public async Task When_testing_a_non_lossy_forwarder()
        {
            var forwarder = new AsyncBufferingForwardingAppender();

            forwarder.BufferSize.ShouldBe(512);
            forwarder.Lossy.ShouldBeFalse();
            forwarder.Name.ShouldBeNull();
            forwarder.Appenders.Count.ShouldBe(0);
            forwarder.Threshold.ShouldBeNull();

            var loggedEvents   = new List <LoggingEvent>();
            var mockedAppender = new Mock <IAppender>();

            mockedAppender
            .Setup(s => s.DoAppend(It.IsAny <LoggingEvent>()))
            .Callback <LoggingEvent>(loggingEvent => loggedEvents.Add(loggingEvent));

            forwarder.AddAppender(mockedAppender.Object);

            forwarder.ActivateOptions();

            loggedEvents.Count.ShouldBe(0);

            forwarder.DoAppend(new LoggingEvent(new LoggingEventData()));

            loggedEvents.Count.ShouldBe(0);

            await Task.Delay(1000);

            loggedEvents.Count.ShouldBe(1);

            forwarder.DoAppend(new[]
            {
                new LoggingEvent(new LoggingEventData()),
                new LoggingEvent(new LoggingEventData())
            });

            await Task.Delay(1000);

            loggedEvents.Count.ShouldBe(3);

            forwarder.DoAppend(new LoggingEvent(new LoggingEventData()));
            loggedEvents.Count.ShouldBe(3);
            forwarder.Close();
            loggedEvents.Count.ShouldBe(4);
        }
        public async Task When_testing_a_lossy_forwarder()
        {
            var forwarder = new AsyncBufferingForwardingAppender
            {
                Lossy          = true,
                LossyEvaluator = new LevelEvaluator(Level.Error),
                Fix            = FixFlags.ThreadName | FixFlags.Exception | FixFlags.Message
            };

            forwarder.BufferSize.ShouldBe(512);
            forwarder.Lossy.ShouldBeTrue();
            forwarder.Name.ShouldBeNull();
            forwarder.Appenders.Count.ShouldBe(0);
            forwarder.Threshold.ShouldBeNull();
            forwarder.LossyEvaluator.ShouldBeOfType <LevelEvaluator>();

            var loggedEvents   = new List <LoggingEvent>();
            var mockedAppender = new Mock <IAppender>();

            mockedAppender
            .Setup(s => s.DoAppend(It.IsAny <LoggingEvent>()))
            .Callback <LoggingEvent>(loggingEvent => loggedEvents.Add(loggingEvent));

            forwarder.AddAppender(mockedAppender.Object);

            forwarder.ActivateOptions();

            await Task.Delay(1000);

            loggedEvents.Count.ShouldBe(1);
            loggedEvents[0].Level.ShouldBe(Level.Warn);
            loggedEvents[0].LoggerName.ShouldBe("AsyncBufferingForwardingAppender");
            loggedEvents[0].RenderedMessage
            .ShouldContain("This is a 'lossy' appender therefore log messages may be dropped.");

            var event1 = new LoggingEvent(new LoggingEventData {
                Level = Level.Info
            });
            var event2 = new LoggingEvent(new LoggingEventData {
                Level = Level.Debug
            });
            var event3 = new LoggingEvent(new LoggingEventData {
                Level = Level.Error
            });
            var event4 = new LoggingEvent(new LoggingEventData {
                Level = Level.Warn
            });
            var event5 = new LoggingEvent(new LoggingEventData {
                Level = Level.Fatal
            });

            forwarder.LossyEvaluator.IsTriggeringEvent(event1).ShouldBeFalse();
            forwarder.LossyEvaluator.IsTriggeringEvent(event2).ShouldBeFalse();
            forwarder.LossyEvaluator.IsTriggeringEvent(event3).ShouldBeTrue();
            forwarder.LossyEvaluator.IsTriggeringEvent(event4).ShouldBeFalse();
            forwarder.LossyEvaluator.IsTriggeringEvent(event5).ShouldBeTrue();

            forwarder.DoAppend(event1);

            await Task.Delay(1000);

            loggedEvents.Count.ShouldBe(1);
            loggedEvents[0].Level.ShouldBe(Level.Warn);

            forwarder.DoAppend(new[] { event2, event3, event4 });
            forwarder.Flush(true);

            await Task.Delay(1000);

            loggedEvents.Count.ShouldBe(2);
            loggedEvents[0].Level.ShouldBe(Level.Warn);
            loggedEvents[1].Level.ShouldBe(Level.Error);

            forwarder.DoAppend(event5);
            loggedEvents.Count.ShouldBe(2);

            loggedEvents[0].Level.ShouldBe(Level.Warn);
            loggedEvents[1].Level.ShouldBe(Level.Error);

            forwarder.Close();

            loggedEvents.Count.ShouldBe(3);
            loggedEvents[0].Level.ShouldBe(Level.Warn);
            loggedEvents[1].Level.ShouldBe(Level.Error);
            loggedEvents[2].Level.ShouldBe(Level.Fatal);
        }