text: // Copyright 2009 The Closure Library Authors. All Rights Reserved.
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  //      http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the License is distributed on an "AS-IS" BASIS,
  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  // See the License for the specific language governing permissions and
  // limitations under the License.
  
  /**
   * @fileoverview Utility for sharding tests.
   *
   * Usage instructions:
   * <ol>
   *   <li>Instead of writing your large test in foo_test.html, write it in
   * foo_test_template.html</li>
   *   <li>Add a call to {@code goog.testing.ShardingTestCase.shardByFileName()}
   * near the top of your test, before any test cases or setup methods.</li>
   *   <li>Symlink foo_test_template.html into different sharded test files
   * named foo_1of4_test.html, foo_2of4_test.html, etc, using `ln -s`.</li>
   *   <li>Add the symlinks as foo_1of4_test.html.
   *       In perforce, run the command `g4 add foo_1of4_test.html` followed
   * by `g4 reopen -t symlink foo_1of4_test.html` so that perforce treats the file
   * as a symlink
   *   </li>
   * </ol>
   *
   */
  
  goog.provide('goog.testing.ShardingTestCase');
  
  goog.require('goog.asserts');
  goog.require('goog.testing.TestCase');
  
  /**
   * A test case that runs tests in per-file shards.
   * @param {number} shardIndex Shard index for this page,
   *     <strong>1-indexed</strong>.
   * @param {number} numShards Number of shards to split up test cases into.
   * @extends {goog.testing.TestCase}
   * @constructor
   */
  goog.testing.ShardingTestCase = function(shardIndex, numShards, opt_name) {
    goog.base(this, opt_name);
  
    goog.asserts.assert(shardIndex > 0, 'Shard index should be positive');
    goog.asserts.assert(numShards > 0, 'Number of shards should be positive');
    goog.asserts.assert(shardIndex <= numShards,
        'Shard index out of bounds');
  
    /**
     * @type {number}
     * @private
     */
    this.shardIndex_ = shardIndex;
  
    /**
     * @type {number}
     * @private
     */
    this.numShards_ = numShards;
  };
  goog.inherits(goog.testing.ShardingTestCase, goog.testing.TestCase);
  
  
  /**
   * Whether we've actually partitioned the tests yet. We may execute twice
   * ('Run again without reloading') without failing.
   * @type {boolean}
   * @private
   */
  goog.testing.ShardingTestCase.prototype.sharded_ = false;
  
  
  /**
   * Installs a runTests global function that goog.testing.JsUnit will use to
   * run tests, which will run a single shard of the tests present on the page.
   * @override
   */
  goog.testing.ShardingTestCase.prototype.runTests = function() {
    if (!this.sharded_) {
      var numTests = this.getCount();
      goog.asserts.assert(numTests >= this.numShards_,
          'Must have at least as many tests as shards!');
      var shardSize = Math.ceil(numTests / this.numShards_);
      var startIndex = (this.shardIndex_ - 1) * shardSize;
      var endIndex = startIndex + shardSize;
      goog.asserts.assert(this.order == goog.testing.TestCase.Order.SORTED,
          'Only SORTED order is allowed for sharded tests');
      this.setTests(this.getTests().slice(startIndex, endIndex));
      this.sharded_ = true;
    }
  
    // Call original runTests method to execute the tests.
    goog.base(this, 'runTests');
  };
  
  
  /**
   * Shards tests based on the test filename. Assumes that the filename is
   * formatted like 'foo_1of5_test.html'.
   * @param {string=} opt_name A descriptive name for the test case.
   */
  goog.testing.ShardingTestCase.shardByFileName = function(opt_name) {
    var path = window.location.pathname;
    var shardMatch = path.match(/_(\d+)of(\d+)_test\.html/);
    goog.asserts.assert(shardMatch,
        'Filename must be of the form "foo_1of5_test.html"');
    var shardIndex = parseInt(shardMatch[1], 10);
    var numShards = parseInt(shardMatch[2], 10);
  
    var testCase = new goog.testing.ShardingTestCase(
        shardIndex, numShards, opt_name);
    goog.testing.TestCase.initializeTestRunner(testCase);
  };
  