request, err = newTestSignedRequest(http.MethodPut, getPutObjectURL(s.endPoint, bucketName, objectName),
		int64(buffer1.Len()), buffer1, s.accessKey, s.secretKey, s.signer)
	c.Assert(err, nil)
	// set the Content-Md5 to be the hash to content.
	request.Header.Set("Content-Md5", etagBase64)
	response, err = s.client.Do(request)
	c.Assert(err, nil)
	// expecting a successful upload.
	c.Assert(response.StatusCode, http.StatusOK)