chunk_get_last
assert(chunk_get_last(base, chunk, exp) == (uint8_t)exp);
assert(chunk_get_last(base, f, exp) == (uint8_t)exp);
assert(chunk_get_last(base, f, exp) == (uint8_t)exp);
assert(chunk_get_last(base, other, exp)==(uint8_t)exp);
assert(chunk_get_last(base, f, exp) == (uint8_t)exp);