如何在 xunit2 中捕获 log4net 输出

Question

我读过 http://xunit.github.io/docs/capturing-output.html 它似乎适用于在测试期间使我的测试输出特定消息运行但我真的希望能够捕获已经存在的 log4net 输出集成到我正在测试的类

过去我将 log4net 设置为使用 TraceLogger，并且测试框架能够将输出与测试相关联。（不同的测试框架）。我怎样才能以某种方式将 log4net 输出关联到 Xunit IOutputHelper？

Answer 1

这是我想出的答案

这是一个 class 我可以让我的测试 class 继承自：

   public class LogOutputTester:IDisposable
    {
        private readonly IAppenderAttachable _attachable;
        private TestOutputAppender _appender;

        protected LogOutputTester(ITestOutputHelper output)
        {
            log4net.Config.XmlConfigurator.Configure(); 
            var root = ((log4net.Repository.Hierarchy.Hierarchy)LogManager.GetRepository()).Root;
            _attachable = root;

            _appender = new TestOutputAppender(output);
            if (_attachable != null)
                _attachable.AddAppender(_appender);
        }

        /// <summary>
        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
        /// </summary>
        public void Dispose()
        {
            _attachable.RemoveAppender(_appender);
        }
    }

这是我在上面的帮助程序中引用的自定义 Appender：

 public class TestOutputAppender : AppenderSkeleton
    {
        private readonly ITestOutputHelper _xunitTestOutputHelper;

        public TestOutputAppender(ITestOutputHelper xunitTestOutputHelper)
        {
            _xunitTestOutputHelper = xunitTestOutputHelper;
            Name = "TestOutputAppender";
            Layout = new PatternLayout("%-5p %d %5rms %-22.22c{1} %-18.18M - %m%n");
        }

        protected override void Append(LoggingEvent loggingEvent)
        {
            _xunitTestOutputHelper.WriteLine(RenderLoggingEvent(loggingEvent));
        }
    }

这可以进一步自定义以采用自定义布局或其他...

最后 - 我只是让我的测试 class 继承自这个助手：

   public class MyTestClass:LogOutputTester
    {
        public EdgeClientTests(ITestOutputHelper output):base(output)
        {
        }
    ...

您也可以让您的测试直接访问输出对象...

Answer 2

基于此处描述的解决方案 https://github.com/damianh/CapturingLogOutputWithXunit2AndParallelTests#capturing-test-specific-log-output-when-using-xunit-2x-parallel-testing，我使用 log4net 重写了它。可能对某人有帮助。

public static class LogHelper
    {
        private static readonly Subject<LoggingEvent> LogEventSubject = new Subject<LoggingEvent>();
        private const string CaptureCorrelationIdKey = "EventId";
        private static readonly ILayout layout;

        static LogHelper()
        {
            XmlConfigurator.Configure();
            var root = ((log4net.Repository.Hierarchy.Hierarchy)LogManager.GetRepository()).Root;
            IAppenderAttachable attachable = root;
            var appender = new XunitAppender(logEvent => LogEventSubject.OnNext(logEvent));
            attachable?.AddAppender(appender);
            layout = appender.Layout;
            appender.ActivateOptions();
        }

        public static IDisposable Capture(ITestOutputHelper testOutputHelper)
        {

            var captureId = Guid.NewGuid();
            Func<LoggingEvent, bool> filter = logEvent =>
                logEvent.GetProperties().Contains(CaptureCorrelationIdKey) &&
                logEvent.LookupProperty(CaptureCorrelationIdKey).ToString() == captureId.ToString();

            var subscription = LogEventSubject.Where(filter).Subscribe(logEvent =>
            {
                using (var writer = new StringWriter())
                {
                    layout.Format(writer, logEvent);
                    testOutputHelper.WriteLine(writer.ToString());
                }
            });

            ThreadContext.Properties[CaptureCorrelationIdKey] = captureId.ToString();

            return new DisposableAction(() =>
            {
                subscription.Dispose();
                ThreadContext.Properties.Clear();
            });
        }

        private class DisposableAction : IDisposable
        {
            private readonly Action _action;

            public DisposableAction(Action action)
            {
                _action = action;
            }

            public void Dispose()
            {
                _action();
            }
        }

        public sealed class XunitAppender : AppenderSkeleton
        {
            private readonly Action<LoggingEvent> _action;

            public XunitAppender(Action<LoggingEvent> action)
            {
                _action = action;
                Name = "XunitAppender";
                Layout = new PatternLayout("%date %-5level %logger - %message");
            }

            protected override void Append(LoggingEvent loggingEvent)
            {
                _action(loggingEvent);
            }
        }
    }

如何在 xunit2 中捕获 log4net 输出

How to capture log4net output in xunit2

.net

log4net

unit-testing

xunit2