Add reference screenshots for the simple notebook

ui-tests/test/general.spec.ts

@@ -0,0 +1,33 @@
+// Copyright (c) Jupyter Development Team.
+// Distributed under the terms of the Modified BSD License.
+
+import path from 'path';
+
+import { expect } from '@playwright/test';
+
+import { test } from './fixtures';
+import { waitForKernelReady } from './utils';
+
+test.describe('General', () => {
+  test('The notebook should render', async ({ page, tmpPath }) => {
+    const notebook = 'simple.ipynb';
+    await page.contents.uploadFile(
+      path.resolve(__dirname, `./notebooks/${notebook}`),
+      `${tmpPath}/${notebook}`
+    );
+    await page.goto(`notebooks/${tmpPath}/${notebook}`);
+
+    // wait for the kernel status animations to be finished
+    await waitForKernelReady(page);
+    await page.waitForSelector(
+      ".jp-Notebook-ExecutionIndicator[data-status='idle']"
+    );
+
+    // force switching back to command mode to avoid capturing the cursor in the screenshot
+    await page.evaluate(async () => {
+      await window.jupyterapp.commands.execute('notebook:enter-command-mode');
+    });
+
+    expect(await page.screenshot()).toMatchSnapshot('notebook.png');
+  });
+});