chrome/browser/resources/chromeos/chromevox/common/string_util_test.unitjs

// 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.

// Include test fixture.
GEN_INCLUDE(['../testing/chromevox_unittest_base.js']);

/**
 * Test fixture.
 * @constructor
 * @extends {ChromeVoxUnitTestBase}
 */
function StringUtilUnitTest() {
  ChromeVoxUnitTestBase.call(this);
}

StringUtilUnitTest.prototype = {
  __proto__: ChromeVoxUnitTestBase.prototype,

  /** @override */
  closureModuleDeps: [
    'StringUtil',
  ],
};

TEST_F('StringUtilUnitTest', 'longestCommonPrefixLength', function() {
  var lcpl = StringUtil.longestCommonPrefixLength;
  assertEquals(0, lcpl('', ''));
  assertEquals(0, lcpl('', 'hello'));
  assertEquals(0, lcpl('hello', ''));
  assertEquals(1, lcpl('hi', 'hello'));
});

var EMOJI = String.fromCodePoint(0X1F30C);  // Milky way
var INVALID_SURROGATE_PAIR = 'a' + EMOJI[0];

TEST_F('StringUtilUnitTest', 'previousCodePointOffset', function() {
  var prev = StringUtil.previousCodePointOffset;
  assertEquals(-1, prev('', 0));
  assertEquals(-1, prev('', -1));
  assertEquals(-1, prev('test', 0));
  assertEquals(0, prev('test', 1));
  assertEquals('test'.length - 1, prev('test', 'test'.length));
  assertEquals(0, prev('a' + EMOJI, 1));
  assertEquals(1, prev('a' + EMOJI + 'b', 3));
  assertEquals(1, prev(INVALID_SURROGATE_PAIR, INVALID_SURROGATE_PAIR.length));
  assertEquals(0, prev('a' + INVALID_SURROGATE_PAIR, 1));
});

TEST_F('StringUtilUnitTest', 'nextCodePointOffset', function() {
  var next = StringUtil.nextCodePointOffset;
  assertEquals(0, next('', 0));
  assertEquals(0, next('', 1));
  assertEquals(1, next('test', 0));
  assertEquals('test'.length, next('test', 'test'.length - 1));
  assertEquals(1, next('a' + EMOJI, 0));
  assertEquals(EMOJI.length, next(EMOJI, 0));
  assertEquals(3, next('a' + EMOJI + 'b', 1));
  assertEquals(1, next(INVALID_SURROGATE_PAIR, 0));
  assertEquals(1, next('a' + INVALID_SURROGATE_PAIR, 0));
});