}
			if string(p[:n]) != res {
				t.Errorf("unexpected bytes: want %q, got %q", res, p[:n])
			}
		}
	}
}

func TestEmptyID(t *testing.T) {
	r := strings.NewReader("aha!")
	matches, hash, err := FindAndHash(r, "", 1000)
	if matches != nil || hash != ([32]byte{}) || err == nil || !strings.Contains(err.Error(), "no id") {