Fix help TUI: set Markdown.Text in Initialized handler, add integrati…

…on tests

The help command's TUI viewer rendered empty content because
Markdown.Text was set before the view was initialized/laid out.
Following the pattern from gui-cs/clet's MarkdownClet, set the text
inside the Initialized event handler on the containing Runnable.

Also switches from RunnableWrapper to a plain Runnable with an embedded
Markdown view — the help viewer is read-only and needs no result
extraction.

Adds integration tests using Application.Create()/Init(ansi) with
StopAfterFirstIteration to verify:
- The TUI renders without hanging
- Driver contents contain expected command text
- Subcommand help renders correctly
- RenderCatAsync produces ANSI output

Co-authored-by: Copilot <[email protected]>

src/Terminal.Gui.Cli/HelpCommand.cs

@@ -1,4 +1,5 @@
 using Terminal.Gui.App;
+using Terminal.Gui.ViewBase;
 using Terminal.Gui.Views;
 
 namespace Terminal.Gui.Cli;
@@ -43,11 +44,27 @@ public async Task<CommandResult> RunAsync (IApplication app, string? initial, Co
     {
         var markdown = ResolveHelp (options);
 
-        RunnableWrapper<Markdown, object?> wrapper = new ();
-        wrapper.GetWrappedView ().Text = markdown;
-        wrapper.Title = options.Title ?? "Help";
+        Runnable window = new ()
+        {
+            Title = options.Title ?? "Help",
+            Width = Dim.Fill (),
+            Height = Dim.Fill ()
+        };
+
+        Markdown markdownView = new ()
+        {
+            Width = Dim.Fill (),
+            Height = Dim.Fill ()
+        };
+
+        window.Add (markdownView);
+
+        window.Initialized += (_, _) =>
+        {
+            markdownView.Text = markdown;
+        };
 
-        await app.RunAsync (wrapper, cancellationToken);
+        await app.RunAsync (window, cancellationToken);
 
