public async Task StartAsyncStop() { var connectionService = new FakeIWebSocketConnectionsService(); var service = new HeartbeatService(connectionService); CancellationTokenSource source = new CancellationTokenSource(); CancellationToken token = source.Token; await service.StartAsync(token); await service.StopAsync(token); Assert.IsTrue(connectionService.FakeSendToAllAsync.LastOrDefault()?.Contains("dateTime")); }