diff --git a/CodeLineCounter.Tests/HashUtilsMockTests.cs b/CodeLineCounter.Tests/HashUtilsMockTests.cs
new file mode 100644
index 0000000..fd269d6
--- /dev/null
+++ b/CodeLineCounter.Tests/HashUtilsMockTests.cs
@@ -0,0 +1,44 @@
+using CodeLineCounter.Utils;
+using Moq;
+
+namespace CodeLineCounter.Tests
+{
+    public class HashUtilsMockTests : TestBase
+    {
+        private readonly Mock<IHashUtils> _mockHashUtils;
+        private readonly IHashUtils _originalImplementation;
+
+        public HashUtilsMockTests()
+        {
+            _originalImplementation = HashUtils.Implementation;
+            _mockHashUtils = new Mock<IHashUtils>();
+            HashUtils.Implementation = _mockHashUtils.Object;
+        }
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                HashUtils.Implementation = _originalImplementation;
+            }
+            
+            base.Dispose(disposing);
+
+        }
+
+        [Fact]
+        public void ComputeHash_WithMockedImplementation_CallsMockMethod()
+        {
+            // Arrange
+            string input = "Test";
+            string expected = "mocked-hash";
+            _mockHashUtils.Setup(m => m.ComputeHash(input)).Returns(expected);
+
+            // Act
+            string result = HashUtils.ComputeHash(input);
+
+            // Assert
+            Assert.Equal(expected, result);
+            _mockHashUtils.Verify(m => m.ComputeHash(input), Times.Once);
+        }
+    }
+}
\ No newline at end of file
diff --git a/CodeLineCounter.Tests/HashUtilsServiceTests.cs b/CodeLineCounter.Tests/HashUtilsServiceTests.cs
new file mode 100644
index 0000000..655147f
--- /dev/null
+++ b/CodeLineCounter.Tests/HashUtilsServiceTests.cs
@@ -0,0 +1,69 @@
+using CodeLineCounter.Utils;
+
+namespace CodeLineCounter.Tests
+{
+    public class HashUtilsServiceTests
+    {
+        private readonly HashUtilsService _hashUtils;
+
+        public HashUtilsServiceTests()
+        {
+            _hashUtils = new HashUtilsService();
+        }
+
+        [Fact]
+        public void ComputeHash_EmptyString_ReturnsEmptyString()
+        {
+            // Arrange
+            string input = "";
+
+            // Act
+            string result = _hashUtils.ComputeHash(input);
+
+            // Assert
+            Assert.Equal("", result);
+        }
+
+        [Fact]
+        public void ComputeHash_NullString_ReturnsEmptyString()
+        {
+            // Arrange
+            string? input = null;
+
+            // Act
+            string result = _hashUtils.ComputeHash(input);
+
+            // Assert
+            Assert.Equal("", result);
+        }
+
+        [Fact]
+        public void ComputeHash_ValidString_ReturnsHash()
+        {
+            // Arrange
+            string input = "Hello, World!";
+
+            // Act
+            string result = _hashUtils.ComputeHash(input);
+
+            // Assert
+            Assert.NotEmpty(result);
+            Assert.IsType<string>(result);
+        }
+
+        [Fact]
+        public void ComputeHash_DuplicateStrings_ReturnSameHash()
+        {
+            // Arrange
+            string input1 = "Hello, World!";
+            string input2 = "Hello, World!";
+
+            // Act
+            string result1 = _hashUtils.ComputeHash(input1);
+            string result2 = _hashUtils.ComputeHash(input2);
+
+            // Assert
+            Assert.Equal(result1, result2);
+        }
+    }
+}
\ No newline at end of file
diff --git a/CodeLineCounter.Tests/HashUtilsTests.cs b/CodeLineCounter.Tests/HashUtilsTests.cs
index e15d2ab..78f16a6 100644
