Fix Print Preview failure state and add test

chrome/test/data/webui/print_preview.js

 // Copyright (c) 2012 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.
 
 GEN('#include "base/feature_list.h"');
 GEN('#include "chrome/common/chrome_features.h"');
 
 /**
  * Test fixture for print preview WebUI testing.
  * @constructor
  * @extends {testing.Test}
  */
 function PrintPreviewWebUITest() {
   testing.Test.call(this);
   this.nativeLayer_ = null;
   this.initialSettings_ = null;
   this.localDestinationInfos_ = null;
+  this.previewArea_ = null;
 }
 
 /**
  * Index of the "Save as PDF" printer.
  * @type {number}
  * @const
  */
 PrintPreviewWebUITest.PDF_INDEX = 0;
 
 /**
@@ skipping 47 matching lines @@
   /**
    * Stub out low-level functionality like the NativeLayer and
    * CloudPrintInterface.
    * @this {PrintPreviewWebUITest}
    * @override
    */
   preLoad: function() {
     window.addEventListener('DOMContentLoaded', function() {
       function NativeLayerStub() {
         cr.EventTarget.call(this);
+        this.printStarted_ = false;
       }
       NativeLayerStub.prototype = {
         __proto__: cr.EventTarget.prototype,
+        isPrintStarted: function() { return this.printStarted_; },
+        previewReadyForTest: function() {},
         startGetInitialSettings: function() {},
         startGetLocalDestinations: function() {},
         startGetPrivetDestinations: function() {},
         startGetExtensionDestinations: function() {},
         startGetLocalDestinationCapabilities: function(destinationId) {},
         startGetPreview: function() {},
+        startHideDialog: function () {},
+        startPrint: function () { this.printStarted_ = true; }
       };
       var oldNativeLayerEventType = print_preview.NativeLayer.EventType;
       var oldDuplexMode = print_preview.NativeLayer.DuplexMode;
       print_preview.NativeLayer = NativeLayerStub;
       print_preview.NativeLayer.EventType = oldNativeLayerEventType;
       print_preview.NativeLayer.DuplexMode = oldDuplexMode;
 
       function CloudPrintInterfaceStub() {
         cr.EventTarget.call(this);
       }
@@ skipping 40 matching lines @@
    * @device - The device whose capabilities should be dispatched.
    */
   setCapabilities: function(device) {
     var capsSetEvent =
         new Event(print_preview.NativeLayer.EventType.CAPABILITIES_SET);
     capsSetEvent.settingsInfo = device;
     this.nativeLayer_.dispatchEvent(capsSetEvent);
   },
 
   /**
+   * Dispatch the PREVIEW_GENERATION_DONE event. This call is NOT async and
+   * will happen in the same thread.
+   */
+  dispatchPreviewDone: function() {
+    var previewDoneEvent =
+        new Event(print_preview.PreviewArea.EventType.PREVIEW_GENERATION_DONE);
+    this.previewArea_.dispatchEvent(previewDoneEvent);
+  },
+
+  /**
+   * Dispatch the SETTINGS_INVALID event. This call is NOT async and will
+   * happen in the same thread.
+   */
+  dispatchInvalidSettings: function() {
+    var invalidSettingsEvent =
+        new Event(print_preview.NativeLayer.EventType.SETTINGS_INVALID);
+    this.nativeLayer_.dispatchEvent(invalidSettingsEvent);
+  },
+
+  /**
+   * @return {boolean} Whether the UI has/has not "printed" (called startPrint
+   *     on the native layer).
+   **/

[dpapad, 2017/04/29 01:20:20]

Extra asterisk.
*/

[rbpotter, 2017/04/29 01:32:47]

Done.

