Add support for IMessageSink

Directory.Packages.props

@@ -11,7 +11,8 @@
   </ItemGroup>
   <ItemGroup Condition=" '$(IsTestProject)' != 'true' ">
     <PackageVersion Include="Microsoft.Extensions.Logging" Version="2.0.0" />
-    <PackageVersion Include="xunit.abstractions" Version="2.0.1" />
+    <PackageVersion Include="xunit.abstractions" Version="2.0.3" />
+    <PackageVersion Include="xunit.extensibility.execution" Version="2.4.1" />
   </ItemGroup>
   <ItemGroup Condition=" '$(IsTestProject)' == 'true' ">
     <PackageVersion Include="Microsoft.Extensions.Logging" Version="5.0.0" />

src/Logging.XUnit/IMessageSinkAccessor.cs

@@ -0,0 +1,18 @@
+// Copyright (c) Martin Costello, 2018. All rights reserved.
+// Licensed under the Apache 2.0 license. See the LICENSE file in the project root for full license information.
+
+using Xunit.Abstractions;
+
+namespace MartinCostello.Logging.XUnit
+{
+    /// <summary>
+    /// Defines a property for accessing an <see cref="IMessageSink"/>.
+    /// </summary>
+    public interface IMessageSinkAccessor
+    {
+        /// <summary>
+        /// Gets or sets the <see cref="IMessageSink"/> to use.
+        /// </summary>
+        IMessageSink? MessageSink { get; set; }
+    }
+}

src/Logging.XUnit/IMessageSinkExtensions.cs

@@ -0,0 +1,50 @@
+// Copyright (c) Martin Costello, 2018. All rights reserved.
+// Licensed under the Apache 2.0 license. See the LICENSE file in the project root for full license information.
+
+using System;
+using System.ComponentModel;
+using Microsoft.Extensions.Logging;
+
+namespace Xunit.Abstractions
+{
+    /// <summary>
+    /// A class containing extension methods for the <see cref="IMessageSink"/> interface. This class cannot be inherited.
+    /// </summary>
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public static class IMessageSinkExtensions
+    {
+        /// <summary>
+        /// Returns an <see cref="ILoggerFactory"/> that logs to the message sink.
+        /// </summary>
+        /// <param name="messageSink">The <see cref="IMessageSink"/> to create the logger factory from.</param>
+        /// <returns>
+        /// An <see cref="ILoggerFactory"/> that writes messages to the message sink.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        /// <paramref name="messageSink"/> is <see langword="null"/>.
+        /// </exception>
+        public static ILoggerFactory ToLoggerFactory(this IMessageSink messageSink)
+        {
+            if (messageSink == null)
+            {
+                throw new ArgumentNullException(nameof(messageSink));
+            }
+
+            return new LoggerFactory().AddXUnit(messageSink);
+        }
+
+        /// <summary>
+        /// Returns an <see cref="ILogger{T}"/> that logs to the message sink.
+        /// </summary>
+        /// <typeparam name="T">The type of the logger to create.</typeparam>
+        /// <param name="messageSink">The <see cref="IMessageSink"/> to create the logger from.</param>
+        /// <returns>
+        /// An <see cref="ILogger{T}"/> that writes messages to the message sink.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        /// <paramref name="messageSink"/> is <see langword="null"/>.
+        /// </exception>
+        public static ILogger<T> ToLogger<T>(this IMessageSink messageSink)
+            => messageSink.ToLoggerFactory().CreateLogger<T>();
+    }
+}

src/Logging.XUnit/MartinCostello.Logging.XUnit.csproj

@@ -17,5 +17,6 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.Logging" />
     <PackageReference Include="xunit.abstractions" />
+    <PackageReference Include="xunit.extensibility.execution" />
   </ItemGroup>
 </Project>

src/Logging.XUnit/MessageSinkAccessor.cs

@@ -0,0 +1,31 @@
+// Copyright (c) Martin Costello, 2018. All rights reserved.
+// Licensed under the Apache 2.0 license. See the LICENSE file in the project root for full license information.
+
+using System;
+using Xunit.Abstractions;
+
+namespace MartinCostello.Logging.XUnit
+{
+    /// <summary>
+    /// A class representing the default implementation of <see cref="IMessageSinkAccessor"/>. This class cannot be inherited.
+    /// </summary>
+    internal sealed class MessageSinkAccessor : IMessageSinkAccessor
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="MessageSinkAccessor"/> class.
+        /// </summary>
+        /// <param name="messageSink">The <see cref="IMessageSink"/> to use.</param>
+        /// <exception cref="ArgumentNullException">
+        /// <paramref name="messageSink"/> is <see langword="null"/>.
+        /// </exception>
+        internal MessageSinkAccessor(IMessageSink messageSink)
+        {
+            MessageSink = messageSink ?? throw new ArgumentNullException(nameof(messageSink));
+        }
+
+        /// <summary>
+        /// Gets or sets the current <see cref="IMessageSink"/>.
+        /// </summary>
+        public IMessageSink? MessageSink { get; set; }
+    }
+}

