// Copyright (c) 2017, 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.

// @dart = 2.9

/// @assertion void writeln([Object obj = ""])
/// Converts obj to a String by invoking Object.toString and adds the result to
/// this, followed by a newline.
/// @description Checks that this method converts obj to a String by invoking
/// Object.toString and adds the result to this, followed by a newline.
/// @author sgrekhov@unipro.ru

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

class C {
  String value;

  C(this.value);

  String toString() => "C:" + this.value;
}

main() {
  StringBuffer stringSink = new StringBuffer();

  ClosableStringSink sink =
      new ClosableStringSink.fromStringSink(stringSink, () {});
  sink.writeln(new C("123"));
  sink.close();
  Expect.equals("C:123\n", stringSink.toString());
}