+  hasPrinted: function() {
+    return this.nativeLayer_.isPrintStarted();
+  },
+
+  /**
    * Even though animation duration and delay is set to zero, it is necessary to
    * wait until the animation has finished.
    */
   waitForAnimationToEnd: function(elementId) {
     // add a listener for the animation end event
     document.addEventListener('animationend', function f(e) {
       if (e.target.id == elementId) {
         document.removeEventListener(f, 'animationend');
         testDone();
       }
@@ skipping 52 matching lines @@
       true /*documentHasSelection*/,
       false /*selectionOnly*/,
       'FooDevice' /*systemDefaultDestinationId*/,
       null /*serializedAppStateStr*/,
       null /*serializedDefaultDestinationSelectionRulesStr*/);
     this.localDestinationInfos_ = [
       { printerName: 'FooName', deviceName: 'FooDevice' },
       { printerName: 'BarName', deviceName: 'BarDevice' }
     ];
     this.nativeLayer_ = printPreview.nativeLayer_;
+    this.previewArea_ = printPreview.previewArea_;
 
     testing.Test.disableAnimationsAndTransitions();
 
     // Enable when failure is resolved.
     // AX_TEXT_03: http://crbug.com/559209
     this.accessibilityAuditConfig.ignoreSelectors(
         'multipleLabelableElementsPerLabel',
         '#page-settings > .right-column > *');
   }
 };
@@ skipping 1113 matching lines @@
   // increments by 1 for each startGetPreview call it makes. It should only
   // make one such call during initialization or there will be a race; see
   // crbug.com/666595
   expectEquals(printPreview.previewArea_.previewGenerator_.inFlightRequestId_,
     -1);
   this.setInitialSettings();
   expectEquals(printPreview.previewArea_.previewGenerator_.inFlightRequestId_,
     0);
   testDone();
 });
+
+// Test that invalid settings errors disable the print preview and display
+// an error and that the preview dialog can be recovered by selecting a
+// new destination.
+TEST_F('PrintPreviewWebUITest', 'TestInvalidSettingsError', function() {
+  // Setup
+  this.setInitialSettings();
+  this.setLocalDestinations();
+  this.setCapabilities(getCddTemplate("FooDevice"));
+
+  // Manually enable the print header. This is needed since there is no
+  // plugin during test, so it will be set as disabled normally.
+  printPreview.printHeader_.isEnabled = true;
+
+  // There will be an error message in the preview area since the plugin is
+  // not running. However, it should not be the invalid settings error.
+  var previewAreaEl = $('preview-area');
+  var customMessageEl =
+      previewAreaEl.getElementsByClassName('preview-area-custom-message')[0];
+  expectFalse(customMessageEl.hidden);
+  var expectedMessageStart = 'The selected printer is not available or not ' +
+      'installed correctly.'
+  expectEquals(-1, customMessageEl.textContent.search(expectedMessageStart));

[dpapad, 2017/04/29 01:20:20]

Nit: Use includes() instead,
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Obje....

[rbpotter, 2017/04/29 01:32:47]

Done.

+
+  // Verify that the print button is enabled.
+  var printHeader = $('print-header');
+  var printButton = printHeader.querySelector('button.print');
+  checkElementDisplayed(printButton, true);
+  expectFalse(printButton.disabled);
+
+  // Report invalid settings error.
+  this.dispatchInvalidSettings();
+
+  // Should be in an error state, print button disabled, invalid custom error
+  // message shown.
+  expectFalse(customMessageEl.hidden);
+  expectTrue(customMessageEl.textContent.search(expectedMessageStart) > -1);
+  expectTrue(printButton.disabled);
+
+  // Select a new destination
+  var barDestination;

[dpapad, 2017/04/29 01:20:20]

var barDestination =
printPreview.destinationStore_.destinations().find(function(d) {
  return d.id == 'BarDevice';
});

[rbpotter, 2017/04/29 01:32:47]

Done.

+  var destinations = printPreview.destinationStore_.destinations();
+  for (var destination, i = 0; destination = destinations[i]; i++) {
+    if (destination.id == 'BarDevice') {
+      barDestination = destination;
+      break;
+    }
+  }
+  printPreview.destinationStore_.selectDestination(barDestination);
+
+  // Dispatch events indicating capabilities were fetched and new preview has
+  // loaded

[dpapad, 2017/04/29 01:20:20]

Per styleguide, full sentence comments should finish with a period.

[rbpotter, 2017/04/29 01:32:47]

Done.

+  this.setCapabilities(getCddTemplate("BarDevice"));
+  this.dispatchPreviewDone();
+
+  // Has active print button and successfully "prints", indicating recovery
+  // from error state.
+  expectFalse(printButton.disabled);
+  expectFalse(this.hasPrinted());
+  printButton.click();
+  expectTrue(this.hasPrinted());
+  testDone();
+});