import pytest
from calculator import add, subtract


def test_add_positive():
    assert add(2, 3) == 5

def test_add_negative():
    assert add(-1, 1) == 0

def test_add_zero():
    assert add(0, 0) == 0

def test_subtract_basic():
    assert subtract(5, 3) == 2

def test_subtract_negative_result():
    assert subtract(3, 5) == -2