Add comprehensive tests for AnswerValidator and logging_config

[moshesham]

Problem

Critical modules lack test coverage:

• infra/AnswerValidator.py - No tests found
• infra/logging_config.py - No tests found
• Integration tests missing for SQl_answer.py

Current Coverage

Existing tests:

• ✅ test_data_generator.py - Basic tests
• ✅ test_difficulty.py - Difficulty system tests
• ✅ test_user_system.py - User management tests

Missing:

• ❌ AnswerValidator tests
• ❌ Logging configuration tests
• ❌ Integration tests
• ❌ Edge case tests

Impact

• Unknown bugs may exist
• Refactoring is risky
• No confidence in code changes
• Hard to maintain code quality

Tasks

• Create tests/test_answer_validator.py
• Create tests/test_logging_config.py
• Create tests/test_integration.py for end-to-end tests
• Add fixtures for test data and databases
• Aim for 80%+ code coverage
• Run coverage report: pytest --cov=infra --cov-report=html
• Document testing approach in README

Coverage Goal

Target: 80%+ coverage for all modules in infra/

References

• PROJECT_REVIEW.md Issue Add comprehensive tests for AnswerValidator and logging_config #12
• PRODUCT_ROADMAP.md TASK-010