Implement boundary engine and close WP-0004

projects/coulomb-pricing/tests/test_api.py

@@ -24,9 +24,15 @@ def test_dashboard_payload_contains_live_ledger_totals() -> None:
     assert payload["membership_analytics"]["active_members"] == 1
     assert payload["usage"]["record_count"] == 1
     assert len(payload["pricing_simulations"]["scenarios"]) == 3
+    assert len(payload["boundary_validation"]["model_results"]) == 3
+    assert payload["boundary_validation"]["policy"]["target_margin_pct"] == "15"
+    assert any(
+        result["decision"] == "rejected"
+        for result in payload["boundary_validation"]["model_results"]
+    )
     assert payload["recommendations"]
 
 
 def test_payload_json_is_valid() -> None:
     parsed = json.loads(payload_json(DATA_DIR, "2026-06"))
-    assert Decimal(parsed["payments"][0]["fees_amount"]) == Decimal("0.44")
+    assert Decimal(parsed["payments"][0]["fees_amount"]) == Decimal("0.44")

projects/coulomb-pricing/tests/test_boundary_engine.py

@@ -0,0 +1,168 @@
+from __future__ import annotations
+
+from decimal import Decimal
+from pathlib import Path
+
+from adaptive_pricing_core.boundary_engine import (
+    BoundaryPolicy,
+    CommitmentTerms,
+    PricingConfiguration,
+    validate_pricing_configuration,
+)
+from observatory.load import load_pricing_models
+
+DATA_DIR = Path(__file__).resolve().parent.parent / "data"
+
+
+def _model(model_id: str):
+    return next(item for item in load_pricing_models(DATA_DIR) if item.id == model_id)
+
+
+def test_commitment_backed_discount_is_accepted_when_economics_stay_strong() -> None:
+    result = validate_pricing_configuration(
+        PricingConfiguration(
+            model=_model("membership-plus-overage"),
+            segment="coulomb-social-members",
+            expected_usage_units=Decimal("100200"),
+            expected_usage_variance_pct=Decimal("25"),
+            allocated_fixed_cost=Decimal("2.00"),
+            unit_cost=Decimal("0.00000125"),
+            payment_fee_rate_pct=Decimal("5"),
+            usage_unit_price=Decimal("0.0015"),
+            commitment_terms=CommitmentTerms(
+                contract_duration_months=6,
+                minimum_monthly_turnover=Decimal("9.30"),
+            ),
+        ),
+        BoundaryPolicy(),
+    )
+
+    assert result.decision == "accepted"
+    assert result.valid is True
+    assert result.requires_approval is False
+    commitment_result = next(
+        item for item in result.constraints if item.id == "commitment-backed-concession"
+    )
+    assert commitment_result.status == "pass"
+    assert "minimum_monthly_turnover" in commitment_result.details["signals"]
+
+
+def test_discount_without_commitment_is_rejected() -> None:
+    result = validate_pricing_configuration(
+        PricingConfiguration(
+            model=_model("membership-plus-overage"),
+            segment="coulomb-social-members",
+            expected_usage_units=Decimal("100200"),
+            expected_usage_variance_pct=Decimal("25"),
+            allocated_fixed_cost=Decimal("2.00"),
+            unit_cost=Decimal("0.00000125"),
+            payment_fee_rate_pct=Decimal("5"),
+            usage_unit_price=Decimal("0.0015"),
+        ),
+        BoundaryPolicy(),
+    )
+
+    assert result.decision == "rejected"
+    assert result.valid is False
+    failing_ids = {
+        item.id for item in result.constraints if item.status == "fail" and item.severity == "hard"
+    }
+    assert "commitment-backed-concession" in failing_ids
+
+
+def test_weak_commitment_trade_is_rejected() -> None:
+    result = validate_pricing_configuration(
+        PricingConfiguration(
+            model=_model("membership-plus-overage"),
+            segment="coulomb-social-members",
+            expected_usage_units=Decimal("100200"),
+            expected_usage_variance_pct=Decimal("25"),
+            allocated_fixed_cost=Decimal("2.00"),
+            unit_cost=Decimal("0.00000125"),
+            payment_fee_rate_pct=Decimal("5"),
+            usage_unit_price=Decimal("0.0015"),
+            commitment_terms=CommitmentTerms(
+                contract_duration_months=2,
+                minimum_monthly_turnover=Decimal("9.00"),
+            ),
+        ),
+        BoundaryPolicy(),
+    )
+
+    assert result.decision == "rejected"
+    commitment_result = next(
+        item for item in result.constraints if item.id == "commitment-backed-concession"
+    )
+    assert commitment_result.status == "fail"
+
+
+def test_large_but_supported_concession_requires_approval() -> None:
+    result = validate_pricing_configuration(
+        PricingConfiguration(
+            model=_model("flat-899-eur-monthly"),
+            segment="coulomb-social-members",
+            allocated_fixed_cost=Decimal("1.00"),
+            payment_fee_rate_pct=Decimal("5"),
+            access_fee_amount=Decimal("7.50"),
+            commitment_terms=CommitmentTerms(
+                contract_duration_months=6,
+                minimum_monthly_turnover=Decimal("8.00"),
+            ),
+        ),
+        BoundaryPolicy(),
+    )
+
+    assert result.decision == "requires_approval"
+    assert result.valid is True
+    assert result.requires_approval is True
+    review_ids = {item.id for item in result.constraints if item.status == "review"}
+    assert "discount-approval-threshold" in review_ids
+
+
+def test_zero_usage_flat_configuration_can_pass() -> None:
+    result = validate_pricing_configuration(
+        PricingConfiguration(
+            model=_model("flat-899-eur-monthly"),
+            segment="coulomb-social-members",
+            expected_usage_units=Decimal("0"),
+            expected_usage_variance_pct=Decimal("0"),
+            allocated_fixed_cost=Decimal("3.00"),
+            payment_fee_rate_pct=Decimal("5"),
+        ),
+        BoundaryPolicy(),
+    )
+
+    assert result.decision == "accepted"
+    assert result.metrics.billable_usage_units == Decimal("0")
+
+
+def test_high_fee_configuration_is_rejected() -> None:
+    result = validate_pricing_configuration(
+        PricingConfiguration(
+            model=_model("flat-899-eur-monthly"),
+            segment="coulomb-social-members",
+            allocated_fixed_cost=Decimal("1.00"),
+            payment_fee_rate_pct=Decimal("30"),
+        ),
+        BoundaryPolicy(),
+    )
+
+    assert result.decision == "rejected"
+    payment_fee_result = next(item for item in result.constraints if item.id == "payment-fee-limit")
+    assert payment_fee_result.status == "fail"
+
+
+def test_unprofitable_configuration_is_rejected() -> None:
+    result = validate_pricing_configuration(
+        PricingConfiguration(
+            model=_model("flat-899-eur-monthly"),
+            segment="coulomb-social-members",
+            allocated_fixed_cost=Decimal("10.00"),
+            payment_fee_rate_pct=Decimal("5"),
+        ),
+        BoundaryPolicy(),
+    )
+
+    assert result.decision == "rejected"
+    assert result.metrics.monthly_margin < Decimal("0")
+    assert any(item.id == "cost-floor-coverage" and item.status == "fail" for item in result.constraints)