src/Logging.XUnit/XUnitLogger.IMessageSink.cs

@@ -0,0 +1,66 @@
+// Copyright (c) Martin Costello, 2018. All rights reserved.
+// Licensed under the Apache 2.0 license. See the LICENSE file in the project root for full license information.
+
+using System;
+using Microsoft.Extensions.Logging;
+using Xunit.Abstractions;
+
+namespace MartinCostello.Logging.XUnit
+{
+    /// <summary>
+    /// A class representing an <see cref="ILogger"/> to use with xunit.
+    /// </summary>
+    public partial class XUnitLogger
+    {
+        /// <summary>
+        /// The <see cref="IMessageSinkAccessor"/> to use. This field is read-only.
+        /// </summary>
+        private readonly IMessageSinkAccessor? _messageSinkAccessor;
+
+        /// <summary>
+        /// Gets or sets the message sink message factory to use when writing to a <see cref="IMessageSink"/>.
+        /// </summary>
+        private Func<string, IMessageSinkMessage> _messageSinkMessageFactory;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="XUnitLogger"/> class.
+        /// </summary>
+        /// <param name="name">The name for messages produced by the logger.</param>
+        /// <param name="messageSink">The <see cref="IMessageSink"/> to use.</param>
+        /// <param name="options">The <see cref="XUnitLoggerOptions"/> to use.</param>
+        /// <exception cref="ArgumentNullException">
+        /// <paramref name="name"/> or <paramref name="messageSink"/> is <see langword="null"/>.
+        /// </exception>
+        public XUnitLogger(string name, IMessageSink messageSink, XUnitLoggerOptions? options)
+            : this(name, new MessageSinkAccessor(messageSink), options)
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="XUnitLogger"/> class.
+        /// </summary>
+        /// <param name="name">The name for messages produced by the logger.</param>
+        /// <param name="accessor">The <see cref="IMessageSinkAccessor"/> to use.</param>
+        /// <param name="options">The <see cref="XUnitLoggerOptions"/> to use.</param>
+        /// <exception cref="ArgumentNullException">
+        /// <paramref name="name"/> or <paramref name="accessor"/> is <see langword="null"/>.
+        /// </exception>
+        public XUnitLogger(string name, IMessageSinkAccessor accessor, XUnitLoggerOptions? options)
+            : this(name, options)
+        {
+            _messageSinkAccessor = accessor ?? throw new ArgumentNullException(nameof(accessor));
+        }
+
+        /// <summary>
+        /// Gets or sets the message sink message factory to use when writing to a <see cref="IMessageSink"/>.
+        /// </summary>
+        /// <exception cref="ArgumentNullException">
+        /// <paramref name="value"/> is <see langword="null"/>.
+        /// </exception>
+        public Func<string, IMessageSinkMessage> MessageSinkMessageFactory
+        {
+            get { return _messageSinkMessageFactory; }
+            set { _messageSinkMessageFactory = value ?? throw new ArgumentNullException(nameof(value)); }
+        }
+    }
+}

src/Logging.XUnit/XUnitLogger.ITestOutputHelper.cs

@@ -0,0 +1,49 @@
+// Copyright (c) Martin Costello, 2018. All rights reserved.
+// Licensed under the Apache 2.0 license. See the LICENSE file in the project root for full license information.
+
+using System;
+using Microsoft.Extensions.Logging;
+using Xunit.Abstractions;
+
+namespace MartinCostello.Logging.XUnit
+{
+    /// <summary>
+    /// A class representing an <see cref="ILogger"/> to use with xunit.
+    /// </summary>
+    public partial class XUnitLogger
+    {
+        /// <summary>
+        /// The <see cref="ITestOutputHelperAccessor"/> to use. This field is read-only.
+        /// </summary>
+        private readonly ITestOutputHelperAccessor? _outputHelperAccessor;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="XUnitLogger"/> class.
+        /// </summary>
+        /// <param name="name">The name for messages produced by the logger.</param>
+        /// <param name="outputHelper">The <see cref="ITestOutputHelper"/> to use.</param>
+        /// <param name="options">The <see cref="XUnitLoggerOptions"/> to use.</param>
+        /// <exception cref="ArgumentNullException">
+        /// <paramref name="name"/> or <paramref name="outputHelper"/> is <see langword="null"/>.
+        /// </exception>
+        public XUnitLogger(string name, ITestOutputHelper outputHelper, XUnitLoggerOptions? options)
+            : this(name, new TestOutputHelperAccessor(outputHelper), options)
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="XUnitLogger"/> class.
+        /// </summary>
+        /// <param name="name">The name for messages produced by the logger.</param>
+        /// <param name="accessor">The <see cref="ITestOutputHelperAccessor"/> to use.</param>
+        /// <param name="options">The <see cref="XUnitLoggerOptions"/> to use.</param>
+        /// <exception cref="ArgumentNullException">
+        /// <paramref name="name"/> or <paramref name="accessor"/> is <see langword="null"/>.
+        /// </exception>
+        public XUnitLogger(string name, ITestOutputHelperAccessor accessor, XUnitLoggerOptions? options)
+            : this(name, options)
+        {
+            _outputHelperAccessor = accessor ?? throw new ArgumentNullException(nameof(accessor));
+        }
+    }
+}

src/Logging.XUnit/XUnitLogger.cs

@@ -2,19 +2,18 @@
 // Licensed under the Apache 2.0 license. See the LICENSE file in the project root for full license information.
 
