Fixed bug when querying root

When we introduced the `Topic.GetTopicByUniqueKey()` extension method (f2cb109), we significantly optimized the implementation relative to the previous, analogous implementation in `CachedTopicRepository.GetTopic()` (867b110). In doing so, however, we also introduced an inadvertent loophole: It fails to return the unique topic is the unique topic is the root topic.

This is easily remedied by checking this condition at the top of the `GetTopicByUniqueKey()` method. In addition, to be safe, I introduced two unit tests for this scenario. One is for the extension itself (as part of `TopicQueryingTest`). The other is for another extension method, `TopicRepositoryExtensions.Load()` (via `TopicRepositoryExtensionsTest`) which currently relies on that extension method.

(In practice, these two unit tests are evaluating the same underlying logic and are, thus, redundant. But in the past we've modified the underlying logic used by `TopicRepositoryExtensions.Load()`, and so it's useful to evaluate this at that level as well.)

Author: JeremyCaney

OnTopic.AspNetCore.Mvc.Tests/TopicRepositoryExtensionsTest.cs

@@ -65,5 +65,27 @@ public void Load_ByRoute_ReturnsTopic() {
 
     }
 
+    /*==========================================================================================================================
+    | TEST: LOAD: BY ROUTE: RETURNS ROOT TOPIC
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <summary>
+    ///   Establishes route data and ensures that the root topic is correctly identified based on that route.
+    /// </summary>
+    [TestMethod]
+    public void Load_ByRoute_ReturnsRootTopic() {
+
+      var routes                = new RouteData();
+      var topic                 = _topicRepository.Load("Root");
+
+      routes.Values.Add("path", "Root/");
+
+      var currentTopic          = _topicRepository.Load(routes);
+
+      Assert.IsNotNull(currentTopic);
+      Assert.ReferenceEquals(topic, currentTopic);
+      Assert.AreEqual<string>("Root", currentTopic.Key);
+
+    }
+
   } //Class
 } //Namespace

OnTopic.Tests/TopicQueryingTest.cs

@@ -64,6 +64,25 @@ public void GetRootTopic_ReturnsRootTopic() {
 
     }
 
+    /*==========================================================================================================================
+    | TEST: GET BY UNIQUE KEY: ROOT KEY: RETURNS ROOT TOPIC
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <summary>
+    ///   Given a root <see cref="Topic"/>, returns the root <see cref="Topic"/>.
+    /// </summary>
+    [TestMethod]
+    public void GetByUniqueKey_RootKey_ReturnsRootTopic() {
+
+      var parentTopic           = TopicFactory.Create("ParentTopic", "Page", 1);
+      _                         = TopicFactory.Create("ChildTopic", "Page", 2, parentTopic);
+
+      var foundTopic = parentTopic.GetByUniqueKey("ParentTopic");
+
+      Assert.IsNotNull(foundTopic);
+      Assert.ReferenceEquals(parentTopic, foundTopic);
+
+    }
+
     /*==========================================================================================================================
     | TEST: GET BY UNIQUE KEY: VALID KEY: RETURNS TOPIC
     \-------------------------------------------------------------------------------------------------------------------------*/

OnTopic/Querying/TopicExtensions.cs

@@ -193,6 +193,13 @@ public static Topic GetRootTopic(this Topic topic) {
       \-----------------------------------------------------------------------------------------------------------------------*/
       var currentTopic          = (Topic?)topic.GetRootTopic();
 
+      /*------------------------------------------------------------------------------------------------------------------------
+      | Handle request for root
+      \-----------------------------------------------------------------------------------------------------------------------*/
+      if (currentTopic!.Key.Equals(uniqueKey, StringComparison.InvariantCultureIgnoreCase)) {
+        return currentTopic;
+      }
+
       /*------------------------------------------------------------------------------------------------------------------------
       | Process keys
       \-----------------------------------------------------------------------------------------------------------------------*/