diff --git a/DocumentOperator.Tests/Unit/Application/Features/ValidatePdf/ValidatePdfHandlerTests.cs b/DocumentOperator.Tests/Unit/Application/Features/ValidatePdf/ValidatePdfHandlerTests.cs
index 149c3d9..ed6db4a 100644
--- a/DocumentOperator.Tests/Unit/Application/Features/ValidatePdf/ValidatePdfHandlerTests.cs
+++ b/DocumentOperator.Tests/Unit/Application/Features/ValidatePdf/ValidatePdfHandlerTests.cs
@@ -3,7 +3,6 @@ using DocumentOperator.Application.Common.DTOs;
 using DocumentOperator.Application.Common.Interfaces;
 using DocumentOperator.Application.ValidatePdf.Queries;
 using DocumentOperator.Domain.Common.Exceptions;
-using DocumentOperator.Domain.Models.ValueObjects;
 using FluentAssertions;
 using Moq;
 using Xunit;
@@ -27,7 +26,7 @@ public class ValidatePdfHandlerTests
     public async Task Handle_ValidPdf_ReturnsPdfMetadata()
     {
         // Arrange
-        var pdfBytes = new byte[] { 0x25, 0x50, 0x44, 0x46 }; // "%PDF"
+        var pdfBytes = "%PDF"u8.ToArray(); // "%PDF"
         var query = new ValidatePdfQuery { PdfBytes = pdfBytes };
 
         var domainMetadata = new PdfMetadata(
@@ -48,7 +47,7 @@ public class ValidatePdfHandlerTests
         );
 
         _mockPdfProcessor
-            .Setup(x => x.ValidateAsync(It.IsAny<byte[]>()))
+            .Setup(x => x.ValidateAsync(It.IsAny<Stream>()))
             .ReturnsAsync(domainMetadata);
 
         _mockMapper
@@ -66,7 +65,7 @@ public class ValidatePdfHandlerTests
         result.HasAttachments.Should().BeFalse();
         result.AttachmentCount.Should().Be(0);
 
-        _mockPdfProcessor.Verify(x => x.ValidateAsync(It.IsAny<byte[]>()), Times.Once);
+        _mockPdfProcessor.Verify(x => x.ValidateAsync(It.IsAny<Stream>()), Times.Once);
         _mockMapper.Verify(x => x.Map<PdfValidationResult>(domainMetadata), Times.Once);
     }
 
@@ -74,19 +73,19 @@ public class ValidatePdfHandlerTests
     public async Task Handle_PdfProcessorThrowsException_PropagatesException()
     {
         // Arrange
-        var pdfBytes = new byte[] { 0x25, 0x50, 0x44, 0x46 }; // "%PDF"
+        var pdfBytes = "%PDF"u8.ToArray(); // "%PDF"
         var query = new ValidatePdfQuery { PdfBytes = pdfBytes };
 
         _mockPdfProcessor
-            .Setup(x => x.ValidateAsync(It.IsAny<byte[]>()))
-            .ThrowsAsync(new PdfProcessingException("Invalid PDF format"));
+            .Setup(x => x.ValidateAsync(It.IsAny<Stream>()))
+            .ThrowsAsync(new BadRequestException("Invalid PDF format"));
 
         // Act & Assert
-        var exception = await Assert.ThrowsAsync<PdfProcessingException>(
+        var exception = await Assert.ThrowsAsync<BadRequestException>(
             () => _handler.Handle(query, CancellationToken.None)
         );
 
         exception.Message.Should().Be("Invalid PDF format");
-        _mockPdfProcessor.Verify(x => x.ValidateAsync(It.IsAny<byte[]>()), Times.Once);
+        _mockPdfProcessor.Verify(x => x.ValidateAsync(It.IsAny<Stream>()), Times.Once);
     }
 }
diff --git a/DocumentOperator.Tests/Unit/Application/Features/ValidatePdfA/ValidatePdfAQueryHandlerTests.cs b/DocumentOperator.Tests/Unit/Application/Features/ValidatePdfA/ValidatePdfAQueryHandlerTests.cs
index 934f8b2..819bd2e 100644
--- a/DocumentOperator.Tests/Unit/Application/Features/ValidatePdfA/ValidatePdfAQueryHandlerTests.cs
+++ b/DocumentOperator.Tests/Unit/Application/Features/ValidatePdfA/ValidatePdfAQueryHandlerTests.cs
@@ -3,7 +3,7 @@ using DocumentOperator.Application.Common.DTOs;
 using DocumentOperator.Application.Common.Interfaces;
 using DocumentOperator.Application.ValidatePdfA.Queries;
 using DocumentOperator.Domain.Common.Exceptions;
-using DocumentOperator.Domain.Models.ValueObjects;
+
 using FluentAssertions;
 using Moq;
 using Xunit;
@@ -27,7 +27,7 @@ public class ValidatePdfAQueryHandlerTests
     public async Task Handle_ValidPdfA_ReturnsPdfAMetadata()
     {
         // Arrange
-        var pdfBytes = new byte[] { 0x25, 0x50, 0x44, 0x46 }; // "%PDF"
+        var pdfBytes = "%PDF"u8.ToArray(); // "%PDF"
         var query = new ValidatePdfAQuery { PdfBytes = pdfBytes };
 
