  /** Virtual time scheduler used for testing applications and libraries built using Reactive Extensions. */
  Rx.TestScheduler = (function (__super__) {
    inherits(TestScheduler, __super__);

    function baseComparer(x, y) {
      return x > y ? 1 : (x < y ? -1 : 0);
    }

    function TestScheduler() {
      __super__.call(this, 0, baseComparer);
    }

    /**
     * Schedules an action to be executed at the specified virtual time.
     *
     * @param state State passed to the action to be executed.
     * @param dueTime Absolute virtual time at which to execute the action.
     * @param action Action to be executed.
     * @return Disposable object used to cancel the scheduled action (best effort).
     */
    TestScheduler.prototype.scheduleAbsolute = function (state, dueTime, action) {
      dueTime <= this.clock && (dueTime = this.clock + 1);
      return __super__.prototype.scheduleAbsolute.call(this, state, dueTime, action);
    };
    /**
     * Adds a relative virtual time to an absolute virtual time value.
     *
     * @param absolute Absolute virtual time value.
     * @param relative Relative virtual time value to add.
     * @return Resulting absolute virtual time sum value.
     */
    TestScheduler.prototype.add = function (absolute, relative) {
      return absolute + relative;
    };
    /**
     * Converts the absolute virtual time value to a DateTimeOffset value.
     *
     * @param absolute Absolute virtual time value to convert.
     * @return Corresponding DateTimeOffset value.
     */
    TestScheduler.prototype.toAbsoluteTime = function (absolute) {
      return new Date(absolute).getTime();
    };
    /**
     * Converts the TimeSpan value to a relative virtual time value.
     *
     * @param timeSpan TimeSpan value to convert.
     * @return Corresponding relative virtual time value.
     */
    TestScheduler.prototype.toRelativeTime = function (timeSpan) {
      return timeSpan;
    };
    /**
     * Starts the test scheduler and uses the specified virtual times to invoke the factory function, subscribe to the resulting sequence, and dispose the subscription.
     *
     * @param create Factory method to create an observable sequence.
     * @param created Virtual time at which to invoke the factory to create an observable sequence.
     * @param subscribed Virtual time at which to subscribe to the created observable sequence.
     * @param disposed Virtual time at which to dispose the subscription.
     * @return Observer with timestamped recordings of notification messages that were received during the virtual time window when the subscription to the source sequence was active.
     */
    TestScheduler.prototype.startScheduler = function (createFn, settings) {
      settings || (settings = {});
      settings.created == null && (settings.created = ReactiveTest.created);
      settings.subscribed == null && (settings.subscribed = ReactiveTest.subscribed);
      settings.disposed == null && (settings.disposed = ReactiveTest.disposed);

      var observer = this.createObserver(), source, subscription;

      this.scheduleAbsolute(null, settings.created, function () {
        source = createFn();
        return disposableEmpty;
      });

      this.scheduleAbsolute(null, settings.subscribed, function () {
        subscription = source.subscribe(observer);
        return disposableEmpty;
      });

      this.scheduleAbsolute(null, settings.disposed, function () {
        subscription.dispose();
        return disposableEmpty;
      });

      this.start();

      return observer;
    };

    /**
     * Creates a hot observable using the specified timestamped notification messages either as an array or arguments.
     * @param messages Notifications to surface through the created sequence at their specified absolute virtual times.
     * @return Hot observable sequence that can be used to assert the timing of subscriptions and notifications.
     */
    TestScheduler.prototype.createHotObservable = function () {
      var len = arguments.length, args;
      if (Array.isArray(arguments[0])) {
        args = arguments[0];
      } else {
        args = new Array(len);
        for (var i = 0; i < len; i++) { args[i] = arguments[i]; }
      }
      return new HotObservable(this, args);
    };

    /**
     * Creates a cold observable using the specified timestamped notification messages either as an array or arguments.
     * @param messages Notifications to surface through the created sequence at their specified virtual time offsets from the sequence subscription time.
     * @return Cold observable sequence that can be used to assert the timing of subscriptions and notifications.
     */
    TestScheduler.prototype.createColdObservable = function () {
      var len = arguments.length, args;
      if (Array.isArray(arguments[0])) {
        args = arguments[0];
      } else {
        args = new Array(len);
        for (var i = 0; i < len; i++) { args[i] = arguments[i]; }
      }
      return new ColdObservable(this, args);
    };

    /**
     * Creates a resolved promise with the given value and ticks
     * @param {Number} ticks The absolute time of the resolution.
     * @param {Any} value The value to yield at the given tick.
     * @returns {MockPromise} A mock Promise which fulfills with the given value.
     */
    TestScheduler.prototype.createResolvedPromise = function (ticks, value) {
      return new MockPromise(this, [Rx.ReactiveTest.onNext(ticks, value), Rx.ReactiveTest.onCompleted(ticks)]);
    };

    /**
     * Creates a rejected promise with the given reason and ticks
     * @param {Number} ticks The absolute time of the resolution.
     * @param {Any} reason The reason for rejection to yield at the given tick.
     * @returns {MockPromise} A mock Promise which rejects with the given reason.
     */
    TestScheduler.prototype.createRejectedPromise = function (ticks, reason) {
      return new MockPromise(this, [Rx.ReactiveTest.onError(ticks, reason)]);
    };

    /**
     * Creates an observer that records received notification messages and timestamps those.
     * @return Observer that can be used to assert the timing of received notifications.
     */
    TestScheduler.prototype.createObserver = function () {
      return new MockObserver(this);
    };

    return TestScheduler;
  })(VirtualTimeScheduler);
