feat: implement TestBuildContext for capturing build-time output

TUnit.Core/Context.cs

@@ -14,6 +14,7 @@ protected Context? Parent
 
     public static Context Current =>
         TestContext.Current as Context
+        ?? TestBuildContext.Current as Context
         ?? ClassHookContext.Current as Context
         ?? AssemblyHookContext.Current as Context
         ?? TestSessionContext.Current as Context
@@ -67,13 +68,13 @@ public void AddAsyncLocalValues()
 #endif
     }
 
-    public string GetStandardOutput()
+    public virtual string GetStandardOutput()
     {
         if (_outputBuilder.Length == 0)
         {
             return string.Empty;
         }
-        
+
         _outputLock.EnterReadLock();
 
         try
@@ -86,7 +87,7 @@ public string GetStandardOutput()
         }
     }
 
-    public string GetErrorOutput()
+    public virtual string GetErrorOutput()
     {
         if (_errorOutputBuilder.Length == 0)
         {

TUnit.Core/Models/TestBuildContext.cs

@@ -0,0 +1,45 @@
+namespace TUnit.Core;
+
+/// <summary>
+/// Context for capturing output during test building and data source initialization.
+/// This context is active during the test building phase, before TestContext is created.
+/// Output captured here is transferred to the TestContext when it's created.
+/// </summary>
+public sealed class TestBuildContext : Context, IDisposable
+{
+    private static readonly AsyncLocal<TestBuildContext?> _current = new();
+
+    public static new TestBuildContext? Current
+    {
+        get => _current.Value;
+        internal set => _current.Value = value;
+    }
+
+    public TestBuildContext() : base(null)
+    {
+    }
+
+    /// <summary>
+    /// Gets the captured standard output during test building.
+    /// </summary>
+    public string GetCapturedOutput() => GetStandardOutput();
+
+    /// <summary>
+    /// Gets the captured error output during test building.
+    /// </summary>
+    public string GetCapturedErrorOutput() => GetErrorOutput();
+
+    internal override void SetAsyncLocalContext()
+    {
+        Current = this;
+    }
+
+    /// <summary>
+    /// Clears the current TestBuildContext.
+    /// </summary>
+    public new void Dispose()
+    {
+        Current = null;
+        base.Dispose();
+    }
+}

TUnit.Core/TestContext.Output.cs

@@ -32,7 +32,7 @@ void ITestOutput.AttachArtifact(Artifact artifact)
     }
 
     string ITestOutput.GetStandardOutput() => GetOutput();
-    string ITestOutput.GetErrorOutput() => GetErrorOutput();
+    string ITestOutput.GetErrorOutput() => GetOutputError();
 
     void ITestOutput.WriteLine(string message)
     {
@@ -46,7 +46,47 @@ void ITestOutput.WriteError(string message)
         _errorWriter.WriteLine(message);
     }
 
-    internal string GetOutput() => _outputWriter?.ToString() ?? string.Empty;
+    /// <summary>
+    /// Gets the combined build-time and execution-time standard output.
+    /// </summary>
+    public override string GetStandardOutput()
+    {
+        return GetOutput();
+    }
+
+    /// <summary>
+    /// Gets the combined build-time and execution-time error output.
+    /// </summary>
+    public override string GetErrorOutput()
+    {
+        return GetOutputError();
+    }
+
+    internal string GetOutput()
+    {
+        var buildOutput = _buildTimeOutput ?? string.Empty;
+        var baseOutput = base.GetStandardOutput();  // Get output from base class (Context)
+        var writerOutput = _outputWriter?.ToString() ?? string.Empty;
 
