Set LastModified to fallback to VersionHistory

Also added unit test to validate behavior.

Author: JeremyCaney

Ignia.Topics.Tests/TopicTest.cs

@@ -224,6 +224,32 @@ public void Topic_TitleTest() {
 
     }
 
+    /*==========================================================================================================================
+    | TEST: LAST MODIFIED
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <summary>
+    ///   Returns the last modified date using a couple of techniques, and ensures it's returned correctly.
+    /// </summary>
+    [TestMethod]
+    public void Topic_LastModifiedTest() {
+
+      var topic1                = TopicFactory.Create("Topic1", "Page");
+      var topic2                = TopicFactory.Create("Topic2", "Page");
+      var topic3                = TopicFactory.Create("Topic3", "Page");
+
+      var lastModified          = new DateTime(1976, 10, 15);
+
+      topic1.LastModified       = lastModified;
+
+      topic2.VersionHistory.Add(lastModified);
+      topic3.Attributes.SetValue("LastModified", lastModified.ToShortDateString());
+
+      Assert.AreEqual<DateTime>(lastModified, topic1.LastModified);
+      Assert.AreEqual<DateTime>(lastModified, topic2.LastModified);
+      Assert.AreEqual<DateTime>(lastModified, topic3.LastModified);
+
+    }
+
     /*==========================================================================================================================
     | TEST: DERIVED TOPIC
     \-------------------------------------------------------------------------------------------------------------------------*/

Ignia.Topics/Topic.cs

@@ -319,16 +319,14 @@ public DateTime LastModified {
       get {
 
         /*----------------------------------------------------------------------------------------------------------------------
-        | Return minimum date value, if LastModified is not already populated
+        | Establish default value
         \---------------------------------------------------------------------------------------------------------------------*/
-        if (String.IsNullOrWhiteSpace(Attributes.GetValue("LastModified", ""))) {
-          return DateTime.MinValue;
-        }
+        var defaultValue = VersionHistory.Count > 0 ? VersionHistory.LastOrDefault() : DateTime.MinValue;
 
         /*----------------------------------------------------------------------------------------------------------------------
         | Return converted string attribute value, if available
         \---------------------------------------------------------------------------------------------------------------------*/
-        var lastModified = Attributes.GetValue("LastModified");
+        var lastModified = Attributes.GetValue("LastModified", defaultValue.ToString());
 
         // Return converted DateTime
         if (DateTime.TryParse(lastModified, out var dateTimeValue)) {
@@ -338,9 +336,7 @@ public DateTime LastModified {
         /*----------------------------------------------------------------------------------------------------------------------
         | Otherwise, return default of minimum value
         \---------------------------------------------------------------------------------------------------------------------*/
-        else {
-          return DateTime.MinValue;
-        }
+        return defaultValue;
 
       }
       set => SetAttributeValue("LastModified", value.ToString());