diff --git a/SabreTools.DatItems/DatItem.cs b/SabreTools.DatItems/DatItem.cs
index 871b9d46..d11bf452 100644
--- a/SabreTools.DatItems/DatItem.cs
+++ b/SabreTools.DatItems/DatItem.cs
@@ -544,7 +544,7 @@ namespace SabreTools.DatItems
                 if (file == null)
                     continue;
 
-                // If we don't have a Dis, Media, or Rom, we skip checking for duplicates
+                // If we don't have a Disk, Media, or Rom, we skip checking for duplicates
                 if (file.ItemType != ItemType.Disk && file.ItemType != ItemType.Media && file.ItemType != ItemType.Rom)
                     continue;
 
diff --git a/SabreTools.FileTypes/Aaru/AaruFormat.cs b/SabreTools.FileTypes/Aaru/AaruFormat.cs
index f5418033..bd7ea957 100644
--- a/SabreTools.FileTypes/Aaru/AaruFormat.cs
+++ b/SabreTools.FileTypes/Aaru/AaruFormat.cs
@@ -40,6 +40,14 @@ namespace SabreTools.FileTypes.Aaru
 
         #region Constructors
 
+        /// <summary>
+        /// Empty constructor
+        /// </summary>
+        public AaruFormat()
+        {
+            Type = FileType.AaruFormat;
+        }
+
         /// <summary>
         /// Create a new AaruFormat from an input file
         /// </summary>
diff --git a/SabreTools.FileTypes/CHD/CHDFile.cs b/SabreTools.FileTypes/CHD/CHDFile.cs
index 76b5dfba..ab77b278 100644
--- a/SabreTools.FileTypes/CHD/CHDFile.cs
+++ b/SabreTools.FileTypes/CHD/CHDFile.cs
@@ -23,6 +23,14 @@ namespace SabreTools.FileTypes.CHD
 