-    internal new string GetErrorOutput() => _errorWriter?.ToString() ?? string.Empty;
+        // Combine all three sources: build-time, base class output, and writer output
+        var parts = new[] { buildOutput, baseOutput, writerOutput }
+            .Where(s => !string.IsNullOrEmpty(s))
+            .ToArray();
+
+        return parts.Length == 0 ? string.Empty : string.Join(Environment.NewLine, parts);
+    }
+
+    internal string GetOutputError()
+    {
+        var buildErrorOutput = _buildTimeErrorOutput ?? string.Empty;
+        var baseErrorOutput = base.GetErrorOutput();  // Get error output from base class (Context)
+        var writerErrorOutput = _errorWriter?.ToString() ?? string.Empty;
+
+        // Combine all three sources: build-time error, base class error output, and writer error output
+        var parts = new[] { buildErrorOutput, baseErrorOutput, writerErrorOutput }
+            .Where(s => !string.IsNullOrEmpty(s))
+            .ToArray();
+
+        return parts.Length == 0 ? string.Empty : string.Join(Environment.NewLine, parts);
+    }
 }

TUnit.Core/TestContext.cs

@@ -55,6 +55,9 @@ public TestContext(string testName, IServiceProvider serviceProvider, ClassHookC
 
     private StringWriter? _errorWriter;
 
+    private string? _buildTimeOutput;
+    private string? _buildTimeErrorOutput;
+
     public static new TestContext? Current
     {
         get => TestContexts.Value;
@@ -152,5 +155,13 @@ internal override void SetAsyncLocalContext()
     internal ConcurrentDictionary<int, HashSet<object>> TrackedObjects =>
         _trackedObjects ??= new();
 
-
+    /// <summary>
+    /// Sets the output captured during test building phase.
+    /// This output is prepended to the test's execution output.
+    /// </summary>
+    internal void SetBuildTimeOutput(string? output, string? errorOutput)
+    {
+        _buildTimeOutput = output;
+        _buildTimeErrorOutput = errorOutput;
+    }
 }

TUnit.Engine/Building/TestBuilder.cs

@@ -136,6 +136,10 @@ public async Task<IEnumerable<AbstractExecutableTest>> BuildTestsFromMetadataAsy
 
         try
         {
+            // Create a context for capturing output during test building
+            using var buildContext = new TestBuildContext();
+            TestBuildContext.Current = buildContext;
+
             // Handle GenericTestMetadata with ConcreteInstantiations
             if (metadata is GenericTestMetadata { ConcreteInstantiations.Count: > 0 } genericMetadata)
             {
@@ -508,6 +512,18 @@ public async Task<IEnumerable<AbstractExecutableTest>> BuildTestsFromMetadataAsy
                     tests.Add(test);
                 }
             }
+
+            // Transfer captured build-time output to all test contexts
+            var capturedOutput = buildContext.GetCapturedOutput();
+            var capturedErrorOutput = buildContext.GetCapturedErrorOutput();
+
+            if (!string.IsNullOrEmpty(capturedOutput) || !string.IsNullOrEmpty(capturedErrorOutput))
+            {
+                foreach (var test in tests)
+                {
+                    test.Context.SetBuildTimeOutput(capturedOutput, capturedErrorOutput);
+                }
+            }
         }
         catch (Exception ex)
         {

TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.DotNet10_0.verified.txt

@@ -399,8 +399,8 @@ namespace
         public void AddAsyncLocalValues() { }
         public void Dispose() { }
         public . GetDefaultLogger() { }
-        public string GetErrorOutput() { }
-        public string GetStandardOutput() { }
+        public virtual string GetErrorOutput() { }
+        public virtual string GetStandardOutput() { }
         public void RestoreExecutionContext() { }
     }
     public class ContextProvider : .
@@ -1241,6 +1241,14 @@ namespace
     {
         public TestAttribute([.] string file = "", [.] int line = 0) { }
     }
+    public sealed class TestBuildContext : .Context, 
+    {
+        public TestBuildContext() { }
+        public new static .TestBuildContext? Current { get; }
+        public new void Dispose() { }
+        public string GetCapturedErrorOutput() { }
+        public string GetCapturedOutput() { }
+    }
     public class TestBuilderContext : <.TestBuilderContext>
     {
         public TestBuilderContext() { }
@@ -1291,6 +1299,8 @@ namespace
         public static string? OutputDirectory { get; }
         public static .<string, .<string>> Parameters { get; }
         public static string WorkingDirectory { get; set; }
+        public override string GetErrorOutput() { }
+        public override string GetStandardOutput() { }
         public static .TestContext? GetById(string id) { }
     }
     public class TestContextEvents : .

TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.DotNet8_0.verified.txt

@@ -399,8 +399,8 @@ namespace
         public void AddAsyncLocalValues() { }
         public void Dispose() { }
         public . GetDefaultLogger() { }
-        public string GetErrorOutput() { }
-        public string GetStandardOutput() { }
+        public virtual string GetErrorOutput() { }
+        public virtual string GetStandardOutput() { }
         public void RestoreExecutionContext() { }
     }
     public class ContextProvider : .
@@ -1241,6 +1241,14 @@ namespace
     {
         public TestAttribute([.] string file = "", [.] int line = 0) { }
     }
+    public sealed class TestBuildContext : .Context, 
+    {
+        public TestBuildContext() { }
+        public new static .TestBuildContext? Current { get; }
+        public new void Dispose() { }
+        public string GetCapturedErrorOutput() { }
+        public string GetCapturedOutput() { }
+    }
     public class TestBuilderContext : <.TestBuilderContext>
     {
         public TestBuilderContext() { }
@@ -1291,6 +1299,8 @@ namespace
         public static string? OutputDirectory { get; }
         public static .<string, .<string>> Parameters { get; }
         public static string WorkingDirectory { get; set; }
+        public override string GetErrorOutput() { }
+        public override string GetStandardOutput() { }
         public static .TestContext? GetById(string id) { }
     }
     public class TestContextEvents : .

TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.DotNet9_0.verified.txt

@@ -399,8 +399,8 @@ namespace
         public void AddAsyncLocalValues() { }
         public void Dispose() { }
         public . GetDefaultLogger() { }
-        public string GetErrorOutput() { }
-        public string GetStandardOutput() { }
+        public virtual string GetErrorOutput() { }
+        public virtual string GetStandardOutput() { }
         public void RestoreExecutionContext() { }
     }
     public class ContextProvider : .
@@ -1241,6 +1241,14 @@ namespace
     {
         public TestAttribute([.] string file = "", [.] int line = 0) { }
     }
+    public sealed class TestBuildContext : .Context, 
+    {
+        public TestBuildContext() { }
+        public new static .TestBuildContext? Current { get; }
+        public new void Dispose() { }
+        public string GetCapturedErrorOutput() { }
+        public string GetCapturedOutput() { }
+    }
     public class TestBuilderContext : <.TestBuilderContext>
     {
         public TestBuilderContext() { }
@@ -1291,6 +1299,8 @@ namespace
         public static string? OutputDirectory { get; }
         public static .<string, .<string>> Parameters { get; }
         public static string WorkingDirectory { get; set; }
+        public override string GetErrorOutput() { }
+        public override string GetStandardOutput() { }
         public static .TestContext? GetById(string id) { }
     }
     public class TestContextEvents : .

TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.Net4_7.verified.txt

@@ -379,8 +379,8 @@ namespace
         public void AddAsyncLocalValues() { }
         public void Dispose() { }
         public . GetDefaultLogger() { }
-        public string GetErrorOutput() { }
-        public string GetStandardOutput() { }
+        public virtual string GetErrorOutput() { }
+        public virtual string GetStandardOutput() { }
         public void RestoreExecutionContext() { }
     }
     public class ContextProvider : .
@@ -1196,6 +1196,14 @@ namespace
     {
         public TestAttribute([.] string file = "", [.] int line = 0) { }
     }
+    public sealed class TestBuildContext : .Context, 
+    {
+        public TestBuildContext() { }
+        public new static .TestBuildContext? Current { get; }
+        public new void Dispose() { }
+        public string GetCapturedErrorOutput() { }
+        public string GetCapturedOutput() { }
+    }
     public class TestBuilderContext : <.TestBuilderContext>
     {
         public TestBuilderContext() { }
@@ -1246,6 +1254,8 @@ namespace
         public static string? OutputDirectory { get; }
         public static .<string, .<string>> Parameters { get; }
         public static string WorkingDirectory { get; set; }
+        public override string GetErrorOutput() { }
+        public override string GetStandardOutput() { }
         public static .TestContext? GetById(string id) { }
     }
     public class TestContextEvents : .