fix: make burst impact coverage envelopes exclusive

tests/unit/test_node_coverage.py

@@ -3,11 +3,12 @@ from datetime import datetime, timezone
 import pytest
 from fastapi.encoders import jsonable_encoder
 from pydantic import ValidationError
-from shapely.geometry import Point, shape
+from shapely.geometry import Point, box, mapping, shape
+from shapely.ops import unary_union
 
 from app.domain.schemas.operational_data import TaskDataSnapshot
 from app.mcp.analysis_models import NodeCoverageInput
-from app.services.node_coverage import build_node_coverage
+from app.services.node_coverage import build_node_coverage, exclusive_coverage_features
 from app.services.operational_presentation import resolve_overlay
 
 
@@ -32,6 +33,44 @@ def test_coverage_can_compare_arbitrary_groups_without_assigning_isolation_seman
     assert coverage["parameters"]["split_by_connectivity"] is False
 
 
+def test_exclusive_envelopes_keep_union_and_counts_with_higher_groups_taking_precedence():
+    originals = [box(0, 0, 4, 4), box(2, 0, 6, 4), box(3, 1, 5, 3)]
+    features = [{"type": "Feature", "id": str(i), "properties": {
+        "coverage_group": str(i), "node_count": 10 + i, "mapped_node_count": 10 + i,
+    }, "geometry": mapping(geometry)} for i, geometry in enumerate(originals)]
+    result = exclusive_coverage_features(features)
+    visible = [shape(feature["geometry"]) for feature in result]
+    assert len(result) == 3
+    assert all(a.intersection(b).area == 0 for i, a in enumerate(visible) for b in visible[i + 1:])
+    assert unary_union(visible).equals(unary_union(originals))
+    assert visible[-1].equals(originals[-1])
+    assert [feature["properties"]["node_count"] for feature in result] == [10, 11, 12]
+    assert [feature["properties"]["mapped_node_count"] for feature in result] == [10, 11, 12]
+    assert all(feature["properties"]["overlap_policy"] == "higher_priority_group_first" for feature in result)
+    assert shape(features[0]["geometry"]).equals(originals[0])  # Never rewrite saved inputs.
+
+
+def test_covered_grade_keeps_node_metadata_without_invalid_empty_geometry():
+    positions = [position("A", 117.24), position("B", 117.24)]
+    groups = [group(["A"], "low"), group(["B"], "high")]
+    ordinary = build_node_coverage(groups, positions, [])
+    assert len(ordinary["map_payload"]["features"]) == 2
+    exclusive = build_node_coverage(groups, positions, [], exclusive_groups=True)
+    assert [feature["id"] for feature in exclusive["map_payload"]["features"]] == ["high"]
+    assert exclusive["groups"]["low"]["node_ids"] == ["A"]
+    assert exclusive["groups"]["low"]["mapped_node_count"] == 1
+    assert exclusive["groups"]["low"]["display_area_available"] is False
+    assert exclusive["groups"]["high"]["display_area_available"] is True
+    summaries = exclusive["map_payload"]["features"][0]["properties"]["coverage_group_summary"]
+    assert summaries["low"]["node_count"] == 1
+    assert summaries["low"]["mapped_node_count"] == 1
+    assert summaries["low"]["display_area_available"] is False
+    # A second application must not drop the summary for the clipped group.
+    repeated = exclusive_coverage_features(exclusive["map_payload"]["features"])
+    assert repeated[0]["properties"]["coverage_group_summary"] == summaries
+    assert exclusive["status"] == "ready"
+
+
 def test_connectivity_option_does_not_bridge_disconnected_groups():
     positions = [position("A", 117.24), position("B", 117.241),
                  position("C", 117.26), position("D", 117.261)]