test-fixture-mocha.js

/**
 * @license
 * Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
 * This code may only be used under the BSD style license found at
 * http://polymer.github.io/LICENSE.txt The complete set of authors may be found
 * at http://polymer.github.io/AUTHORS.txt The complete set of contributors may
 * be found at http://polymer.github.io/CONTRIBUTORS.txt Code distributed by
 * Google as part of the polymer project is also subject to an additional IP
 * rights grant found at http://polymer.github.io/PATENTS.txt
 */
function extendInterfaceWithFixture(interfaceName) {
  var originalInterface = window.Mocha.interfaces[interfaceName];
  var teardownProperty = interfaceName === 'bdd' ? 'afterEach' : 'teardown';

  window.Mocha.interfaces[interfaceName] = function(suite) {
    originalInterface.apply(this, arguments);

    suite.on('pre-require', function(context, file, mocha) {
      if (!(context[teardownProperty])) {
        return;
      }

      context.fixture = function(fixtureId, model) {
        context[teardownProperty](function() {
          document.getElementById(fixtureId).restore();
        });

        return document.getElementById(fixtureId).create(model);
      };
    });
  };
}

Object.keys(window.Mocha.interfaces).forEach(extendInterfaceWithFixture);