Add tests for pdf converter

[NadChern]

Summary

Added comprehensive unit tests for the PDF converter module to improve test coverage and ensure reliability.

What I Did

• Created a new test file tests/test_pdf_converter.py with 12 test cases
• Tests cover the PdfConverter class methods and module constants
• All tests validate correct behavior for PDF file detection and conversion

Test Coverage

• 9 tests for accepts() method - verifying PDF file recognition by extension and MIME type
• 1 test for convert() method - testing error handling when dependencies are missing
• 2 tests for module constants - validating accepted file extensions and MIME types

Results

12 tests written, 12 tests passed

To run all tests follow the command: pytest tests/test_pdf_converter.py -v

Screenshort of tests