feat(pid): line classes, orthogonal routing, labels, markers, crossings

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd

tests/test_pid_lines.py

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+# tests/test_pid_lines.py
+"""Routing is geometry, so it is tested without a backend."""
+
+from __future__ import annotations
+
+import pytest
+
+from engineering.pid.lines import (
+    DEFAULT_NUMBER_FORMAT,
+    LINE_CLASSES,
+    count_crossings,
+    format_line_number,
+    label_placement,
+    marker_positions,
+    route,
+    snap_axis,
+)
+
+
+def test_line_classes_map_to_layers_and_markers():
+    assert set(LINE_CLASSES) == {
+        "process_major",
+        "process_minor",
+        "utility",
+        "pneumatic",
+        "electric",
+        "hydraulic",
+        "capillary",
+        "data",
+    }
+    assert LINE_CLASSES["process_major"].layer == "PROCESS-PIPING-MAIN"
+    assert (
+        LINE_CLASSES["electric"].layer == "INSTRUMENT-LINE-SIGNAL"
+        and LINE_CLASSES["electric"].linetype is None
+    )
+    assert (
+        LINE_CLASSES["pneumatic"].linetype == "Continuous"
+        and LINE_CLASSES["pneumatic"].marker == "mark_pneumatic"
+    )
+    assert LINE_CLASSES["process_major"].arrow is True and LINE_CLASSES["pneumatic"].arrow is False
+    assert LINE_CLASSES["utility"].kind == "process" and LINE_CLASSES["data"].kind == "signal"
+
+
+def test_snap_axis_picks_the_dominant_component():
+    assert snap_axis(10, 1) == 0.0 and snap_axis(-10, 1) == 180.0
+    assert snap_axis(1, 10) == 90.0 and snap_axis(1, -10) == 270.0
+
+
+def test_straight_when_aligned_and_facing():
+    assert route((0, 0), 0.0, (50, 0), 180.0) == [(0.0, 0.0), (50.0, 0.0)]
+
+
+def test_l_route_when_perpendicular():
+    path = route((0, 0), 0.0, (50, 30), 270.0)
+    assert path == [(0.0, 0.0), (50.0, 0.0), (50.0, 30.0)]
+
+
+def test_z_route_when_parallel_and_offset():
+    path = route((0, 0), 0.0, (60, 20), 180.0, stub=5.0)
+    assert path == [(0.0, 0.0), (30.0, 0.0), (30.0, 20.0), (60.0, 20.0)]
+
+
+def test_ports_facing_away_on_one_axis_need_waypoints():
+    with pytest.raises(ValueError, match="waypoints"):
+        route((0, 0), 180.0, (40, 0), 0.0, stub=5.0)
+    path = route((0, 0), 180.0, (40, 0), 0.0, mode=[(-5, 0), (-5, -10), (45, -10), (45, 0)])
+    assert len(path) == 6
+
+
+def test_stub_is_honoured_or_refused():
+    with pytest.raises(ValueError, match="stub"):
+        route((0, 0), 0.0, (3, 8), 180.0, stub=5.0)
+    assert route((0, 0), 0.0, (3, 0), 180.0, stub=5.0) == [(0.0, 0.0), (3.0, 0.0)], (
+        "a straight run is exempt"
+    )
+
+
+def test_radial_ends_take_the_axis_towards_the_other_end():
+    path = route((0, 0), None, (0, 40), None)
+    assert path == [(0.0, 0.0), (0.0, 40.0)]
+
+
+def test_direct_and_waypoints():
+    assert route((0, 0), 0.0, (10, 7), 90.0, mode="direct") == [(0.0, 0.0), (10.0, 7.0)]
+    assert route((0, 0), 0.0, (10, 7), 90.0, mode=[(10, 0)]) == [
+        (0.0, 0.0),
+        (10.0, 0.0),
+        (10.0, 7.0),
+    ]
+    with pytest.raises(ValueError, match="repeat"):
+        route((0, 0), 0.0, (10, 7), 90.0, mode=[(0, 0)])
+    with pytest.raises(ValueError, match="zero"):
+        route((0, 0), 0.0, (0, 0), 90.0)
+
+
+def test_label_sits_left_of_the_longest_segment_and_never_upside_down():
+    x, y, rot, index = label_placement([(0, 0), (10, 0), (10, 40), (0, 40)])
+    assert index == 1 and rot == 90.0
+    assert (x, y) == pytest.approx((8.5, 20.0))
+    x, y, rot, index = label_placement([(50, 0), (0, 0)])
+    assert rot == 0.0 and y == pytest.approx(1.5)
+
+
+def test_markers_only_on_segments_long_enough():
+    marks = marker_positions([(0, 0), (10, 0), (10, 40)], min_len=15.0)
+    assert marks == [(10.0, 20.0, 90.0)]
+    assert marker_positions([(0, 0), (30, 0)]) == [(15.0, 0.0, 0.0)]
+
+
+def test_crossings_count_proper_intersections_only():
+    others = [[(5, -5), (5, 5)], [(20, 0), (20, 10)], [(0, 3), (8, 3)]]
+    assert count_crossings([(0, 0), (10, 0)], others) == 1
+    assert count_crossings([(0, 0), (20, 0)], [[(20, 0), (20, 10)]]) == 0, (
+        "touching an endpoint is a junction"
+    )
+
+
+def test_line_number_format_drops_empty_fields():
+    assert DEFAULT_NUMBER_FORMAT == "{size}-{service}-{seq}-{spec}-{insulation}"
+    assert (
+        format_line_number(
+            DEFAULT_NUMBER_FORMAT, size="100", service="P", seq=1001, spec="CS1", insulation="IH"
+        )
+        == "100-P-1001-CS1-IH"
+    )
+    assert (
+        format_line_number(DEFAULT_NUMBER_FORMAT, size="100", service="P", seq=1001) == "100-P-1001"
+    )
+    assert format_line_number("L-{seq}", seq=7) == "L-7"
+    with pytest.raises(ValueError, match="unknown"):
+        format_line_number("{bogus}", seq=1)