tests: UI + API smoke tests for chat plugin

Covers the flyout lifecycle (footer button, toggle, header-back
visibility tracking thread/list view), the pick-view detour, DOM
structural invariants (peer strip inside thread view, form/input/send
present) and the three read-only chat endpoints. Send/receive requires
a real relay and is intentionally skipped.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

public/plugins/tests/chat.test.js

@@ -0,0 +1,102 @@
+import { describe, it, expect, click, $, sleep, waitFor } from './runner.js?v=4';
+
+// Chat plugin tests — UI-focused. No send/receive here: that would
+// require a real relay, and the user's "no mocks" rule means we don't
+// fake one. Runs against the real /api/chat endpoints, which respond
+// cleanly on a fresh install (empty conversation list).
+
+const ensureFlyoutClosed = async () => {
+    const f = $('#chat-flyout');
+    if (!f) return;
+    if (!f.classList.contains('hidden')) {
+        click('#chat-close-btn');
+        await waitFor(() => f.classList.contains('hidden'));
+    }
+};
+
+describe('Chat: flyout', () => {
+    it('footer button is injected', () => {
+        expect($('#chat-footer-btn')).toExist();
+    });
+
+    it('toggles open and closed', async () => {
+        await ensureFlyoutClosed();
+        const f = $('#chat-flyout');
+        click('#chat-footer-btn');
+        await waitFor(() => !f.classList.contains('hidden'));
+        expect(f.classList.contains('hidden')).toBe(false);
+        click('#chat-close-btn');
+        await waitFor(() => f.classList.contains('hidden'));
+        expect(f.classList.contains('hidden')).toBe(true);
+    });
+
+    it('header-back visibility matches active view', async () => {
+        await ensureFlyoutClosed();
+        click('#chat-footer-btn');
+        await waitFor(() => !$('#chat-flyout').classList.contains('hidden'));
+        // Wait for loadConversations + initial view pick to settle.
+        await sleep(150);
+        const back = $('#chat-header-back');
+        const threadShown = !$('#chat-thread-view').classList.contains('hidden');
+        const listShown = !$('#chat-list-view').classList.contains('hidden');
+        // Exactly one of thread / list should be active here (pick view
+        // is only reached via the + button).
+        expect(threadShown || listShown).toBe(true);
+        if (threadShown) expect(back.classList.contains('hidden')).toBe(false);
+        if (listShown) expect(back.classList.contains('hidden')).toBe(true);
+        await ensureFlyoutClosed();
+    });
+
+    it('new-conversation button opens pick view', async () => {
+        await ensureFlyoutClosed();
+        click('#chat-footer-btn');
+        await waitFor(() => !$('#chat-flyout').classList.contains('hidden'));
+        await sleep(100);
+        click('#chat-new-btn');
+        await sleep(50);
+        expect($('#chat-pick-view').classList.contains('hidden')).toBe(false);
+        expect($('#chat-list-view').classList.contains('hidden')).toBe(true);
+        expect($('#chat-thread-view').classList.contains('hidden')).toBe(true);
+        // Header back is only for thread view — not needed when pick has
+        // its own dedicated back button.
+        expect($('#chat-header-back').classList.contains('hidden')).toBe(true);
+        click('#chat-pick-back');
+        await sleep(50);
+        expect($('#chat-pick-view').classList.contains('hidden')).toBe(true);
+        await ensureFlyoutClosed();
+    });
+});
+
+describe('Chat: thread DOM structure', () => {
+    it('peer-strip element lives inside thread view', () => {
+        const strip = $('#chat-thread-peers');
+        expect(strip).toExist();
+        expect(strip.closest('#chat-thread-view')).toExist();
+    });
+
+    it('thread form, input and send button exist', () => {
+        expect($('#chat-thread-form')).toExist();
+        expect($('#chat-thread-input')).toExist();
+        expect($('#chat-thread-send')).toExist();
+    });
+});
+
+describe('Chat: API', () => {
+    it('/api/chat/conversations returns expected shape', async () => {
+        const res = await fetch('api/chat/conversations').then(r => r.json());
+        expect(Array.isArray(res.conversations)).toBe(true);
+        expect(typeof res.total_unread).toBe('number');
+    });
+
+    it('/api/chat/messages without peer returns 400', async () => {
+        const r = await fetch('api/chat/messages');
+        expect(r.status).toBe(400);
+    });
+
+    it('/api/chat/messages with unknown peer returns empty array', async () => {
+        const res = await fetch('api/chat/messages?peer=__test_no_such_peer__')
+            .then(r => r.json());
+        expect(Array.isArray(res.messages)).toBe(true);
+        expect(res.messages.length).toBe(0);
+    });
+});

public/plugins/tests/tests.js

@@ -54,6 +54,7 @@ const FILES = [
     './asset-picker.test.js',
     './terminal.test.js',
     './theme.test.js',
+    './chat.test.js',
 ];
 
 // Await all imports so the runner can start in a deterministic state.