Add timeline slider test

ui-tests/tests/timeline-slider.spec.ts

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) Jupyter Development Team.
+ * Distributed under the terms of the Modified BSD License.
+ */
+
+import { expect, test } from '@jupyterlab/galata';
+import { Page } from '@playwright/test';
+
+async function capturePageErrors(page: Page) {
+  const pageErrors: string[] = [];
+  page.on('pageerror', (error) => pageErrors.push(error.message));
+  return pageErrors;
+}
+
+async function openNotebook(page: Page, notebookPath: string) {
+  await page.click('text=File');
+  await page.click('.lm-Menu-itemLabel:text("Open from Path…")');
+  await page.fill(
+    'input[placeholder="/path/relative/to/jlab/root"]',
+    notebookPath
+  );
+  await page.click('.jp-Dialog-buttonLabel:text("Open")');
+  await page.waitForSelector('.jp-Notebook', { state: 'visible' });
+}
+
+test.describe('Open from Path', () => {
+
+  test('should fail if there are console errors', async ({ page, tmpPath }) => {
+    const pageErrors = await capturePageErrors(page);
+
+    await page.notebook.createNew();
+    await page.notebook.save();
+    await page.notebook.close();
+
+    await openNotebook(page, `${tmpPath}/Untitled.ipynb`);
+
+    expect(pageErrors).toHaveLength(0);
+  });
+});