LibTest/io/RawDatagramSocket/firstWhere_A03_t01.dart

// Copyright (c) 2018, 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 Future
/// Future<RawSocketEvent> firstWhere (
///     bool test(T element), {
///     dynamic defaultValue(),
///     T orElse()
/// })
/// Finds the first element of this stream matching test.
/// . . .
/// Stops listening to the stream after the first matching element has been
/// received.
///
/// Internally the method cancels its subscription after the first element that
/// matches the predicate. This means that single-subscription (non-broadcast)
/// streams are closed and cannot be reused after a call to this method.
///
/// @description Checks that the method cancels its subscription after the first
/// element that matches the predicate, and single-subscription (non-broadcast)
/// streams are closed and cannot be reused after a call to this method.
/// @author ngl@unipro.ru

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

main() {
  asyncStart();
  var address = InternetAddress.loopbackIPv4;
  RawDatagramSocket.bind(address, 0).then((producer) {
    RawDatagramSocket.bind(address, 0).then((receiver) {
      int sent = 0;
      producer.send([sent++], address, receiver.port);
      producer.send([sent++], address, receiver.port);
      producer.send([sent], address, receiver.port);
      producer.close();

      Future fValue = receiver.firstWhere((e) => true);
      fValue.then((value) {
        Expect.equals(RawSocketEvent.write, value);
      }).whenComplete(() {
        Expect.throws(() => receiver.listen((e) {
              print(e);
            }));
        asyncEnd();
      });
    });
  });
}