test: mvvm tests.

tests/HeadlessTest.Ursa/Controls/AnchorTests/TestView2.axaml

@@ -0,0 +1,27 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             xmlns:u="https://irihi.tech/ursa"
+             xmlns:vm="clr-namespace:HeadlessTest.Ursa.Controls.AnchorTests"
+             mc:Ignorable="d" d:DesignWidth="800"
+             d:DesignHeight="450"
+             x:DataType="vm:AnchorDemoViewModel"
+             x:CompileBindings="True"
+             x:Class="HeadlessTest.Ursa.Controls.AnchorTests.TestView2">
+    <u:Anchor
+        Width="200"
+        Margin="24"
+        ItemsSource="{Binding AnchorItems}">
+        <u:Anchor.Styles>
+            <Style x:DataType="vm:AnchorItemViewModel" Selector="u|AnchorItem">
+                <Setter Property="AnchorId" Value="{Binding AnchorId}" />
+            </Style>
+        </u:Anchor.Styles>
+        <u:Anchor.ItemTemplate>
+            <TreeDataTemplate ItemsSource="{Binding Children}">
+                <TextBlock Text="{Binding Header}"/>
+            </TreeDataTemplate>
+        </u:Anchor.ItemTemplate>
+    </u:Anchor>
+</UserControl>

tests/HeadlessTest.Ursa/Controls/AnchorTests/TestView2.axaml.cs

@@ -0,0 +1,46 @@
+using System.Collections.ObjectModel;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml;
+using CommunityToolkit.Mvvm.ComponentModel;
+
+namespace HeadlessTest.Ursa.Controls.AnchorTests;
+
+public partial class TestView2 : UserControl
+{
+    public TestView2()
+    {
+        InitializeComponent();
+        DataContext = new AnchorDemoViewModel();
+    }
+}
+
+public partial class AnchorDemoViewModel: ObservableObject
+{
+    public List<AnchorItemViewModel> AnchorItems { get; } = new()
+    {
+        new AnchorItemViewModel { AnchorId = "anchor1", Header = "Anchor 1" },
+        new AnchorItemViewModel { AnchorId = "anchor2", Header = "Anchor 2" },
+        new AnchorItemViewModel
+        {
+            AnchorId = "anchor3", Header = "Anchor 3",
+            Children =
+            [
+                new AnchorItemViewModel() { AnchorId = "anchor3-1", Header = "Anchor 3.1" },
+                new AnchorItemViewModel() { AnchorId = "anchor3-2", Header = "Anchor 3.2" },
+                new AnchorItemViewModel() { AnchorId = "anchor3-3", Header = "Anchor 3.3" }
+            ]
+        },
+        new AnchorItemViewModel { AnchorId = "anchor4", Header = "Anchor 4" },
+        new AnchorItemViewModel { AnchorId = "anchor5", Header = "Anchor 5" },
+        new AnchorItemViewModel { AnchorId = "anchor6", Header = "Anchor 6" },
+        new AnchorItemViewModel { AnchorId = "anchor7", Header = "Anchor 7" },
+    };
+}
+
+public partial class AnchorItemViewModel: ObservableObject
+{
+    [ObservableProperty] private string? _anchorId;
+    [ObservableProperty] private string? _header;
+    public ObservableCollection<AnchorItemViewModel>? Children { get; set; }
+}

tests/HeadlessTest.Ursa/Controls/AnchorTests/Tests.cs

@@ -4,6 +4,7 @@ using Avalonia.Headless;
 using Avalonia.Headless.XUnit;
 using Avalonia.Input;
 using Avalonia.Threading;
+using Avalonia.VisualTree;
 using Ursa.Controls;
 
 namespace HeadlessTest.Ursa.Controls.AnchorTests;
@@ -39,7 +40,7 @@ public class Tests
         Dispatcher.UIThread.RunJobs();
         await Task.Delay(800);
         Assert.True(item4.IsSelected);
-        Assert.Equal(300.0 * 3, scrollViewer.Offset.Y, 1.0);
+        Assert.Equal(300.0 * 3, scrollViewer.Offset.Y, 50.0);
     }
     
     [AvaloniaFact]
@@ -79,4 +80,18 @@ public class Tests
         Assert.True(item2.IsSelected);
         Assert.False(item4.IsSelected);
     }
+
+    [AvaloniaFact]
+    public void MVVM_Support()
+    {
+        var window = new Window();
+        var view = new TestView2();
+        window.Content = view;
+        window.Show();
+        Dispatcher.UIThread.RunJobs();
+        var items = window.GetVisualDescendants().OfType<AnchorItem>().ToList();
+        Assert.NotEmpty(items);
+        Assert.Equal(10, items.Count);
+
+    }
 }