Merge pull request #8 from martincostello/ITestOutputHandlerAccessor

Add ITestOutputHelperAccessor

Logging.XUnit.sln

@@ -52,6 +52,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MartinCostello.Logging.XUni
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MartinCostello.Logging.XUnit", "src\Logging.XUnit\MartinCostello.Logging.XUnit.csproj", "{BB443063-F523-474D-83E3-D5FF5B075950}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SampleApp", "tests\SampleApp\SampleApp.csproj", "{B690F271-3B5D-4975-A607-AED1768595B1}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -66,6 +68,10 @@ Global
 		{BB443063-F523-474D-83E3-D5FF5B075950}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{BB443063-F523-474D-83E3-D5FF5B075950}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{BB443063-F523-474D-83E3-D5FF5B075950}.Release|Any CPU.Build.0 = Release|Any CPU
+		{B690F271-3B5D-4975-A607-AED1768595B1}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{B690F271-3B5D-4975-A607-AED1768595B1}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{B690F271-3B5D-4975-A607-AED1768595B1}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{B690F271-3B5D-4975-A607-AED1768595B1}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -76,6 +82,7 @@ Global
 		{F37263E7-6656-4A2B-B02E-538B5F9970BD} = {D0426D09-1FF8-4E1F-A9AF-38DDEE5D7CCA}
 		{331BC69B-DFFC-4174-8A97-6335BF6D86CF} = {278BCCB1-39B2-46DB-9395-7F85995A6132}
 		{BB443063-F523-474D-83E3-D5FF5B075950} = {2684B19D-7D49-4099-8BD2-4D281455EB29}
+		{B690F271-3B5D-4975-A607-AED1768595B1} = {278BCCB1-39B2-46DB-9395-7F85995A6132}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {3B9E157C-5E92-4357-B233-281B4530EABD}

src/Logging.XUnit/AmbientTestOutputHelperAccessor.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.Threading;
+using Xunit.Abstractions;
+
+namespace MartinCostello.Logging.XUnit
+{
+    /// <summary>
+    /// A class representing an implementation of <see cref="ITestOutputHelperAccessor"/> that
+    /// stores the <see cref="ITestOutputHelper"/> as an asynchronous local value. This class cannot be inherited.
+    /// </summary>
+    internal sealed class AmbientTestOutputHelperAccessor : ITestOutputHelperAccessor
+    {
+        /// <summary>
+        /// A backing field for the <see cref="ITestOutputHelper"/> for the current thread.
+        /// </summary>
+        private static readonly AsyncLocal<ITestOutputHelper> _current = new AsyncLocal<ITestOutputHelper>();
+
+#pragma warning disable CA1822
+        /// <summary>
+        /// Gets or sets the current <see cref="ITestOutputHelper"/>.
+        /// </summary>
+        public ITestOutputHelper OutputHelper
+        {
+            get { return _current.Value; }
+            set { _current.Value = value; }
+        }
+#pragma warning restore CA1822
+    }
+}

src/Logging.XUnit/ITestOutputHelperAccessor.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="ITestOutputHelper"/>.
+    /// </summary>
+    public interface ITestOutputHelperAccessor
+    {
+        /// <summary>
+        /// Gets or sets the <see cref="ITestOutputHelper"/> to use.
+        /// </summary>
+        ITestOutputHelper OutputHelper { get; set; }
+    }
+}

src/Logging.XUnit/TestOutputHelperAccessor.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="ITestOutputHelperAccessor"/>. This class cannot be inherited.
+    /// </summary>
+    internal sealed class TestOutputHelperAccessor : ITestOutputHelperAccessor
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="TestOutputHelperAccessor"/> class.
+        /// </summary>
+        /// <param name="outputHelper">The <see cref="ITestOutputHelper"/> to use.</param>
+        /// <exception cref="ArgumentNullException">
+        /// <paramref name="outputHelper"/> is <see langword="null"/>.
+        /// </exception>
+        internal TestOutputHelperAccessor(ITestOutputHelper outputHelper)
+        {
+            OutputHelper = outputHelper ?? throw new ArgumentNullException(nameof(outputHelper));
+        }
+
+        /// <summary>
+        /// Gets or sets the current <see cref="ITestOutputHelper"/>.
+        /// </summary>
+        public ITestOutputHelper OutputHelper { get; set; }
+    }
+}

