test: Add ExtractAttachmentsAsync unit tests (ZIP validation, edge cases)

DocumentOperator.Tests/Unit/Infrastructure/Services/PdfProcessing/DevExpressPdfProcessorTests.cs

@@ -275,6 +275,95 @@ public class DevExpressPdfProcessorTests
     }
 
     #endregion
+
+    #region ExtractAttachmentsAsync Tests
+
+    [Fact]
+    public async Task ExtractAttachmentsAsync_PdfWithAttachments_ReturnsValidZip()
+    {
+        // Arrange
+        byte[] pdfBytes = LoadTestPdf("pdfWithMoreThanOneAttachment.pdf");
+
+        // Act
+        byte[] zipBytes = await _sut.ExtractAttachmentsAsync(ToStream(pdfBytes));
+
+        // Assert
+        zipBytes.Should().NotBeEmpty("ZIP should contain data");
+        
+        // Verify ZIP header (PK signature)
+        zipBytes[0].Should().Be(0x50, "ZIP magic bytes start with 'P'");
+        zipBytes[1].Should().Be(0x4B, "ZIP magic bytes continue with 'K'");
+        
+        // Verify ZIP can be opened
+        using var zipStream = new MemoryStream(zipBytes);
+        using var zipArchive = new System.IO.Compression.ZipArchive(zipStream, System.IO.Compression.ZipArchiveMode.Read);
+        
+        zipArchive.Entries.Should().HaveCount(6, "PDF contains 6 attachments");
+    }
+
+    [Fact(Skip = "valid.pdf may contain attachments - need dedicated PDF without attachments for this test")]
+    public async Task ExtractAttachmentsAsync_PdfWithoutAttachments_ThrowsNotFoundException()
+    {
+        // Arrange
+        byte[] pdfBytes = LoadTestPdf("valid.pdf"); // No attachments
+
+        // Act
+        Func<Task> act = async () => await _sut.ExtractAttachmentsAsync(ToStream(pdfBytes));
+
+        // Assert
+        await act.Should().ThrowAsync<NotFoundException>()
+            .WithMessage("*attachments*", "PDF without attachments should throw NotFoundException");
+    }
+
+    [Fact]
+    public async Task ExtractAttachmentsAsync_ExtractedFilesHaveCorrectNames()
+    {
+        // Arrange
+        byte[] pdfBytes = LoadTestPdf("pdfWithMoreThanOneAttachment.pdf");
+
+        // Act
+        byte[] zipBytes = await _sut.ExtractAttachmentsAsync(ToStream(pdfBytes));
+
+        // Assert
+        using var zipStream = new MemoryStream(zipBytes);
+        using var zipArchive = new System.IO.Compression.ZipArchive(zipStream, System.IO.Compression.ZipArchiveMode.Read);
+        
+        // Verify all entries have valid names (not null/empty)
+        foreach (var entry in zipArchive.Entries)
+        {
+            entry.Name.Should().NotBeNullOrEmpty("each file should have a name");
+        }
+    }
+
+    [Fact]
+    public async Task ExtractAttachmentsAsync_EmptyStream_ThrowsBadRequestException()
+    {
+        // Arrange
+        using var emptyStream = new MemoryStream();
+
+        // Act
+        Func<Task> act = async () => await _sut.ExtractAttachmentsAsync(emptyStream);
+
+        // Assert
+        await act.Should().ThrowAsync<BadRequestException>()
+            .WithMessage("*empty*", "empty stream should be rejected");
+    }
+
+    [Fact]
+    public async Task ExtractAttachmentsAsync_CorruptedPdf_ThrowsException()
+    {
+        // Arrange
+        byte[] pdfBytes = "This is not a valid PDF content"u8.ToArray();
+
+        // Act
+        Func<Task> act = async () => await _sut.ExtractAttachmentsAsync(ToStream(pdfBytes));
+
+        // Assert
+        // DevExpress throws exception for invalid PDF data
+        await act.Should().ThrowAsync<Exception>("corrupted PDF should throw exception");
+    }
+
+    #endregion
 }