apctest: 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:

/sbin/apctest - from package: apcupsd

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

On Debian possible default full paths are:

/sbin/apctest - from package: apcupsd

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

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