src/Logging.XUnit/XUnitLogger.cs

@@ -37,9 +37,9 @@ public class XUnitLogger : ILogger
         private static StringBuilder _logBuilder;
 
         /// <summary>
-        /// The <see cref="ITestOutputHelper"/> to use. This field is read-only.
+        /// The <see cref="ITestOutputHelperAccessor"/> to use. This field is read-only.
         /// </summary>
-        private readonly ITestOutputHelper _outputHelper;
+        private readonly ITestOutputHelperAccessor _accessor;
 
         /// <summary>
         /// Gets or sets the filter to use.
@@ -56,9 +56,23 @@ public class XUnitLogger : ILogger
         /// <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)
         {
             Name = name ?? throw new ArgumentNullException(nameof(name));
-            _outputHelper = outputHelper ?? throw new ArgumentNullException(nameof(outputHelper));
+            _accessor = accessor ?? throw new ArgumentNullException(nameof(accessor));
 
             Filter = options?.Filter ?? ((category, logLevel) => true);
             IncludeScopes = options?.IncludeScopes ?? false;
@@ -143,6 +157,13 @@ public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Except
         /// <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;
 
@@ -186,7 +207,7 @@ public virtual void WriteMessage(LogLevel logLevel, int eventId, string message,
             }
 
             string formatted = logBuilder.ToString();
-            _outputHelper.WriteLine($"[{Clock():u}] {logLevelString}{formatted}");
+            outputHelper.WriteLine($"[{Clock():u}] {logLevelString}{formatted}");
 
             logBuilder.Clear();
 

src/Logging.XUnit/XUnitLoggerExtensions.cs

@@ -4,6 +4,7 @@
 using System;
 using System.ComponentModel;
 using MartinCostello.Logging.XUnit;
+using Microsoft.Extensions.DependencyInjection.Extensions;
 using Xunit.Abstractions;
 
 namespace Microsoft.Extensions.Logging
@@ -14,6 +15,91 @@ namespace Microsoft.Extensions.Logging
     [EditorBrowsable(EditorBrowsableState.Never)]
     public static class XUnitLoggerExtensions
     {
+        /// <summary>
+        /// Adds an xunit logger to the logging builder.
+        /// </summary>
+        /// <param name="builder">The <see cref="ILoggingBuilder"/> to use.</param>
+        /// <returns>
+        /// The instance of <see cref="ILoggingBuilder"/> specified by <paramref name="builder"/>.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        /// <paramref name="builder"/>  is <see langword="null"/>.
+        /// </exception>
+        public static ILoggingBuilder AddXUnit(this ILoggingBuilder builder)
+        {
+            if (builder == null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+            return builder.AddXUnit(new AmbientTestOutputHelperAccessor(), (_) => { });
+        }
+
+        /// <summary>
+        /// Adds an xunit logger to the logging builder.
+        /// </summary>
+        /// <param name="builder">The <see cref="ILoggingBuilder"/> to use.</param>
+        /// <param name="accessor">The <see cref="ITestOutputHelperAccessor"/> to use.</param>
+        /// <returns>
+        /// The instance of <see cref="ILoggingBuilder"/> specified by <paramref name="builder"/>.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        /// <paramref name="builder"/> or <paramref name="accessor"/> is <see langword="null"/>.
+        /// </exception>
+        public static ILoggingBuilder AddXUnit(this ILoggingBuilder builder, ITestOutputHelperAccessor accessor)
+        {
+            if (builder == null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+            if (accessor == null)
+            {
+                throw new ArgumentNullException(nameof(accessor));
+            }
+
+            return builder.AddXUnit(accessor, (_) => { });
+        }
+
+        /// <summary>
+        /// Adds an xunit logger to the logging builder.
+        /// </summary>
+        /// <param name="builder">The <see cref="ILoggingBuilder"/> to use.</param>
+        /// <param name="accessor">The <see cref="ITestOutputHelperAccessor"/> to use.</param>
+        /// <param name="configure">A delegate to a method to use to configure the logging options.</param>
+        /// <returns>
+        /// The instance of <see cref="ILoggingBuilder"/> specified by <paramref name="builder"/>.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        /// <paramref name="builder"/>, <paramref name="accessor"/> OR <paramref name="configure"/> is <see langword="null"/>.
+        /// </exception>
+        public static ILoggingBuilder AddXUnit(this ILoggingBuilder builder, ITestOutputHelperAccessor accessor, Action<XUnitLoggerOptions> configure)
+        {
+            if (builder == null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+            if (accessor == null)
+            {
+                throw new ArgumentNullException(nameof(accessor));
+            }
+
+            if (configure == null)
+            {
+                throw new ArgumentNullException(nameof(configure));
+            }
+
+            var options = new XUnitLoggerOptions();
+
+            configure(options);
+
+            builder.AddProvider(new XUnitLoggerProvider(accessor, options));
+            builder.Services.TryAddSingleton(accessor);
+
+            return builder;
+        }
+
         /// <summary>
         /// Adds an xunit logger to the logging builder.
         /// </summary>

