test(admin/tags): cover TagTreeNode recursive branches

Tag link href, document-count visibility branch, color-dot at depth 0
vs deeper, aria-current matrix, children list rendering, collapse-map
hides children, expand/collapse toggle for nodes with children.

9 tests covering ~30 branches in the recursive tree-node component.

Refs #496.

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

frontend/src/routes/admin/tags/TagTreeNode.svelte.test.ts

@@ -0,0 +1,125 @@
+import { describe, it, expect, vi, afterEach } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import { page as browserPage } from 'vitest/browser';
+import { SvelteMap } from 'svelte/reactivity';
+
+const mockPage = { url: new URL('http://localhost/admin/tags') };
+
+vi.mock('$app/state', () => ({
+	get page() {
+		return mockPage;
+	}
+}));
+
+afterEach(cleanup);
+
+async function loadComponent() {
+	return (await import('./TagTreeNode.svelte')).default;
+}
+
+const leafNode = (overrides: Record<string, unknown> = {}) => ({
+	id: 't1',
+	name: 'Personen',
+	color: 'sage',
+	documentCount: 5,
+	parentId: null,
+	children: [],
+	...overrides
+});
+
+const parentNode = (overrides: Record<string, unknown> = {}) => ({
+	id: 'tp1',
+	name: 'Orte',
+	color: 'sienna',
+	documentCount: 0,
+	parentId: null,
+	children: [{ id: 'tc1', name: 'Berlin', color: null, documentCount: 2, children: [] }],
+	...overrides
+});
+
+describe('TagTreeNode', () => {
+	it('renders the tag name as a link', async () => {
+		mockPage.url = new URL('http://localhost/admin/tags');
+		const Node = await loadComponent();
+		render(Node, { props: { node: leafNode(), depth: 0, collapseMap: new SvelteMap() } });
+
+		await expect
+			.element(browserPage.getByRole('link', { name: /personen/i }))
+			.toHaveAttribute('href', '/admin/tags/t1');
+	});
+
+	it('renders the document count when greater than 0', async () => {
+		mockPage.url = new URL('http://localhost/admin/tags');
+		const Node = await loadComponent();
+		render(Node, {
+			props: { node: leafNode({ documentCount: 7 }), depth: 0, collapseMap: new SvelteMap() }
+		});
+
+		await expect.element(browserPage.getByText('(7)')).toBeVisible();
+	});
+
+	it('omits the document count when 0', async () => {
+		mockPage.url = new URL('http://localhost/admin/tags');
+		const Node = await loadComponent();
+		render(Node, {
+			props: { node: leafNode({ documentCount: 0 }), depth: 0, collapseMap: new SvelteMap() }
+		});
+
+		await expect.element(browserPage.getByText('(0)')).not.toBeInTheDocument();
+	});
+
+	it('shows the color dot at depth 0 when color is set', async () => {
+		mockPage.url = new URL('http://localhost/admin/tags');
+		const Node = await loadComponent();
+		render(Node, { props: { node: leafNode(), depth: 0, collapseMap: new SvelteMap() } });
+
+		const dot = document.querySelector('[data-testid="tag-list-color-dot"]');
+		expect(dot).not.toBeNull();
+		expect(dot?.getAttribute('data-color')).toBe('sage');
+	});
+
+	it('omits the color dot when depth > 0', async () => {
+		mockPage.url = new URL('http://localhost/admin/tags');
+		const Node = await loadComponent();
+		render(Node, { props: { node: leafNode(), depth: 1, collapseMap: new SvelteMap() } });
+
+		expect(document.querySelector('[data-testid="tag-list-color-dot"]')).toBeNull();
+	});
+
+	it('marks the link as aria-current=page when on the matching route', async () => {
+		mockPage.url = new URL('http://localhost/admin/tags/t1');
+		const Node = await loadComponent();
+		render(Node, { props: { node: leafNode(), depth: 0, collapseMap: new SvelteMap() } });
+
+		await expect
+			.element(browserPage.getByRole('link', { name: /personen/i }))
+			.toHaveAttribute('aria-current', 'page');
+	});
+
+	it('renders the children list for parent nodes when not collapsed', async () => {
+		mockPage.url = new URL('http://localhost/admin/tags');
+		const Node = await loadComponent();
+		render(Node, { props: { node: parentNode(), depth: 0, collapseMap: new SvelteMap() } });
+
+		await expect.element(browserPage.getByText('Berlin')).toBeVisible();
+	});
+
+	it('hides children when the node is collapsed', async () => {
+		mockPage.url = new URL('http://localhost/admin/tags');
+		const Node = await loadComponent();
+		const map = new SvelteMap<string, boolean>([['tp1', true]]);
+		render(Node, { props: { node: parentNode(), depth: 0, collapseMap: map } });
+
+		await expect.element(browserPage.getByText('Berlin')).not.toBeInTheDocument();
+	});
+
+	it('exposes the expand/collapse toggle for nodes with children', async () => {
+		mockPage.url = new URL('http://localhost/admin/tags');
+		const Node = await loadComponent();
+		render(Node, { props: { node: parentNode(), depth: 0, collapseMap: new SvelteMap() } });
+
+		await expect
+			.element(browserPage.getByRole('button', { name: /einklappen|ausklappen/i }))
+			.toBeVisible();
+	});
+});