Port braille related tests from ChromeVox upstream.

chrome/browser/resources/chromeos/chromevox/testing/assert_additions.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.
 
 /**
  * Asserts that a given argument's value is undefined.
  * @param {object} a The argument to check.
  */
 function assertUndefined(a) {
   if (a !== undefined) {
     throw new Error('Assertion failed: expected undefined');
   }
 }
 
 /**
+ * Asserts that the argument is neither null nor undefined.
+ * @param {object} a The argument to check.

[David Tseng, 2014/09/08 21:45:59]

arg or obj?

+ * @param {string=} opt_message Error message if the condition is not met.
+ */
+function assertNotNullNorUndefined(a, opt_message) {
+  if (a === undefined || a === null) {
+    throw new Error('Can\'t be null or undefined: ' + (opt_message || '') +
+        '\n' + 'Actual: ' + a);
+  }
+}
+
+/**
  * Asserts that a given function call throws an exception.
  * @param {string} msg Message to print if exception not thrown.
  * @param {Function} fn The function to call.
  * @param {string} error The name of the exception we expect {@code fn} to
  *     throw.
  */
 function assertException(msg, fn, error) {
   try {
     fn();
   } catch (e) {
@@ skipping 23 matching lines @@
     }
   }
   if (!same) {
     throw new Error('Expected ' + JSON.stringify(array1) +
                     ', got ' + JSON.stringify(array2));
   }
 }
 
 /**
  * Asserts that two objects have the same JSON serialization.
- * @param {Object} obj1 The expected object.
- * @param {Object} obj2 The actual object.
+ * @param {Object} expected The expected object.
+ * @param {Object} actual The actual object.
+ * @param {string=} opt_message Message used for errors.
  */
-function assertEqualsJSON(obj1, obj2) {
-  if (!eqJSON(obj1, obj2)) {
-    throw new Error('Expected ' + JSON.stringify(obj1) +
-                    ', got ' + JSON.stringify(obj2));
+function assertEqualsJSON(expected, actual, opt_message) {
+  if (JSON.stringify(actual) !== JSON.stringify(expected)) {
+    throw new Error((opt_message ? opt_message + '\n' : '') +
+        'Expected ' + JSON.stringify(expected) + '\n' +
+        'Got      ' + JSON.stringify(actual));
   }
 }
 
 assertSame = assertEquals;
 assertNotSame = assertNotEquals;