 using System;
-using System.Collections;
 using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Microsoft.Extensions.Logging;
 using Xunit.Abstractions;
+using Xunit.Sdk;
 
 namespace MartinCostello.Logging.XUnit
 {
     /// <summary>
     /// A class representing an <see cref="ILogger"/> to use with xunit.
     /// </summary>
-    public class XUnitLogger : ILogger
+    public partial class XUnitLogger : ILogger
     {
         //// Based on https://github.com/aspnet/Logging/blob/master/src/Microsoft.Extensions.Logging.Console/ConsoleLogger.cs
 
@@ -39,11 +38,6 @@ public class XUnitLogger : ILogger
         [ThreadStatic]
         private static StringBuilder? _logBuilder;
 
-        /// <summary>
-        /// The <see cref="ITestOutputHelperAccessor"/> to use. This field is read-only.
-        /// </summary>
-        private readonly ITestOutputHelperAccessor _accessor;
-
         /// <summary>
         /// Gets or sets the filter to use.
         /// </summary>
@@ -53,31 +47,13 @@ public class XUnitLogger : ILogger
         /// Initializes a new instance of the <see cref="XUnitLogger"/> class.
         /// </summary>
         /// <param name="name">The name for messages produced by the logger.</param>
-        /// <param name="outputHelper">The <see cref="ITestOutputHelper"/> to use.</param>
-        /// <param name="options">The <see cref="XUnitLoggerOptions"/> to use.</param>
-        /// <exception cref="ArgumentNullException">
-        /// <paramref name="name"/> or <paramref name="outputHelper"/> is <see langword="null"/>.
-        /// </exception>
-        public XUnitLogger(string name, ITestOutputHelper outputHelper, XUnitLoggerOptions? options)
-            : this(name, new TestOutputHelperAccessor(outputHelper), options)
-        {
-        }
-
-        /// <summary>
-        /// Initializes a new instance of the <see cref="XUnitLogger"/> class.
-        /// </summary>
-        /// <param name="name">The name for messages produced by the logger.</param>
-        /// <param name="accessor">The <see cref="ITestOutputHelperAccessor"/> to use.</param>
         /// <param name="options">The <see cref="XUnitLoggerOptions"/> to use.</param>
-        /// <exception cref="ArgumentNullException">
-        /// <paramref name="name"/> or <paramref name="accessor"/> is <see langword="null"/>.
-        /// </exception>
-        public XUnitLogger(string name, ITestOutputHelperAccessor accessor, XUnitLoggerOptions? options)
+        private XUnitLogger(string name, XUnitLoggerOptions? options)
         {
             Name = name ?? throw new ArgumentNullException(nameof(name));
-            _accessor = accessor ?? throw new ArgumentNullException(nameof(accessor));
 
-            _filter = options?.Filter ?? ((category, logLevel) => true);
+            _filter = options?.Filter ?? ((_, _) => true);
+            _messageSinkMessageFactory = options?.MessageSinkMessageFactory ?? (message => new DiagnosticMessage(message));
             IncludeScopes = options?.IncludeScopes ?? false;
         }
 
@@ -152,21 +128,14 @@ public void Log<TState>(LogLevel logLevel, EventId eventId, TState? state, Excep
         }
 
         /// <summary>
-        /// Writes a message to the <see cref="ITestOutputHelper"/> associated with the instance.
+        /// Writes a message to the <see cref="ITestOutputHelper"/> or <see cref="IMessageSink"/> associated with the instance.
         /// </summary>
         /// <param name="logLevel">The message to write will be written on this level.</param>
         /// <param name="eventId">The Id of the event.</param>
         /// <param name="message">The message to write.</param>
         /// <param name="exception">The exception related to this message.</param>
         public virtual void WriteMessage(LogLevel logLevel, int eventId, string? message, Exception? exception)
         {
-            ITestOutputHelper? outputHelper = _accessor.OutputHelper;
-
-            if (outputHelper == null)
-            {
-                return;
-            }
-
             StringBuilder? logBuilder = _logBuilder;
             _logBuilder = null;
 
@@ -213,7 +182,20 @@ public virtual void WriteMessage(LogLevel logLevel, int eventId, string? message
 
             try
             {
-                outputHelper.WriteLine($"[{Clock():u}] {logLevelString}{formatted}");
+                ITestOutputHelper? outputHelper = _outputHelperAccessor?.OutputHelper;
+                IMessageSink? messageSink = _messageSinkAccessor?.MessageSink;
+
+                var line = $"[{Clock():u}] {logLevelString}{formatted}";
+                if (outputHelper != null)
+                {
+                    outputHelper.WriteLine(line);
+                }
+
+                if (messageSink != null)
+                {
+                    var sinkMessage = MessageSinkMessageFactory(line);
+                    messageSink.OnMessage(sinkMessage);
+                }
             }
 #pragma warning disable CA1031
             catch (InvalidOperationException)