test: add failing test case for issue 460.

tests/HeadlessTest.Ursa/Controls/UrsaWindowTests/UrsaWindowWithCloseInference.axaml.cs

@@ -0,0 +1,40 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+using Avalonia.Markup.Xaml;
+using Irihi.Avalonia.Shared.Contracts;
+using Ursa.Controls;
+
+namespace HeadlessTest.Ursa.Controls.UrsaWindowTests;
+
+public partial class UrsaWindowWithCloseInference : UrsaWindow
+{
+    public UrsaWindowWithCloseInference()
+    {
+        InitializeComponent();
+    }
+    
+    internal TextBox TextBox = new TextBox();
+    internal DialogViewModel DialogViewModel = new DialogViewModel();
+
+    protected override async Task<bool> CanClose()
+    {
+        var result = await OverlayDialog.ShowModal(TextBox, DialogViewModel);
+        return result == DialogResult.Yes;
+    }
+}
+
+class DialogViewModel : IDialogContext
+{
+    public void Close()
+    {
+        RequestClose?.Invoke(this, DialogResult.No);
+    }
+    
+    public void CloseYes()
+    {
+        RequestClose?.Invoke(this, DialogResult.Yes);
+    }
+
+    public event EventHandler<object?>? RequestClose;
+}