Merge branch 'bugfix/TopicRepository.Move-first-child' into develop

Fixed a bug where moving the first (or only) child of a topic to after a sibling in another topic would be inadvertently trip an escape condition meant to bypass cases where the topic was being moved to the same location that it was already located. As part of this, introduced two unit tests—one to validate that the bug no longer appears, and another to ensure that the escape condition still works. This resolves Issue #76.

Author: JeremyCaney

OnTopic.Tests/TopicRepositoryBaseTest.cs

@@ -849,6 +849,30 @@ public void Delete_ContentTypeDescriptor_UpdatesContentTypeCache() {
 
     }
 
+    /*==========================================================================================================================
+    | TEST: MOVE: AFTER SIBLING: SET CORRECTLY
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <summary>
+    ///   Moves a <see cref="Topic"/> after a sibling in another parent, and ensures it is set correctly.
+    /// </summary>
+    [Fact]
+    public void Move_AfterSibling_SetCorrectly() {
+
+      var source                = new Topic("Source", "Page");
+      var topic                 = new Topic("Test", "Page", source);
+      var target                = new Topic("Target", "Page");
+      var sibling               = new Topic("Sibling", "Page", target);
+      var olderSibling          = new Topic("OlderSibling", "Page", target);
+
+      _topicRepository.Move(topic, target, sibling);
+
+      Assert.Equal<Topic?>(target, topic.Parent);
+      Assert.Equal<int>(0, target.Children.IndexOf(sibling));
+      Assert.Equal<int>(1, target.Children.IndexOf(topic));
+      Assert.Equal<int>(2, target.Children.IndexOf(olderSibling));
+
+    }
+
     /*==========================================================================================================================
     | TEST: MOVE: CONTENT TYPE DESCRIPTOR: UPDATES CONTENT TYPE CACHE
     \-------------------------------------------------------------------------------------------------------------------------*/
@@ -1105,5 +1129,30 @@ public void Move_TopicMovedEvent_IsRaised() {
 
     }
 
+    /*==========================================================================================================================
+    | TEST: MOVE: SAME LOCATION: EVENT NOT RAISED
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <summary>
+    ///   Creates a <see cref="Topic"/> and then moves it to the exact same location in the tree. Ensures that the <see cref="
+    ///   ITopicRepository.TopicMoved"/> event is not raised.
+    /// </summary>
+    [Fact]
+    public void Move_SameLocation_EventNotRaised() {
+
+      var parent                = new Topic("Parent", "Page", null, 1);
+      var sibling               = new Topic("Sibling", "Page", parent, 2);
+      var topic                 = new Topic("Test", "Page", parent, 3);
+      var hasFired              = false;
+
+      _cachedTopicRepository.TopicMoved += eventHandler;
+      _cachedTopicRepository.Move(topic, parent, sibling);
+      _cachedTopicRepository.TopicMoved -= eventHandler;
+
+      Assert.False(hasFired);
+
+      void eventHandler(object? sender, TopicMoveEventArgs eventArgs) => hasFired = true;
+
+    }
+
   } //Class
 } //Namespace

OnTopic/Repositories/TopicRepository.cs

@@ -492,6 +492,7 @@ public override sealed void Move([ValidatedNotNull]Topic topic, [ValidatedNotNul
       if (
         sibling is not null &&
         topic.Parent is not null &&
+        topic.Parent == target &&
         topic.Parent.Children.IndexOf(sibling) == topic.Parent.Children.IndexOf(topic)-1) {
         return;
       }