ILSpy/ILSpy.Tests/Editor/DocumentationRendererTooltipWidthTests.cs

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using System.Linq;

using Avalonia.Controls;
using Avalonia.Controls.Primitives;
using Avalonia.Headless.NUnit;
using Avalonia.LogicalTree;
using Avalonia.Media;

using AvaloniaEdit.Highlighting;

using AwesomeAssertions;

using ICSharpCode.Decompiler.CSharp.OutputVisitor;

using ICSharpCode.ILSpy.TextView;

using NUnit.Framework;

namespace ICSharpCode.ILSpy.Tests.TextView;

/// <summary>
/// Pins the rendering shape of method-signature tooltips so a long signature isn't
/// clipped horizontally. Two failure modes the original implementation suffered from:
/// (1) the signature <see cref="SelectableTextBlock"/> was created with
/// <see cref="TextWrapping.NoWrap"/>, so text past the popup's MaxWidth was simply cut
/// off (no horizontal scrolling because the outer ScrollViewer disables it);
/// (2) the popup MaxWidth defaulted to a snug 600px, narrower than most real C#
/// generic-method signatures. WPF parity is wrap-friendly, so we mirror that — these
/// tests fail if either property regresses.
/// </summary>
[TestFixture]
public class DocumentationRendererTooltipWidthTests
{
	[AvaloniaTest]
	public void Signature_Block_Wraps_So_Long_Method_Signatures_Are_Not_Clipped()
	{
		var renderer = new DocumentationRenderer(
			new CSharpAmbience(),
			new FontFamily("Consolas, Menlo, Monospace"),
			12);

		// A real C# Zip overload — long enough that it exceeds the previous 600px cap at
		// the popup's monospace 12pt size. The bug shows up on any method whose rendered
		// signature is wider than the popup's outer MaxWidth.
		var longSignature = new RichText(
			"public static IEnumerable<TResult> Zip<TFirst, TSecond, TThird, TResult>("
			+ "this IEnumerable<TFirst> first, IEnumerable<TSecond> second, "
			+ "IEnumerable<TThird> third, "
			+ "Func<TFirst, TSecond, TThird, TResult> resultSelector)");

		renderer.AddSignatureBlock(longSignature);

		var view = renderer.CreateView();
		var signature = view.GetLogicalDescendants()
			.OfType<SelectableTextBlock>()
			.FirstOrDefault();
		signature.Should().NotBeNull(
			"DocumentationRenderer must materialise the signature as a SelectableTextBlock");
		signature!.TextWrapping.Should().Be(TextWrapping.Wrap,
			"the signature must wrap inside the popup — without wrapping a long signature is "
			+ "clipped at the outer MaxWidth because the ScrollViewer disables horizontal scrolling");
	}

	[AvaloniaTest]
	public void CreateView_Default_MaxWidth_Is_Generous_Enough_For_Typical_Signatures()
	{
		// 600 was too narrow — generic methods + ref-struct parameters routinely exceed it.
		// Pin the bumped default so a future tweak doesn't silently shrink it back.
		var renderer = new DocumentationRenderer(
			new CSharpAmbience(),
			new FontFamily("Consolas, Menlo, Monospace"),
			12);

		var view = (Border)renderer.CreateView();
		view.MaxWidth.Should().BeGreaterThanOrEqualTo(900,
			"the popup's outer MaxWidth must be wide enough that most realistic method "
			+ "signatures fit without aggressive wrapping");
	}
}