diff --git a/src/Core/Services/DabGraphQLResultSerializer.cs b/src/Core/Services/DabGraphQLResultSerializer.cs
index b9cce8334c..f71f7dc130 100644
--- a/src/Core/Services/DabGraphQLResultSerializer.cs
+++ b/src/Core/Services/DabGraphQLResultSerializer.cs
@@ -11,10 +11,17 @@ namespace Azure.DataApiBuilder.Core.Services;
 /// <summary>
 /// The DabGraphQLResultSerializer inspects the IExecutionResult created by HotChocolate
 /// and determines the appropriate HTTP error code to return based on the errors in the result.
-/// By Default, without this serializer, HotChocolate will return a 500 status code when database errors
-/// exist. However, there is a specific error code we check for that should return a 400 status code:
-/// - DatabaseInputError. This indicates that the client can make a change to request contents to influence
-/// a change in the response.
+/// 
+/// By default, without this serializer, HotChocolate will return a 500 status code for errors.
+/// This serializer maps DataApiBuilderException.SubStatusCodes to their appropriate HTTP status codes.
+/// 
+/// For example:
+/// - Authentication/Authorization errors will return 401/403
+/// - Database input validation errors will return 400 BadRequest
+/// - Entity not found errors will return 404 NotFound
+/// 
+/// This ensures that GraphQL endpoints return appropriate and consistent HTTP status codes 
+/// for all types of DataApiBuilderException errors.
 /// </summary>
 public class DabGraphQLResultSerializer : DefaultHttpResultSerializer
 {
@@ -22,12 +29,62 @@ public override HttpStatusCode GetStatusCode(IExecutionResult result)
     {
         if (result is IQueryResult queryResult && queryResult.Errors?.Count > 0)
         {
-            if (queryResult.Errors.Any(error => error.Code == DataApiBuilderException.SubStatusCodes.DatabaseInputError.ToString()))
+            // Check if any of the errors are from DataApiBuilderException by looking at error.Code
+            foreach (var error in queryResult.Errors)
             {
-                return HttpStatusCode.BadRequest;
+                if (error.Code != null && 
+                    Enum.TryParse<DataApiBuilderException.SubStatusCodes>(error.Code, out var subStatusCode))
+                {
+                    return MapSubStatusCodeToHttpStatusCode(subStatusCode);
+                }
             }
         }
 
         return base.GetStatusCode(result);
     }
+
+    /// <summary>
+    /// Maps DataApiBuilderException.SubStatusCodes to appropriate HTTP status codes.
+    /// </summary>
+    private static HttpStatusCode MapSubStatusCodeToHttpStatusCode(DataApiBuilderException.SubStatusCodes subStatusCode) => subStatusCode switch
+    {
+        // Authentication/Authorization errors
+        DataApiBuilderException.SubStatusCodes.AuthenticationChallenge
+            => HttpStatusCode.Unauthorized, // 401
+
+        DataApiBuilderException.SubStatusCodes.AuthorizationCheckFailed or
+        DataApiBuilderException.SubStatusCodes.DatabasePolicyFailure or
+        DataApiBuilderException.SubStatusCodes.AuthorizationCumulativeColumnCheckFailed
+            => HttpStatusCode.Forbidden, // 403
+
+        // Not Found errors
+        DataApiBuilderException.SubStatusCodes.EntityNotFound or
+        DataApiBuilderException.SubStatusCodes.ItemNotFound or
+        DataApiBuilderException.SubStatusCodes.RelationshipNotFound or
+        DataApiBuilderException.SubStatusCodes.RelationshipFieldNotFound or
+        DataApiBuilderException.SubStatusCodes.DataSourceNotFound
+            => HttpStatusCode.NotFound, // 404
+
+        // Bad Request errors
+        DataApiBuilderException.SubStatusCodes.BadRequest or
+        DataApiBuilderException.SubStatusCodes.DatabaseInputError or
+        DataApiBuilderException.SubStatusCodes.InvalidIdentifierField or
+        DataApiBuilderException.SubStatusCodes.ErrorProcessingData or
+        DataApiBuilderException.SubStatusCodes.ExposedColumnNameMappingError or
+        DataApiBuilderException.SubStatusCodes.UnsupportedClaimValueType or
+        DataApiBuilderException.SubStatusCodes.ErrorProcessingEasyAuthHeader
+            => HttpStatusCode.BadRequest, // 400
+
+        // Not Implemented errors
+        DataApiBuilderException.SubStatusCodes.NotSupported or
+        DataApiBuilderException.SubStatusCodes.GlobalRestEndpointDisabled
+            => HttpStatusCode.NotImplemented, // 501
+
+        // Conflict errors
+        DataApiBuilderException.SubStatusCodes.OpenApiDocumentAlreadyExists
+            => HttpStatusCode.Conflict, // 409
+
+        // Server errors - Internal Server Error (default)
+        _ => HttpStatusCode.InternalServerError // 500
+    };
 }
diff --git a/src/Service.Tests/Unittests/DabGraphQLResultSerializerTests.cs b/src/Service.Tests/Unittests/DabGraphQLResultSerializerTests.cs
new file mode 100644
index 0000000000..62789130b4
--- /dev/null
+++ b/src/Service.Tests/Unittests/DabGraphQLResultSerializerTests.cs
