test(260928-ujj): rote Tests fuer Dashboard-Hintergrund in der Datenbank

- PATCH me/dashboard-background: Allowlist, UUID-Bildkennung, Mandantenbindung
- getMe liefert dashboardBackground normalisiert
- Web: Uebernahme der alten localStorage-Wahl, Hook liest aus dem Auth-Store

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

apps/web/src/lib/dashboard-background.test.ts

@@ -1,48 +1,72 @@
+import { DASHBOARD_BACKGROUND_PRESET_IDS } from '@tessera/shared';
 import { afterEach, describe, expect, it, vi } from 'vitest';
 import {
   BACKGROUND_PRESETS,
   DARK_FALLBACK_ID,
-  loadDashboardBackground,
   presetBackground,
-  saveDashboardBackground,
+  takeLegacyDashboardBackground,
 } from './dashboard-background';
 
+const IMAGE_ID = '3f2b8c1e-9a4d-4e7f-8b21-0c5d6e7f8a9b';
+
 afterEach(() => {
   window.localStorage.clear();
   vi.restoreAllMocks();
 });
 
-describe('dashboard-background (Design „Mosaik“, Prototyp)', () => {
-  it('ohne gespeicherte Wahl: kein Hintergrund', () => {
-    expect(loadDashboardBackground('u1')).toEqual({ kind: 'none' });
-  });
-
-  it('speichert je Benutzer getrennt', () => {
-    saveDashboardBackground('u1', { kind: 'preset', id: 'bloom' });
-    saveDashboardBackground('u2', { kind: 'image', imageId: 'img-1' });
-    expect(loadDashboardBackground('u1')).toEqual({ kind: 'preset', id: 'bloom' });
-    expect(loadDashboardBackground('u2')).toEqual({ kind: 'image', imageId: 'img-1' });
-  });
-
-  it('verwirft kaputte oder unbekannte Werte', () => {
-    window.localStorage.setItem('tessera.dashboardBackground.u1', '{kaputt');
-    expect(loadDashboardBackground('u1')).toEqual({ kind: 'none' });
-    window.localStorage.setItem(
-      'tessera.dashboardBackground.u1',
-      JSON.stringify({ kind: 'preset', id: 'regenbogen' }),
-    );
-    expect(loadDashboardBackground('u1')).toEqual({ kind: 'none' });
-  });
-
-  it('gesperrter Speicher wirft nicht', () => {
-    vi.spyOn(Storage.prototype, 'getItem').mockImplementation(() => {
-      throw new Error('blocked');
+describe('dashboard-background (Design „Mosaik“)', () => {
+  describe('takeLegacyDashboardBackground (quick-260928-ujj)', () => {
+    it('ohne alte Wahl: null', () => {
+      expect(takeLegacyDashboardBackground('u1')).toBeNull();
     });
-    vi.spyOn(Storage.prototype, 'setItem').mockImplementation(() => {
-      throw new Error('blocked');
+
+    it('liefert eine gueltige alte Wahl je Benutzer und entfernt den Schluessel', () => {
+      window.localStorage.setItem(
+        'tessera.dashboardBackground.u1',
+        JSON.stringify({ kind: 'preset', id: 'bloom' }),
+      );
+      window.localStorage.setItem(
+        'tessera.dashboardBackground.u2',
+        JSON.stringify({ kind: 'image', imageId: IMAGE_ID }),
+      );
+
+      expect(takeLegacyDashboardBackground('u1')).toEqual({ kind: 'preset', id: 'bloom' });
+      expect(window.localStorage.getItem('tessera.dashboardBackground.u1')).toBeNull();
+      // der Schluessel des anderen Benutzers bleibt, bis dieser sich anmeldet
+      expect(window.localStorage.getItem('tessera.dashboardBackground.u2')).not.toBeNull();
+      expect(takeLegacyDashboardBackground('u2')).toEqual({ kind: 'image', imageId: IMAGE_ID });
+      // zweiter Aufruf: nichts mehr da
+      expect(takeLegacyDashboardBackground('u1')).toBeNull();
     });
-    expect(() => saveDashboardBackground('u1', { kind: 'preset', id: 'mist' })).not.toThrow();
-    expect(loadDashboardBackground('u1')).toEqual({ kind: 'none' });
+
+    it.each([
+      ['{kaputt'],
+      [JSON.stringify({ kind: 'preset', id: 'regenbogen' })],
+      // Prototyp-Werte mit beliebiger Bildkennung werden nicht uebernommen
+      [JSON.stringify({ kind: 'image', imageId: 'img-1' })],
+      [JSON.stringify(null)],
+    ])('ungueltiger Wert %j: null, Schluessel entfernt', (raw) => {
+      window.localStorage.setItem('tessera.dashboardBackground.u1', raw);
+
+      expect(takeLegacyDashboardBackground('u1')).toBeNull();
+      expect(window.localStorage.getItem('tessera.dashboardBackground.u1')).toBeNull();
+    });
+
+    it('gesperrter Speicher: null ohne Ausnahme', () => {
+      vi.spyOn(Storage.prototype, 'getItem').mockImplementation(() => {
+        throw new Error('blocked');
+      });
+      vi.spyOn(Storage.prototype, 'removeItem').mockImplementation(() => {
+        throw new Error('blocked');
+      });
+
+      expect(() => takeLegacyDashboardBackground('u1')).not.toThrow();
+      expect(takeLegacyDashboardBackground('u1')).toBeNull();
+    });
+  });
+
+  it('die eingebauten Hintergruende sind deckungsgleich mit der Pruefregel in @tessera/shared', () => {
+    expect(BACKGROUND_PRESETS.map((p) => p.id).sort()).toEqual([...DASHBOARD_BACKGROUND_PRESET_IDS].sort());
   });
 
   it('jeder eingebaute Hintergrund liefert hell und dunkel ein Bild (dunkel notfalls den Ersatz)', () => {