fix: Resource leak in the tests

src/Spice86.Core/Emulator/Devices/Video/Renderer.cs

@@ -7,7 +7,7 @@ namespace Spice86.Core.Emulator.Devices.Video;
 using Spice86.Core.Emulator.Devices.Video.Registers;
 using Spice86.Core.Emulator.Devices.Video.Registers.Graphics;
 using Spice86.Core.Emulator.Memory;
-using Spice86.Logging;
+using Spice86.Shared.Interfaces;
 
 using ClockSelect = Registers.General.MiscellaneousOutput.ClockSelectValue;
 
@@ -74,7 +74,7 @@ public class Renderer : IVgaRenderer {
     /// <param name="blinkState">Shared blink state for text-mode attribute blinking.</param>
     /// <param name="loggerService">The logger service implementation.</param>
     /// <param name="renderer256Color">The 256-color scanline renderer selected for the current CPU.</param>
-    public Renderer(IMemory memory, IVideoState state, VgaBlinkState blinkState, LoggerService loggerService, IVgaRenderer256Color renderer256Color) {
+    public Renderer(IMemory memory, IVideoState state, VgaBlinkState blinkState, ILoggerService loggerService, IVgaRenderer256Color renderer256Color) {
         _state = state;
         _blinkState = blinkState;
         _renderer256Color = renderer256Color;

src/Spice86.Logging/LoggerService.cs

@@ -14,7 +14,6 @@ public class LoggerService : ILoggerService, IDisposable {
 
     private static readonly object?[] EmptyProperties = [];
 
-    private LoggerConfiguration _loggerConfiguration;
     private Logger? _logger;
     private LoggingLevelSwitch _logLevelSwitch;
     private bool _disposed;
@@ -25,16 +24,13 @@ public class LoggerService : ILoggerService, IDisposable {
     public LoggerService() {
         _logLevelSwitch = new LoggingLevelSwitch();
         LoggerPropertyBag = new LoggerPropertyBag();
-        _loggerConfiguration = CreateLoggerConfiguration();
-        _loggerConfiguration.MinimumLevel.ControlledBy(_logLevelSwitch);
     }
 
     /// <inheritdoc />
     public LoggingLevelSwitch LogLevelSwitch {
         get => _logLevelSwitch;
         set {
             _logLevelSwitch = value ?? throw new ArgumentNullException(nameof(value));
-            _loggerConfiguration.MinimumLevel.ControlledBy(_logLevelSwitch);
             ResetLogger();
         }
     }
@@ -49,28 +45,14 @@ public LoggingLevelSwitch LogLevelSwitch {
     public LoggerConfiguration CreateLoggerConfiguration() {
         LoggerConfiguration configuration = new LoggerConfiguration()
             .Enrich.FromLogContext()
-            .Enrich.With(new LoggerPropertyBagEnricher(LoggerPropertyBag))
-            .WriteTo.Async(conf => conf.Console(outputTemplate: LogFormat))
-            .WriteTo.Async(conf2 => conf2.Debug(outputTemplate: LogFormat))
-            .WriteTo.Async(conf3 =>
-                conf3.File("logs/log-.txt", outputTemplate: LogFormat, rollingInterval: RollingInterval.Day));
+            .Enrich.With(new LoggerPropertyBagEnricher(LoggerPropertyBag));
+        configuration.WriteTo.Async(conf => conf.Console(outputTemplate: LogFormat));
+        configuration.WriteTo.Async(conf2 => conf2.Debug(outputTemplate: LogFormat));
+        configuration.WriteTo.Async(conf3 =>
+            conf3.File("logs/log-.txt", outputTemplate: LogFormat, rollingInterval: RollingInterval.Day));
         return configuration;
     }
 
-    /// <inheritdoc />
-    public void UseStderrForConsoleOutput() {
-        _logger?.Dispose();
-        _logger = null;
-        _loggerConfiguration = new LoggerConfiguration()
-            .Enrich.FromLogContext()
-            .Enrich.With(new LoggerPropertyBagEnricher(LoggerPropertyBag))
-            .WriteTo.Async(conf => conf.Console(outputTemplate: LogFormat, standardErrorFromLevel: Serilog.Events.LogEventLevel.Verbose))
-            .WriteTo.Async(conf2 => conf2.Debug(outputTemplate: LogFormat))
-            .WriteTo.Async(conf3 =>
-                conf3.File("logs/log-.txt", outputTemplate: LogFormat, rollingInterval: RollingInterval.Day));
-        _loggerConfiguration.MinimumLevel.ControlledBy(_logLevelSwitch);
-    }
-
     public void Write(LogEventLevel level, string messageTemplate) {
         GetLoggerForLevel(level)?.Write(level, messageTemplate);
     }
@@ -139,19 +121,23 @@ public void Dispose() {
     private void ResetLogger() {
         _logger?.Dispose();
         _logger = null;
-        _loggerConfiguration = CreateLoggerConfiguration();
-        _loggerConfiguration.MinimumLevel.ControlledBy(_logLevelSwitch);
     }
 
