MD Settings: Deflake attempt for CrSettingsPrivacyPageTest.PrivacyPage.

In one of the test cases, showModal() was called after the dialog had already
been removed from the DOM from tearDown().

BUG=642574
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2341493003
Cr-Commit-Position: refs/heads/master@{#418953}

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

@@ -606,20 +606,6 @@ cr.define('settings_about_page', function() {
     }
 
     function registerChannelSwitcherDialogTests() {
-      /**
-       * Converts an event occurrence to a promise.
-       * @param {string} eventType
-       * @param {!HTMLElement} target
-       * @return {!Promise} A promise firing once the event occurs.
-       * TODO(dpapad); Share this code with certificate_manager_page_test.js
-       * identical helper method.
-       */
-      function eventToPromise(eventType, target) {
-        return new Promise(function(resolve, reject) {
-          target.addEventListener(eventType, resolve);
-        });
-      }
-
       suite('ChannelSwitcherDialogTest', function() {
         var dialog = null;
         var radioButtons = null;
@@ -671,7 +657,7 @@ cr.define('settings_about_page', function() {
           assertTrue(dialog.$.changeChannelAndPowerwash.hidden);
           assertFalse(dialog.$.changeChannel.hidden);
 
-          var whenTargetChannelChangedFired = eventToPromise(
+          var whenTargetChannelChangedFired = test_util.eventToPromise(
               'target-channel-changed', dialog);
 
           MockInteractions.tap(dialog.$.changeChannel);
@@ -696,7 +682,7 @@ cr.define('settings_about_page', function() {
           assertFalse(dialog.$.changeChannelAndPowerwash.hidden);
           assertTrue(dialog.$.changeChannel.hidden);
 
-          var whenTargetChannelChangedFired = eventToPromise(
+          var whenTargetChannelChangedFired = test_util.eventToPromise(
               'target-channel-changed', dialog);
 
           MockInteractions.tap(dialog.$.changeChannelAndPowerwash);

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

@@ -182,18 +182,6 @@ cr.define('certificate_manager_page', function() {
     MockInteractions.keyEventOn(element, 'input', kSpaceBar);
   }
 
-  /**
-   * Converts an event occurrence to a promise.
-   * @param {string} eventType
-   * @param {!HTMLElement} target
-   * @return {!Promise} A promise firing once the event occurs.
-   */
-  function eventToPromise(eventType, target) {
-    return new Promise(function(resolve, reject) {
-      target.addEventListener(eventType, resolve);
-    });
-  }
-
   function registerCaTrustEditDialogTests() {
     /** @type {?SettingsCaTrustEditDialogElement} */
     var dialog = null;
@@ -274,7 +262,8 @@ cr.define('certificate_manager_page', function() {
         document.body.appendChild(dialog);
         browserProxy.forceCertificatesError();
 
-        var whenErrorEventFired = eventToPromise('certificates-error', dialog);
+        var whenErrorEventFired =
+            test_util.eventToPromise('certificates-error', dialog);
 
         return browserProxy.whenCalled('getCaCertificateTrust').then(
             function() {
@@ -331,7 +320,8 @@ cr.define('certificate_manager_page', function() {
 
       test('DeleteError', function() {
         browserProxy.forceCertificatesError();
-        var whenErrorEventFired = eventToPromise('certificates-error', dialog);
+        var whenErrorEventFired =
+            test_util.eventToPromise('certificates-error', dialog);
 
         // Simulate clicking 'OK'.
         MockInteractions.tap(dialog.$.ok);
@@ -414,7 +404,8 @@ cr.define('certificate_manager_page', function() {
         confirmPasswordInputElement.value = passwordInputElement.value;
         triggerInputEvent(passwordInputElement);
 
-        var whenErrorEventFired = eventToPromise('certificates-error', dialog);
+        var whenErrorEventFired =
+            test_util.eventToPromise('certificates-error', dialog);
         MockInteractions.tap(dialog.$.ok);
 
         return browserProxy.whenCalled(methodName).then(function() {
@@ -477,7 +468,8 @@ cr.define('certificate_manager_page', function() {
         passwordInputElement.value = 'foopassword';
         triggerInputEvent(passwordInputElement);
 
-        var whenErrorEventFired = eventToPromise('certificates-error', dialog);
+        var whenErrorEventFired =
+            test_util.eventToPromise('certificates-error', dialog);
         MockInteractions.tap(dialog.$.ok);
         return browserProxy.whenCalled(methodName).then(function() {
           return whenErrorEventFired;
@@ -497,7 +489,8 @@ cr.define('certificate_manager_page', function() {
      *     |settings.CertificateActionEvent| fires.
      */
     var actionEventToPromise = function() {
-      return eventToPromise(settings.CertificateActionEvent, subentry);
+      return test_util.eventToPromise(
+          settings.CertificateActionEvent, subentry);
     };
 
     suite('CertificateSubentryTests', function() {
@@ -722,24 +715,10 @@ cr.define('certificate_manager_page', function() {
         var dialog = page.shadowRoot.querySelector(dialogTagName);
         assertTrue(!!dialog);
 
