t.Errorf("(%d) expected to get %s, instead got %s", i, niceError(testCase.expected), niceError(errCode))
			}
		} else {
			err = preSignV2(req, accessKey, secretKey, now.Unix()+60)
			if err != nil {
				t.Fatalf("(%d) failed to preSignV2 http request, got %v", i, err)
			}
			// Should be set since we are simulating a http server.
			req.RequestURI = req.URL.RequestURI()

	// Construct the final presigned URL.
	return nil
}

// preSignV2 - presign the request in following style.
// https://${S3_BUCKET}.s3.amazonaws.com/${S3_OBJECT}?AWSAccessKeyId=${S3_ACCESS_KEY}&Expires=${TIMESTAMP}&Signature=${SIGNATURE}.
func preSignV2(req *http.Request, accessKeyID, secretAccessKey string, expires int64) error {
	// Presign is not needed for anonymous credentials.

			instanceType, bucketName, mpartResp.UploadID)
	}

	req.Header = http.Header{}
	err = preSignV2(req, credentials.AccessKey, credentials.SecretKey, int64(10*60*60))
	if err != nil {
		t.Fatalf("[%s] - Failed to presignV2 an unsigned request to list object parts for bucket %s, uploadId %s",
			instanceType, bucketName, mpartResp.UploadID)
	}
	apiRouter.ServeHTTP(rec, req)