fix(central-ui): resolve CentralUI-015..019 — pager windowing, logout CSRF, narrowed catch blocks, coverage; CentralUI-015 re-triaged Won't Fix

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

@@ -0,0 +1,62 @@
+using Bunit;
+using Microsoft.AspNetCore.Components;
+using ScadaLink.CentralUI.Components.Shared;
+
+namespace ScadaLink.CentralUI.Tests.Shared;
+
+/// <summary>
+/// Regression tests for CentralUI-018. <c>TreeView</c>'s storage-restore path
+/// called <c>JsonSerializer.Deserialize</c> on the raw <c>treeviewStorage</c>
+/// payload outside any try block — a corrupt payload threw an uncaught
+/// <c>JsonException</c> during <c>OnAfterRenderAsync</c>, breaking the
+/// component. The fix guards the deserialize and ignores a corrupt payload.
+/// </summary>
+public class TreeViewStorageResilienceTests : BunitContext
+{
+    private record TestNode(string Key, string Label, List<TestNode> Children);
+
+    private static List<TestNode> Roots() => new()
+    {
+        new("a", "Alpha", new() { new("a1", "Alpha-1", new()) }),
+        new("b", "Beta", new()),
+    };
+
+    private IRenderedComponent<TreeView<TestNode>> BuildTree()
+        => Render<TreeView<TestNode>>(parameters => parameters
+            .Add(p => p.Items, Roots())
+            .Add(p => p.ChildrenSelector, n => n.Children)
+            .Add(p => p.HasChildrenSelector, n => n.Children.Count > 0)
+            .Add(p => p.KeySelector, n => n.Key)
+            .Add(p => p.NodeContent, (RenderFragment<TestNode>)(node => b =>
+                b.AddMarkupContent(0, $"<span>{node.Label}</span>")))
+            .Add(p => p.StorageKey, "corrupt-tree"));
+
+    [Fact]
+    public void StorageRestore_CorruptJsonPayload_DoesNotThrow_AndStillRenders()
+    {
+        // A garbage payload that is not valid JSON for a List<string>.
+        JSInterop.Setup<string?>("treeviewStorage.load", _ => true)
+            .SetResult("{not json at all]");
+        JSInterop.SetupVoid("treeviewStorage.save", _ => true);
+
+        // Pre-fix: OnAfterRenderAsync threw JsonException out of the unguarded
+        // Deserialize call. Post-fix: the corrupt payload is ignored.
+        var cut = BuildTree();
+
+        Assert.Contains("Alpha", cut.Markup);
+        Assert.Contains("Beta", cut.Markup);
+    }
+
+    [Fact]
+    public void StorageRestore_WrongShapeJson_DoesNotThrow()
+    {
+        // Valid JSON, but not a List<string> — an object, not an array.
+        JSInterop.Setup<string?>("treeviewStorage.load", _ => true)
+            .SetResult("{\"unexpected\": true}");
+        JSInterop.SetupVoid("treeviewStorage.save", _ => true);
+
+        var cut = BuildTree();
+
+        Assert.Contains("Alpha", cut.Markup);
+    }
+}