feat: add JUnit reporter and command provider for test results output

TUnit.Engine.Tests/JUnitReporterTests.cs

@@ -0,0 +1,120 @@
+using Microsoft.Testing.Platform.Extensions;
+using TUnit.Core;
+using TUnit.Engine.Reporters;
+
+namespace TUnit.Engine.Tests;
+
+[NotInParallel]
+public class JUnitReporterTests
+{
+    private sealed class MockExtension : IExtension
+    {
+        public string Uid => "MockExtension";
+        public string DisplayName => "Mock";
+        public string Version => "1.0.0";
+        public string Description => "Mock Extension";
+        public Task<bool> IsEnabledAsync() => Task.FromResult(true);
+    }
+
+    [After(Test)]
+    public void Cleanup()
+    {
+        // Clean up environment variables after each test
+        Environment.SetEnvironmentVariable("TUNIT_DISABLE_JUNIT_REPORTER", null);
+        Environment.SetEnvironmentVariable("TUNIT_ENABLE_JUNIT_REPORTER", null);
+        Environment.SetEnvironmentVariable("GITLAB_CI", null);
+        Environment.SetEnvironmentVariable("CI_SERVER", null);
+        Environment.SetEnvironmentVariable("JUNIT_XML_OUTPUT_PATH", null);
+    }
+
+    [Test]
+    public async Task IsEnabledAsync_Should_Return_False_When_TUNIT_DISABLE_JUNIT_REPORTER_Is_Set()
+    {
+        // Arrange
+        Environment.SetEnvironmentVariable("TUNIT_DISABLE_JUNIT_REPORTER", "true");
+        Environment.SetEnvironmentVariable("GITLAB_CI", "true"); // Even with GitLab CI, should be disabled
+        var extension = new MockExtension();
+        var reporter = new JUnitReporter(extension);
+
+        // Act
+        var isEnabled = await reporter.IsEnabledAsync();
+
+        // Assert
+        await Assert.That(isEnabled).IsFalse();
+    }
+
+    [Test]
+    public async Task IsEnabledAsync_Should_Return_True_When_GITLAB_CI_Is_Set()
+    {
+        // Arrange
+        Environment.SetEnvironmentVariable("GITLAB_CI", "true");
+        var extension = new MockExtension();
+        var reporter = new JUnitReporter(extension);
+
+        // Act
+        var isEnabled = await reporter.IsEnabledAsync();
+
+        // Assert
+        await Assert.That(isEnabled).IsTrue();
+    }
+
+    [Test]
+    public async Task IsEnabledAsync_Should_Return_True_When_CI_SERVER_Is_Set()
+    {
+        // Arrange
+        Environment.SetEnvironmentVariable("CI_SERVER", "yes");
+        var extension = new MockExtension();
+        var reporter = new JUnitReporter(extension);
+
+        // Act
+        var isEnabled = await reporter.IsEnabledAsync();
+
+        // Assert
+        await Assert.That(isEnabled).IsTrue();
+    }
+
+    [Test]
+    public async Task IsEnabledAsync_Should_Return_True_When_TUNIT_ENABLE_JUNIT_REPORTER_Is_Set()
+    {
+        // Arrange
+        Environment.SetEnvironmentVariable("TUNIT_ENABLE_JUNIT_REPORTER", "true");
+        var extension = new MockExtension();
+        var reporter = new JUnitReporter(extension);
+
+        // Act
+        var isEnabled = await reporter.IsEnabledAsync();
+
+        // Assert
+        await Assert.That(isEnabled).IsTrue();
+    }
+
+    [Test]
+    public async Task IsEnabledAsync_Should_Return_False_When_No_Environment_Variables_Are_Set()
+    {
+        // Arrange
+        var extension = new MockExtension();
+        var reporter = new JUnitReporter(extension);
+
+        // Act
+        var isEnabled = await reporter.IsEnabledAsync();
+
+        // Assert
+        await Assert.That(isEnabled).IsFalse();
+    }
+
+    [Test]
+    public async Task IsEnabledAsync_Should_Prefer_Disable_Over_Enable()
+    {
+        // Arrange
+        Environment.SetEnvironmentVariable("TUNIT_DISABLE_JUNIT_REPORTER", "true");
+        Environment.SetEnvironmentVariable("TUNIT_ENABLE_JUNIT_REPORTER", "true");
+        var extension = new MockExtension();
+        var reporter = new JUnitReporter(extension);
+
+        // Act
+        var isEnabled = await reporter.IsEnabledAsync();
+
+        // Assert
+        await Assert.That(isEnabled).IsFalse();
+    }
+}

