = aggregate_obligation("transfer", evals, applicable_fn=lambda c, t: False)
+        assert res.status == "NA"
+        assert res.bucket == "NICHT_ANWENDBAR"
+        assert res.applicable is False
+
+    def test_conditional_true_evaluates_normally(self):
+        evals = [_ce("transfer", LM, False, "C1", "Art. 44", cond="has_third_country_transfer")]
+        res = aggregate_obligation("transfer", evals, applicable_fn=lambda c, t: True)
+        assert res.status == "FAILED"
+
+    def test_conditional_unknown_defaults_applicable(self):
+        evals = [_ce("transfer", LM, True, "C1", "Art. 44", cond="x")]
+        res = aggregate_obligation("transfer", evals, applicable_fn=lambda c, t: None)
+        assert res.applicable is True and res.status == "MET"
+
+    def test_no_predicate_means_applicable(self):
+        evals = [_ce("transfer", LM, True, "C1", cond="x")]
+        assert aggregate_obligation("transfer", evals).applicable is True
+
+
+class TestUndetermined:
+    def test_all_lm_none_is_undetermined(self):
+        evals = [_ce("ob", LM, None, "C1", "b"), _ce("ob", LM, None, "C2", "b")]
+        res = aggregate_obligation("ob", evals)
+        assert res.status == "UNDETERMINED"
+        assert res.bucket == "PFLICHT"
+
+    def test_one_determinable_requirement_decides(self):
+        # eine Anforderung unbestimmt, die andere klar erfüllt → MET über die bewertbare
+        evals = [_ce("ob", LM, None, "C1", "b1"), _ce("ob", LM, True, "C2", "b2")]
+        res = aggregate_obligation("ob", evals)
+        assert res.status == "MET"
+        assert res.lm_total == 1   # nur die bewertbare Anforderung zählt
+
+
+class TestBestPracticeOnly:
+    def test_pure_bp_covered_is_met_recommendation_bucket(self):
+        evals = [_ce("art20_format", OPT, True, "C1")]
+        res = aggregate_obligation("art20_format", evals)
+        assert res.status == "MET"
+        assert res.bucket == "EMPFEHLUNG"
+
+    def test_pure_bp_not_covered_is_open_never_failed(self):
+        evals = [_ce("art20_format", OPT, False, "C1", crit="JSON/CSV")]
+        res = aggregate_obligation("art20_format", evals)
+        assert res.status == "OPEN"
+        assert res.bucket == "EMPFEHLUNG"
+        assert len(res.recommendations) == 1
+
+
+class TestRecommendationsWithinLm:
+    def test_unmet_bp_in_lm_obligation_becomes_recommendation(self):
+        # objection_direct_marketing: LM erfüllt + 3 BP teils offen
+        evals = [
+            _ce("obj_dm", LM, True, "SEC-8410", "Art. 21(2)", "Recht"),
+            _ce("obj_dm", BP, False, "SEC-8410", "", "Kontaktweg"),
+            _ce("obj_dm", BP, True, "SEC-8410", "", "kostenlos"),
+        ]
+        res = aggregate_obligation("obj_dm", evals)
+        assert res.status == "MET" and res.bucket == "PFLICHT"
+        assert len(res.recommendations) == 1
+        assert res.recommendations[0]["criterion"] == "Kontaktweg"
+
+
+class TestAdapterAndSummary:
+    def test_evals_from_tiered_zips_and_skips_no_obligation(self):
+        tc = [
+            {"criterion": "Recht", "compliance_tier": "LEGAL_MINIMUM",
+             "legal_basis": "Art. 21(1)", "obligation_id": "obj_gen"},
+            {"criterion": "Weg", "compliance_tier": "BEST_PRACTICE",
+             "legal_basis": "", "obligation_id": "obj_gen"},
+            {"criterion": "ohne", "compliance_tier": "OPTIONAL"},   # kein obligation_id → skip
+        ]
+        detail = [{"met": True}, {"met": False}, {"met": True}]
+        evals = evals_from_tiered("AUTH-2051", tc, detail, conditional="x")
+        assert len(evals) == 2
+        assert evals[0].met is True and evals[0].conditional == "x"
+        assert evals[1].tier == BP and evals[1].met is False
+
+    def test_aggregate_obligations_groups_by_id(self):
+        evals = [
+            _ce("a", LM, True, "C1", "b"),
+            _ce("a", LM, True, "C2", "b"),
+            _ce("b", LM, False, "C3", "b"),
+        ]
+        results = {r.obligation_id: r for r in aggregate_obligations(evals)}
+        assert set(results) == {"a", "b"}
+        assert results["a"].status == "MET"
+        assert results["b"].status == "FAILED"
+
+    def test_summarize_counts_buckets_and_failures(self):
+        evals = [
+            _ce("a", LM, False, "C1", "b"),         # FAILED Pflicht
+            _ce("c", OPT, False, "C3", crit="x"),   # OPEN Empfehlung
+        ]
+        s = summarize(aggregate_obligations(evals))
+        assert s["obligations"] == 2
+        assert s["pflicht_failed"] == 1
+        assert s["buckets"]["PFLICHT"] == 1
+        assert s["buckets"]["EMPFEHLUNG"] == 1