LibTest/io/RawDatagramSocket/singleWhere_A01_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<RawSocketEvent> singleWhere (
///     bool test(T element), {
///     T orElse()
/// })
/// Finds the single element in this stream matching test.
///
/// Like lastWhere, except that it is an error if more than one matching element
/// occurs in the stream.
///
/// @description Checks that method [singleWhere] returns Future that is
/// completed with (1) the event of this stream, if this event is single event
/// that matches the test, or (2) an error otherwise.
/// @author ngl@unipro.ru

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

check(event, valueExpected, errorExpected) {
  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();
      receiver.close();

      Future fValue = receiver.singleWhere((e) => e == event);
      fValue.then((value) {
        if (valueExpected) {
          Expect.equals(event, value);
        } else {
          Expect.fail('Future should be completed with error');
        }
      }).catchError((error) {
        if (errorExpected) {
          Expect.isTrue((error is StateError));
        } else {
          Expect.fail('Future should be completed with event');
        }
      }).whenComplete(() {
        asyncEnd();
      });
    });
  });
}

main() {
  check(RawSocketEvent.closed, true, false);
  check(RawSocketEvent.write, false, true);
  check(RawSocketEvent.read, false, true);
}