test/isolate_channel_test.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.

@TestOn('vm')

import 'dart:async';
import 'dart:isolate';

import 'package:pedantic/pedantic.dart';
import 'package:stream_channel/isolate_channel.dart';
import 'package:stream_channel/stream_channel.dart';
import 'package:test/test.dart';

void main() {
  ReceivePort receivePort;
  SendPort sendPort;
  StreamChannel channel;
  setUp(() {
    receivePort = ReceivePort();
    var receivePortForSend = ReceivePort();
    sendPort = receivePortForSend.sendPort;
    channel = IsolateChannel(receivePortForSend, receivePort.sendPort);
  });

  tearDown(() {
    receivePort.close();
    channel.sink.close();
  });

  test('the channel can send messages', () {
    channel.sink.add(1);
    channel.sink.add(2);
    channel.sink.add(3);

    expect(receivePort.take(3).toList(), completion(equals([1, 2, 3])));
  });

  test('the channel can receive messages', () {
    sendPort.send(1);
    sendPort.send(2);
    sendPort.send(3);

    expect(channel.stream.take(3).toList(), completion(equals([1, 2, 3])));
  });

  test("events can't be added to an explicitly-closed sink", () {
    expect(channel.sink.close(), completes);
    expect(() => channel.sink.add(1), throwsStateError);
    expect(() => channel.sink.addError('oh no'), throwsStateError);
    expect(() => channel.sink.addStream(Stream.fromIterable([])),
        throwsStateError);
  });

  test("events can't be added while a stream is being added", () {
    var controller = StreamController();
    channel.sink.addStream(controller.stream);

    expect(() => channel.sink.add(1), throwsStateError);
    expect(() => channel.sink.addError('oh no'), throwsStateError);
    expect(() => channel.sink.addStream(Stream.fromIterable([])),
        throwsStateError);
    expect(() => channel.sink.close(), throwsStateError);

    controller.close();
  });

  group('stream channel rules', () {
    test(
        'closing the sink causes the stream to close before it emits any more '
        'events', () {
      sendPort.send(1);
      sendPort.send(2);
      sendPort.send(3);
      sendPort.send(4);
      sendPort.send(5);

      channel.stream.listen(expectAsync1((message) {
        expect(message, equals(1));
        channel.sink.close();
      }, count: 1));
    });

    test("cancelling the stream's subscription has no effect on the sink",
        () async {
      unawaited(channel.stream.listen(null).cancel());
      await pumpEventQueue();

      channel.sink.add(1);
      channel.sink.add(2);
      channel.sink.add(3);
      expect(receivePort.take(3).toList(), completion(equals([1, 2, 3])));
    });

    test('the sink closes as soon as an error is added', () async {
      channel.sink.addError('oh no');
      channel.sink.add(1);
      expect(channel.sink.done, throwsA('oh no'));

      // Since the sink is closed, the stream should also be closed.
      expect(channel.stream.isEmpty, completion(isTrue));

      // The other end shouldn't receive the next event, since the sink was
      // closed. Pump the event queue to give it a chance to.
      receivePort.listen(expectAsync1((_) {}, count: 0));
      await pumpEventQueue();
    });

    test('the sink closes as soon as an error is added via addStream',
        () async {
      var canceled = false;
      var controller = StreamController(onCancel: () {
        canceled = true;
      });

      // This future shouldn't get the error, because it's sent to [Sink.done].
      expect(channel.sink.addStream(controller.stream), completes);

      controller.addError('oh no');
      expect(channel.sink.done, throwsA('oh no'));
      await pumpEventQueue();
      expect(canceled, isTrue);

      // Even though the sink is closed, this shouldn't throw an error because
      // the user didn't explicitly close it.
      channel.sink.add(1);
    });
  });

  group('connect constructors', () {
    ReceivePort connectPort;
    setUp(() {
      connectPort = ReceivePort();
    });

    tearDown(() {
      connectPort.close();
    });

    test('create a connected pair of channels', () {
      var channel1 = IsolateChannel<int>.connectReceive(connectPort);
      var channel2 = IsolateChannel<int>.connectSend(connectPort.sendPort);

      channel1.sink.add(1);
      channel1.sink.add(2);
      channel1.sink.add(3);
      expect(channel2.stream.take(3).toList(), completion(equals([1, 2, 3])));

      channel2.sink.add(4);
      channel2.sink.add(5);
      channel2.sink.add(6);
      expect(channel1.stream.take(3).toList(), completion(equals([4, 5, 6])));
    });

    test('the receiving channel produces an error if it gets the wrong message',
        () {
      var connectedChannel = IsolateChannel.connectReceive(connectPort);
      connectPort.sendPort.send('wrong value');

      expect(connectedChannel.stream.toList(), throwsStateError);
      expect(connectedChannel.sink.done, completes);
    });
  });
}