     private Logger? GetLoggerForLevel(LogEventLevel level) {
         if (_disposed || AreLogsSilenced || !IsEnabled(level)) {
             return null;
         }
 
-        _logger ??= _loggerConfiguration.CreateLogger();
+        _logger ??= BuildLogger();
         return _logger;
     }
 
+    private Logger BuildLogger() {
+        LoggerConfiguration configuration = CreateLoggerConfiguration();
+        configuration.MinimumLevel.ControlledBy(_logLevelSwitch);
+        return configuration.CreateLogger();
+    }
+
     private static object?[] Normalize(object?[]? properties) {
         return properties is { Length: > 0 } ? properties : EmptyProperties;
     }

src/Spice86.Shared/Interfaces/ILoggerService.cs

@@ -33,9 +33,4 @@ public interface ILoggerService : ILogger {
     /// </summary>
     /// <returns>The new <see cref="LoggerConfiguration"/></returns>
     LoggerConfiguration CreateLoggerConfiguration();
-
-    /// <summary>
-    /// Redirects console log output to stderr, freeing stdout for protocol transports (e.g., MCP stdio).
-    /// </summary>
-    void UseStderrForConsoleOutput();
 }

src/Spice86/Spice86DependencyInjection.cs

@@ -726,24 +726,26 @@ internal Spice86DependencyInjection(Configuration configuration, MainWindow? mai
 
         McpHttpHost? mcpHttpTransport = null;
 
-        // Collect additional MCP tool assemblies and services from override supplier
-        IEnumerable<Assembly>? additionalToolAssemblies = null;
-        IEnumerable<object>? additionalMcpServices = null;
-        if (configuration.OverrideSupplier is IMcpToolSupplier mcpToolSupplier) {
-            additionalToolAssemblies = mcpToolSupplier.GetMcpToolAssemblies();
-            additionalMcpServices = mcpToolSupplier.GetMcpServices();
-        }
+        if (configuration.McpHttpPort != 0) {
+            // Collect additional MCP tool assemblies and services from override supplier
+            IEnumerable<Assembly>? additionalToolAssemblies = null;
+            IEnumerable<object>? additionalMcpServices = null;
+            if (configuration.OverrideSupplier is IMcpToolSupplier mcpToolSupplier) {
+                additionalToolAssemblies = mcpToolSupplier.GetMcpToolAssemblies();
+                additionalMcpServices = mcpToolSupplier.GetMcpServices();
+            }
 
-        mcpHttpTransport = new McpHttpHost(loggerService);
-        try {
-            mcpHttpTransport.Start(emulatorMcpServices, configuration.McpHttpPort, additionalToolAssemblies, additionalMcpServices);
-            if (loggerService.IsEnabled(LogEventLevel.Information)) {
-                loggerService.Information("MCP HTTP transport started on port {Port}", configuration.McpHttpPort);
+            mcpHttpTransport = new McpHttpHost(loggerService);
+            try {
+                mcpHttpTransport.Start(emulatorMcpServices, configuration.McpHttpPort, additionalToolAssemblies, additionalMcpServices);
+                if (loggerService.IsEnabled(LogEventLevel.Information)) {
+                    loggerService.Information("MCP HTTP transport started on port {Port}", configuration.McpHttpPort);
+                }
+            } catch (InvalidOperationException ex) {
+                loggerService.Warning(ex, "Failed to configure MCP HTTP transport on port {Port}; MCP HTTP will be unavailable", configuration.McpHttpPort);
+                mcpHttpTransport.Dispose();
+                mcpHttpTransport = null;
             }
-        } catch (InvalidOperationException ex) {
-            loggerService.Warning(ex, "Failed to configure MCP HTTP transport on port {Port}; MCP HTTP will be unavailable", configuration.McpHttpPort);
-            mcpHttpTransport.Dispose();
-            mcpHttpTransport = null;
         }
 
         if (loggerService.IsEnabled(LogEventLevel.Information)) {

tests/Spice86.Tests/CfgCpu/CfgGraphReloadTest.cs

@@ -1,5 +1,7 @@
 namespace Spice86.Tests.CfgCpu;
 
