As per discussed in #2848 and #2874:

Interesting suggestion from the bot, do we want this for later tests elsewhere?

It can be useful. We could also add something like cls.full_range = range(..., ...) and use it in the required places as self.full_range.

I think, we need to pass years range to setUpClass, and let it create cls.full_range, cls.holidays, cls.holidays_non_observed, ...

cls.no_estimated_holidays - if test_class inherited from IslamicHolidays (or even EasternCalendarHolidays),
cls.subdiv_holidays - if test_class have subdivisions...

• Migration to cls.full_range in place of range(start_year, 2050) that's still in widespread usage
• Migration to years_islamic_no_estimated parameter from cls.no_estimated_holidays for setUpClass
• Migration to years_subdiv parameter from cls.subdiv_holidays for setUpClass
• Migration to year_subdiv_non_observed parameter from cls.subdiv_holidays_non_observed for setUpClass