Unit tests for utility.js

chrome/browser/resources/google_now/common_test_util.js

+// Copyright 2013 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.
+
+// Common test utilities.
+
+function emptyMock() {}
+
+// Container for event handlers added by mocked 'addListener' functions.
+var mockEventHandlers = {};
+
+/**
+ * Mocks 'addListener' function of an API event. The mocked function will keep
+ * track of handlers.
+ * @param {Object} topLevelContainer Top-level container of the original
+ *     function. Can be either 'chrome' or 'instrumented'.
+ * @param {string} eventIdentifier Event identifier, such as
+ *     'runtime.onSuspend'.
+ */
+function mockChromeEvent(topLevelContainer, eventIdentifier) {
+  var eventIdentifierParts = eventIdentifier.split('.');
+  var eventName = eventIdentifierParts.pop();
+  var originalMethodContainer = topLevelContainer;
+  var mockEventContainer = mockEventHandlers;
+  eventIdentifierParts.forEach(function(fragment) {
+    originalMethodContainer =

[skare_, 2013/08/29 21:28:22]

if I'm reading this right (and I might not be) I think you can just do
originalMethodContainer = originalMethodContainer[fragment] || {}.
and skip the middle assignment?

[skare_, 2013/08/29 21:46:33]

never mind -- this can already exist and you need to create so the check is
needed.

[vadimt, 2013/08/29 21:46:58]

Discussed in person. Needed to create intermediate levels.

+        originalMethodContainer[fragment] =
+        originalMethodContainer[fragment] || {};
+    mockEventContainer =
+        mockEventContainer[fragment] =
+        mockEventContainer[fragment] || {};
+  });
+
+  mockEventContainer[eventName] = [];
+  originalMethodContainer[eventName] = {
+    addListener: function(callback) {
+      mockEventContainer[eventName].push(callback);
+    }
+  };
+}
+
+/**
+ * Gets the array of event handlers added by a mocked 'addListener' function.
+ * @param {string} eventIdentifier Event identifier, such as
+ *     'runtime.onSuspend'.
+ * @return {Array.<Function>} Array of handlers.
+ */
+function getMockHandlerContainer(eventIdentifier) {
+  var eventIdentifierParts = eventIdentifier.split('.');
+  var mockEventContainer = mockEventHandlers;
+  eventIdentifierParts.forEach(function(fragment) {
+    mockEventContainer = mockEventContainer[fragment];
+  });
+
+  return mockEventContainer;
+}