refactor: separate application UI state owners

src/testSupport/readShellSource.mjs

@@ -0,0 +1,39 @@
+import { readFileSync } from 'node:fs';
+import { StyleManager } from '../ui/applicationShell.js';
+import { NavigationController } from '../ui/navigationController.js';
+import { ShareRestoration } from '../ui/shareRestoration.js';
+import { VisualSettings } from '../ui/visualSettings.js';
+import { PanelChrome } from '../ui/panelChrome.js';
+
+/** Read the state owners as well as the compatibility/composition facade. */
+export function readShellSource() {
+  return [
+    'navigationController',
+    'shareRestoration',
+    'visualSettings',
+    'panelChrome',
+    'applicationShell',
+  ]
+    .map((name) =>
+      readFileSync(new URL(`../ui/${name}.js`, import.meta.url), 'utf8'),
+    )
+    .join('\n');
+}
+
+/** Select the implementation owner instead of testing a forwarding facade. */
+export function shellMethod(name) {
+  for (const owner of [
+    NavigationController,
+    ShareRestoration,
+    VisualSettings,
+    PanelChrome,
+    StyleManager,
+  ]) {
+    const method = Object.getOwnPropertyDescriptor(
+      owner.prototype,
+      name,
+    )?.value;
+    if (typeof method === 'function') return method;
+  }
+  return null;
+}