src/Logging.XUnit/XUnitLoggerProvider.cs

@@ -13,9 +13,9 @@ namespace MartinCostello.Logging.XUnit
     public class XUnitLoggerProvider : ILoggerProvider
     {
         /// <summary>
-        /// The <see cref="ITestOutputHelper"/> to use. This field is readonly.
+        /// The <see cref="ITestOutputHelperAccessor"/> to use. This field is readonly.
         /// </summary>
-        private readonly ITestOutputHelper _outputHelper;
+        private readonly ITestOutputHelperAccessor _accessor;
 
         /// <summary>
         /// The <see cref="XUnitLoggerOptions"/> to use. This field is readonly.
@@ -31,8 +31,21 @@ public class XUnitLoggerProvider : ILoggerProvider
         /// <paramref name="outputHelper"/> or <paramref name="options"/> is <see langword="null"/>.
         /// </exception>
         public XUnitLoggerProvider(ITestOutputHelper outputHelper, XUnitLoggerOptions options)
+            : this(new TestOutputHelperAccessor(outputHelper), options)
         {
-            _outputHelper = outputHelper ?? throw new ArgumentNullException(nameof(outputHelper));
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="XUnitLoggerProvider"/> class.
+        /// </summary>
+        /// <param name="accessor">The <see cref="ITestOutputHelperAccessor"/> to use.</param>
+        /// <param name="options">The options to use for logging to xunit.</param>
+        /// <exception cref="ArgumentNullException">
+        /// <paramref name="accessor"/> or <paramref name="options"/> is <see langword="null"/>.
+        /// </exception>
+        public XUnitLoggerProvider(ITestOutputHelperAccessor accessor, XUnitLoggerOptions options)
+        {
+            _accessor = accessor ?? throw new ArgumentNullException(nameof(accessor));
             _options = options ?? throw new ArgumentNullException(nameof(options));
         }
 
@@ -45,7 +58,7 @@ public XUnitLoggerProvider(ITestOutputHelper outputHelper, XUnitLoggerOptions op
         }
 
         /// <inheritdoc />
-        public virtual ILogger CreateLogger(string categoryName) => new XUnitLogger(categoryName, _outputHelper, _options);
+        public virtual ILogger CreateLogger(string categoryName) => new XUnitLogger(categoryName, _accessor, _options);
 
         /// <inheritdoc />
         public void Dispose()