Avalonia/tests/Avalonia.RenderTests/Controls/AdornerTests.cs

using System.Threading.Tasks;
using Avalonia.Controls;
using Avalonia.Controls.Primitives;
using Avalonia.Layout;
using Avalonia.Media;
using Xunit;

#if AVALONIA_SKIA
namespace Avalonia.Skia.RenderTests;
#else
namespace Avalonia.Direct2D1.RenderTests.Controls;
#endif

public class AdornerTests : TestBase
{
    public AdornerTests()
        : base(@"Controls\Adorner")
    {
    }

    [Fact]
    public async Task Focus_Adorner_Is_Properly_Clipped()
    {
        Border adorned;
        var tree = new Decorator
        {
            Child = new VisualLayerManager
            {
                Child = new Border
                {
                    Background = Brushes.Red,
                    Padding = new Thickness(10, 50, 10,10),
                    Child = new Border()
                    {
                        Background = Brushes.White,
                        ClipToBounds = true,
                        Padding = new Thickness(0, -30, 0, 0),
                        Child = adorned = new Border
                        {
                            Background = Brushes.Green, 
                            VerticalAlignment = VerticalAlignment.Top,
                            Height = 100,
                            Width = 50
                        }
                    }
                }
            },
            Width = 200,
            Height = 200
        };
        var adorner = new Border
        {
            BorderThickness = new Thickness(2),
            BorderBrush = Brushes.Black
        };

        var size = new Size(tree.Width, tree.Height);
        tree.Measure(size);
        tree.Arrange(new Rect(size));


        adorned.AttachedToVisualTree += delegate
        {
            AdornerLayer.SetAdornedElement(adorner, adorned);
            AdornerLayer.GetAdornerLayer(adorned)!.Children.Add(adorner);
        };
        tree.Measure(size);
        tree.Arrange(new Rect(size));
        
        await RenderToFile(tree);
        CompareImages(skipImmediate: true, skipDeferred: true);
    }
}