@@ -0,0 +1,591 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System.Collections.Generic;
+using System.Net;
+using Azure.DataApiBuilder.Core.Services;
+using Azure.DataApiBuilder.Service.Exceptions;
+using HotChocolate;
+using HotChocolate.Execution;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Moq;
+
+namespace Azure.DataApiBuilder.Service.Tests.UnitTests
+{
+    /// <summary>
+    /// Unit tests for DabGraphQLResultSerializer
+    /// </summary>
+    [TestClass]
+    public class DabGraphQLResultSerializerTests
+    {
+        private DabGraphQLResultSerializer _serializer = null!;
+
+        [TestInitialize]
+        public void TestInitialize()
+        {
+            _serializer = new DabGraphQLResultSerializer();
+        }
+
+        #region Authentication/Authorization Tests
+
+        /// <summary>
+        /// Verify that AuthenticationChallenge maps to 401 Unauthorized
+        /// </summary>
+        [TestMethod]
+        public void AuthenticationChallenge_Returns401()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.AuthenticationChallenge);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.Unauthorized, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that AuthorizationCheckFailed maps to 403 Forbidden
+        /// </summary>
+        [TestMethod]
+        public void AuthorizationCheckFailed_Returns403()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.AuthorizationCheckFailed);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.Forbidden, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that DatabasePolicyFailure maps to 403 Forbidden
+        /// </summary>
+        [TestMethod]
+        public void DatabasePolicyFailure_Returns403()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.DatabasePolicyFailure);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.Forbidden, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that AuthorizationCumulativeColumnCheckFailed maps to 403 Forbidden
+        /// </summary>
+        [TestMethod]
+        public void AuthorizationCumulativeColumnCheckFailed_Returns403()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.AuthorizationCumulativeColumnCheckFailed);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.Forbidden, statusCode);
+        }
+
+        #endregion
+
+        #region Not Found Tests
+
+        /// <summary>
+        /// Verify that EntityNotFound maps to 404 NotFound
+        /// </summary>
+        [TestMethod]
+        public void EntityNotFound_Returns404()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.EntityNotFound);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.NotFound, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that ItemNotFound maps to 404 NotFound
+        /// </summary>
+        [TestMethod]
+        public void ItemNotFound_Returns404()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.ItemNotFound);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.NotFound, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that RelationshipNotFound maps to 404 NotFound
+        /// </summary>
+        [TestMethod]
+        public void RelationshipNotFound_Returns404()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.RelationshipNotFound);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.NotFound, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that RelationshipFieldNotFound maps to 404 NotFound
+        /// </summary>
+        [TestMethod]
+        public void RelationshipFieldNotFound_Returns404()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.RelationshipFieldNotFound);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.NotFound, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that DataSourceNotFound maps to 404 NotFound
+        /// </summary>
+        [TestMethod]
+        public void DataSourceNotFound_Returns404()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.DataSourceNotFound);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.NotFound, statusCode);
+        }
+
+        #endregion
+
+        #region Bad Request Tests
+
+        /// <summary>
+        /// Verify that BadRequest maps to 400 BadRequest
+        /// </summary>
+        [TestMethod]
+        public void BadRequest_Returns400()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.BadRequest);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.BadRequest, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that DatabaseInputError maps to 400 BadRequest
+        /// </summary>
+        [TestMethod]
+        public void DatabaseInputError_Returns400()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.DatabaseInputError);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.BadRequest, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that InvalidIdentifierField maps to 400 BadRequest
+        /// </summary>
+        [TestMethod]
+        public void InvalidIdentifierField_Returns400()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.InvalidIdentifierField);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.BadRequest, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that ErrorProcessingData maps to 400 BadRequest
