test: Add unit tests for encrypt_pdf function

[ambicuity]

Summary

This PR adds comprehensive unit tests for the encrypt_pdf() function to improve test coverage and ensure reliable PDF encryption functionality.

Linked Issue

Fixes #2

Changes Made

Added 5 unit tests in tests/unittests/test_encryptpdf.py:

1. test_encrypt_pdf_creates_output_file - Verifies that an encrypted PDF file is created
2. test_encrypt_pdf_output_is_encrypted - Confirms the output PDF is properly encrypted
3. test_encrypt_pdf_with_correct_password - Tests decryption with the correct password
4. test_encrypt_pdf_preserves_page_count - Ensures page count is preserved during encryption
5. test_encrypt_pdf_with_invalid_input - Validates error handling for non-existent input files

Testing

All tests use:

• unittest.TestCase framework (consistent with existing tests)
• Temporary directories for output files (proper cleanup)
• Sample PDF from tests/resources/Sample_PDF.pdf
• Proper setup and teardown methods

Checklist

• Tests cover the main functionality of encrypt_pdf()
• Tests follow existing code style and structure
• All tests include docstrings
• Temporary files are cleaned up properly
• Tests validate both success and error cases

[nirmalchandra]

Thanks @ambicuity for the PR.
Waiting for this CI ticket to be picked up #7 .

Even otherwise, will review soon and merge if all looks good.

[nirmalchandra]

@ambicuity , can you please resolve the conflicts? Also, check if CI goes Green, then we can merge

[Copilot]

Pull request overview

This PR adds comprehensive unit tests for the encrypt_pdf() function to improve test coverage. The tests verify that the function correctly encrypts PDF files, preserves content during encryption, and handles error cases appropriately.

Changes:

• Added 5 new integration-style unit tests covering file creation, encryption verification, decryption, page count preservation, and error handling
• Renamed test class from TestPdfUnitTests to TestEncryptPdf for better clarity
• Added poetry.lock file with dependency specifications

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated 2 comments.

File	Description
tests/unittests/test_encryptpdf.py	Added 5 new unit tests for encrypt_pdf function with proper setup/teardown and docstrings
poetry.lock	Auto-generated lock file specifying exact versions of all dependencies

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[Copilot]

The tearDown method uses os.rmdir() which will fail if the directory is not empty. If a test fails before removing the output_pdf file, or if multiple files are created during testing, the directory removal will raise an OSError. Consider using shutil.rmtree(self.temp_dir) instead, or wrap it in a try-except block for more robust cleanup.

[Copilot]

The assertion pattern here is inconsistent with the integration test at tests/integrationtests/test_encryptpdf_integration.py:40, which uses self.assertTrue(reader.decrypt(password)). While both approaches work (decrypt returns 0 for failure and non-zero for success), consider using assertTrue for consistency with the existing test pattern.

Suggested change

	# Decrypt with correct password
	decrypt_result = reader.decrypt(self.test_password)
	self.assertNotEqual(
	decrypt_result,
	0,
	# Decrypt with correct password and assert success
	self.assertTrue(
	reader.decrypt(self.test_password),