for _, rangeString := range invalidRangeStrings {
		if _, err := parseCopyPartRangeSpec(rangeString); err == nil {
			t.Fatalf("expected: an error, got: <nil> for range %s", rangeString)
		}
	}

	// Test error range strings.
	errorRangeString := []string{
		"bytes=10-10",
		"bytes=20-30",
	}
	for _, rangeString := range errorRangeString {
		rs, err := parseCopyPartRangeSpec(rangeString)
		if err == nil {

// offsets. See
// http://docs.aws.amazon.com/AmazonS3/latest/API/mpUploadUploadPartCopy.html
// for full details. This function treats an empty rangeString as
// referring to the whole resource.
func parseCopyPartRangeSpec(rangeString string) (hrange *HTTPRangeSpec, err error) {
	hrange, err = parseRequestRangeSpec(rangeString)
	if err != nil {
		return nil, err
	}
	if hrange.IsSuffixLength || hrange.Start < 0 || hrange.End < 0 {

	// Get request range.
	var rs *HTTPRangeSpec
	var parseRangeErr error
	if rangeHeader := r.Header.Get(xhttp.AmzCopySourceRange); rangeHeader != "" {
		rs, parseRangeErr = parseCopyPartRangeSpec(rangeHeader)
	} else {
		// This check is to see if client specified a header but the value
		// is empty for 'x-amz-copy-source-range'
		_, ok := r.Header[xhttp.AmzCopySourceRange]
		if ok {