refactor: replace Environment.MachineName with cached EnvironmentHelp…

…er.MachineName to improve performance

TUnit.Core/AbstractExecutableTest.cs

@@ -1,4 +1,5 @@
 using System.Diagnostics;
+using TUnit.Core.Helpers;
 using TUnit.Core.Models;
 
 namespace TUnit.Core;
@@ -8,7 +9,7 @@ public abstract class AbstractExecutableTest
 {
     public required string TestId { get; init; }
 
-    public virtual TestMetadata Metadata { get; init; } = null!;
+    public TestMetadata Metadata { get; init; } = null!;
 
     public required object?[] Arguments { get; init; }
 
@@ -70,15 +71,26 @@ public DateTimeOffset? StartTime
     public void SetResult(TestState state, Exception? exception = null)
     {
         State = state;
+
+        // Lazy output building - avoid string allocation when there's no output
+        var output = Context.GetOutput();
+        var errorOutput = Context.GetErrorOutput();
+        var combinedOutput = string.Empty;
+
+        if (output.Length > 0 || errorOutput.Length > 0)
+        {
+            combinedOutput = string.Concat(output, Environment.NewLine, Environment.NewLine, errorOutput);
+        }
+
         Context.Execution.Result ??= new TestResult
         {
             State = state,
             Exception = exception,
-            ComputerName = Environment.MachineName,
+            ComputerName = EnvironmentHelper.MachineName,
             Duration = Duration,
             End = EndTime ??= DateTimeOffset.UtcNow,
             Start = StartTime ??= DateTimeOffset.UtcNow,
-            Output = string.Concat(Context.GetOutput(), Environment.NewLine, Environment.NewLine, Context.GetErrorOutput())
+            Output = combinedOutput
         };
     }
 }

TUnit.Core/Helpers/EnvironmentHelper.cs

@@ -0,0 +1,13 @@
+namespace TUnit.Core.Helpers;
+
+/// <summary>
+/// Provides cached environment information to avoid repeated system calls.
+/// </summary>
+internal static class EnvironmentHelper
+{
+    /// <summary>
+    /// Cached machine name - avoids system call overhead on every test completion.
+    /// Environment.MachineName requires a P/Invoke call which is expensive when called millions of times.
+    /// </summary>
+    public static readonly string MachineName = Environment.MachineName;
+}

TUnit.Core/TestContext.Execution.cs

@@ -1,4 +1,5 @@
 using TUnit.Core.Enums;
+using TUnit.Core.Helpers;
 using TUnit.Core.Interfaces;
 
 namespace TUnit.Core;
@@ -112,7 +113,7 @@ internal void OverrideResult(TestState state, string reason)
                 End = DateTimeOffset.UtcNow,
                 Duration = DateTimeOffset.UtcNow - (TestStart ?? DateTimeOffset.UtcNow),
                 Exception = exceptionForResult,
-                ComputerName = Environment.MachineName,
+                ComputerName = EnvironmentHelper.MachineName,
                 TestContext = this
             };
 

TUnit.Engine/Building/TestBuilderPipeline.cs

@@ -390,7 +390,7 @@ private AbstractExecutableTest CreateFailedTestForDataGenerationError(TestMetada
                 End = DateTimeOffset.UtcNow,
                 Duration = TimeSpan.Zero,
                 Exception = exception,
-                ComputerName = Environment.MachineName,
+                ComputerName = EnvironmentHelper.MachineName,
                 TestContext = context
             }
         };
@@ -441,7 +441,7 @@ private AbstractExecutableTest CreateFailedTestForGenericResolutionError(TestMet
                 End = DateTimeOffset.UtcNow,
                 Duration = TimeSpan.Zero,
                 Exception = exception,
-                ComputerName = Environment.MachineName,
+                ComputerName = EnvironmentHelper.MachineName,
                 TestContext = context
             }
         };

TUnit.Engine/Services/TestDependencyResolver.cs

@@ -1,4 +1,5 @@
 using TUnit.Core;
+using TUnit.Core.Helpers;
 
 namespace TUnit.Engine.Services;
 
@@ -263,7 +264,7 @@ private static void CreateDependencyResolutionFailedResult(AbstractExecutableTes
             Duration = TimeSpan.Zero,
             Exception = new InvalidOperationException(
                 $"Could not resolve all dependencies for test {test.Metadata.TestClassType.Name}.{test.Metadata.TestMethodName}"),
-            ComputerName = Environment.MachineName
+            ComputerName = EnvironmentHelper.MachineName
         };
     }
 }

TUnit.Engine/Services/TestExecution/TestStateManager.cs

@@ -1,5 +1,6 @@
 using TUnit.Core;
 using TUnit.Core.Exceptions;
+using TUnit.Core.Helpers;
 
 namespace TUnit.Engine.Services.TestExecution;
 
@@ -27,7 +28,7 @@ public Task MarkCompletedAsync(AbstractExecutableTest test)
             End = now,
             Duration = now - test.StartTime.GetValueOrDefault(),
             Exception = null,
-            ComputerName = Environment.MachineName
+            ComputerName = EnvironmentHelper.MachineName
         };
 
         test.State = test.Result.State;
@@ -55,7 +56,7 @@ public Task MarkFailedAsync(AbstractExecutableTest test, Exception exception)
                 Start = test.StartTime,
                 End = test.EndTime,
                 Duration = test.EndTime - test.StartTime.GetValueOrDefault(),
-                ComputerName = Environment.MachineName
+                ComputerName = EnvironmentHelper.MachineName
             };
         }
 
@@ -81,7 +82,7 @@ public Task MarkSkippedAsync(AbstractExecutableTest test, string reason)
             Start = test.StartTime.Value,
             End = test.EndTime,
             Duration = test.EndTime - test.StartTime.GetValueOrDefault(),
-            ComputerName = Environment.MachineName
+            ComputerName = EnvironmentHelper.MachineName
         };
 
         return Task.CompletedTask;
@@ -98,7 +99,7 @@ public Task MarkCircularDependencyFailedAsync(AbstractExecutableTest test, Excep
             Start = now,
             End = now,
             Duration = TimeSpan.Zero,
-            ComputerName = Environment.MachineName
+            ComputerName = EnvironmentHelper.MachineName
         };
 
         return Task.CompletedTask;
@@ -117,7 +118,7 @@ public Task MarkDependencyResolutionFailedAsync(AbstractExecutableTest test, Exc
             Start = now,
             End = now,
             Duration = TimeSpan.Zero,
-            ComputerName = Environment.MachineName
+            ComputerName = EnvironmentHelper.MachineName
         };
 
         return Task.CompletedTask;