LibTest/async/StreamIterator/moveNext_A01_t02.dart

// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/// @assertion Future<bool> moveNext()
/// Wait for the next stream value to be available.
///
/// Returns a future which will complete with either true or false. Completing
/// with true means that another event has been received and can be read as
/// current. Completing with false means that the stream itearation is done and
/// no further events will ever be available. The future may complete with an
/// error, if the stream produces an error, which also ends iteration.
///
/// The function must not be called again until the future returned by a previous
/// call is completed.
///
/// @description Checks that future returned by moveNext() completes with
/// an error if stream produces an error and that iterator is automatically
/// cancelled after that (see doc on cancel).
/// @author ilya

import "dart:async";
import "../../../Utils/expect.dart";

main() {
  var c = new StreamController();
  var si = new StreamIterator(c.stream);

  asyncStart();

  si.moveNext().then((value) {
    Expect.identical(true, value);
    Expect.identical(1, si.current);
    si.moveNext().catchError((value) {
      Expect.identical(2, value);
      si.moveNext().then((value) {
        Expect.identical(false, value);
        asyncEnd();
        return true;
      });
      return false;
    });
    return true;
  });

  c.add(1);
  c.addError(2);
  c.add(3);
  c.close();
}