selftest: 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 Debian possible default full paths are:

/usr/bin/selftest - from package: yagiuda

You may install the required package with command apt-get install {package}

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