feat: implement AirAppRuntimeBridge for managing runtime lifecycle and add corresponding unit tests for launcher window and runtime orchestration

LanMountainDesktop.Tests/SplashWindowLifecycleTests.cs

@@ -0,0 +1,77 @@
+using Avalonia.Controls;
+using Avalonia.Headless.XUnit;
+using Avalonia.Threading;
+using LanMountainDesktop.Launcher.Shell;
+using LanMountainDesktop.Launcher.Views;
+using Xunit;
+
+namespace LanMountainDesktop.Tests;
+
+public sealed class SplashWindowLifecycleTests
+{
+    [AvaloniaFact]
+    public async Task DismissAsync_WhenCalledConcurrentlyOffUiThread_ClosesExactlyOnce()
+    {
+        var window = new SplashWindow();
+        var closedCount = 0;
+        window.Closed += (_, _) => Interlocked.Increment(ref closedCount);
+        window.Show();
+
+        var dismissTasks = await Task.Run(() =>
+            Enumerable.Range(0, 8)
+                .Select(_ => window.DismissAsync())
+                .ToArray());
+
+        Assert.All(dismissTasks, task => Assert.Same(dismissTasks[0], task));
+        await Task.WhenAll(dismissTasks);
+
+        await Dispatcher.UIThread.InvokeAsync(() =>
+        {
+            Assert.False(window.IsVisible);
+            Assert.False(window.IsHitTestVisible);
+            Assert.Equal(1, closedCount);
+        });
+    }
+
+    [AvaloniaFact]
+    public async Task CloseWindowsAsync_WaitsUntilSplashIsNoLongerVisible()
+    {
+        var window = new SplashWindow();
+        var closed = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
+        window.Closed += (_, _) => closed.TrySetResult();
+        window.Show();
+
+        await Task.Run(() => LaunchUiPresenter.CloseWindowsAsync(window, loadingDetailsWindow: null));
+
+        Assert.True(closed.Task.IsCompleted);
+        await Dispatcher.UIThread.InvokeAsync(() => Assert.False(window.IsVisible));
+    }
+
+    [AvaloniaFact]
+    public async Task DismissAsync_WhenCloseIsCancelled_LeavesWindowHiddenAndNonHitTestable()
+    {
+        var window = new SplashWindow();
+        var closeWasCancelled = false;
+
+        void CancelClose(object? sender, WindowClosingEventArgs args)
+        {
+            closeWasCancelled = true;
+            args.Cancel = true;
+        }
+
+        window.Closing += CancelClose;
+        window.Show();
+
+        await Task.Run(() => window.DismissAsync());
+
+        await Dispatcher.UIThread.InvokeAsync(() =>
+        {
+            Assert.True(closeWasCancelled);
+            Assert.False(window.IsVisible);
+            Assert.False(window.IsHitTestVisible);
+
+            window.Closing -= CancelClose;
+            window.Close();
+        });
+    }
+}