mysqltest: 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/mysqltest - from package: mysql55w-server
/usr/bin/mysqltest - from package: mysql-server

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

On Debian possible default full paths are:

/usr/bin/mysqltest - from package: mariadb-test-10.0
/usr/bin/mysqltest - from package: mysql-server-5.5

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

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