[FR] Make tests for util.py

[DiFronzo]

Is your feature request related to a problem? Please describe.
There are currently no automated tests for util.py, making it difficult to ensure that the utility functions work as intended and to catch regressions during development.

Describe 1~3 use cases of the purposed feature

• Verify that functions like unix_time, cleanup_input, merge, and load_config behave correctly for a variety of input values and edge cases.
• Ensure that parse_infobox correctly parses infobox templates from page text and handles different contest configurations.
• Confirm that error handling and logging for malformed input, missing configuration, or unusual Unicode/control characters works as intended.

Describe alternatives you've considered

• Relying on manual testing or indirect coverage through higher-level tests, but this does not guarantee that all code paths in util.py are exercised.
• Adding only integration tests, which may not catch issues specific to the utility logic and infobox parsing.

Additional context
Unit tests for util.py will help maintain code quality and reliability. Tests could be implemented using pytest or unittest, and should cover both typical and edge-case usage of the utility functions.