invalidPartNumber:  true,
			accessKey:          credentials.AccessKey,
			secretKey:          credentials.SecretKey,
			expectedRespStatus: http.StatusOK,
		},
		// Test case - 13.
		// maximum part number.
		{
			bucketName:         bucketName,
			uploadID:           uploadID,

	for k := range m {
		keys = append(keys, k)
	}
	sort.Strings(keys)
	for _, k := range keys {
		v := m[k]
		keyEscaped := url.QueryEscape(k)
		if buf.Len() > 1 {
			buf.WriteByte('&')
		}
		buf.WriteString(keyEscaped)
		buf.WriteByte('=')
		buf.WriteString(url.QueryEscape(v))
	}
	return buf.String()
}

// NewBytes returns a new Bytes.
// A slice is preallocated.
func NewBytes() *Bytes {

	signature := getSignature(signingKey, stringToSign)

	req.URL.RawQuery = query.Encode()

	// Add signature header to RawQuery.
	req.URL.RawQuery += "&X-Amz-Signature=" + url.QueryEscape(signature)

	// Construct the final presigned URL.
	return nil
}

// preSignV2 - presign the request in following style.

	c.Assert(err, nil)
	// setting the "X-Amz-Copy-Source" to allow copying the content of previously uploaded object.
	request.Header.Set("X-Amz-Copy-Source", url.QueryEscape(SlashSeparator+bucketName+SlashSeparator+objectName))
	if s.signer == signerV4 {
		err = signRequestV4(request, s.accessKey, s.secretKey)
	} else {
		err = signRequestV2(request, s.accessKey, s.secretKey)
	}