Split ApplyRemovals for testability

SabreTools.DatFiles.Test/DatFileTests.Removal.cs

@@ -2,6 +2,35 @@ namespace SabreTools.DatFiles.Test
 {
     public partial class DatFileTests
     {
-        
+        #region RemoveHeaderFields
+
+        // TODO: Write RemoveHeaderFields tests
+        // - Null header
+        // - Empty list
+        // - Full list
+
+        #endregion
+
+        #region RemoveItemFields
+
+        // TODO: Write RemoveItemFields tests
+        // - Null item dict
+        // - Both lists empty
+        // - Machine only
+        // - Item only
+        // - Nested
+
+        #endregion
+
+        #region RemoveItemFieldsDB
+
+        // TODO: Write RemoveItemFieldsDB tests
+        // - Null item dict
+        // - Both lists empty
+        // - Machine only
+        // - Item only
+        // - Nested
+
+        #endregion
     }
 }