--- a/CodeLineCounter.Tests/HashUtilsTests.cs
+++ b/CodeLineCounter.Tests/HashUtilsTests.cs
@@ -3,7 +3,7 @@
 namespace CodeLineCounter.Tests
 {
     public class HashUtilsTests
-    {
+    {      
         [Fact]
         public void ComputeHash_EmptyString_ReturnsEmptyString()
         {
@@ -62,5 +62,13 @@ public void ComputeHash_DuplicateStrings_ReturnSameHash()
             // Assert
             Assert.Equal(result1, result2);
         }
+
+        [Fact]
+        public void Implementation_IsInitializedByDefault()
+        {
+            // Act & Assert
+            Assert.NotNull(HashUtils.Implementation);
+            Assert.IsType<IHashUtils>(HashUtils.Implementation, exactMatch: false);
+        }
     }
 }
\ No newline at end of file
diff --git a/CodeLineCounter/AssemblyInfo.cs b/CodeLineCounter/AssemblyInfo.cs
new file mode 100644
index 0000000..70937a3
--- /dev/null
+++ b/CodeLineCounter/AssemblyInfo.cs
@@ -0,0 +1,3 @@
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("CodeLineCounter.Tests")]
\ No newline at end of file
diff --git a/CodeLineCounter/Utils/HashUtils.cs b/CodeLineCounter/Utils/HashUtils.cs
index 59349d7..9d8eb22 100644
--- a/CodeLineCounter/Utils/HashUtils.cs
+++ b/CodeLineCounter/Utils/HashUtils.cs
@@ -5,23 +5,12 @@ namespace CodeLineCounter.Utils
 {
     public static class HashUtils
     {
+        private static readonly IHashUtils _defaultImplementation = new HashUtilsService();
+        
+        internal static IHashUtils Implementation { get; set; } = _defaultImplementation;
         public static string ComputeHash(string? input)
         {
-            if (string.IsNullOrEmpty(input))
-            {
-                return "";
-            }
-
-            byte[] bytes = SHA256.HashData(Encoding.UTF8.GetBytes(input));
-
-            return string.Create(bytes.Length * 2, bytes, static (span, byteArray) =>
-            {
-              const string format = "x2";
-              for (int i = 0; i < byteArray.Length; i++)
-              {
-                  byteArray[i].TryFormat(span.Slice(i * 2, 2), out _, format);
-                }
-            });
+            return Implementation.ComputeHash(input);
         }
     }
-}
+}
\ No newline at end of file
diff --git a/CodeLineCounter/Utils/HashUtilsService.cs b/CodeLineCounter/Utils/HashUtilsService.cs
new file mode 100644
index 0000000..195e68c
--- /dev/null
+++ b/CodeLineCounter/Utils/HashUtilsService.cs
@@ -0,0 +1,27 @@
+using System.Security.Cryptography;
+using System.Text;
+
+namespace CodeLineCounter.Utils
+{
+    public class HashUtilsService : IHashUtils
+    {
+        public string ComputeHash(string? input)
+        {
+            if (string.IsNullOrEmpty(input))
+            {
+                return string.Empty;
+            }
+
+            byte[] bytes = SHA256.HashData(Encoding.UTF8.GetBytes(input));
+
+            return string.Create(bytes.Length * 2, bytes, static (span, byteArray) =>
+            {
+                const string format = "x2";
+                for (int i = 0; i < byteArray.Length; i++)
+                {
+                    byteArray[i].TryFormat(span.Slice(i * 2, 2), out _, format);
+                }
+            });
+        }
+    }
+}
\ No newline at end of file
diff --git a/CodeLineCounter/Utils/IHashUtils.cs b/CodeLineCounter/Utils/IHashUtils.cs
new file mode 100644
index 0000000..060490f
--- /dev/null
+++ b/CodeLineCounter/Utils/IHashUtils.cs
@@ -0,0 +1,7 @@
+namespace CodeLineCounter.Utils
+{
+    public interface IHashUtils
+    {
+        string ComputeHash(string? input);
+    }
+}
\ No newline at end of file