Added mock_xhr module w/ unit tests.

remoting/webapp/base/js/base_unittest.js

 // Copyright 2014 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.
 
 (function() {
 
 'use strict';
 
 QUnit.module('base');
 
@@ skipping 36 matching lines @@
     assert.equal(base.deepCopy(null), null);
     assert.deepEqual(base.deepCopy([1, 2]), [1, 2]);
     assert.deepEqual(base.deepCopy({'key': 'value'}), {'key': 'value'});
     assert.deepEqual(base.deepCopy(
       {'key': {'key_nested': 'value_nested'}}),
       {'key': {'key_nested': 'value_nested'}}
     );
     assert.deepEqual(base.deepCopy([1, [2, [3]]]), [1, [2, [3]]]);
 });
 
+QUnit.test('copyWithoutNullFields returns a new object',
+  function(assert) {
+    var obj = {
+      a: 'foo',
+      b: 42
+    };
+    var copy = base.copyWithoutNullFields(obj);
+    assert.notEqual(obj, copy);
+    assert.deepEqual(obj, copy);
+});
+
+QUnit.test('copyWithoutNullFields removes null and undefined fields',
+  function(assert) {
+    /** @const */
+    var obj = {
+      a: 'foo',
+      b: 42,
+      nullField: null,
+      undefinedField: undefined

[Jamie, 2015/04/03 01:45:57]

Add zero and '' fields to address my earlier comment.

[John Williams, 2015/04/04 01:40:25]

Done.

+    };
+    var copy = base.copyWithoutNullFields(obj);
+    assert.equal(copy['a'], obj['a']);
+    assert.equal(copy['b'], obj['b']);
+    assert.ok(!('nullField' in copy));
+    assert.ok(!('undefinedField' in copy));
+});
+
+QUnit.test('copyWithoutNullFields(null) returns a new empty bject',
+  function(assert) {
+    assert.deepEqual(
+        base.copyWithoutNullFields(null),
+        {});
+    assert.notEqual(
+        base.copyWithoutNullFields(null),
+        base.copyWithoutNullFields(null));
+    assert.deepEqual(
+        base.copyWithoutNullFields(undefined),
+        {});
+    assert.notEqual(
+        base.copyWithoutNullFields(undefined),
+        base.copyWithoutNullFields(undefined));
+});
+
 QUnit.test('modify the original after deepCopy(obj) should not affect the copy',
   function(assert) {
     var original = [1, 2, 3, 4];
     var copy = base.deepCopy(original);
     original[2] = 1000;
     assert.deepEqual(copy, [1, 2, 3, 4]);
 });
 
 QUnit.test('dispose(obj) should invoke the dispose method on |obj|',
   function(assert) {
@@ skipping 245 matching lines @@
                           /* Ѓ */ 0xD0, 0x83,
                           /* ф */ 0xD1, 0x84]).buffer),
       "挂Ѓф");
 
   // Unicode surrogate pair for U+1F603.
   assert.equal(base.decodeUtf8(new Uint8Array([0xF0, 0x9F, 0x98, 0x83]).buffer),
               "😃");
 });
 
 })();