docs: fix testing example (#31120)

PR Close #31120

aio/content/examples/testing/e2e/src/app.e2e-spec.ts

@@ -0,0 +1,35 @@
+'use strict'; // necessary for es6 output in node
+
+import { browser, element, by, ElementFinder } from 'protractor';
+
+describe('Testing Example', () => {
+  const expectedViewNames = ['Dashboard', 'Heroes', 'About'];
+
+  beforeAll(() => browser.get(''));
+
+  function getPageElts() {
+    let navElts = element.all(by.css('app-root nav a'));
+
+    return {
+      navElts: navElts,
+
+      appDashboard: element(by.css('app-root app-dashboard')),
+    };
+  }
+
+  it('has title', async() => {
+    expect(await browser.getTitle()).toEqual('App Under Test');
+  });
+
+  it(`has views ${expectedViewNames}`, async () => {
+    let viewNames = getPageElts().navElts.map(async(el: ElementFinder) => await el.getText());
+
+    expect(viewNames).toEqual(expectedViewNames);
+  });
+
+  it('has dashboard as the active view', () => {
+    let page = getPageElts();
+
+    expect(page.appDashboard.isPresent()).toBeTruthy();
+  });
+});