Add resizable panes with drag handles, min widths, and persistence

src/app/infrastructure/ux-prefs.test.ts

@@ -0,0 +1,63 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { loadPanelLayout, savePanelLayout } from './ux-prefs';
+
+const KEY = 'astrolabe:ux-prefs';
+
+/** In-memory localStorage stub (Node's global one is non-functional). */
+function makeStorageStub() {
+  const map = new Map<string, string>();
+  return {
+    getItem: (k: string) => (map.has(k) ? map.get(k)! : null),
+    setItem: (k: string, v: string) => void map.set(k, String(v)),
+    removeItem: (k: string) => void map.delete(k),
+    clear: () => map.clear(),
+    key: (i: number) => [...map.keys()][i] ?? null,
+    get length() {
+      return map.size;
+    },
+  };
+}
+
+describe('ux-prefs · panelLayout', () => {
+  beforeEach(() => vi.stubGlobal('localStorage', makeStorageStub()));
+  afterEach(() => vi.unstubAllGlobals());
+
+  it('returns empty widths when nothing is stored', () => {
+    expect(loadPanelLayout()).toEqual({ libraryWidth: undefined, previewWidth: undefined });
+  });
+
+  it('round-trips stored widths', () => {
+    savePanelLayout({ libraryWidth: 300, previewWidth: 420 });
+    expect(loadPanelLayout()).toEqual({ libraryWidth: 300, previewWidth: 420 });
+  });
+
+  it('merges partial writes without dropping the other width', () => {
+    savePanelLayout({ libraryWidth: 300, previewWidth: 420 });
+    savePanelLayout({ libraryWidth: 250 });
+    expect(loadPanelLayout()).toEqual({ libraryWidth: 250, previewWidth: 420 });
+  });
+
+  it('rejects non-positive / non-finite junk', () => {
+    localStorage.setItem(
+      KEY,
+      JSON.stringify({ panelLayout: { libraryWidth: -5, previewWidth: 'wide' } }),
+    );
+    expect(loadPanelLayout()).toEqual({ libraryWidth: undefined, previewWidth: undefined });
+  });
+
+  it('tolerates malformed JSON', () => {
+    localStorage.setItem(KEY, '{ not json');
+    expect(loadPanelLayout()).toEqual({ libraryWidth: undefined, previewWidth: undefined });
+  });
+
+  it('preserves unrelated keys in the record (forward-compatible merge)', () => {
+    localStorage.setItem(KEY, JSON.stringify({ sort: { sortBy: 'name', sortOrder: 'asc' } }));
+    savePanelLayout({ libraryWidth: 260 });
+    const stored = JSON.parse(localStorage.getItem(KEY)!) as {
+      sort: { sortBy: string };
+      panelLayout: { libraryWidth: number };
+    };
+    expect(stored.sort.sortBy).toBe('name');
+    expect(stored.panelLayout.libraryWidth).toBe(260);
+  });
+});