test: add more coverage

TODO

@@ -0,0 +1,37 @@
+Missing or Inadequate Test Coverage
+1. SessionConfig Class (session_config.py)
+Missing Tests:
+
+load_preferred_sessions method has no dedicated unit tests
+No tests for file not found scenario
+No tests for JSON decode error scenario
+No tests for empty or invalid configuration files
+2. SessionNotifier Class (session_notifier.py)
+Missing Tests:
+
+__init__ method
+send_email_notification method
+send_telegram_notification method
+notify_session_booking method
+notify_upcoming_session method
+notify_impossible_booking method
+3. CrossFitBooker Class (crossfit_booker_functional.py) - Missing Tests
+get_auth_headers function (functional version)
+prepare_booking_data function
+is_bookable_and_preferred function
+process_booking_results function
+is_upcoming_preferred function
+4. CrossFitBooker Class (crossfit_booker.py) - Missing Tests
+is_session_bookable method (non-functional version)
+_make_request method
+5. Integration and Edge Cases
+No tests for the main entry point (book_crossfit.py)
+Limited testing of error conditions and edge cases for many methods
+No performance or stress tests
+No tests for concurrent booking scenarios
+
+
+
+Test private methods like _make_request through their public interfaces or consider making them protected
+Add integration tests for the complete booking flow
+Improve edge case coverage in existing tests