fix(central-ui): resolve CentralUI-007..014 — nav authz, UTC date filters, disposal guards, N+1 fix, async script analysis

tests/ScadaLink.CentralUI.Tests/Shared/ToastNotificationTests.cs

@@ -0,0 +1,80 @@
+using Bunit;
+using ScadaLink.CentralUI.Components.Shared;
+
+namespace ScadaLink.CentralUI.Tests.Shared;
+
+/// <summary>
+/// Regression tests for CentralUI-010. <c>ToastNotification.AddToast</c>
+/// scheduled <c>Task.Delay(dismissMs).ContinueWith(...)</c> with the result
+/// discarded; the continuation called <c>InvokeAsync(StateHasChanged)</c>. When
+/// the host page is disposed before the delay elapses, the continuation ran
+/// against a disposed component and threw <c>ObjectDisposedException</c> on a
+/// thread-pool thread with no catch (an unobserved task exception). The fix
+/// holds a <c>CancellationTokenSource</c> cancelled in <c>Dispose()</c>.
+/// </summary>
+public class ToastNotificationTests : BunitContext
+{
+    [Fact]
+    public async Task ShowToast_AfterDisposal_IsNoOp_AndSchedulesNothing()
+    {
+        // Regression: the pre-fix AddToast always added the toast and scheduled
+        // a Task.Delay continuation, even after Dispose() — the continuation
+        // then ran InvokeAsync(StateHasChanged) against the disposed component.
+        // The fix short-circuits AddToast once the disposal token is cancelled.
+        var cut = Render<ToastNotification>();
+
+        await cut.InvokeAsync(() => cut.Instance.Dispose());
+        await cut.InvokeAsync(() => cut.Instance.ShowError("after dispose", autoDismissMs: 20));
+
+        Assert.Equal(0, cut.Instance.ToastCount);
+    }
+
+    [Fact]
+    public async Task AutoDismiss_AfterDisposal_DoesNotThrowUnobservedException()
+    {
+        var unobserved = new List<Exception>();
+        void Handler(object? s, UnobservedTaskExceptionEventArgs e)
+        {
+            unobserved.Add(e.Exception);
+            e.SetObserved();
+        }
+        TaskScheduler.UnobservedTaskException += Handler;
+        try
+        {
+            var cut = Render<ToastNotification>();
+            // Auto-dismiss after a very short delay so the continuation is
+            // guaranteed to fire well after we dispose the component.
+            await cut.InvokeAsync(() => cut.Instance.ShowSuccess("hello", autoDismissMs: 20));
+
+            // Dispose the component while the auto-dismiss is still pending.
+            await cut.InvokeAsync(() => cut.Instance.Dispose());
+
+            // Give the (now-cancelled) auto-dismiss well past its delay.
+            await Task.Delay(250);
+            GC.Collect();
+            GC.WaitForPendingFinalizers();
+            GC.Collect();
+        }
+        finally
+        {
+            TaskScheduler.UnobservedTaskException -= Handler;
+        }
+
+        Assert.Empty(unobserved);
+    }
+
+    [Fact]
+    public async Task AutoDismiss_BeforeDisposal_StillRemovesToast()
+    {
+        var cut = Render<ToastNotification>();
+        await cut.InvokeAsync(() => cut.Instance.ShowInfo("transient", autoDismissMs: 20));
+
+        // The toast is visible immediately.
+        Assert.Contains("transient", cut.Markup);
+
+        // After the dismiss delay it is removed (auto-dismiss still works).
+        cut.WaitForAssertion(
+            () => Assert.DoesNotContain("transient", cut.Markup),
+            timeout: TimeSpan.FromSeconds(2));
+    }
+}