feat: add reasoning tests (#856)

tests/reasoning.setup.ts

@@ -0,0 +1,20 @@
+import path from 'path';
+import { expect, test as setup } from '@playwright/test';
+import { ChatPage } from './pages/chat';
+
+const reasoningFile = path.join(
+  __dirname,
+  '../playwright/.reasoning/session.json',
+);
+
+setup('switch to reasoning model', async ({ page }) => {
+  const chatPage = new ChatPage(page);
+  await chatPage.createNewChat();
+
+  await chatPage.chooseModelFromSelector('chat-model-reasoning');
+
+  await expect(chatPage.getSelectedModel()).resolves.toEqual('Reasoning model');
+
+  await page.waitForTimeout(1000);
+  await page.context().storageState({ path: reasoningFile });
+});