test(fig): cover derived glyph override patches

tests/engine/io/fig/import/derived-symbol-data.test.ts

@@ -0,0 +1,51 @@
+import { describe, expect, test } from 'bun:test'
+
+import { buildDsdLayoutUpdates } from '#core/kiwi/instance-overrides/derived-symbol-data/layout'
+import type { OverrideContext } from '#core/kiwi/instance-overrides'
+import { SceneGraph } from '#core/scene-graph'
+
+function pageId(graph: SceneGraph): string {
+  return graph.getPages()[0].id
+}
+
+describe('fig import derived symbol data', () => {
+  test('routes derived text glyphs through layout patch updates', () => {
+    const graph = new SceneGraph()
+    const target = graph.createNode('TEXT', pageId(graph), { text: 'Menu Item' })
+    const glyphBlob = new Uint8Array([0])
+    const ctx = {
+      graph,
+      blobs: [glyphBlob]
+    } as OverrideContext
+
+    const { updates } = buildDsdLayoutUpdates(
+      ctx,
+      new Map(),
+      {
+        derivedTextData: {
+          layoutSize: { x: 64, y: 20 },
+          glyphs: [
+            {
+              commandsBlob: 0,
+              position: { x: 4, y: 15 },
+              fontSize: 14,
+              firstCharacter: 0,
+              advance: 1,
+              rotation: 0
+            }
+          ]
+        }
+      },
+      target
+    )
+
+    expect(updates.figmaDerivedTextGlyphs).toEqual([
+      {
+        commandsBlob: glyphBlob,
+        x: 4,
+        y: 15,
+        fontSize: 14
+      }
+    ])
+  })
+})