+        /// </summary>
+        [TestMethod]
+        public void ErrorProcessingData_Returns400()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.ErrorProcessingData);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.BadRequest, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that ExposedColumnNameMappingError maps to 400 BadRequest
+        /// </summary>
+        [TestMethod]
+        public void ExposedColumnNameMappingError_Returns400()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.ExposedColumnNameMappingError);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.BadRequest, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that UnsupportedClaimValueType maps to 400 BadRequest
+        /// </summary>
+        [TestMethod]
+        public void UnsupportedClaimValueType_Returns400()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.UnsupportedClaimValueType);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.BadRequest, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that ErrorProcessingEasyAuthHeader maps to 400 BadRequest
+        /// </summary>
+        [TestMethod]
+        public void ErrorProcessingEasyAuthHeader_Returns400()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.ErrorProcessingEasyAuthHeader);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.BadRequest, statusCode);
+        }
+
+        #endregion
+
+        #region Not Implemented Tests
+
+        /// <summary>
+        /// Verify that NotSupported maps to 501 NotImplemented
+        /// </summary>
+        [TestMethod]
+        public void NotSupported_Returns501()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.NotSupported);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.NotImplemented, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that GlobalRestEndpointDisabled maps to 501 NotImplemented
+        /// </summary>
+        [TestMethod]
+        public void GlobalRestEndpointDisabled_Returns501()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.GlobalRestEndpointDisabled);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.NotImplemented, statusCode);
+        }
+
+        #endregion
+
+        #region Conflict Tests
+
+        /// <summary>
+        /// Verify that OpenApiDocumentAlreadyExists maps to 409 Conflict
+        /// </summary>
+        [TestMethod]
+        public void OpenApiDocumentAlreadyExists_Returns409()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.OpenApiDocumentAlreadyExists);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.Conflict, statusCode);
+        }
+
+        #endregion
+
+        #region Server Error Tests
+
+        /// <summary>
+        /// Verify that ConfigValidationError maps to 500 InternalServerError
+        /// </summary>
+        [TestMethod]
+        public void ConfigValidationError_Returns500()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.ConfigValidationError);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.InternalServerError, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that ErrorInInitialization maps to 500 InternalServerError
+        /// </summary>
+        [TestMethod]
+        public void ErrorInInitialization_Returns500()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.ErrorInInitialization);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.InternalServerError, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that DatabaseOperationFailed maps to 500 InternalServerError
+        /// </summary>
+        [TestMethod]
+        public void DatabaseOperationFailed_Returns500()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.DatabaseOperationFailed);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.InternalServerError, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that GraphQLMapping maps to 500 InternalServerError
+        /// </summary>
+        [TestMethod]
+        public void GraphQLMapping_Returns500()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.GraphQLMapping);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.InternalServerError, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that UnexpectedError maps to 500 InternalServerError
+        /// </summary>
+        [TestMethod]
+        public void UnexpectedError_Returns500()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.UnexpectedError);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.InternalServerError, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that OpenApiDocumentCreationFailure maps to 500 InternalServerError
+        /// </summary>
+        [TestMethod]
+        public void OpenApiDocumentCreationFailure_Returns500()
+        {
+            // Arrange
+            IExecutionResult result = CreateResultWithError(DataApiBuilderException.SubStatusCodes.OpenApiDocumentCreationFailure);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(result);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.InternalServerError, statusCode);
