docs(forms): add example apps for ngModelGroup (#11525)

modules/@angular/examples/forms/ts/ngModelGroup/e2e_test/ng_model_group_spec.ts

@@ -0,0 +1,41 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {verifyNoBrowserErrors} from '../../../../_common/e2e_util';
+
+describe('ngModelGroup example', () => {
+  afterEach(verifyNoBrowserErrors);
+  let inputs: ElementFinder;
+  let buttons: ElementFinder;
+
+  beforeEach(() => {
+    browser.get('/forms/ts/ngModelGroup/index.html');
+    inputs = element.all(by.css('input'));
+    buttons = element.all(by.css('button'));
+  });
+
+  it('should populate the UI with initial values', () => {
+    expect(inputs.get(0).getAttribute('value')).toEqual('Nancy');
+    expect(inputs.get(1).getAttribute('value')).toEqual('Drew');
+  });
+
+  it('should show the error when name is invalid', () => {
+    inputs.get(0).click();
+    inputs.get(0).clear();
+    inputs.get(0).sendKeys('a');
+
+    expect(element(by.css('p')).getText()).toEqual('Name is invalid.');
+  });
+
+  it('should set the value when changing the domain model', () => {
+    buttons.get(1).click();
+    expect(inputs.get(0).getAttribute('value')).toEqual('Bess');
+    expect(inputs.get(1).getAttribute('value')).toEqual('Marvin');
+  });
+
+});