test(notification-outbox): cover Discard and query-failure paths on the Outbox page

src/ScadaLink.CentralUI/Components/Pages/Monitoring/NotificationOutbox.razor

@@ -299,6 +299,8 @@
 
     private async Task RefreshAll()
     {
+        // Race-free despite both tasks mutating component fields: Blazor Server runs
+        // every continuation on the circuit's single-threaded synchronization context.
         await Task.WhenAll(LoadKpis(), FetchPage());
     }
 

tests/ScadaLink.CentralUI.Tests/Pages/NotificationOutboxPageTests.cs

@@ -165,6 +165,27 @@ public class NotificationOutboxPageTests : BunitContext
         });
     }
 
+    [Fact]
+    public void ClickDiscard_OnParkedRow_CallsDiscardNotification()
+    {
+        var cut = Render<NotificationOutboxPage>();
+
+        cut.WaitForState(() => cut.Markup.Contains("Pump fault at Plant-A"));
+
+        var parkedRow = cut.FindAll("tbody tr")
+            .First(r => r.TextContent.Contains("Pump fault at Plant-A"));
+        var discardButton = parkedRow.QuerySelectorAll("button")
+            .First(b => b.TextContent.Contains("Discard"));
+
+        discardButton.Click();
+
+        cut.WaitForAssertion(() =>
+        {
+            Assert.Single(_discardRequests);
+            Assert.Equal("notif-aaaaaaaa-1111", _discardRequests[0].NotificationId);
+        });
+    }
+
     [Fact]
     public void KpiFailure_ShowsErrorMessage()
     {
@@ -177,6 +198,19 @@ public class NotificationOutboxPageTests : BunitContext
             Assert.Contains("outbox repository unavailable", cut.Markup));
     }
 
+    [Fact]
+    public void QueryFailure_ShowsErrorMessage()
+    {
+        _queryReply = new NotificationOutboxQueryResponse(
+            "q", false, "outbox query backend unavailable",
+            new List<NotificationSummary>(), TotalCount: 0);
+
+        var cut = Render<NotificationOutboxPage>();
+
+        cut.WaitForAssertion(() =>
+            Assert.Contains("outbox query backend unavailable", cut.Markup));
+    }
+
     protected override void Dispose(bool disposing)
     {
         if (disposing)