selenium-webdriver/test/promise_aplus_test.js

The official WebDriver JavaScript bindings from the Selenium project

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// distributed with this work for additional information
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// to you 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.

'use strict';

describe('Promises/A+ Compliance Tests', function() {
  var promise = require('../_base').require('webdriver.promise');

  // The promise spec does not define behavior for unhandled rejections and
  // assumes they are effectively swallowed. This is not the case with our
  // implementation, so we have to disable error propagation to test that the
  // rest of our behavior is compliant.
  // We run the tests with a separate instance of the control flow to ensure
  // disablign error propagation does not impact other tests.
  var flow = new promise.ControlFlow();
  flow.setPropagateUnhandledRejections(false);

  function startsWith(str, prefix) {
    return str.indexOf(prefix) === 0;
  }

  function endsWith(str, suffix) {
    let len = str.length - suffix.length;
    return len >= 0 && str.indexOf(suffix, len) === len;
  }

  // Skip the tests in 2.2.6.1/2. We are not compliant in these scenarios.
  var realDescribe = global.describe;
  global.describe = function(name, fn) {
    realDescribe(name, function() {
      var prefix = 'Promises/A+ Compliance Tests 2.2.6: '
          + '`then` may be called multiple times on the same promise.';
      var suffix = 'even when one handler is added inside another handler';
      if (startsWith(this.fullTitle(), prefix)
          && endsWith(this.fullTitle(), suffix)) {
        var realSpecify = global.specify;
        try {
          global.specify = function(name) {
            realSpecify(name);
          };
          fn();
        } finally {
          global.specify = realSpecify;
        }
      } else {
        fn();
      }
    });
  };

  require('promises-aplus-tests').mocha({
    resolved: function(value) {
      return new promise.Promise((fulfill) => fulfill(value), flow);
    },
    rejected: function(error) {
      return new promise.Promise((_, reject) => reject(error), flow);
    },
    deferred: function() {
      var d = new promise.Deferred(flow);
      return {
        resolve: d.fulfill,
        reject: d.reject,
        promise: d.promise
      };
    }
  });

  global.describe = realDescribe;
});