Avalonia/tests/Perspex.Controls.UnitTests/BorderTests.cs

namespace Perspex.Controls.UnitTests
{
    using Xunit;

    public class BorderTests
    {
        [Fact]
        public void Measure_Should_Return_BorderThickness_Plus_Padding_When_No_Child_Present()
        {
            var target = new Border
            {
                Padding = new Thickness(6),
                BorderThickness = 4,
            };

            target.Measure(new Size(100, 100));

            Assert.Equal(new Size(20, 20), target.DesiredSize);
        }
    }
}