TUnit.Engine/CommandLineProviders/JUnitReporterCommandProvider.cs

@@ -0,0 +1,45 @@
+using Microsoft.Testing.Platform.CommandLine;
+using Microsoft.Testing.Platform.Extensions;
+using Microsoft.Testing.Platform.Extensions.CommandLine;
+
+namespace TUnit.Engine.CommandLineProviders;
+
+internal class JUnitReporterCommandProvider(IExtension extension) : ICommandLineOptionsProvider
+{
+    public const string JUnitOutputPathOption = "junit-output-path";
+
+    public Task<bool> IsEnabledAsync() => extension.IsEnabledAsync();
+
+    public string Uid => extension.Uid;
+
+    public string Version => extension.Version;
+
+    public string DisplayName => extension.DisplayName;
+
+    public string Description => extension.Description;
+
+    public IReadOnlyCollection<CommandLineOption> GetCommandLineOptions()
+    {
+        return
+        [
+            new CommandLineOption(
+                JUnitOutputPathOption,
+                "Path to output JUnit XML file (default: TestResults/{AssemblyName}-junit.xml)",
+                ArgumentArity.ExactlyOne,
+                false)
+        ];
+    }
+
+    public Task<ValidationResult> ValidateOptionArgumentsAsync(
+        CommandLineOption commandOption,
+        string[] arguments)
+    {
+        return ValidationResult.ValidTask;
+    }
+
+    public Task<ValidationResult> ValidateCommandLineOptionsAsync(
+        ICommandLineOptions commandLineOptions)
+    {
+        return ValidationResult.ValidTask;
+    }
+}

TUnit.Engine/Extensions/TestApplicationBuilderExtensions.cs

@@ -21,6 +21,9 @@ public static void AddTUnit(this ITestApplicationBuilder testApplicationBuilder)
         var githubReporter = new GitHubReporter(extension);
         var githubReporterCommandProvider = new GitHubReporterCommandProvider(extension);
 
+        var junitReporter = new JUnitReporter(extension);
+        var junitReporterCommandProvider = new JUnitReporterCommandProvider(extension);
+
         testApplicationBuilder.RegisterTestFramework(
             serviceProvider => new TestFrameworkCapabilities(CreateCapabilities(serviceProvider)),
             (capabilities, serviceProvider) => new TUnitTestFramework(extension, serviceProvider, capabilities));
@@ -46,6 +49,9 @@ public static void AddTUnit(this ITestApplicationBuilder testApplicationBuilder)
         // GitHub reporter configuration
         testApplicationBuilder.CommandLine.AddProvider(() => githubReporterCommandProvider);
 
+        // JUnit reporter configuration
+        testApplicationBuilder.CommandLine.AddProvider(() => junitReporterCommandProvider);
+
         testApplicationBuilder.TestHost.AddDataConsumer(serviceProvider =>
         {
             // Apply command-line configuration if provided
@@ -58,6 +64,18 @@ public static void AddTUnit(this ITestApplicationBuilder testApplicationBuilder)
             return githubReporter;
         });
         testApplicationBuilder.TestHost.AddTestHostApplicationLifetime(_ => githubReporter);
+
+        testApplicationBuilder.TestHost.AddDataConsumer(serviceProvider =>
+        {
+            // Apply command-line configuration if provided
+            var commandLineOptions = serviceProvider.GetRequiredService<ICommandLineOptions>();
+            if (commandLineOptions.TryGetOptionArgumentList(JUnitReporterCommandProvider.JUnitOutputPathOption, out var pathArgs))
+            {
+                junitReporter.SetOutputPath(pathArgs[0]);
+            }
+            return junitReporter;
+        });
+        testApplicationBuilder.TestHost.AddTestHostApplicationLifetime(_ => junitReporter);
     }
 
     private static IReadOnlyCollection<ITestFrameworkCapability> CreateCapabilities(IServiceProvider serviceProvider)