test(platform-server): add initial e2e tests for platform-server (#15061)

packages/platform-server/integrationtest/e2e/helloworld-spec.ts

@@ -0,0 +1,38 @@
+/**
+ * @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 {browser, by, element} from 'protractor';
+
+import {verifyNoBrowserErrors} from './util';
+
+describe('Hello world E2E Tests', function() {
+  it('should display: Hello world!', function() {
+    // Load the page without waiting for Angular since it is not boostrapped automatically.
+    browser.driver.get(browser.baseUrl + 'helloworld');
+
+    const style = browser.driver.findElement(by.css('style[ng-transition="hlw"]'));
+    expect(style.getText()).not.toBeNull();
+
+    // Test the contents from the server.
+    const serverDiv = browser.driver.findElement(by.css('div'));
+    expect(serverDiv.getText()).toEqual('Hello world!');
+
+    // Bootstrap the client side app.
+    browser.executeScript('doBootstrap()');
+
+    // Retest the contents after the client bootstraps.
+    expect(element(by.css('div')).getText()).toEqual('Hello world!');
+
+    // Make sure the server styles got replaced by client side ones.
+    expect(element(by.css('style[ng-transition="hlw"]')).isPresent()).toBe(false);
+    expect(element(by.css('style')).getText()).toBe('');
+
+    // Make sure there were no client side errors.
+    verifyNoBrowserErrors();
+  });
+});