Add Clone tests, add remark to Clone

SabreTools.DatItems.Test/DatItemTests.cs

@@ -898,13 +898,31 @@ namespace SabreTools.DatItems.Test
 
         #region Clone
 
-        // TODO: Implement Clone tests
+        [Fact]
+        public void CloneTest()
+        {
+            DatItem item = new Sample();
+            item.SetName("name");
+
+            object clone = item.Clone();
+            Sample? actual = clone as Sample;
+            Assert.NotNull(actual);
+            Assert.Equal("name", actual.GetName());
+        }
 
         #endregion
 
         #region GetInternalClone
 
-        // TODO: Implement GetInternalClone tests
+        [Fact]
+        public void GetInternalCloneTest()
+        {
+            DatItem<TestDatItemModel> item = new TestDatItem();
+            item.SetName("name");
+
+            TestDatItemModel actual = item.GetInternalClone();
+            Assert.Equal("name", actual[TestDatItemModel.NameKey]);
+        }
 
         #endregion
     }

SabreTools.DatItems/DatItem.cs

@@ -539,6 +539,10 @@ namespace SabreTools.DatItems
         /// Clone the DatItem
         /// </summary>
         /// <returns>Clone of the DatItem</returns>
+        /// <remarks>
+        /// Throws an exception if there is a DatItem implementation
+        /// that is not a part of this library.
+        /// </remarks>
         public override object Clone()
         {
             var concrete = Array.Find(Assembly.GetExecutingAssembly().GetTypes(),