////using System.Collections.ObjectModel;
////using System.Linq;
////using System.Reactive.Subjects;
////using Avalonia.Controls.Presenters;
////using Avalonia.Controls.Templates;
////using Avalonia.Data;
////using Avalonia.LogicalTree;
////using Avalonia.UnitTests;
////using Avalonia.VisualTree;
////using Xunit;

////namespace Avalonia.Controls.UnitTests
////{
////    public class CarouselTests
////    {
////        [Fact]
////        public void First_Item_Should_Be_Selected_By_Default()
////        {
////            var target = new Carousel
////            {
////                Template = new FuncControlTemplate<Carousel>(CreateTemplate),
////                Items = new[]
////                {
////                    "Foo",
////                    "Bar"
////                }
////            };

////            target.ApplyTemplate();

////            Assert.Equal(0, target.SelectedIndex);
////            Assert.Equal("Foo", target.SelectedItem);
////        }

////        [Fact]
////        public void LogicalChild_Should_Be_Selected_Item()
////        {
////            var target = new Carousel
////            {
////                Template = new FuncControlTemplate<Carousel>(CreateTemplate),
////                Items = new[]
////                {
////                    "Foo",
////                    "Bar"
////                }
////            };

////            target.ApplyTemplate();
////            ((Control)target.Presenter).ApplyTemplate();

////            Assert.Single(target.GetLogicalChildren());

////            var child = GetContainerTextBlock(target.GetLogicalChildren().Single());

////            Assert.Equal("Foo", child.Text);
////        }

////        [Fact]
////        public void Should_Remove_NonCurrent_Page_When_IsVirtualized_True()
////        {
////            var target = new Carousel
////            {
////                Template = new FuncControlTemplate<Carousel>(CreateTemplate),
////                Items = new[] { "foo", "bar" },
////                IsVirtualized = true,
////                SelectedIndex = 0,
////            };

////            target.ApplyTemplate();
////            ((Control)target.Presenter).ApplyTemplate();

////            Assert.Single(target.ItemContainerGenerator.Containers);
////            target.SelectedIndex = 1;
////            Assert.Single(target.ItemContainerGenerator.Containers);
////        }

////        [Fact]
////        public void Selected_Item_Changes_To_First_Item_When_Items_Property_Changes()
////        {
////            var items = new ObservableCollection<string>
////            {
////                "Foo",
////                "Bar",
////                "FooBar"
////            };

////            var target = new Carousel
////            {
////                Template = new FuncControlTemplate<Carousel>(CreateTemplate),
////                Items = items,
////                IsVirtualized = false
////            };

////            target.ApplyTemplate();
////            ((Control)target.Presenter).ApplyTemplate();

////            Assert.Equal(3, target.GetLogicalChildren().Count());

////            var child = GetContainerTextBlock(target.GetLogicalChildren().First());

////            Assert.Equal("Foo", child.Text);

////            var newItems = items.ToList();
////            newItems.RemoveAt(0);

////            target.Items = newItems;

////            child = GetContainerTextBlock(target.GetLogicalChildren().First());

////            Assert.Equal("Bar", child.Text);
////        }

////        [Fact]
////        public void Selected_Item_Changes_To_First_Item_When_Items_Property_Changes_And_Virtualized()
////        {
////            var items = new ObservableCollection<string>
////            {
////                "Foo",
////                "Bar",
////                "FooBar"
////            };

////            var target = new Carousel
////            {
////                Template = new FuncControlTemplate<Carousel>(CreateTemplate),
////                Items = items,
////                IsVirtualized = true,
////            };

////            target.ApplyTemplate();
////            ((Control)target.Presenter).ApplyTemplate();

////            Assert.Single(target.GetLogicalChildren());

////            var child = GetContainerTextBlock(target.GetLogicalChildren().Single());

////            Assert.Equal("Foo", child.Text);

////            var newItems = items.ToList();
////            newItems.RemoveAt(0);

////            target.Items = newItems;

////            child = GetContainerTextBlock(target.GetLogicalChildren().Single());

////            Assert.Equal("Bar", child.Text);
////        }

////        [Fact]
////        public void Selected_Item_Changes_To_First_Item_When_Item_Added()
////        {
////            var items = new ObservableCollection<string>();
////            var target = new Carousel
////            {
////                Template = new FuncControlTemplate<Carousel>(CreateTemplate),
////                Items = items,
////                IsVirtualized = false
////            };

////            target.ApplyTemplate();
////            ((Control)target.Presenter).ApplyTemplate();

////            Assert.Equal(-1, target.SelectedIndex);
////            Assert.Empty(target.GetLogicalChildren());

////            items.Add("Foo");

////            Assert.Equal(0, target.SelectedIndex);
////            Assert.Single(target.GetLogicalChildren());
////        }

////        [Fact]
////        public void Selected_Index_Changes_To_None_When_Items_Assigned_Null()
////        {
////            var items = new ObservableCollection<string>
////            {
////                "Foo",
////                "Bar",
////                "FooBar"
////            };

