"timezone_out works with a specified timezone"
"timezone_out works with '' and converts to local timezime"
"timezone_out works with UTC and tz_out_convert = 'force'"
"timezone_out works with a specified timezone and tz_out_convert = 'force'"
"timezone_out works with '' and tz_out_convert = 'force': forces local timezime"
"timezone_out works with a specified local timezone and tz_out_convert = 'force': forces local timezime"
"timezone_out gives a warning with invalid timezone, and converts to UTC"
"timezone_out gives a warning with NULL timezone, and converts to UTC"
"dbConnect fails when tz_out_convert is misspecified"
"timezone_out and tz_out_convert = force with midnight times (#8547)"
"POSIXct with local time zone and existing but empty attribute"
"tz_out_convert = force handles invalid timestamps during DST transitions"

POSIXct with local time zone and existing but empty attribute