refactor(central-ui): contextual errors, parallel recipient load, delete-path test for Notification Lists

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

@@ -44,8 +44,11 @@ public class NotificationListsPageTests : BunitContext
 
         var cut = Render<NotificationListsPage>();
 
-        Assert.Contains("Ops On-Call", cut.Markup);
-        Assert.Contains("jane@example.com", cut.Markup);
+        cut.WaitForAssertion(() =>
+        {
+            Assert.Contains("Ops On-Call", cut.Markup);
+            Assert.Contains("jane@example.com", cut.Markup);
+        });
     }
 
     [Fact]
@@ -60,7 +63,38 @@ public class NotificationListsPageTests : BunitContext
 
         var cut = Render<NotificationListsPage>();
 
-        Assert.Contains("No notification lists", cut.Markup);
+        cut.WaitForAssertion(() =>
+            Assert.Contains("No notification lists", cut.Markup));
+    }
+
+    [Fact]
+    public void DeleteList_ConfirmsThenDeletesAndReloads()
+    {
+        var repo = Substitute.For<INotificationRepository>();
+        repo.GetAllNotificationListsAsync()
+            .Returns(Task.FromResult<IReadOnlyList<NotificationList>>(
+                new List<NotificationList> { new("Ops On-Call") { Id = 1 } }));
+        repo.GetRecipientsByListIdAsync(1)
+            .Returns(Task.FromResult<IReadOnlyList<NotificationRecipient>>(
+                new List<NotificationRecipient>()));
+        Services.AddSingleton(repo);
+        WireAuthAndDialog();
+
+        var cut = Render<NotificationListsPage>();
+
+        cut.WaitForState(() => cut.Markup.Contains("Ops On-Call"));
+
+        var deleteButton = cut.FindAll("tbody tr button")
+            .First(b => b.TextContent.Contains("Delete"));
+        deleteButton.Click();
+
+        cut.WaitForAssertion(() =>
+        {
+            repo.Received().DeleteNotificationListAsync(1);
+            repo.Received().SaveChangesAsync();
+            // Reload re-invokes the list query (once on init, once after delete).
+            repo.Received(2).GetAllNotificationListsAsync();
+        });
     }
 
     /// <summary>A dialog service that auto-confirms, so action paths run end-to-end.</summary>