return nil, err
	}

	return req, nil
}

var src = rand.NewSource(time.Now().UnixNano())

func randString(n int) string {
	b := make([]byte, n)
	// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
	for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
		if remain == 0 {
			cache, remain = src.Int63(), letterIdxMax
		}

			} else if isSysErrIO(err) {
				return errFaultyDisk
			}
			return err
		}
	}
	srcIsDir := HasSuffix(srcPath, SlashSeparator)
	dstIsDir := HasSuffix(dstPath, SlashSeparator)
	// Either src and dst have to be directories or files, else return error.
	if !(srcIsDir && dstIsDir || !srcIsDir && !dstIsDir) {
		return errFileAccessDenied
	}
	srcFilePath := pathutil.Join(srcVolumeDir, srcPath)

	if err := xlStorage.AppendFile(context.Background(), "src-vol", "file2", []byte("Hello, world")); err != nil {
		t.Fatalf("Unable to create file, %s", err)
	}
	if err := xlStorage.AppendFile(context.Background(), "src-vol", "file3", []byte("Hello, world")); err != nil {
		t.Fatalf("Unable to create file, %s", err)
	}
	if err := xlStorage.AppendFile(context.Background(), "src-vol", "file4", []byte("Hello, world")); err != nil {