Language/Statements/Yield_and_Yield_Each/Yield_Each/execution_async_t01.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 m is marked async*, then:
 *    • It is a dynamic error if the class of o does not implement Stream.
 *  Otherwise
 *    • For each element x of o:
 *    – If the stream u associated with m has been paused, then execution
 * of m is suspended until u is resumed or canceled.
 *    – If the stream u associated with m has been canceled, then let c be
 * the finally clause of the innermost enclosing try-finally statement, if any.
 * If c is defined, let h be the handler induced by c. If h is defined,
 * control is transferred to h. If h is undefined, the immediately enclosing
 * function terminates.
 *    – Otherwise, x is added to the stream associated with m in the order
 * it appears in o. The function m may suspend.
 *    • If the stream o is done, execution of s is complete.
 *
 * @description Check that dynamic error occurs if the class of o does not
 * implement Stream.
 *
 * @issue #25634 - the test assumes that dynamic error is added to the stream.
 * @author a.semenov@unipro.ru
 */
import 'dart:async';
import '../../../../Utils/expect.dart';

Stream<int> generator() async* {
  dynamic a = 'a';
  yield* a;
}

main() {
  asyncStart();
  generator().listen(
      (_) {},
      onError: (e) {
        Expect.isTrue(e is Error);
        asyncEnd();
      }
  );
}