libbluray_test: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/libbluray_test - from package: libbluray

You may install the required package with command yum install {package}

Error in other languages:
libbluray_test: bevel nie gevind nie
libbluray_test: comandă negăsită
libbluray_test: comando não encontrado
libbluray_test: commande introuvable
libbluray_test: command not found
libbluray_test: käsku ei ole
libbluray_test: không tìm thấy lệnh
libbluray_test: komanda nerasta
libbluray_test: Kommando nicht gefunden.
libbluray_test: kommandot finns inte
libbluray_test: komut yok
libbluray_test: nie znaleziono polecenia
libbluray_test: níor aimsíodh an t-ordú
libbluray_test: no se encontró la orden
libbluray_test: no s'ha trobat l'ordre
libbluray_test: opdracht niet gevonden
libbluray_test: parancs nem található
libbluray_test: perintah tidak ditemukan
libbluray_test: príkaz nenájdený
libbluray_test: příkaz nenalezen
libbluray_test: команда не найдена
libbluray_test: командата не е открита
libbluray_test: 命令找不到
libbluray_test: コマンドが見つかりません