         #region Constructors
 
+        /// <summary>
+        /// Empty constructor
+        /// </summary>
+        public CHDFile()
+        {
+            Type = FileType.CHD;
+        }
+
         /// <summary>
         /// Create a new CHDFile from an input file
         /// </summary>
diff --git a/SabreTools.FileTypes/CHD/CHDFileV1.cs b/SabreTools.FileTypes/CHD/CHDFileV1.cs
index 2f6ffba5..6611f159 100644
--- a/SabreTools.FileTypes/CHD/CHDFileV1.cs
+++ b/SabreTools.FileTypes/CHD/CHDFileV1.cs
@@ -9,7 +9,7 @@ namespace SabreTools.FileTypes.CHD
     /// <summary>
     /// CHD V1 File
     /// </summary>
-    internal class CHDFileV1 : CHDFile
+    public class CHDFileV1 : CHDFile
     {
         /// <summary>
         /// CHD flags
diff --git a/SabreTools.FileTypes/CHD/CHDFileV2.cs b/SabreTools.FileTypes/CHD/CHDFileV2.cs
index d89bec34..dcf1dff4 100644
--- a/SabreTools.FileTypes/CHD/CHDFileV2.cs
+++ b/SabreTools.FileTypes/CHD/CHDFileV2.cs
@@ -9,7 +9,7 @@ namespace SabreTools.FileTypes.CHD
     /// <summary>
     /// CHD V2 File
     /// </summary>
-    internal class CHDFileV2 : CHDFile
+    public class CHDFileV2 : CHDFile
     {
         /// <summary>
         /// CHD flags
diff --git a/SabreTools.FileTypes/CHD/CHDFileV3.cs b/SabreTools.FileTypes/CHD/CHDFileV3.cs
index a18d2d07..0d2829fb 100644
--- a/SabreTools.FileTypes/CHD/CHDFileV3.cs
+++ b/SabreTools.FileTypes/CHD/CHDFileV3.cs
@@ -9,7 +9,7 @@ namespace SabreTools.FileTypes.CHD
     /// <summary>
     /// CHD V3 File
     /// </summary>
-    internal class CHDFileV3 : CHDFile
+    public class CHDFileV3 : CHDFile
     {
         /// <summary>
         /// CHD flags
diff --git a/SabreTools.FileTypes/CHD/CHDFileV4.cs b/SabreTools.FileTypes/CHD/CHDFileV4.cs
index b26a6663..3ebb9cca 100644
--- a/SabreTools.FileTypes/CHD/CHDFileV4.cs
+++ b/SabreTools.FileTypes/CHD/CHDFileV4.cs
@@ -9,7 +9,7 @@ namespace SabreTools.FileTypes.CHD
     /// <summary>
     /// CHD V4 File
     /// </summary>
-    internal class CHDFileV4 : CHDFile
+    public class CHDFileV4 : CHDFile
     {
         /// <summary>
         /// CHD flags
diff --git a/SabreTools.FileTypes/CHD/CHDFileV5.cs b/SabreTools.FileTypes/CHD/CHDFileV5.cs
index ab55c3a2..a50658e0 100644
--- a/SabreTools.FileTypes/CHD/CHDFileV5.cs
+++ b/SabreTools.FileTypes/CHD/CHDFileV5.cs
@@ -8,7 +8,7 @@ namespace SabreTools.FileTypes.CHD
     /// <summary>
     /// CHD V5 File
     /// </summary>
-    internal class CHDFileV5 : CHDFile
+    public class CHDFileV5 : CHDFile
     {
         /// <summary>
         /// Uncompressed map format
diff --git a/SabreTools.Test/DatItems/DatItemTests.cs b/SabreTools.Test/DatItems/DatItemTests.cs
new file mode 100644
index 00000000..d8d276e6
--- /dev/null
+++ b/SabreTools.Test/DatItems/DatItemTests.cs
@@ -0,0 +1,214 @@
+using SabreTools.Core;
+using SabreTools.DatItems;
+using SabreTools.FileTypes;
+using SabreTools.FileTypes.Aaru;
+using SabreTools.FileTypes.Archives;
+using SabreTools.FileTypes.CHD;
+using Xunit;
+
+namespace SabreTools.Test.DatItems
+{
+    public class DatItemTests
+    {
+        [Theory]
+        [InlineData(null, ItemType.Rom)]
+        [InlineData(ItemType.Disk, ItemType.Disk)]
+        [InlineData(ItemType.Media, ItemType.Media)]
+        [InlineData(ItemType.Rom, ItemType.Rom)]
+        public void CreateItemTypeTest(ItemType? itemType, ItemType expected)
+        {
+            var actual = DatItem.Create(itemType);
+            Assert.Equal(expected, actual.ItemType);
+        }
+
+        [Theory]
+        [InlineData(FileType.None, ItemType.Rom)]
+        [InlineData(FileType.Folder, null)]
+        [InlineData(FileType.AaruFormat, ItemType.Media)]
+        [InlineData(FileType.CHD, ItemType.Disk)]
+        [InlineData(FileType.ZipArchive, ItemType.Rom)]
+        public void CreateBaseFileTest(FileType fileType, ItemType? expected)
+        {
+            var baseFile = CreateBaseFile(fileType);
+            var actual = DatItem.Create(baseFile);
+            Assert.Equal(expected, actual?.ItemType);
+        }
+    
+        [Fact]
+        public void DuplicateStatusUnequalTest()
+        {
+            var rom = new Rom();
+            var disk = new Disk();
+            var actual = rom.GetDuplicateStatus(disk);
+            Assert.Equal((DupeType)0x00, actual);
+        }
+
+        [Fact]
+        public void DuplicateStatusExternalAllTest()
+        {
+            var romA = new Rom
+            {
+                Name = "same-name",
+                CRC = "DEADBEEF",
+                Machine = new Machine
+                {
+                    Name = "name-same",
+                },
+                Source = new Source
+                {
+                    Index = 0,
+                },
+            };
+            var romB = new Rom
+            {
+                Name = "same-name",
+                CRC = "DEADBEEF",
+                Machine = new Machine
+                {
+                    Name = "name-same",
+                },
+                Source = new Source
+                {
