test(admin/groups): cover the group-edit page branches

Heading, name hydration, per-permission checkbox checked-state matrix,
success/error banner branches, cancel link, delete + save buttons.
Mocks confirm service.

7 tests, ~30 branches.

Refs #496.

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

frontend/src/routes/admin/groups/[id]/page.svelte.test.ts

@@ -0,0 +1,90 @@
+import { describe, it, expect, vi, afterEach } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import { page } from 'vitest/browser';
+
+vi.mock('$lib/shared/services/confirm.svelte.js', () => ({
+	getConfirmService: () => ({ confirm: async () => false })
+}));
+
+const { default: AdminGroupEditPage } = await import('./+page.svelte');
+
+afterEach(cleanup);
+
+const baseGroup = (overrides: Record<string, unknown> = {}) => ({
+	id: 'g1',
+	name: 'Familie',
+	permissions: ['READ_ALL'] as string[],
+	...overrides
+});
+
+describe('admin/groups/[id] page', () => {
+	it('renders the edit heading with the group name', async () => {
+		render(AdminGroupEditPage, { props: { data: { group: baseGroup() }, form: undefined } });
+
+		await expect.element(page.getByRole('heading', { name: /familie/i })).toBeVisible();
+	});
+
+	it('hydrates the name input from data.group.name', async () => {
+		render(AdminGroupEditPage, {
+			props: { data: { group: baseGroup({ name: 'Admins' }) }, form: undefined }
+		});
+
+		const input = document.querySelector('input[name="name"]') as HTMLInputElement;
+		expect(input.value).toBe('Admins');
+	});
+
+	it('checks the permission checkboxes that are in data.group.permissions', async () => {
+		render(AdminGroupEditPage, {
+			props: {
+				data: { group: baseGroup({ permissions: ['READ_ALL', 'ADMIN_TAG'] }) },
+				form: undefined
+			}
+		});
+
+		const readAll = document.querySelector(
+			'input[name="permissions"][value="READ_ALL"]'
+		) as HTMLInputElement;
+		const adminTag = document.querySelector(
+			'input[name="permissions"][value="ADMIN_TAG"]'
+		) as HTMLInputElement;
+		const writeAll = document.querySelector(
+			'input[name="permissions"][value="WRITE_ALL"]'
+		) as HTMLInputElement;
+		expect(readAll.checked).toBe(true);
+		expect(adminTag.checked).toBe(true);
+		expect(writeAll.checked).toBe(false);
+	});
+
+	it('shows the success banner when form.success is true', async () => {
+		render(AdminGroupEditPage, {
+			props: { data: { group: baseGroup() }, form: { success: true } }
+		});
+
+		await expect.element(page.getByText('Gruppe gespeichert.')).toBeVisible();
+	});
+
+	it('shows the error banner when form.error is set', async () => {
+		render(AdminGroupEditPage, {
+			props: {
+				data: { group: baseGroup() },
+				form: { error: 'Name darf nicht leer sein.' }
+			}
+		});
+
+		await expect.element(page.getByText('Name darf nicht leer sein.')).toBeVisible();
+	});
+
+	it('renders the cancel link to /admin/groups', async () => {
+		render(AdminGroupEditPage, { props: { data: { group: baseGroup() }, form: undefined } });
+
+		const links = document.querySelectorAll('a[href="/admin/groups"]');
+		expect(links.length).toBeGreaterThan(0);
+	});
+
+	it('renders the delete and save buttons', async () => {
+		render(AdminGroupEditPage, { props: { data: { group: baseGroup() }, form: undefined } });
+
+		await expect.element(page.getByRole('button', { name: /löschen/i })).toBeVisible();
+		await expect.element(page.getByRole('button', { name: /speichern/i })).toBeVisible();
+	});
+});