func commaSplit(data []byte, atEOF bool) (advance int, token []byte, err error) {
	for i := 0; i < len(data); i++ {
		if data[i] == ',' {
			return i + 1, data[:i], nil
		}
	}
	return 0, data, ErrFinalToken
}

func testEmptyTokens(t *testing.T, text string, values []string) {
	s := NewScanner(strings.NewReader(text))
	s.Split(commaSplit)
	var i int
	for i = 0; s.Scan(); i++ {