cstest: 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/cstest - from package: clearsilver

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

On Debian possible default full paths are:

/usr/bin/cstest - from package: clearsilver-dev

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

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