diff --git a/SabreTools.Core/Tools/Utilities.cs b/SabreTools.Core/Tools/Utilities.cs
index 01809743..1d8d51e9 100644
--- a/SabreTools.Core/Tools/Utilities.cs
+++ b/SabreTools.Core/Tools/Utilities.cs
@@ -124,6 +124,10 @@ namespace SabreTools.Core.Tools
         /// <returns>Subfolder path for the given hash</returns>
         public static string GetDepotPath(string hash, int depth)
         {
+            // If the hash is null or empty, then we return null
+            if (string.IsNullOrEmpty(hash))
+                return null;
+
             // If the hash isn't the right size, then we return null
             if (hash.Length != Constants.SHA1Length)
                 return null;
@@ -153,8 +157,12 @@ namespace SabreTools.Core.Tools
         /// <returns>True if the extension is valid, false otherwise</returns>
         public static bool HasValidDatExtension(string path)
         {
+            // If the path is null or empty, then we return false
+            if (string.IsNullOrEmpty(path))
+                return false;
+
             // Get the extension from the path, if possible
-            string ext = Path.GetExtension(path).TrimStart('.');
+            string ext = Path.GetExtension(path).TrimStart('.').ToLowerInvariant();
 
             // Check against the list of known DAT extensions
             switch (ext)
diff --git a/SabreTools.Test/Core/ConvertersTests.cs b/SabreTools.Test/Core/ConvertersTests.cs
new file mode 100644
index 00000000..d9168d49
--- /dev/null
+++ b/SabreTools.Test/Core/ConvertersTests.cs
@@ -0,0 +1,70 @@
+using SabreTools.Core;
+using SabreTools.Core.Tools;
+using Xunit;
+
+namespace SabreTools.Test.Core
+{
+    public class ConvertersTests
+    {
+        [Theory]
+        [InlineData(null, DatHeaderField.NULL)]
+        [InlineData("datname", DatHeaderField.NULL)]
+        [InlineData("dat-datname", DatHeaderField.Name)]
+        [InlineData("dat.datname", DatHeaderField.Name)]
+        [InlineData("dat_datname", DatHeaderField.Name)]
+        [InlineData("dat datname", DatHeaderField.Name)]
+        [InlineData("datheader-datname", DatHeaderField.Name)]
+        [InlineData("datheader.datname", DatHeaderField.Name)]
+        [InlineData("datheader_datname", DatHeaderField.Name)]
+        [InlineData("datheader datname", DatHeaderField.Name)]
+        [InlineData("header-datname", DatHeaderField.Name)]
+        [InlineData("header.datname", DatHeaderField.Name)]
+        [InlineData("header_datname", DatHeaderField.Name)]
+        [InlineData("header datname", DatHeaderField.Name)]
+        [InlineData("DAT.DATNAME", DatHeaderField.Name)]
+        [InlineData("dAt.DAtnamE", DatHeaderField.Name)]
+        public void AsDatHeaderFieldTest(string field, DatHeaderField expected)
+        {
+            DatHeaderField actual = field.AsDatHeaderField();
+            Assert.Equal(expected, actual);
+        }
+
+        [Theory]
+        [InlineData(null, DatItemField.NULL)]
+        [InlineData("name", DatItemField.NULL)]
+        [InlineData("item-name", DatItemField.Name)]
+        [InlineData("item.name", DatItemField.Name)]
+        [InlineData("item_name", DatItemField.Name)]
+        [InlineData("item name", DatItemField.Name)]
+        [InlineData("datitem-name", DatItemField.Name)]
+        [InlineData("datitem.name", DatItemField.Name)]
+        [InlineData("datitem_name", DatItemField.Name)]
+        [InlineData("datitem name", DatItemField.Name)]
+        [InlineData("ITEM.NAME", DatItemField.Name)]
+        [InlineData("iTeM.namE", DatItemField.Name)]
+        public void AsDatItemFieldTest(string field, DatItemField expected)
+        {
+            DatItemField actual = field.AsDatItemField();
+            Assert.Equal(expected, actual);
+        }
+
+        [Theory]