+        }
+
+        #endregion
+
+        #region Edge Case Tests
+
+        /// <summary>
+        /// Verify that when there are no errors, the base status code is returned (500)
+        /// </summary>
+        [TestMethod]
+        public void NoErrors_ReturnsBaseStatusCode()
+        {
+            // Arrange
+            Mock<IQueryResult> mockResult = new();
+            mockResult.Setup(r => r.Errors).Returns((IReadOnlyList<IError>)null);
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(mockResult.Object);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.InternalServerError, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that when errors list is empty, the base status code is returned (500)
+        /// </summary>
+        [TestMethod]
+        public void EmptyErrorsList_ReturnsBaseStatusCode()
+        {
+            // Arrange
+            Mock<IQueryResult> mockResult = new();
+            mockResult.Setup(r => r.Errors).Returns(new List<IError>());
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(mockResult.Object);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.InternalServerError, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that when error has null code, the base status code is returned (500)
+        /// </summary>
+        [TestMethod]
+        public void NullErrorCode_ReturnsBaseStatusCode()
+        {
+            // Arrange
+            Mock<IError> mockError = new();
+            mockError.Setup(e => e.Code).Returns((string)null);
+
+            Mock<IQueryResult> mockResult = new();
+            mockResult.Setup(r => r.Errors).Returns(new List<IError> { mockError.Object });
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(mockResult.Object);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.InternalServerError, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that when error code is not a valid SubStatusCode, the base status code is returned (500)
+        /// </summary>
+        [TestMethod]
+        public void InvalidErrorCode_ReturnsBaseStatusCode()
+        {
+            // Arrange
+            Mock<IError> mockError = new();
+            mockError.Setup(e => e.Code).Returns("InvalidErrorCode");
+
+            Mock<IQueryResult> mockResult = new();
+            mockResult.Setup(r => r.Errors).Returns(new List<IError> { mockError.Object });
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(mockResult.Object);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.InternalServerError, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that when there are multiple errors, the first DAB exception error code is used
+        /// </summary>
+        [TestMethod]
+        public void MultipleErrors_ReturnsFirstDabExceptionStatusCode()
+        {
+            // Arrange
+            Mock<IError> mockError1 = new();
+            mockError1.Setup(e => e.Code).Returns("InvalidCode"); // Not a DAB exception
+
+            Mock<IError> mockError2 = new();
+            mockError2.Setup(e => e.Code).Returns(DataApiBuilderException.SubStatusCodes.EntityNotFound.ToString());
+
+            Mock<IError> mockError3 = new();
+            mockError3.Setup(e => e.Code).Returns(DataApiBuilderException.SubStatusCodes.BadRequest.ToString());
+
+            Mock<IQueryResult> mockResult = new();
+            mockResult.Setup(r => r.Errors).Returns(new List<IError> { mockError1.Object, mockError2.Object, mockError3.Object });
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(mockResult.Object);
+
+            // Assert - Should return status code for first valid DAB exception (EntityNotFound = 404)
+            Assert.AreEqual(HttpStatusCode.NotFound, statusCode);
+        }
+
+        /// <summary>
+        /// Verify that result that is not IQueryResult returns base status code (500)
+        /// </summary>
+        [TestMethod]
+        public void NonQueryResult_ReturnsBaseStatusCode()
+        {
+            // Arrange
+            Mock<IExecutionResult> mockResult = new();
+
+            // Act
+            HttpStatusCode statusCode = _serializer.GetStatusCode(mockResult.Object);
+
+            // Assert
+            Assert.AreEqual(HttpStatusCode.InternalServerError, statusCode);
+        }
+
+        #endregion
+
+        #region Helper Methods
+
+        /// <summary>
+        /// Creates a mock IExecutionResult with a single error containing the specified SubStatusCode
+        /// </summary>
+        private static IExecutionResult CreateResultWithError(DataApiBuilderException.SubStatusCodes subStatusCode)
+        {
+            Mock<IError> mockError = new();
+            mockError.Setup(e => e.Code).Returns(subStatusCode.ToString());
+
+            Mock<IQueryResult> mockResult = new();
+            mockResult.Setup(r => r.Errors).Returns(new List<IError> { mockError.Object });
+
+            return mockResult.Object;
+        }
+
+        #endregion
+    }
+}