import sys, os
sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
from egcd import egcd, gcd, lcm

def test_basic():
    assert egcd(30, 12) == (6, -1, 3) or egcd(30,12)[0]==6
    assert gcd(30,12)==6
    assert lcm(4,6)==12

def test_negatives():
    g,x,y = egcd(-30,12)
    assert g==6 and -30*x + 12*y == g

def test_zero():
    assert gcd(0,5)==5
    assert gcd(5,0)==5
    assert lcm(0,5)==0

def test_identity():
    g,x,y = egcd(17,31)
    assert g==1 and 17*x+31*y==1
if __name__=="__main__":
    for f in [test_basic,test_negatives,test_zero,test_identity]:
        f()
    print("ALL PASS")