         var domainMetadata = new PdfAMetadata(
@@ -38,8 +38,8 @@ public class ValidatePdfAQueryHandlerTests
             encrypted: false,
             pdfaVersion: "PDF/A-3b",
             pdfaCompliant: true,
-            errors: new List<string>(),
-            warnings: new List<string>()
+            errors: [],
+            warnings: []
         );
 
         var expectedDto = new PdfAValidationResult
@@ -56,7 +56,7 @@ public class ValidatePdfAQueryHandlerTests
         };
 
         _mockPdfProcessor
-            .Setup(x => x.ValidatePdfAAsync(It.IsAny<byte[]>()))
+            .Setup(x => x.ValidatePdfAAsync(It.IsAny<Stream>()))
             .ReturnsAsync(domainMetadata);
 
         _mockMapper
@@ -77,7 +77,7 @@ public class ValidatePdfAQueryHandlerTests
         result.Errors.Should().BeEmpty();
         result.Warnings.Should().BeEmpty();
 
-        _mockPdfProcessor.Verify(x => x.ValidatePdfAAsync(It.IsAny<byte[]>()), Times.Once);
+        _mockPdfProcessor.Verify(x => x.ValidatePdfAAsync(It.IsAny<Stream>()), Times.Once);
         _mockMapper.Verify(x => x.Map<PdfAValidationResult>(domainMetadata), Times.Once);
     }
 
@@ -117,7 +117,7 @@ public class ValidatePdfAQueryHandlerTests
         };
 
         _mockPdfProcessor
-            .Setup(x => x.ValidatePdfAAsync(It.IsAny<byte[]>()))
+            .Setup(x => x.ValidatePdfAAsync(It.IsAny<Stream>()))
             .ReturnsAsync(domainMetadata);
 
         _mockMapper
@@ -136,7 +136,7 @@ public class ValidatePdfAQueryHandlerTests
         result.Errors.Should().Contain("Missing XMP metadata");
         result.Warnings.Should().HaveCount(1);
 
-        _mockPdfProcessor.Verify(x => x.ValidatePdfAAsync(It.IsAny<byte[]>()), Times.Once);
+        _mockPdfProcessor.Verify(x => x.ValidatePdfAAsync(It.IsAny<Stream>()), Times.Once);
     }
 
     [Fact]
@@ -172,7 +172,7 @@ public class ValidatePdfAQueryHandlerTests
         };
 
         _mockPdfProcessor
-            .Setup(x => x.ValidatePdfAAsync(It.IsAny<byte[]>()))
+            .Setup(x => x.ValidatePdfAAsync(It.IsAny<Stream>()))
             .ReturnsAsync(domainMetadata);
 
         _mockMapper
@@ -188,7 +188,7 @@ public class ValidatePdfAQueryHandlerTests
         result.PdfACompliant.Should().BeFalse();
         result.Errors.Should().Contain("Encrypted PDFs cannot be PDF/A compliant");
 
-        _mockPdfProcessor.Verify(x => x.ValidatePdfAAsync(It.IsAny<byte[]>()), Times.Once);
+        _mockPdfProcessor.Verify(x => x.ValidatePdfAAsync(It.IsAny<Stream>()), Times.Once);
     }
 
     [Fact]
@@ -199,15 +199,16 @@ public class ValidatePdfAQueryHandlerTests
         var query = new ValidatePdfAQuery { PdfBytes = pdfBytes };
 
         _mockPdfProcessor
-            .Setup(x => x.ValidatePdfAAsync(It.IsAny<byte[]>()))
-            .ThrowsAsync(new PdfProcessingException("Invalid PDF format"));
+            .Setup(x => x.ValidatePdfAAsync(It.IsAny<Stream>()))
+            .ThrowsAsync(new BadRequestException("Invalid PDF format"));
 
         // Act & Assert
-        var exception = await Assert.ThrowsAsync<PdfProcessingException>(
+        var exception = await Assert.ThrowsAsync<BadRequestException>(
             () => _handler.Handle(query, CancellationToken.None)
         );
 
         exception.Message.Should().Be("Invalid PDF format");
-        _mockPdfProcessor.Verify(x => x.ValidatePdfAAsync(It.IsAny<byte[]>()), Times.Once);
+        _mockPdfProcessor.Verify(x => x.ValidatePdfAAsync(It.IsAny<Stream>()), Times.Once);
     }
 }
+