+using NSubstitute;
+
 using Spice86.Core.CLI;
 using Spice86.Core.Emulator.CPU;
 using Spice86.Core.Emulator.CPU.CfgCpu;
@@ -12,7 +14,6 @@ namespace Spice86.Tests.CfgCpu;
 using Spice86.Core.Emulator.StateSerialization;
 using Spice86.Core.Emulator.StateSerialization.CfgReload;
 using Spice86.Core.Emulator.VM;
-using Spice86.Logging;
 using Spice86.Shared.Emulator.Memory;
 using Spice86.Shared.Interfaces;
 using Spice86.Tests.Utility;
@@ -95,7 +96,7 @@ public void ReloadedGraphMatchesOriginal(string binName) {
 
         // Reload into a fresh machine (no execution) and export.
         string reloadedJson;
-        using (LoggerService loggerService = new())
+        ILoggerService loggerService = Substitute.For<ILoggerService>();
         using (Spice86Creator creator = CreateCreator(binName))
         using (Spice86DependencyInjection di = creator.Create()) {
             using CfgNodeExecutionCompiler compiler = NewCompiler(loggerService);
@@ -120,7 +121,7 @@ public void ReloadedGraphReExportsToSameDump(string binName) {
         // restore: typed instruction edges, per-node MaxSucc, selector dispatch edges and ids.
         CfgReloadDump original = CaptureDump(binName);
 
-        using LoggerService loggerService = new();
+        ILoggerService loggerService = Substitute.For<ILoggerService>();
         using Spice86Creator creator = CreateCreator(binName);
         using Spice86DependencyInjection di = creator.Create();
         using CfgNodeExecutionCompiler compiler = NewCompiler(loggerService);
@@ -144,7 +145,7 @@ public void ReloadPreservesIdsAndSeedsAllocator(string binName) {
         HashSet<int> expectedIds = new(scaledDump.Nodes.Select(n => n.Id).Concat(scaledDump.Blocks.Select(b => b.Id)));
         int maxId = expectedIds.Count == 0 ? -1 : expectedIds.Max();
 
-        using LoggerService loggerService = new();
+        ILoggerService loggerService = Substitute.For<ILoggerService>();
         using Spice86Creator creator = CreateCreator(binName);
         using Spice86DependencyInjection di = creator.Create();
         using CfgNodeExecutionCompiler compiler = NewCompiler(loggerService);
@@ -173,7 +174,7 @@ public void NewDiscoveryAfterReloadGetsNonCollidingId(string binName) {
         HashSet<int> reloadedIds = new(scaledDump.Nodes.Select(n => n.Id).Concat(scaledDump.Blocks.Select(b => b.Id)));
         int maxReloadedId = reloadedIds.Max();
 
-        using LoggerService loggerService = new();
+        ILoggerService loggerService = Substitute.For<ILoggerService>();
         using Spice86Creator creator = CreateCreator(binName);
         using Spice86DependencyInjection di = creator.Create();
         Machine machine = di.Machine;
@@ -227,7 +228,7 @@ public void ResumeAfterReloadReconnectsAndPromotesToLive(string binName) {
             .Select(n => n.Id)
             .Single();
 
-        using LoggerService loggerService = new();
+        ILoggerService loggerService = Substitute.For<ILoggerService>();
         using Spice86Creator creator = CreateCreator(binName);
         using Spice86DependencyInjection di = creator.Create();
         Machine machine = di.Machine;
@@ -262,7 +263,7 @@ public void PromotedReloadedNodeHasMemoryWriteBreakpoint(string binName) {
         (CfgReloadDump dump, byte[] memoryImage) = CaptureDumpAndMemory(binName);
         SegmentedAddress entryAddress = ParseAddress(dump.EntryPoints[0]);
 