+        [InlineData(null, MachineField.NULL)]
+        [InlineData("name", MachineField.NULL)]
+        [InlineData("game-name", MachineField.Name)]
+        [InlineData("game.name", MachineField.Name)]
+        [InlineData("game_name", MachineField.Name)]
+        [InlineData("game name", MachineField.Name)]
+        [InlineData("machine-name", MachineField.Name)]
+        [InlineData("machine.name", MachineField.Name)]
+        [InlineData("machine_name", MachineField.Name)]
+        [InlineData("machine name", MachineField.Name)]
+        [InlineData("GAME.NAME", MachineField.Name)]
+        [InlineData("gAmE.namE", MachineField.Name)]
+        public void AsMachineFieldTest(string field, MachineField expected)
+        {
+            MachineField actual = field.AsMachineField();
+            Assert.Equal(expected, actual);
+        }
+    }
+}
\ No newline at end of file
diff --git a/SabreTools.Test/Core/UtilitiesTests.cs b/SabreTools.Test/Core/UtilitiesTests.cs
new file mode 100644
index 00000000..1956125f
--- /dev/null
+++ b/SabreTools.Test/Core/UtilitiesTests.cs
@@ -0,0 +1,51 @@
+using SabreTools.Core.Tools;
+using Xunit;
+
+namespace SabreTools.Test.Core
+{
+    public class UtiltiesTests
+    {
+        [Theory]
+        [InlineData(null, null)]
+        [InlineData("null", null)]
+        [InlineData("0b00001", null)]
+        [InlineData("12345", 12345)]
+        [InlineData("00000000012345", 12345)]
+        [InlineData("10h", null)]
+        [InlineData("0x10", 16)]
+        [InlineData(" 12345 ", 12345)]
+        public void CleanLongTest(string input, long? expected)
+        {
+            long? actual = Utilities.CleanLong(input);
+            Assert.Equal(expected, actual);
+        }
+
+        [Theory]
+        [InlineData(null, 0, null)]
+        [InlineData(null, 4, null)]
+        [InlineData("123456", 0, null)]
+        [InlineData("123456", 4, null)]
+        [InlineData("da39a3ee5e6b4b0d3255bfef95601890afd80709", -1, "da39a3ee5e6b4b0d3255bfef95601890afd80709.gz")]
+        [InlineData("da39a3ee5e6b4b0d3255bfef95601890afd80709", 0, "da39a3ee5e6b4b0d3255bfef95601890afd80709.gz")]
+        [InlineData("da39a3ee5e6b4b0d3255bfef95601890afd80709", 1, "da\\da39a3ee5e6b4b0d3255bfef95601890afd80709.gz")]
+        public void GetDepotPathTest(string hash, int depth, string expected)
+        {
+            string actual = Utilities.GetDepotPath(hash, depth);
+            Assert.Equal(expected, actual);
+        }
+
+        [Theory]
+        [InlineData(null, false)]
+        [InlineData("", false)]
+        [InlineData("no-extension", false)]
+        [InlineData("invalid.ext", false)]
+        [InlineData("INVALID.EXT", false)]
+        [InlineData("valid_extension.dat", true)]
+        [InlineData("valid_extension.DAT", true)]
+        public void HasValidDatExtensionTest(string path, bool expected)
+        {
+            bool actual = Utilities.HasValidDatExtension(path);
+            Assert.Equal(expected, actual);
+        }
+    }
+}
\ No newline at end of file
diff --git a/SabreTools.Test/SabreTools.Test.csproj b/SabreTools.Test/SabreTools.Test.csproj
index c0dc1ace..e37fefe1 100644
--- a/SabreTools.Test/SabreTools.Test.csproj
+++ b/SabreTools.Test/SabreTools.Test.csproj
@@ -1,11 +1,16 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net5.0</TargetFramework>
-
+    <TargetFrameworks>netcoreapp3.1;net5.0</TargetFrameworks>
+    <Configurations>Debug;Release</Configurations>
+    <Platforms>AnyCPU;x64</Platforms>
     <IsPackable>false</IsPackable>
   </PropertyGroup>
 
+  <ItemGroup>
+    <ProjectReference Include="..\SabreTools.Core\SabreTools.Core.csproj" />
+  </ItemGroup>
+
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.7.1" />
     <PackageReference Include="xunit" Version="2.4.1" />