test(notification): cover NotificationDropdown branches

Dialog with bell label, empty state vs populated list, mark-all-read
visibility branch, REPLY vs MENTION text, unread-dot rendering, all
three callback wirings (onMarkRead, onMarkAllRead, onClose).

10 tests covering the notification dropdown surface.

Refs #496.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/lib/notification/NotificationDropdown.svelte.test.ts

@@ -0,0 +1,171 @@
+import { describe, it, expect, vi, afterEach } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import { page } from 'vitest/browser';
+import NotificationDropdown from './NotificationDropdown.svelte';
+
+afterEach(cleanup);
+
+const makeNotification = (overrides: Record<string, unknown> = {}) => ({
+	id: 'n1',
+	type: 'REPLY' as 'REPLY' | 'MENTION',
+	documentId: 'd1',
+	documentTitle: 'Brief',
+	referenceId: 'c1',
+	annotationId: null,
+	read: false,
+	createdAt: new Date().toISOString(),
+	actorName: 'Anna Schmidt',
+	...overrides
+});
+
+describe('NotificationDropdown', () => {
+	it('renders the dialog with the bell label', async () => {
+		render(NotificationDropdown, {
+			props: {
+				notifications: [],
+				onMarkRead: () => {},
+				onMarkAllRead: () => {},
+				onClose: () => {}
+			}
+		});
+
+		await expect.element(page.getByRole('dialog', { name: /benachrichtigungen/i })).toBeVisible();
+	});
+
+	it('renders the empty state when there are no notifications', async () => {
+		render(NotificationDropdown, {
+			props: {
+				notifications: [],
+				onMarkRead: () => {},
+				onMarkAllRead: () => {},
+				onClose: () => {}
+			}
+		});
+
+		await expect.element(page.getByText('Keine neuen Benachrichtigungen')).toBeVisible();
+	});
+
+	it('hides the mark-all-read action when the list is empty', async () => {
+		render(NotificationDropdown, {
+			props: {
+				notifications: [],
+				onMarkRead: () => {},
+				onMarkAllRead: () => {},
+				onClose: () => {}
+			}
+		});
+
+		await expect
+			.element(page.getByRole('button', { name: /alle gelesen/i }))
+			.not.toBeInTheDocument();
+	});
+
+	it('renders the mark-all-read action when notifications are present', async () => {
+		render(NotificationDropdown, {
+			props: {
+				notifications: [makeNotification()],
+				onMarkRead: () => {},
+				onMarkAllRead: () => {},
+				onClose: () => {}
+			}
+		});
+
+		await expect.element(page.getByRole('button', { name: /alle gelesen/i })).toBeVisible();
+	});
+
+	it('renders one item per notification with the reply text for REPLY type', async () => {
+		render(NotificationDropdown, {
+			props: {
+				notifications: [makeNotification({ type: 'REPLY', actorName: 'Bert' })],
+				onMarkRead: () => {},
+				onMarkAllRead: () => {},
+				onClose: () => {}
+			}
+		});
+
+		await expect
+			.element(page.getByText(/Bert hat auf deinen Kommentar geantwortet/i))
+			.toBeVisible();
+	});
+
+	it('renders the mention text for MENTION type', async () => {
+		render(NotificationDropdown, {
+			props: {
+				notifications: [makeNotification({ type: 'MENTION', actorName: 'Clara' })],
+				onMarkRead: () => {},
+				onMarkAllRead: () => {},
+				onClose: () => {}
+			}
+		});
+
+		await expect
+			.element(page.getByText(/Clara hat dich in einem Kommentar erwähnt/i))
+			.toBeVisible();
+	});
+
+	it('renders the unread dot only for unread notifications', async () => {
+		render(NotificationDropdown, {
+			props: {
+				notifications: [
+					makeNotification({ id: 'n1', read: false }),
+					makeNotification({ id: 'n2', read: true })
+				],
+				onMarkRead: () => {},
+				onMarkAllRead: () => {},
+				onClose: () => {}
+			}
+		});
+
+		const unreadDots = document.querySelectorAll('[aria-label="ungelesen"]');
+		expect(unreadDots.length).toBe(1);
+	});
+
+	it('calls onMarkRead with the notification when an item is clicked', async () => {
+		const onMarkRead = vi.fn();
+		const n = makeNotification({ id: 'n42', actorName: 'Anna' });
+		render(NotificationDropdown, {
+			props: {
+				notifications: [n],
+				onMarkRead,
+				onMarkAllRead: () => {},
+				onClose: () => {}
+			}
+		});
+
+		await page.getByRole('button', { name: /Anna hat auf deinen/i }).click();
+
+		expect(onMarkRead).toHaveBeenCalledWith(n);
+	});
+
+	it('calls onMarkAllRead when the mark-all-read button is clicked', async () => {
+		const onMarkAllRead = vi.fn();
+		render(NotificationDropdown, {
+			props: {
+				notifications: [makeNotification()],
+				onMarkRead: () => {},
+				onMarkAllRead,
+				onClose: () => {}
+			}
+		});
+
+		await page.getByRole('button', { name: /alle gelesen/i }).click();
+
+		expect(onMarkAllRead).toHaveBeenCalledOnce();
+	});
+
+	it('calls onClose when the view-all link is clicked', async () => {
+		const onClose = vi.fn();
+		render(NotificationDropdown, {
+			props: {
+				notifications: [],
+				onMarkRead: () => {},
+				onMarkAllRead: () => {},
+				onClose
+			}
+		});
+
+		await page.getByRole('link').click();
+
+		expect(onClose).toHaveBeenCalledOnce();
+	});
+});