chocolate.py

def calculate(small, big, total):
    maxBigBoxes = total // 5
    bigBoxesWeCanUse = maxBigBoxes if maxBigBoxes < big else big

    total -= (bigBoxesWeCanUse * 5)

    if(small < total):
        return(-1)
    else:
        return(total)


def test_total_is_higher():
    assert calculate(1, 1, 10) == -1

def test_need_for_big_and_small_bars():
    assert calculate(5, 3, 17) == 2

def test_only_big_bars():
    assert calculate(5, 3, 10) == 0

def test_only_small_bars():
    assert calculate(4, 2, 3) == 3

def test_boundary_1():
    assert calculate(2, 3, 17) == 2