-        if (dialog.$.dialog.open)
-          return Promise.resolve();
-
         // Some dialogs are opened after some async operation to fetch initial
-        // data. Ensure that the underlying cr-dialog is actually opened by
-        // listening for changes for the 'open' attribute.
-        return new Promise(function(resolve, reject) {
-          var observer = new MutationObserver(function(mutations) {
-            assertEquals(1, mutations.length);
-            assertEquals('attributes', mutations[0].type);
-            assertEquals('open', mutations[0].attributeName);
-            observer.disconnect();
-            resolve();
-          });
-          observer.observe(
-              dialog.$.dialog,
-              {attributes: true, childList: false, characterData: false});
-        });
+        // data. Ensure that the underlying cr-dialog is actually opened before
+        // returning.
+        return test_util.whenAttributeIs(dialog.$.dialog, 'open', true);
       }
 
       test('OpensDialog_DeleteConfirmation', function() {
@@ -830,7 +809,7 @@ cr.define('certificate_manager_page', function() {
         assertTrue(!!importButton);
 
         var waitForActionEvent = actionEventExpected ?
-            eventToPromise(settings.CertificateActionEvent, element) :
+            test_util.eventToPromise(settings.CertificateActionEvent, element) :
             Promise.resolve(null);
 
         MockInteractions.tap(importButton);

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

@@ -138,6 +138,7 @@ CrSettingsAboutPageTest.prototype = {
 
   /** @override */
   extraLibraries: CrSettingsBrowserTest.prototype.extraLibraries.concat([
+    'test_util.js',
     'test_browser_proxy.js',
     'test_lifetime_browser_proxy.js',
     'about_page_tests.js',
@@ -438,6 +439,7 @@ CrSettingsCertificateManagerTest.prototype = {
 
   /** @override */
   extraLibraries: CrSettingsBrowserTest.prototype.extraLibraries.concat([
+    'test_util.js',
     'test_browser_proxy.js',
     'certificate_manager_page_test.js',
   ]),
@@ -465,13 +467,13 @@ CrSettingsPrivacyPageTest.prototype = {
   /** @override */
   extraLibraries: CrSettingsBrowserTest.prototype.extraLibraries.concat([
     ROOT_PATH + 'ui/webui/resources/js/promise_resolver.js',
+    'test_util.js',
     'test_browser_proxy.js',
     'privacy_page_test.js',
   ]),
 };
 
-// TODO(crbug.com/642574) Disabled because test is flaky.
-TEST_F('CrSettingsPrivacyPageTest', 'DISABLED_PrivacyPage', function() {
+TEST_F('CrSettingsPrivacyPageTest', 'PrivacyPage', function() {
   settings_privacy_page.registerTests();
   mocha.run();
 });

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

@@ -105,7 +105,14 @@ cr.define('settings_privacy_page', function() {
         assertFalse(!!page.$$('settings-clear-browsing-data-dialog'));
         MockInteractions.tap(page.$.clearBrowsingData);
         Polymer.dom.flush();
-        assertTrue(!!page.$$('settings-clear-browsing-data-dialog'));
+
+        var dialog = page.$$('settings-clear-browsing-data-dialog');
+        assertTrue(!!dialog);
+
+        // Ensure that the dialog is fully opened before returning from this
+        // test, otherwise asynchronous code run in attached() can cause flaky
+        // errors.
+        return test_util.whenAttributeIs(dialog.$.dialog, 'open', true);
       });
     });
   }

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

+// Copyright 2016 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.
+
+cr.define('test_util', function() {
+  /**
+   * Observes an HTML attribute and fires a promise when it matches a given
+   * value.
+   * @param {!HTMLElement} target
+   * @param {string} attributeName
+   * @param {*} attributeValue
+   * @return {!Promise}
+   */
+  function whenAttributeIs(target, attributeName, attributeValue) {
+    function isDone() { return target[attributeName] === attributeValue; }
+
+    return isDone() ? Promise.resolve() : new Promise(function(resolve) {
+      new MutationObserver(function(mutations, observer) {
+        for (var mutation of mutations) {
+          assertEquals('attributes', mutation.type);
+          if (mutation.attributeName == attributeName && isDone()) {
+            observer.disconnect();
+            resolve();
+            return;
+          }
+        }
+      }).observe(
+          target, {attributes: true, childList: false, characterData: false});
+    });
+  }
+
+  /**
+   * Converts an event occurrence to a promise.
+   * @param {string} eventType
+   * @param {!HTMLElement} target
+   * @return {!Promise} A promise firing once the event occurs.
+   */
+  function eventToPromise(eventType, target) {
+    return new Promise(function(resolve, reject) {
+      target.addEventListener(eventType, resolve);
+    });
+  }
+
+  return {
+    eventToPromise: eventToPromise,
+    whenAttributeIs: whenAttributeIs,
+  };
+});