return ""
	}
	off, length, err := h.GetOffsetLength(resourceSize)
	if err != nil {
		return ""
	}
	return fmt.Sprintf("%d-%d", off, off+length-1)
}

// ToHeader returns the Range header value.
func (h *HTTPRangeSpec) ToHeader() (string, error) {
	if h == nil {
		return "", nil
	}
	start := strconv.Itoa(int(h.Start))
	end := strconv.Itoa(int(h.End))
	switch {
	case h.Start >= 0 && h.End >= 0:

		if err != nil {
			if !testCase.errExpected || err == nil && testCase.errExpected {
				t.Errorf("unexpected err: %v", err)
			}
			continue
		}
		h, err := rs.ToHeader()
		if err != nil && !testCase.errExpected || err == nil && testCase.errExpected {
			t.Errorf("expected error with invalid range: %v", err)
		}
		if h != testCase.spec {