Fill ferrite bead impedance from the MPN datasheet PDF.

graph_build searches project uploads and library blob refs, persists recovered Z, and still loads when the PDF has no impedance. Ohms are not written to henries.

tests/test_inductor_specs.py

@@ -147,3 +147,109 @@ def test_bead_mpn_datasheet_without_z_does_not_invent():
     assert filled.impedance_ohm is None
     model = ComponentModel(mpn="BLM21PG121SN1D", specs=filled)
     assert model.specs.impedance_ohm is None
+
+
+def _write_text_pdf(path: Path, text: str) -> None:
+    """Write a one-page PDF pypdf can extract without PyMuPDF."""
+    escaped = (
+        text.replace("\\", "\\\\").replace("(", "\\(").replace(")", "\\)")
+    )
+    lines = escaped.split("\n")
+    ops = ["BT /F1 12 Tf 72 720 Td"]
+    for i, line in enumerate(lines):
+        if i:
+            ops.append("0 -16 Td")
+        ops.append(f"({line}) Tj")
+    ops.append("ET")
+    stream = "\n".join(ops).encode("latin-1", "replace")
+    objects = [
+        b"1 0 obj << /Type /Catalog /Pages 2 0 R >> endobj\n",
+        b"2 0 obj << /Type /Pages /Kids [3 0 R] /Count 1 >> endobj\n",
+        (
+            b"3 0 obj << /Type /Page /Parent 2 0 R /MediaBox [0 0 612 792] "
+            b"/Contents 4 0 R /Resources << /Font << /F1 5 0 R >> >> >> endobj\n"
+        ),
+        b"4 0 obj << /Length %d >> stream\n" % len(stream) + stream + b"\nendstream endobj\n",
+        b"5 0 obj << /Type /Font /Subtype /Type1 /BaseFont /Helvetica >> endobj\n",
+    ]
+    header = b"%PDF-1.4\n"
+    body = header
+    offsets = [0]
+    for obj in objects:
+        offsets.append(len(body))
+        body += obj
+    xref_pos = len(body)
+    xref = [b"xref\n0 6\n0000000000 65535 f \n"]
+    for off in offsets[1:]:
+        xref.append(f"{off:010d} 00000 n \n".encode())
+    trailer = (
+        b"trailer << /Root 1 0 R /Size 6 >>\nstartxref\n"
+        + str(xref_pos).encode()
+        + b"\n%%EOF\n"
+    )
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_bytes(body + b"".join(xref) + trailer)
+
+
+_BEAD_MODEL = {
+    "mpn": "BLM21PG121SN1D",
+    "specs": {
+        "specs_type": "inductor",
+        "component_subtype": "passive.ferrite_bead",
+        "value_formatted": "FB",
+        "current_rating_a": "3A",
+        "dcr_ohms": 0.03,
+    },
+}
+
+
+def test_bead_mpn_datasheet_pdf_fills_z(tmp_path: Path):
+    models = tmp_path / "models"
+    models.mkdir()
+    (models / "BLM21PG121SN1D.json").write_text(json.dumps(_BEAD_MODEL) + "\n")
+    _write_text_pdf(
+        tmp_path / "uploads" / "datasheets" / "BLM21PG121SN1D.pdf",
+        "BLM21PG121SN1D\nImpedance (at 100MHz / 20C) 120 ohm\nRated current 3A",
+    )
+    loaded = _load_component_models(models)
+    assert loaded["BLM21PG121SN1D"].impedance_ohm == 120.0
+    assert loaded["BLM21PG121SN1D"].value_henries is None
+    persisted = json.loads((models / "BLM21PG121SN1D.json").read_text())
+    assert persisted["specs"]["impedance_ohm"] == 120.0
+    assert persisted["specs"]["value_henries"] is None
+    assert "100" in (persisted["specs"].get("value_formatted") or "")
+
+
+def test_bead_mpn_datasheet_pdf_without_z_does_not_invent(tmp_path: Path):
+    models = tmp_path / "models"
+    models.mkdir()
+    (models / "BLM21PG121SN1D.json").write_text(json.dumps(_BEAD_MODEL) + "\n")
+    _write_text_pdf(
+        tmp_path / "uploads" / "datasheets" / "BLM21PG121SN1D.pdf",
+        "BLM21PG121SN1D\nRated current 3 A\nDCR 0.03 ohm max\nPackage 0805",
+    )
+    loaded = _load_component_models(models)
+    assert "BLM21PG121SN1D" in loaded
+    assert loaded["BLM21PG121SN1D"].impedance_ohm is None
+    assert loaded["BLM21PG121SN1D"].value_henries is None
+
+
+def test_bead_mpn_library_blob_fills_z(tmp_path: Path):
+    models = tmp_path / "proj" / "models"
+    models.mkdir(parents=True)
+    (models / "BLM21PG121SN1D.json").write_text(json.dumps(_BEAD_MODEL) + "\n")
+    blob = tmp_path / "library" / "datasheets" / "blobs" / "deadbeef.pdf"
+    _write_text_pdf(
+        blob,
+        "Impedance (at 100MHz / 20C) 120 ohm\nRated current 3A",
+    )
+    ref = tmp_path / "library" / "datasheets" / "refs" / "BLM21PG121SN1D.json"
+    ref.parent.mkdir(parents=True, exist_ok=True)
+    ref.write_text(json.dumps({
+        "hash": "deadbeef",
+        "blob_key": "library/datasheets/blobs/deadbeef.pdf",
+        "mpn": "BLM21PG121SN1D",
+    }) + "\n")
+    loaded = _load_component_models(models, extra_pdf_dirs=[tmp_path])
+    assert loaded["BLM21PG121SN1D"].impedance_ohm == 120.0
+    assert loaded["BLM21PG121SN1D"].value_henries is None