The TEST-DAY-YYYYDDD function tests the validity of a date in Julian date form (YYYYDDD) against the Gregorian calendar

- Argument-1 must be an integer.

- The possible values returned by this function are:
- 0 - the date is valid.
- 1 - the date is outside of the date range 1601-9999; that is, the value of argument-1 is less than 1601000 or greater than 9999999; therefore, .
- 2 - the day is not valid in the given year; that is, the value of FUNCTION MOD (argument-1 1000) is less than 1 or greater than the number of days in the year determined by FUNCTION INTEGER (argument-1 / 1000).