-        using LoggerService loggerService = new();
+        ILoggerService loggerService = Substitute.For<ILoggerService>();
         using Spice86Creator creator = CreateCreator(binName);
         using Spice86DependencyInjection di = creator.Create();
         Machine machine = di.Machine;

tests/Spice86.Tests/CfgCpu/InstructionsFeederTest.cs

@@ -41,7 +41,7 @@ private InstructionsFeeder CreateInstructionsFeeder() {
     }
 
     private InstructionsFeeder CreateInstructionsFeeder(IMmu mmu) {
-        ILoggerService loggerService = Substitute.For<LoggerService>();
+        ILoggerService loggerService = Substitute.For<ILoggerService>();
         State state = new(CpuModel.INTEL_80286);
         AddressReadWriteBreakpoints memoryBreakpoints = new();
         AddressReadWriteBreakpoints ioBreakpoints = new();

tests/Spice86.Tests/CollectibleAssemblyLoadContext.cs

@@ -0,0 +1,17 @@
+namespace Spice86.Tests;
+
+using System.Reflection;
+using System.Runtime.Loader;
+
+/// <summary>
+/// Collectible load context used to host a single compiled generated-override assembly so it can be
+/// unloaded once the test that produced it completes, instead of permanently growing the default context.
+/// </summary>
+internal sealed class CollectibleAssemblyLoadContext : AssemblyLoadContext {
+    public CollectibleAssemblyLoadContext() : base(isCollectible: true) {
+    }
+
+    protected override Assembly? Load(AssemblyName assemblyName) {
+        return null;
+    }
+}

tests/Spice86.Tests/CompiledGeneratedOverride.cs

@@ -2,6 +2,21 @@ namespace Spice86.Tests;
 
 using Spice86.Core.Emulator.Function;
 
-internal sealed class CompiledGeneratedOverride(IOverrideSupplier supplier) {
-    public IOverrideSupplier Supplier { get; } = supplier;
+using System.Runtime.Loader;
+
+internal sealed class CompiledGeneratedOverride : IDisposable {
+    private readonly AssemblyLoadContext _loadContext;
+
+    public CompiledGeneratedOverride(AssemblyLoadContext loadContext, IOverrideSupplier supplier) {
+        _loadContext = loadContext;
+        Supplier = supplier;
+    }
+
+    public IOverrideSupplier Supplier { get; }
+
+    public void Dispose() {
+        if (_loadContext.IsCollectible) {
+            _loadContext.Unload();
+        }
+    }
 }

tests/Spice86.Tests/GeneratedCodeMachineTest.cs

@@ -250,7 +250,7 @@ public void WideSegmentSpanProgramInitializesSegmentFieldsFromObservedConstants(
         source.Should().NotContain("relocationBaseSegment");
         source.Should().NotContain("relocated from the runtime entry segment");
         // The generated source still compiles.
-        new GeneratedOverrideCompiler().CompileSupplier(source);
+        using CompiledGeneratedOverride compiledOverride = new GeneratedOverrideCompiler().CompileSupplier(source);
     }
 
     [Fact]

tests/Spice86.Tests/GeneratedCodeMachineTestRunner.cs

@@ -27,7 +27,7 @@ public void TestGeneratedCode(string binName, byte[] expected, long maxCycles =
     }
 
     public void TestGeneratedCode(string binName, byte[] expected, GeneratedCodeRunOptions options, Action<Machine>? assertions = null) {
-        CompiledGeneratedOverride compiledOverride = GenerateAndCompileSupplier(binName, options);
+        using CompiledGeneratedOverride compiledOverride = GenerateAndCompileSupplier(binName, options);
 
         using Spice86Creator creator = new(binName: binName, maxCycles: options.MaxCycles, enablePit: options.EnablePit,
             installInterruptVectors: options.InstallInterruptVectors, failOnUnhandledPort: options.FailOnUnhandledPort,

tests/Spice86.Tests/GeneratedOverrideCompiler.cs

@@ -12,12 +12,14 @@ namespace Spice86.Tests;
 using System.Runtime.Loader;
 
 internal sealed class GeneratedOverrideCompiler {
+    private static readonly MetadataReference[] PlatformMetadataReferences = CreateMetadataReferences();
+
     public CompiledGeneratedOverride CompileSupplier(string source) {
         SyntaxTree syntaxTree = CSharpSyntaxTree.ParseText(source, CSharpParseOptions.Default.WithLanguageVersion(LanguageVersion.Preview));
         CSharpCompilation compilation = CSharpCompilation.Create(
             assemblyName: "Spice86.GeneratedCode.Tests." + Guid.NewGuid().ToString("N"),
             syntaxTrees: [syntaxTree],
-            references: GetMetadataReferences(),
+            references: PlatformMetadataReferences,
             options: new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary));
 
         using MemoryStream peStream = new();
@@ -30,14 +32,20 @@ public CompiledGeneratedOverride CompileSupplier(string source) {
         }
 
