feat: ensure initial state is respected in EnumSelector

tests/HeadlessTest.Ursa/Controls/EnumSelectorTests/InitialStateTest.cs

@@ -0,0 +1,24 @@
+using Avalonia.Controls;
+using Avalonia.Headless.XUnit;
+using Ursa.Controls;
+
+namespace HeadlessTest.Ursa.Controls.EnumSelectorTests;
+
+public class InitialStateTest
+{
+    [AvaloniaFact]
+    public void Initial_State_Respected()
+    {
+        var window = new Window();
+        var selector = new EnumSelector()
+        {
+            Value = HorizontalPosition.Right,
+            EnumType = typeof(HorizontalPosition),
+        };
+        window.Content = selector;
+        window.Show();
+        Assert.Equal(HorizontalPosition.Right, selector.Value);
+        Assert.NotNull(selector.SelectedValue);
+        Assert.Equal(HorizontalPosition.Right, selector.SelectedValue?.Value);
+    }
+}