Integration Tests:
- Test that Cal takes arguments
- Test a Month with 30 days
- Test a Month with 31 days
- Test a Month with 4 weeks
- Test a Month with 6 weeks
- Test a Common Year in the Past
- Test a Common Year in the Future
- Test a Leap Year in the Past
- Test a Leap Year in the Future
Unit Tests (more on their way):
- initialize_stores_month
- initialize_stores_year
- invalid_argument_throws_error(a-b)
- print_month -- from_fixnum (realized I probably won't need this, but haven't refactored yet) -- from_string
- print_header (a-c)
- print_weekdays
- print_full_header
- test_if_leap_year
- find_start_day (a-c)
- format_week
- month_to_Fixnum (a-c)