Add tests for box brush face editing and update existing tests

tests/geometry/box-face-uvs.test.ts

@@ -0,0 +1,78 @@
+import { BoxGeometry } from "three";
+import { describe, expect, it } from "vitest";
+
+import { createBoxBrush } from "../../src/document/brushes";
+import { applyBoxBrushFaceUvsToGeometry, createFitToFaceBoxBrushFaceUvState, transformProjectedFaceUv } from "../../src/geometry/box-face-uvs";
+
+describe("box face UV projection", () => {
+  it("fit-to-face produces finite UVs normalized across the target face", () => {
+    const brush = createBoxBrush({
+      size: {
+        x: 4,
+        y: 2,
+        z: 6
+      }
+    });
+
+    brush.faces.posZ.uv = createFitToFaceBoxBrushFaceUvState(brush, "posZ");
+
+    const geometry = new BoxGeometry(brush.size.x, brush.size.y, brush.size.z);
+    applyBoxBrushFaceUvsToGeometry(geometry, brush);
+
+    const uvAttribute = geometry.getAttribute("uv");
+    const indexAttribute = geometry.getIndex();
+    const posZGroup = geometry.groups.find((group) => group.materialIndex === 4);
+
+    expect(indexAttribute).not.toBeNull();
+    expect(posZGroup).toBeDefined();
+
+    const uniqueVertexIndices = new Set<number>();
+
+    for (let indexOffset = posZGroup!.start; indexOffset < posZGroup!.start + posZGroup!.count; indexOffset += 1) {
+      uniqueVertexIndices.add(indexAttribute!.getX(indexOffset));
+    }
+
+    const uvValues = Array.from(uniqueVertexIndices, (vertexIndex) => ({
+      u: uvAttribute.getX(vertexIndex),
+      v: uvAttribute.getY(vertexIndex)
+    }));
+
+    expect(uvValues).toHaveLength(4);
+    expect(uvValues.every((uv) => Number.isFinite(uv.u) && Number.isFinite(uv.v))).toBe(true);
+    expect(Math.min(...uvValues.map((uv) => uv.u))).toBeCloseTo(0);
+    expect(Math.max(...uvValues.map((uv) => uv.u))).toBeCloseTo(1);
+    expect(Math.min(...uvValues.map((uv) => uv.v))).toBeCloseTo(0);
+    expect(Math.max(...uvValues.map((uv) => uv.v))).toBeCloseTo(1);
+  });
+
+  it("applies rotation, scale, and offset deterministically to projected UVs", () => {
+    const transformedUv = transformProjectedFaceUv(
+      {
+        x: 4,
+        y: 0
+      },
+      {
+        x: 4,
+        y: 2
+      },
+      {
+        offset: {
+          x: 0.5,
+          y: -0.25
+        },
+        scale: {
+          x: 0.5,
+          y: 1
+        },
+        rotationQuarterTurns: 1,
+        flipU: true,
+        flipV: false
+      }
+    );
+
+    expect(transformedUv).toEqual({
+      x: expect.closeTo(1.5),
+      y: expect.closeTo(1.75)
+    });
+  });
+});