LibTest/async/Stream/listen_A05_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 StreamSubscription<T> listen(void onData(T event),
///   {Function onError, void onDone(), bool cancelOnError})
/// The onError callback must be of type void onError(error) or
/// void onError(error, StackTrace stackTrace). If onError accepts two
/// arguments it is called with the stack trace (which could be null if the
/// stream itself received an error without stack trace). Otherwise
/// it is called with just the error object.
/// @description Checks that stack trace from Future.error constructor is
/// propagated correctly to onError callback.
/// @author ilya

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

main() {
  Error error = new Error();
  StackTrace stackTrace;
  var s;
  try {
    throw error;
  } catch (e,st) {
    stackTrace = st;
    s = new Stream.fromFuture(new Future.error(e, st));
  }

  asyncStart();

  s.listen((_) {
    Expect.fail('unexpected call to onData');
  }, onError: (e, st) {
    Expect.identical(error, e);
    Expect.identical(stackTrace, st);
    asyncEnd();
  });
}