         peStream.Position = 0;
-        Assembly assembly = AssemblyLoadContext.Default.LoadFromStream(peStream);
-        Type supplierType = assembly.GetTypes().Single(type => typeof(IOverrideSupplier).IsAssignableFrom(type) && !type.IsAbstract);
-        object supplierInstance = Activator.CreateInstance(supplierType)
-            ?? throw new InvalidOperationException($"Could not instantiate generated supplier type {supplierType.FullName}.");
-        return new CompiledGeneratedOverride((IOverrideSupplier)supplierInstance);
+        CollectibleAssemblyLoadContext loadContext = new();
+        try {
+            Assembly assembly = loadContext.LoadFromStream(peStream);
+            Type supplierType = assembly.GetTypes().Single(type => typeof(IOverrideSupplier).IsAssignableFrom(type) && !type.IsAbstract);
+            object supplierInstance = Activator.CreateInstance(supplierType)
+                ?? throw new InvalidOperationException($"Could not instantiate generated supplier type {supplierType.FullName}.");
+            return new CompiledGeneratedOverride(loadContext, (IOverrideSupplier)supplierInstance);
+        } catch {
+            loadContext.Unload();
+            throw;
+        }
     }
 
-    private static MetadataReference[] GetMetadataReferences() {
+    private static MetadataReference[] CreateMetadataReferences() {
         string trustedAssemblies = (string?)AppContext.GetData("TRUSTED_PLATFORM_ASSEMBLIES") ?? string.Empty;
         IEnumerable<string> trustedPaths = trustedAssemblies.Split(Path.PathSeparator, StringSplitOptions.RemoveEmptyEntries);
         IEnumerable<string> loadedPaths = AppDomain.CurrentDomain.GetAssemblies()

tests/Spice86.Tests/Spice86.Tests.csproj

@@ -5,6 +5,15 @@
 		<ImplicitUsings>enable</ImplicitUsings>
 		<WarningsAsErrors>nullable</WarningsAsErrors>
 		<IsPackable>false</IsPackable>
+		<!--
+		  Use workstation GC for the test host. Server GC is lazy about reclaiming
+		  collectible memory while RAM is abundant, which lets per-test allocations
+		  (the multi-MB Ram array, audio reverb buffers, CFG graphs) pile up and push
+		  RSS into the tens of GB over a full run eventually OOM-killing the host on
+		  memory-constrained machines/CI.
+		-->
+		<ServerGarbageCollection>false</ServerGarbageCollection>
+		<ConcurrentGarbageCollection>false</ConcurrentGarbageCollection>
 	</PropertyGroup>
 	<ItemGroup>
 		<PackageReference Include="ErrorProne.NET.CoreAnalyzers">
@@ -84,4 +93,4 @@
 			<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
 		</Content>
 	</ItemGroup>
-</Project>
+</Project>

tests/Spice86.Tests/Spice86Creator.cs

@@ -74,6 +74,7 @@ public Spice86Creator(string binName, bool enablePit = false,
             RecordedDataDirectory = exportFolder,
             SilencedLogs = true,
             HttpApiPort = 0,
+            McpHttpPort = 0,
             // Deterministic cycle-based clock (CyclesClock) to avoid
             // wall-clock non-determinism in tests.
             // 333333 is the value that allowed most wall clock based tests to pass without changing all the expected values.

tests/Spice86.Tests/Video/RendererTestsBase.cs

@@ -8,7 +8,7 @@
 using Spice86.Core.Emulator.Devices.Video.Registers.CrtController;
 using Spice86.Core.Emulator.Devices.Video.Registers.Graphics;
 using Spice86.Core.Emulator.Memory;
-using Spice86.Logging;
+using Spice86.Shared.Interfaces;
 
 using Xunit;
 
@@ -1408,7 +1408,7 @@ public void HorizontalPixelPanning_TextMode_9DotWithLineGraphics_AddsOnePan() {
         mockMemory.When(m => m.RegisterMapping(Arg.Any<uint>(), Arg.Any<uint>(), Arg.Any<IMemoryDevice>()))
             .Do(callInfo => captured = (VideoMemory)callInfo.ArgAt<IMemoryDevice>(2));
 
-        LoggerService loggerService = new();
+        ILoggerService loggerService = Substitute.For<ILoggerService>();
         IVgaRenderer256Color renderer256Color = Create256ColorRenderer();
         Renderer renderer = new(mockMemory, state, blinkState, loggerService, renderer256Color);