docs(aio): add NgModule docs (#20306)

PR Close #20306

aio/content/examples/providers/e2e/app.e2e-spec.ts

@@ -0,0 +1,37 @@
+import { AppPage } from './app.po';
+import { browser, element, by } from 'protractor';
+
+describe('providers App', () => {
+  let page: AppPage;
+
+  beforeEach(() => {
+    page = new AppPage();
+  });
+
+  function getUsersStruct() {
+    return {
+      user: element.all(by.css('ng-component li')).get(0),
+      userId: element.all(by.css('ng-component span')).get(0)
+    };
+  }
+
+  function getListSectionStruct() {
+    return {
+      items: element.all(by.css('app-root li'))
+    };
+  }
+
+  it('should display header that says Users list', () => {
+    page.navigateTo();
+    expect(page.getParagraphText()).toEqual('Users list');
+  });
+
+
+  it('shows a list of customers', function() {
+    const list = getListSectionStruct();
+    expect(list.items.count()).toBe(10);
+    expect(list.items.get(0).getText()).toBe('1 Maria');
+    expect(list.items.get(9).getText()).toBe('10 Seth');
+  });
+
+});