Add Mocha based tests for Settings pages

chrome/test/data/webui/settings/settings_page_browsertest.js

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/** @fileoverview Prototype for Settings page tests. */
+
+/** @const {string} Path to root from chrome/test/data/webui/settings/. */
+var ROOT_PATH = '../../../../../';
+
+// Polymer BrowserTest fixture.
+GEN_INCLUDE(
+    [ROOT_PATH + 'chrome/test/data/webui/polymer_browser_test_base.js']);
+
+/**
+ * @constructor
+ * @extends {PolymerTest}
+*/
+function SettingsPageBrowserTest() {}
+
+SettingsPageBrowserTest.prototype = {
+  __proto__: PolymerTest.prototype,
+
+  /** @override */
+  browsePreload: 'chrome://md-settings/',
+
+  /** @override */
+  extraLibraries: PolymerTest.getLibraries(ROOT_PATH),
+
+  runAccessibilityChecks: false,
+
+  getPage: function(type) {

[dpapad, 2015/11/18 01:44:54]

Can we add type annotations for all parameters and return types (@param
{string})?

[stevenjb, 2015/11/18 20:02:33]

Done.

+    var settings = document.querySelector('cr-settings');
+    assertTrue(!!settings);

[dpapad, 2015/11/18 01:44:54]

How about
assertNotNull(settings);

[stevenjb, 2015/11/18 20:02:33]

ReferenceError: assertNotNull is not defined

I don't think we have this in Chrome.

+    var settingsUi = settings.shadowRoot.querySelector('settings-ui');
+    assertTrue(!!settingsUi);
+    var settingsMain = settingsUi.shadowRoot.querySelector('settings-main');
+    assertTrue(!!settingsMain);
+    var pages = settingsMain.$.pageContainer;
+    assertTrue(!!pages);
+    var pageType = 'settings-' + type + '-page';

[dpapad, 2015/11/18 01:44:54]

@dbeam
Can we start using relatively new v8 feature as follows?

var pageType = `settings-${type}-page`;

+    var page = pages.querySelector(pageType);
+    assertTrue(!!page);
+    return page;
+  },
+
+  getSection: function(page, section) {
+    var sections = page.shadowRoot.querySelectorAll('settings-section');
+    assertTrue(!!sections);
+    var len = sections.length;
+    assertGT(len, 0);
+    for (var i = 0; i < len; ++i) {
+      var s = sections[i];
+      if (s.section == section)
+      return s;
+    }
+    assertNotReached('Section not found: ' + section + ' in ' + page);
+    return undefined;
+  },
+};