mono-test-install: 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/mono-test-install - from package: mono-core

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

On Debian possible default full paths are:

/usr/bin/mono-test-install - from package: mono-devel

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

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