+                    Index = 1,
+                },
+            };
+
+            var actual = romA.GetDuplicateStatus(romB);
+            Assert.Equal(DupeType.External | DupeType.All, actual);
+        }
+
+        [Fact]
+        public void DuplicateStatusExternalHashTest()
+        {
+            var romA = new Rom
+            {
+                Name = "same-name",
+                CRC = "DEADBEEF",
+                Machine = new Machine
+                {
+                    Name = "name-same",
+                },
+                Source = new Source
+                {
+                    Index = 0,
+                },
+            };
+            var romB = new Rom
+            {
+                Name = "same-name",
+                CRC = "DEADBEEF",
+                Machine = new Machine
+                {
+                    Name = "not-name-same",
+                },
+                Source = new Source
+                {
+                    Index = 1,
+                },
+            };
+
+            var actual = romA.GetDuplicateStatus(romB);
+            Assert.Equal(DupeType.External | DupeType.Hash, actual);
+        }
+
+        [Fact]
+        public void DuplicateStatusInternalAllTest()
+        {
+            var romA = new Rom
+            {
+                Name = "same-name",
+                CRC = "DEADBEEF",
+                Machine = new Machine
+                {
+                    Name = "name-same",
+                },
+                Source = new Source
+                {
+                    Index = 0,
+                },
+            };
+            var romB = new Rom
+            {
+                Name = "same-name",
+                CRC = "DEADBEEF",
+                Machine = new Machine
+                {
+                    Name = "name-same",
+                },
+                Source = new Source
+                {
+                    Index = 0,
+                },
+            };
+
+            var actual = romA.GetDuplicateStatus(romB);
+            Assert.Equal(DupeType.Internal | DupeType.All, actual);
+        }
+
+        [Fact]
+        public void DuplicateStatusInternalHashTest()
+        {
+            var romA = new Rom
+            {
+                Name = "same-name",
+                CRC = "DEADBEEF",
+                Machine = new Machine
+                {
+                    Name = "name-same",
+                },
+                Source = new Source
+                {
+                    Index = 0,
+                },
+            };
+            var romB = new Rom
+            {
+                Name = "same-name",
+                CRC = "DEADBEEF",
+                Machine = new Machine
+                {
+                    Name = "not-name-same",
+                },
+                Source = new Source
+                {
+                    Index = 0,
+                },
+            };
+
+            var actual = romA.GetDuplicateStatus(romB);
+            Assert.Equal(DupeType.Internal | DupeType.Hash, actual);
+        }
+    
+        [Theory]
+        [InlineData(null, null, true)]
+        [InlineData(null, new byte[0], true)]
+        [InlineData(new byte[0], null, true)]
+        [InlineData(new byte[] { 0x00 }, new byte[] { 0x00, 0x01 }, false)]
+        [InlineData(new byte[] { 0x00 }, new byte[] { 0x01 }, false)]
+        [InlineData(new byte[] { 0x00 }, new byte[] { 0x00 }, true)]
+        public void ConditionalHashEqualsTest(byte[] first, byte[] second, bool expected)
+        {
+            bool actual = DatItem.ConditionalHashEquals(first, second);
+            Assert.Equal(expected, actual);
+        }
+    
+        // TODO: Add tests for DatItem.Merge
+        // TODO: Add tests for ResolveNames
+        // TODO: Add tests for Sort
+
+        /// <summary>
+        /// Create a BaseFile for testing
+        /// </summary>
+        private BaseFile CreateBaseFile(FileType fileType)
+        {
+            return fileType switch
+            {
+                FileType.Folder => new Folder(),
+                FileType.AaruFormat => new AaruFormat(),
+                FileType.CHD => new CHDFileV5(),
+                FileType.ZipArchive => new ZipArchive(),
+                _ => new BaseFile(),
+            };
+        }
+    }
+}
\ No newline at end of file
diff --git a/SabreTools.Test/SabreTools.Test.csproj b/SabreTools.Test/SabreTools.Test.csproj
index fa4e2890..a87e1791 100644
--- a/SabreTools.Test/SabreTools.Test.csproj
+++ b/SabreTools.Test/SabreTools.Test.csproj
@@ -8,6 +8,7 @@
   <ItemGroup>
     <ProjectReference Include="..\SabreTools.Core\SabreTools.Core.csproj" />
     <ProjectReference Include="..\SabreTools.DatItems\SabreTools.DatItems.csproj" />
+    <ProjectReference Include="..\SabreTools.FileTypes\SabreTools.FileTypes.csproj" />
     <ProjectReference Include="..\SabreTools.Filtering\SabreTools.Filtering.csproj" />
     <ProjectReference Include="..\SabreTools.IO\SabreTools.IO.csproj" />
     <ProjectReference Include="..\SabreTools.Skippers\SabreTools.Skippers.csproj" />