Add protocol-certification M2 L0 structural certifier (2.66.0).

Presence and connection only. FAIL solely on missing MANDATORY structure.
AXI4 internal is NOT_APPLICABLE, not FAIL. RECOMMENDED never FAIL. No L1–L3
and no invented ohms/mm/ps.

tests/pcb/test_protocol_l0_m2.py

@@ -0,0 +1,155 @@
+"""M2 L0 structural certifier: presence/connection; AXI N/A; RECOMMENDED not FAIL."""
+
+from __future__ import annotations
+
+import json
+
+from backend.periscopex.models import (
+    Component,
+    ComponentType,
+    DesignGraph,
+    Net,
+    NetType,
+    PinConnection,
+)
+from backend.periscopex.protocol_l0 import (
+    PACK_MACROPHASE,
+    _pack,
+    certify_l0,
+    protocol_exam,
+)
+from backend.periscopex.protocol_recognize import recognize_physical_buses
+
+
+def _ic(ref: str, pins: dict[str, str], *, mpn: str = "", value: str = "") -> Component:
+    return Component(
+        reference=ref, value=value or mpn, footprint="",
+        component_type=ComponentType.IC, mpn=mpn or None, pins=pins,
+    )
+
+
+def _net(name: str, *pairs: tuple[str, str]) -> Net:
+    return Net(
+        name=name, net_type=NetType.SIGNAL,
+        pins=[PinConnection(component_ref=r, pin_number=p) for r, p in pairs],
+    )
+
+
+def _usb_connected() -> DesignGraph:
+    return DesignGraph(
+        components={
+            "U1": _ic("U1", {"1": "USB_D+", "2": "USB_D-"}, mpn="CH340E"),
+            "J2": Component(
+                reference="J2", value="USB2_TypeA",
+                footprint="USB_A",
+                component_type=ComponentType.CONNECTOR,
+                pins={"2": "USB_D+", "3": "USB_D-"},
+            ),
+        },
+        nets={
+            "USB_D+": _net("USB_D+", ("U1", "1"), ("J2", "2")),
+            "USB_D-": _net("USB_D-", ("U1", "2"), ("J2", "3")),
+        },
+    )
+
+
+def _usb_dangling_minus() -> DesignGraph:
+    return DesignGraph(
+        components={
+            "U1": _ic("U1", {"1": "USB_D+"}, mpn="CH340E"),
+            "J2": Component(
+                reference="J2", value="USB2_TypeA",
+                footprint="USB_A",
+                component_type=ComponentType.CONNECTOR,
+                pins={"2": "USB_D+", "3": "USB_D-"},
+            ),
+        },
+        nets={
+            "USB_D+": _net("USB_D+", ("U1", "1"), ("J2", "2")),
+            "USB_D-": _net("USB_D-", ("J2", "3")),
+        },
+    )
+
+
+def _axi_graph() -> DesignGraph:
+    return DesignGraph(
+        components={
+            "U3": _ic("U3", {"1": "AXI_AWVALID"}, mpn="XC7A100T", value="AXI4 interconnect"),
+        },
+        nets={"AXI_AWVALID": _net("AXI_AWVALID", ("U3", "1"))},
+    )
+
+
+def _ddr_one_ended() -> DesignGraph:
+    pins = {str(i): f"DDR4_DQ{i}" for i in range(8)}
+    pins.update({"8": "DDR4_DQS0_P", "9": "DDR4_DQS0_N"})
+    return DesignGraph(
+        components={"U5": _ic("U5", pins, mpn="MT41K256M16TW", value="DDR4")},
+        nets={n: _net(n, ("U5", p)) for p, n in pins.items()},
+    )
+
+
+def _l0_for(graph: DesignGraph, logical_sub: str) -> list:
+    insts = recognize_physical_buses(graph)
+    by, _ = certify_l0(graph, insts)
+    rows = []
+    for inst in insts:
+        if logical_sub in inst.logical_protocol_id:
+            rows.extend(by.get(inst.instance_id, []))
+    return rows
+
+
+def test_usb_connected_pair_l0_topology_pass():
+    rows = _l0_for(_usb_connected(), "usb2")
+    topo = [r for r in rows if r.check == "topology"]
+    assert topo
+    assert topo[0].result == "PASS"
+    assert topo[0].level == "L0"
+    blob = json.dumps(topo[0].model_dump())
+    assert "ohm" not in blob.lower()
+    assert "90" not in blob
+
+
+def test_usb_unconnected_dminus_l0_fail_mandatory():
+    g = _usb_dangling_minus()
+    insts = recognize_physical_buses(g)
+    usb = [i for i in insts if "usb" in i.logical_protocol_id]
+    assert usb
+    by, findings = certify_l0(g, insts)
+    rows = [r for i in usb for r in by[i.instance_id]]
+    topo = [r for r in rows if r.check == "topology"]
+    assert topo
+    assert topo[0].result == "FAIL"
+    assert topo[0].mandatory == "MANDATORY"
+    assert any(f.status == "ERROR" and f.rule_id == "PE-PRT-L0-001" for f in findings)
+
+
+def test_axi_internal_l0_not_applicable_not_fail():
+    rows = _l0_for(_axi_graph(), "axi4")
+    assert rows
+    assert all(r.result == "NOT_APPLICABLE" for r in rows)
+    assert all(r.result != "FAIL" for r in rows)
+    sec, findings = protocol_exam(_axi_graph())
+    assert sec.max_level_reached == "L0"
+    assert sec.macrophase == PACK_MACROPHASE
+    assert all(f.status != "ERROR" for f in findings)
+    assert all("AXI_AWVALID" not in (f.net or "") for f in findings if f.rule_id == "PE-PRT-L0-001")
+
+
+def test_ddr_unconnected_memory_fails_l0_connection():
+    rows = _l0_for(_ddr_one_ended(), "ddr4")
+    mapping = [r for r in rows if r.check == "byte_lane_mapping"]
+    assert mapping
+    assert mapping[0].result == "FAIL"
+    assert "unconnected" in mapping[0].notes
+
+
+def test_recommended_never_parses_as_fail():
+    rec = _pack("return_path", "FAIL", "RECOMMENDED", notes="missing")
+    assert rec.result != "FAIL"
+    assert rec.status != "ERROR"
+
+
+def test_l0_does_not_run_impedance():
+    rows = _l0_for(_usb_connected(), "usb2")
+    assert not any(r.check in {"differential_impedance", "intra_pair_skew", "length"} for r in rows)

tests/pcb/test_protocol_recognize_m1.py

@@ -13,7 +13,6 @@ from backend.periscopex.models import (
     PinConnection,
 )
 from backend.periscopex.protocol_recognize import (
-    PACK_MACROPHASE,
     protocol_section_for_graph,
     recognize_physical_buses,
 )
@@ -143,7 +142,6 @@ def test_empty_graph_keeps_nessun_protocollo():
     sec = protocol_section_for_graph(DesignGraph())
     assert sec.message == "nessun protocollo riconosciuto"
     assert sec.recognized_instances == []
-    assert sec.macrophase == PACK_MACROPHASE
     blob = json.dumps(sec.model_dump())
     assert "ohm" not in blob.lower()
 
@@ -151,7 +149,6 @@ def test_empty_graph_keeps_nessun_protocollo():
 def test_report_section_lists_usb_without_z():
     sec = protocol_section_for_graph(_usb_graph())
     assert sec.recognized_instances
-    assert sec.max_level_reached is None
     blob = json.dumps(sec.model_dump())
     assert "90" not in blob
     assert "Zdiff" not in blob