Repro added see bad expansion of node

pages/gap-fill-h-shape-should-expand-node.page.tsx

@@ -0,0 +1,23 @@
+import fixture from "../test-assets/gap-fill-h-shape-should-expand-node.json"
+import { GapFillSolverPipeline } from "../lib/solvers/GapFillSolver/GapFillSolverPipeline"
+import type { CapacityMeshNode } from "../lib/types/capacity-mesh-types"
+import { useMemo } from "react"
+import { SolverDebugger3d } from "../components/SolverDebugger3d"
+
+export default () => {
+  const solver = useMemo(
+    () =>
+      new GapFillSolverPipeline({
+        meshNodes: fixture.meshNodes as CapacityMeshNode[],
+      }),
+    [],
+  )
+
+  return (
+    <SolverDebugger3d
+      solver={solver}
+      defaultShowOutput={true}
+      defaultShowRoot={true}
+    />
+  )
+}

test-assets/gap-fill-h-shape-should-expand-node.json

@@ -0,0 +1,72 @@
+{
+  "description": "H-shaped configuration - two vertical nodes with a horizontal connector in the middle",
+  "expectedBehavior": "Should detect segments on all exposed edges and expand into empty spaces around the H shape",
+  "meshNodes": [
+    {
+      "capacityMeshNodeId": "node-left-vertical",
+      "center": { "x": -3, "y": 0 },
+      "width": 1,
+      "height": 6,
+      "layer": "top",
+      "availableZ": [0]
+    },
+    {
+      "capacityMeshNodeId": "node-right-vertical",
+      "center": { "x": 3, "y": 0 },
+      "width": 1,
+      "height": 6,
+      "layer": "top",
+      "availableZ": [0]
+    },
+    {
+      "capacityMeshNodeId": "node-middle-horizontal",
+      "center": { "x": 0, "y": 0 },
+      "width": 2,
+      "height": 1,
+      "layer": "top",
+      "availableZ": [0]
+    }
+  ],
+  "expectedSegments": [
+    {
+      "description": "Left vertical - left edge",
+      "parentNodeId": "node-left-vertical",
+      "facingDirection": "x-"
+    },
+    {
+      "description": "Left vertical - top edge (above horizontal)",
+      "parentNodeId": "node-left-vertical",
+      "facingDirection": "y+"
+    },
+    {
+      "description": "Left vertical - bottom edge (below horizontal)",
+      "parentNodeId": "node-left-vertical",
+      "facingDirection": "y-"
+    },
+    {
+      "description": "Right vertical - right edge",
+      "parentNodeId": "node-right-vertical",
+      "facingDirection": "x+"
+    },
+    {
+      "description": "Right vertical - top edge (above horizontal)",
+      "parentNodeId": "node-right-vertical",
+      "facingDirection": "y+"
+    },
+    {
+      "description": "Right vertical - bottom edge (below horizontal)",
+      "parentNodeId": "node-right-vertical",
+      "facingDirection": "y-"
+    },
+    {
+      "description": "Middle horizontal - top edge",
+      "parentNodeId": "node-middle-horizontal",
+      "facingDirection": "y+"
+    },
+    {
+      "description": "Middle horizontal - bottom edge",
+      "parentNodeId": "node-middle-horizontal",
+      "facingDirection": "y-"
+    }
+  ]
+}

tests/should-expand-node.test.ts

@@ -0,0 +1,34 @@
+import { expect, test } from "bun:test"
+import middleGapFixture from "test-assets/gap-fill-h-shape-should-expand-node.json"
+import { getSvgFromGraphicsObject } from "graphics-debug"
+import { GapFillSolverPipeline } from "lib/solvers/GapFillSolver/GapFillSolverPipeline"
+import type { CapacityMeshNode } from "lib/types/capacity-mesh-types"
+import { makeCapacityMeshNodeWithLayerInfo } from "./fixtures/makeCapacityMeshNodeWithLayerInfo"
+
+test("should expand capacityMeshNode to fill the gap", async () => {
+  const solver = new GapFillSolverPipeline({
+    meshNodes: middleGapFixture.meshNodes as CapacityMeshNode[],
+  })
+
+  solver.solve()
+
+  const { outputNodes } = solver.getOutput()
+
+  expect(outputNodes.length).toBeGreaterThanOrEqual(
+    middleGapFixture.meshNodes.length,
+  )
+
+  const finalGraphics = makeCapacityMeshNodeWithLayerInfo(outputNodes)
+  const svg = getSvgFromGraphicsObject(
+    { rects: finalGraphics.values().toArray().flat() },
+    {
+      svgWidth: 640,
+      svgHeight: 480,
+    },
+  )
+
+  // More means we have added new nodes to fill the gap
+  // expect(outputNodes.length).toEqual(3)
+
+  await expect(svg).toMatchSvgSnapshot(import.meta.path)
+})