Language/Expressions/Function_Invocation/async_generator_invokation_t06.dart

// Copyright (c) 2016, 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 If f is marked async*, then a fresh instance s implementing
/// the built-in class Stream is associated with the invocation and
/// immediately returned. When s is listened to, execution of the body of f will
/// begin. When f terminates:
///   • If the current return value is defined then, if s has been canceled
///   then its cancellation future is completed with null.
///   • If the current exception x is defined:
///     – x is added to s.
///     – If s has been canceled then its cancellation future is completed with
///     x as an error.
///   • s is closed.
///
/// @description Check that if s has been canceled then its cancellation future
/// is completed with current exception x as an error.
///
/// @author a.semenov@unipro.ru

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

Stream generator1() async* {
  throw 'abc';
}

Stream generator2() async* {
  try {
    throw 'abc';
  } on String catch (e) {
    throw 3.14;
  }
}

test1() {
  asyncStart();
  Stream stream = generator1();
  Future cancelFuture = stream.listen((v) {} ).cancel();
  cancelFuture.then(
      (v) {
        Expect.fail('cancellation future has completed without error');
      },
      onError: (e) {
        Expect.equals('abc', e);
        asyncEnd();
      }
  );
}

test2() {
  asyncStart();
  Stream stream = generator2();
  Future cancelFuture = stream.listen((v) {} ).cancel();
  cancelFuture.then(
      (v) {
        Expect.fail('cancellation future has completed without error');
      },
      onError: (e) {
        Expect.equals(3.14, e);
        asyncEnd();
      }
  );
}

main() {
  test1();
  test2();
}