WebUI: Allow rejecting a promise that is returned from cr.sendWithPromise().

chrome/test/data/webui/webui_resource_async_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 Framework for running async JS tests for cr.js utility methods.
  */
 
 /** @const {string} Path to source root. */
 var ROOT_PATH = '../../../../';
@@ skipping 17 matching lines @@
   /** @override */
   isAsync: true,
 
   /** @override */
   runAccessibilityChecks: false,
 
   /** @override */
   extraLibraries: [
     ROOT_PATH + 'third_party/mocha/mocha.js',
     ROOT_PATH + 'chrome/test/data/webui/mocha_adapter.js',
-    ROOT_PATH + 'chrome/test/data/webui/promise_resolver.js',
+    ROOT_PATH + 'ui/webui/resources/js/promise_resolver.js',
     ROOT_PATH + 'ui/webui/resources/js/cr.js',
   ],
 };
 
 TEST_F('WebUIResourceAsyncTest', 'SendWithPromise', function() {
   /**
    * TODO(dpapad): Move this helper method in test_api.js.
    * @param {string} name chrome.send message name.
    * @return {!Promise} Fires when chrome.send is called with the given message
    *     name.
    */
   function whenChromeSendCalled(name) {
     return new Promise(function(resolve, reject) {
       registerMessageCallback(name, null, resolve);
     });
   }
 
   suite('SendWithPromise', function() {
+    var rejectPromises = false;
+
     setup(function() {
       // Simulate a WebUI handler that echoes back all parameters passed to it.
+      // Rejects the promise depending on |rejectPromises|.
       whenChromeSendCalled(CHROME_SEND_NAME).then(function(args) {
-        cr.webUIResponse.apply(null, args);
+        var callbackId = args[0];
+        cr.webUIResponse.apply(
+            null, [callbackId, !rejectPromises].concat(args.slice(1)));
       });
     });
+    teardown(function() { rejectPromises = false; });
 
     test('sendWithPromise_ResponseObject', function() {
       var expectedResponse = {'foo': 'bar'};
       return cr.sendWithPromise(CHROME_SEND_NAME, expectedResponse).then(
           function(response) {
             assertEquals(
                 JSON.stringify(expectedResponse), JSON.stringify(response));
           });
     });
 
@@ skipping 12 matching lines @@
           function(response) {
             assertEquals(expectedResponse, response);
           });
     });
 
     test('sendWithPromise_ResponseVoid', function() {
       return cr.sendWithPromise(CHROME_SEND_NAME).then(function(response) {
         assertEquals(undefined, response);
       });
     });
+
+    test('sendWithPromise_Reject', function() {
+      rejectPromises = true;
+      var expectedResponse = 1234;
+      return cr.sendWithPromise(CHROME_SEND_NAME, expectedResponse).then(
+          function() {
+            assertNotReached('should have rejected promise');
+          },
+          function(error) {
+            assertEquals(expectedResponse, error);
+          });
+    });
   });
 
   // Run all registered tests.
   mocha.run();
 });
 
 
 TEST_F('WebUIResourceAsyncTest', 'WebUIListeners', function() {
   suite('WebUIListeners', function() {
     var listener1 = null;
@@ skipping 55 matching lines @@
       listener2 = cr.addWebUIListener(EVENT_NAME, resolver2.resolve);
       cr.webUIListenerCallback(EVENT_NAME);
       // Check that both listeners registered are invoked.
       return Promise.all([resolver1.promise, resolver2.promise]);
     });
   });
 
   // Run all registered tests.
   mocha.run();
 });