test: add headless test.

tests/HeadlessTest.Ursa/Controls/FormTests/Dynamic_Item_Generation/TestViewModel.cs

@@ -0,0 +1,51 @@
+using System.Collections.ObjectModel;
+using CommunityToolkit.Mvvm.ComponentModel;
+using Irihi.Avalonia.Shared.Contracts;
+
+namespace HeadlessTest.Ursa.Controls.FormTests.Dynamic_Item_Generation;
+
+public class TestViewModel
+{
+    public ObservableCollection<IFormElement> Items { get; set; } = [];
+}
+
+public interface IFormElement
+{
+    
+}
+
+public interface IFormGroupViewModel : IFormGroup, IFormElement
+{
+    public string? Title { get; set; }
+    public ObservableCollection<IFromItemViewModel> Items { get; set; }
+}
+
+public interface IFromItemViewModel: IFormElement
+{
+    public string? Label { get; set; }
+}
+
+public partial class FormGroupViewModel : ObservableObject, IFormGroupViewModel
+{
+    [ObservableProperty] private string? _title;
+    public ObservableCollection<IFromItemViewModel> Items { get; set; } = [];
+}
+
+public partial class FormTextViewModel : ObservableObject, IFromItemViewModel
+{
+    [ObservableProperty] private string? _label;
+    [ObservableProperty] private string? _value;
+}
+
+public partial class FormAgeViewModel : ObservableObject, IFromItemViewModel
+{
+    [ObservableProperty] private uint? _age;
+    [ObservableProperty] private string? _label;
+}
+
+public partial class FormDateRangeViewModel : ObservableObject, IFromItemViewModel
+{
+    [ObservableProperty] private DateTime? _end;
+    [ObservableProperty] private string? _label;
+    [ObservableProperty] private DateTime? _start;
+}