         return new CommandResult (CommandStatus.Ok, null, null, null);
     }

tests/Terminal.Gui.Cli.IntegrationTests/HelpCommandIntegrationTests.cs

@@ -0,0 +1,152 @@
+using Terminal.Gui.App;
+using Terminal.Gui.Drivers;
+using Xunit;
+
+namespace Terminal.Gui.Cli.IntegrationTests;
+
+public sealed class HelpCommandIntegrationTests
+{
+    [Fact]
+    public async Task RunAsync_WithStopAfterFirstIteration_RendersMarkdownInViewer ()
+    {
+        using IApplication app = Application.Create ();
+        app.Init (DriverRegistry.Names.ANSI);
+        app.StopAfterFirstIteration = true;
+
+        CommandRegistry registry = new ();
+        MetadataHelpProvider helpProvider = new ();
+        HelpCommand helpCommand = new (registry, helpProvider);
+        registry.Register (helpCommand);
+
+        CommandRunOptions options = new ();
+
+        CommandResult result = await helpCommand.RunAsync (app, null, options, CancellationToken.None);
+
+        Assert.Equal (CommandStatus.Ok, result.Status);
+    }
+
+    [Fact]
+    public async Task RunAsync_CancellationToken_AlreadyCancelled_DoesNotHang ()
+    {
+        using IApplication app = Application.Create ();
+        app.Init (DriverRegistry.Names.ANSI);
+
+        CommandRegistry registry = new ();
+        MetadataHelpProvider helpProvider = new ();
+        HelpCommand helpCommand = new (registry, helpProvider);
+        registry.Register (helpCommand);
+
+        CommandRunOptions options = new ();
+
+        using CancellationTokenSource cts = new ();
+        await cts.CancelAsync ();
+
+        // Should either throw OperationCanceledException or return quickly
+        try
+        {
+            await helpCommand.RunAsync (app, null, options, cts.Token);
+        }
+        catch (OperationCanceledException)
+        {
+            // Expected
+        }
+    }
+
+    [Fact]
+    public async Task RunAsync_RendersHelpText_ContainingCommandName ()
+    {
+        using IApplication app = Application.Create ();
+        app.Init (DriverRegistry.Names.ANSI);
+        app.StopAfterFirstIteration = true;
+
+        // Set screen size for deterministic rendering
+        app.Driver!.SetScreenSize (80, 24);
+
+        CommandRegistry registry = new ();
+        MetadataHelpProvider helpProvider = new ();
+        HelpCommand helpCommand = new (registry, helpProvider);
+        registry.Register (helpCommand);
+
+        CommandRunOptions options = new ();
+
+        CommandResult result = await helpCommand.RunAsync (app, null, options, CancellationToken.None);
+
+        Assert.Equal (CommandStatus.Ok, result.Status);
+
+        // Verify the driver rendered content containing the "help" command
+        var driverContents = app.Driver.ToString ();
+        Assert.Contains ("help", driverContents);
+    }
+
+    [Fact]
+    public async Task RunAsync_WithSubcommandArgument_RendersCommandHelp ()
+    {
+        using IApplication app = Application.Create ();
+        app.Init (DriverRegistry.Names.ANSI);
+        app.StopAfterFirstIteration = true;
+
+        app.Driver!.SetScreenSize (80, 24);
+
+        CommandRegistry registry = new ();
+        MetadataHelpProvider helpProvider = new ();
+        HelpCommand helpCommand = new (registry, helpProvider);
+        registry.Register (helpCommand);
+        registry.Register (new StubCommand ("greet", "Say hello."));
+
+        CommandRunOptions options = new ()
+        {
+            Arguments = ["greet"]
+        };
+
+        CommandResult result = await helpCommand.RunAsync (app, null, options, CancellationToken.None);
+
+        Assert.Equal (CommandStatus.Ok, result.Status);
+
+        var driverContents = app.Driver.ToString ();
+        Assert.Contains ("greet", driverContents);
+    }
+
+    [Fact]
+    public async Task RenderCatAsync_ProducesAnsiOutput ()
+    {
+        CommandRegistry registry = new ();
+        MetadataHelpProvider helpProvider = new ();
+        HelpCommand helpCommand = new (registry, helpProvider);
+        registry.Register (helpCommand);
+
+        CommandRunOptions options = new ();
+        using StringWriter stdout = new ();
+
+        CommandResult? result = await helpCommand.RenderCatAsync (options, stdout, CancellationToken.None);
+
+        Assert.NotNull (result);
+        Assert.Equal (CommandStatus.Ok, result.Value.Status);
+
+        var output = stdout.ToString ();
+
+        // ANSI escape sequences present
+        Assert.Contains ("\x1b[", output);
+        Assert.Contains ("help", output);
+    }
+
+    private sealed class StubCommand (string alias, string description) : ICliCommand
+    {
+        public string PrimaryAlias { get; } = alias;
+
+        public IReadOnlyList<string> Aliases => [PrimaryAlias];
+
+        public string Description => description;
+
+        public CommandKind Kind => CommandKind.Input;
+
+        public Type ResultType => typeof (string);
+
+        public IReadOnlyList<CommandOptionDescriptor> Options { get; } = [];
+
+        public Task<CommandResult> RunAsync (IApplication app, string? initial, CommandRunOptions options,
+            CancellationToken cancellationToken)
+        {
+            return Task.FromResult (new CommandResult (CommandStatus.Ok, "ok", null, null));
+        }
+    }
+}

tests/Terminal.Gui.Cli.IntegrationTests/TestSetup.cs

@@ -0,0 +1,16 @@
+using System.Runtime.CompilerServices;
+
+namespace Terminal.Gui.Cli.IntegrationTests;
+
+/// <summary>
+///     Disables real driver I/O so tests never interact with the terminal or launch processes.
+/// </summary>
+internal static class TestSetup
+{
+    [ModuleInitializer]
+    internal static void Init ()
+    {
+        Environment.SetEnvironmentVariable ("DisableRealDriverIO", "1");
+        Console.SetIn (TextReader.Null);
+    }
+}