diff --git a/frontend/src/routes/admin/groups/GroupsListPanel.svelte.test.ts b/frontend/src/routes/admin/groups/GroupsListPanel.svelte.test.ts
new file mode 100644
index 00000000..7101b295
--- /dev/null
+++ b/frontend/src/routes/admin/groups/GroupsListPanel.svelte.test.ts
@@ -0,0 +1,109 @@
+import { describe, it, expect, vi, afterEach, beforeEach } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import { page as browserPage } from 'vitest/browser';
+
+const mockPage = { url: new URL('http://localhost/admin/groups') };
+
+vi.mock('$app/state', () => ({
+	get page() {
+		return mockPage;
+	}
+}));
+
+beforeEach(() => {
+	localStorage.clear();
+});
+
+afterEach(cleanup);
+
+async function loadComponent() {
+	return (await import('./GroupsListPanel.svelte')).default;
+}
+
+const baseGroups = [
+	{ id: 'g1', name: 'Familie', permissions: ['READ_ALL'] },
+	{ id: 'g2', name: 'Admins', permissions: ['ADMIN', 'WRITE_ALL'] }
+];
+
+describe('GroupsListPanel', () => {
+	it('renders the expanded list with header by default', async () => {
+		mockPage.url = new URL('http://localhost/admin/groups');
+		const Panel = await loadComponent();
+		render(Panel, { props: { groups: baseGroups } });
+
+		await expect.element(browserPage.getByText('Alle Gruppen')).toBeVisible();
+	});
+
+	it('renders one row per group with permission count', async () => {
+		mockPage.url = new URL('http://localhost/admin/groups');
+		const Panel = await loadComponent();
+		render(Panel, { props: { groups: baseGroups } });
+
+		await expect.element(browserPage.getByText('Familie')).toBeVisible();
+		await expect.element(browserPage.getByText('Admins')).toBeVisible();
+		await expect.element(browserPage.getByText('1 Berechtigungen')).toBeVisible();
+		await expect.element(browserPage.getByText('2 Berechtigungen')).toBeVisible();
+	});
+
+	it('renders the empty placeholder when groups is empty', async () => {
+		mockPage.url = new URL('http://localhost/admin/groups');
+		const Panel = await loadComponent();
+		render(Panel, { props: { groups: [] } });
+
+		await expect.element(browserPage.getByText('Keine Gruppen vorhanden.')).toBeVisible();
+	});
+
+	it('renders the new-group link to /admin/groups/new', async () => {
+		mockPage.url = new URL('http://localhost/admin/groups');
+		const Panel = await loadComponent();
+		render(Panel, { props: { groups: baseGroups } });
+
+		await expect
+			.element(browserPage.getByRole('link', { name: /neue gruppe/i }))
+			.toHaveAttribute('href', '/admin/groups/new');
+	});
+
+	it('marks the active group with aria-current=page', async () => {
+		mockPage.url = new URL('http://localhost/admin/groups/g2');
+		const Panel = await loadComponent();
+		render(Panel, { props: { groups: baseGroups } });
+
+		const links = Array.from(
+			document.querySelectorAll('a[href^="/admin/groups/"]')
+		) as HTMLAnchorElement[];
+		const adminsLink = links.find((a) => a.href.endsWith('/admin/groups/g2'));
+		expect(adminsLink?.getAttribute('aria-current')).toBe('page');
+	});
+
+	it('renders collapsed view when autocollapse is true', async () => {
+		mockPage.url = new URL('http://localhost/admin/groups');
+		const Panel = await loadComponent();
+		render(Panel, { props: { groups: baseGroups, autocollapse: true } });
+
+		await expect
+			.element(browserPage.getByRole('button', { name: /liste ausklappen/i }))
+			.toBeVisible();
+	});
+
+	it('honours the localStorage manual-collapse preference', async () => {
+		localStorage.setItem('admin_groups_list_collapsed', 'true');
+		mockPage.url = new URL('http://localhost/admin/groups');
+		const Panel = await loadComponent();
+		render(Panel, { props: { groups: baseGroups } });
+
+		await expect
+			.element(browserPage.getByRole('button', { name: /liste ausklappen/i }))
+			.toBeVisible();
+	});
+
+	it('expands the panel when the collapsed handle is clicked', async () => {
+		localStorage.setItem('admin_groups_list_collapsed', 'true');
+		mockPage.url = new URL('http://localhost/admin/groups');
+		const Panel = await loadComponent();
+		render(Panel, { props: { groups: baseGroups } });
+
+		await browserPage.getByRole('button', { name: /liste ausklappen/i }).click();
+
+		await expect.element(browserPage.getByText('Alle Gruppen')).toBeVisible();
+	});
+});