////            var target = new Carousel
////            {
////                Template = new FuncControlTemplate<Carousel>(CreateTemplate),
////                Items = items,
////                IsVirtualized = false
////            };

////            target.ApplyTemplate();
////            ((Control)target.Presenter).ApplyTemplate();

////            Assert.Equal(3, target.GetLogicalChildren().Count());

////            var child = GetContainerTextBlock(target.GetLogicalChildren().First());

////            Assert.Equal("Foo", child.Text);

////            target.Items = null;

////            var numChildren = target.GetLogicalChildren().Count();

////            Assert.Equal(0, numChildren);
////            Assert.Equal(-1, target.SelectedIndex);
////        }

////        [Fact]
////        public void Selected_Index_Is_Maintained_Carousel_Created_With_Non_Zero_SelectedIndex()
////        {
////            var items = new ObservableCollection<string>
////            {
////                "Foo",
////                "Bar",
////                "FooBar"
////            };

////            var target = new Carousel
////            {
////                Template = new FuncControlTemplate<Carousel>(CreateTemplate),
////                Items = items,
////                IsVirtualized = false,
////                SelectedIndex = 2
////            };

////            target.ApplyTemplate();
////            ((Control)target.Presenter).ApplyTemplate();

////            Assert.Equal("FooBar", target.SelectedItem);

////            var child = GetContainerTextBlock(target.GetVisualDescendants().LastOrDefault());

////            Assert.IsType<TextBlock>(child);
////            Assert.Equal("FooBar", ((TextBlock)child).Text);
////        }

////        [Fact]
////        public void Selected_Item_Changes_To_Next_First_Item_When_Item_Removed_From_Beggining_Of_List()
////        {
////            var items = new ObservableCollection<string>
////            {
////                "Foo",
////                "Bar",
////                "FooBar"
////            };

////            var target = new Carousel
////            {
////                Template = new FuncControlTemplate<Carousel>(CreateTemplate),
////                Items = items,
////                IsVirtualized = false
////            };

////            target.ApplyTemplate();
////            ((Control)target.Presenter).ApplyTemplate();

////            Assert.Equal(3, target.GetLogicalChildren().Count());

////            var child = GetContainerTextBlock(target.GetLogicalChildren().First());

////            Assert.Equal("Foo", child.Text);

////            items.RemoveAt(0);

////            child = GetContainerTextBlock(target.GetLogicalChildren().First());

////            Assert.IsType<TextBlock>(child);
////            Assert.Equal("Bar", ((TextBlock)child).Text);
////        }

////        [Fact]
////        public void Selected_Item_Changes_To_First_Item_If_SelectedItem_Is_Removed_From_Middle()
////        {
////            var items = new ObservableCollection<string>
////            {
////                "Foo",
////                "Bar",
////                "FooBar"
////            };

////            var target = new Carousel
////            {
////                Template = new FuncControlTemplate<Carousel>(CreateTemplate),
////                Items = items,
////                IsVirtualized = false
////            };

////            target.ApplyTemplate();
////            ((Control)target.Presenter).ApplyTemplate();

////            target.SelectedIndex = 1;

////            items.RemoveAt(1);

////            Assert.Equal(0, target.SelectedIndex);
////            Assert.Equal("Foo", target.SelectedItem);
////        }

////        private Control CreateTemplate(Carousel control, INameScope scope)
////        {
////            return new CarouselPresenter
////            {
////                Name = "PART_ItemsPresenter",
////                [~CarouselPresenter.IsVirtualizedProperty] = control[~Carousel.IsVirtualizedProperty],
////                [~CarouselPresenter.ItemsPanelProperty] = control[~Carousel.ItemsPanelProperty],
////                [~CarouselPresenter.SelectedIndexProperty] = control[~Carousel.SelectedIndexProperty],
////                [~CarouselPresenter.PageTransitionProperty] = control[~Carousel.PageTransitionProperty],
////            }.RegisterInNameScope(scope);
////        }

////        private static TextBlock GetContainerTextBlock(object control)
////        {
////            var contentPresenter = Assert.IsType<ContentPresenter>(control);
////            contentPresenter.UpdateChild();
////            return Assert.IsType<TextBlock>(contentPresenter.Child);
////        }

////        [Fact]
////        public void SelectedItem_Validation()
////        {
////            using (UnitTestApplication.Start(TestServices.MockThreadingInterface))
////            {
////                var target = new Carousel
////                {
////                    Template = new FuncControlTemplate<Carousel>(CreateTemplate),
////                    IsVirtualized = false
////                };

////                target.ApplyTemplate();
////                ((Control)target.Presenter).ApplyTemplate();

////                var exception = new System.InvalidCastException("failed validation");
////                var textObservable =
////                    new BehaviorSubject<BindingNotification>(new BindingNotification(exception,
////                        BindingErrorType.DataValidationError));
////                target.Bind(ComboBox.SelectedItemProperty, textObservable);

////                Assert.True(DataValidationErrors.GetHasErrors(target));
////                Assert.True(DataValidationErrors.GetErrors(target).SequenceEqual(new[] { exception }));
////            }
////        }
////    }
////}