busbar-designer/tests/test_export.py

"""Sanity tests for busbar_export — exercise STEP/DXF/SVG writers end-to-end."""

import sys
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parents[1]))

from busbar_export import to_step, to_dxf, to_svg


def _payload():
    return {
        "extrude": False,
        "busbars": [
            {
                "name": "P1",
                "color": "#ff8800",
                "strip_width": 8.0,
                "pad_radius": 7.0,
                "hole_radius": 5.0,
                "cells": [
                    {"id": 1, "x": 0.0, "y": 0.0},
                    {"id": 2, "x": 22.8, "y": 0.0},
                    {"id": 3, "x": 45.6, "y": 0.0},
                ],
            }
        ],
    }


def test_step_export_is_iso_10303():
    data = to_step(_payload())
    text = data[:200].decode("ascii", errors="ignore")
    assert "ISO-10303-21" in text, f"STEP header missing, got: {text!r}"
    assert len(data) > 500


def test_dxf_export_is_nonempty():
    data = to_dxf(_payload())
    assert b"SECTION" in data[:2000]


def test_svg_export_is_svg():
    data = to_svg(_payload())
    assert b"<svg" in data[:2000]


def test_extruded_step_includes_solid():
    payload = _payload()
    payload["extrude"] = True
    payload["thickness"] = 0.2
    data = to_step(payload)
    assert b"MANIFOLD_SOLID_BREP" in data or b"CLOSED_SHELL" in data


def test_panel_5p_row_is_stadium():
    """5 cells in a row → collinear hull → stadium-shaped panel."""
    payload = {
        "busbars": [{
            "name": "5P",
            "shape": "panel",
            "pad_radius": 10.0,
            "hole_radius": 5.0,
            "cells": [{"id": i + 1, "x": i * 22.8, "y": 0.0} for i in range(5)],
        }]
    }
    data = to_step(payload)
    assert b"ISO-10303-21" in data[:200]
    assert len(data) > 500


def test_panel_grid_uses_convex_hull():
    """4-cell square → 4-vertex hull → rounded rectangle."""
    payload = {
        "busbars": [{
            "name": "4P",
            "shape": "panel",
            "pad_radius": 10.0,
            "hole_radius": 5.0,
            "cells": [
                {"id": 1, "x": 0.0,  "y": 0.0},
                {"id": 2, "x": 22.8, "y": 0.0},
                {"id": 3, "x": 22.8, "y": 19.746},
                {"id": 4, "x": 0.0,  "y": 19.746},
            ],
        }]
    }
    data = to_step(payload)
    assert b"ISO-10303-21" in data[:200]


def test_panel_single_cell_is_disc_with_hole():
    payload = {
        "busbars": [{
            "name": "1P",
            "shape": "panel",
            "pad_radius": 10.0,
            "hole_radius": 5.0,
            "cells": [{"id": 1, "x": 0.0, "y": 0.0}],
        }]
    }
    data = to_step(payload)
    assert b"ISO-10303-21" in data[:200]


def test_wire_shape_still_works():
    payload = {
        "busbars": [{
            "name": "wire",
            "shape": "wire",
            "strip_width": 6.0,
            "pad_radius": 7.0,
            "hole_radius": 5.0,
            "cells": [{"x": 0, "y": 0}, {"x": 22.8, "y": 0}],
        }]
    }
    data = to_step(payload)
    assert b"ISO-10303-21" in data[:200]


def test_panel_L_shape_has_no_diagonal_bridge():
    """L-shape (7 cells in column + 2 cells across top) must not bridge across
    non-selected cells. The convex-hull approach would have, but neighbor-edge
    must not — verify by checking that the area of the resulting face is close
    to the sum of stadium-chain segments, not the area of the L's bounding box.
    """
    from busbar_export import parse_payload, busbar_sketch
    cells = [{"x": 0, "y": i * 19.75} for i in range(7)]
    cells += [{"x": 22.8, "y": 6 * 19.75}, {"x": 45.6, "y": 6 * 19.75}]
    payload = {"busbars": [{
        "name": "L", "shape": "panel",
        "pad_radius": 10.0, "hole_radius": 6.0,
        "hole_shape": "cross", "slit_width": 1.8,
        "cells": cells,
    }]}
    busbars, *_ = parse_payload(payload)
    face = busbar_sketch(busbars[0])
    area = face.area

    # Pad disc area = π·10² ≈ 314 per cell, 9 cells → 2826 max if all disjoint.
    # Bridges add some, holes subtract some. The L's bounding box is
    # 65.6 × 138.25 ≈ 9070 — convex hull would be at least ~4500. Neighbor
    # chain should be well under 3500.
    assert 2000 < area < 3500, f"area {area} suggests convex-hull bridging"


def test_cross_slit_punches_through():
    """Cross slit must remove area from the panel (vs. no holes baseline)."""
    from busbar_export import parse_payload, busbar_sketch
    base = {
        "busbars": [{
            "name": "P", "shape": "panel", "pad_radius": 10.0,
            "hole_radius": 6.0, "hole_shape": "cross", "slit_width": 1.8,
            "cells": [{"x": 0, "y": 0}, {"x": 22.8, "y": 0}],
        }]
    }
    with_cross, *_ = parse_payload(base)
    area_cross = busbar_sketch(with_cross[0]).area

    # Same payload, tiny hole — should be nearly the same area as un-punched.
    base["busbars"][0]["hole_radius"] = 0.1
    base["busbars"][0]["slit_width"] = 0.1
    tiny, *_ = parse_payload(base)
    area_tiny = busbar_sketch(tiny[0]).area

    assert area_tiny > area_cross + 50, \
        f"cross didn't punch much: tiny={area_tiny:.1f}, cross={area_cross:.1f}"