This is the IRS method for determining residency for tax purposes based on either presence in the US or holding a Lawful Permanent Residency.
The Substantial Presence Test (SPT) is used to determine your residency status for tax purposes. Sprintax Calculus applies this test to assess whether you qualify as a resident or nonresident for US tax purposes. It is essential that you accurately answer all the questions on Step 1 Residency so that Calculus software would be able to correctly determine your residency for tax purposes.
The Green Card Test determines that you are a resident for tax purposes automatically the day when you become a lawful permanent resident.