Application Handler Tests:
- ValidatePdfHandlerTests: PdfStream = new MemoryStream(pdfBytes)
- ValidatePdfAQueryHandlerTests: PdfStream = new MemoryStream(pdfBytes)
- CheckPdfAttachmentsQueryHandlerTests: PdfStream = new MemoryStream(pdfBytes)
- Remove Base64/PdfBytes property usage
Infrastructure Tests:
- DevExpressSwissQrCodeProcessorTests: LoadTestPdf() returns Stream
- All test methods use 'using var stream' pattern
- Add test: ExtractSwissQrCodeAsync_StreamNotAtBeginning_ThrowsBadRequestException
Result: All unit tests pass with Stream-based API
- Unit tests for CheckPdfAttachmentsQueryHandler (3 tests)
- Integration tests for PdfAttachmentController (14 tests covering both multipart and JSON endpoints)
- Tests verify: attachment detection, metadata extraction, empty PDF handling, validation errors
- All tests using Stream API (mocks with It.IsAny<Stream>())
- Total: 17 new tests, all passing
