public static int hashToIndex(int hash, int length) {
        checkPositive("length", length);

        if (hash == Integer.MIN_VALUE) {
            return 0;
        }

        return abs(hash) % length;
    }
@Test
    public void hashToIndex_whenHashPositive() {
        assertEquals(20, hashToIndex(20, 100));
        assertEquals(20, hashToIndex(420, 100));
    }