fakes function

(WebSocket, WebSocket) fakes({ String protocol = '', })

Create a pair of fake WebSockets that are connected to each other.

Sending a message on one WebSocket will result in that same message being received by the other.

This can be useful in constructing tests.

For example:

import 'dart:async';

import 'package:test/test.dart';
import 'package:web_socket/src/web_socket.dart';
import 'package:web_socket/testing.dart';
import 'package:web_socket/web_socket.dart';

Future<void> fakeTimeServer(WebSocket webSocket, String time) async {
  await webSocket.events.forEach((event) {
    switch (event) {
      case TextDataReceived():
      case BinaryDataReceived():
        webSocket.sendText(time);
      case CloseReceived():
    }
  });
}

Future<DateTime> getTime(WebSocket webSocket) async {
  webSocket.sendText('');
  final time = switch (await webSocket.events.first) {
    TextDataReceived(:final text) => DateTime.parse(text),
    _ => throw Exception('unexpected response')
  };
  await webSocket.close();
  return time;
}

void main() async {
  late WebSocket client;
  late WebSocket server;

  setUp(() {
    (client, server) = fakes();
  });

  test('test valid time', () async {
    unawaited(fakeTimeServer(server, '2024-05-15T01:18:10.456Z'));
    expect(
        await getTime(client),
        DateTime.parse('2024-05-15T01:18:10.456Z'));
  });
}

Implementation

(WebSocket, WebSocket) fakes({String protocol = ''}) {
  final peer1 = FakeWebSocket(protocol);
  final peer2 = FakeWebSocket(protocol);

  peer1._other = peer2;
  peer2._other = peer1;

  return (peer1, peer2);
}