subunit-1to2: 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/subunit-1to2 - from package: python-subunit

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

On Debian possible default full paths are:

/usr/bin/subunit-1to2 - from package: subunit

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

Error in other languages:
subunit-1to2: bevel nie gevind nie
subunit-1to2: comandă negăsită
subunit-1to2: comando não encontrado
subunit-1to2: commande introuvable
subunit-1to2: command not found
subunit-1to2: käsku ei ole
subunit-1to2: không tìm thấy lệnh
subunit-1to2: komanda nerasta
subunit-1to2: Kommando nicht gefunden.
subunit-1to2: kommandot finns inte
subunit-1to2: komut yok
subunit-1to2: nie znaleziono polecenia
subunit-1to2: níor aimsíodh an t-ordú
subunit-1to2: no se encontró la orden
subunit-1to2: no s'ha trobat l'ordre
subunit-1to2: opdracht niet gevonden
subunit-1to2: parancs nem található
subunit-1to2: perintah tidak ditemukan
subunit-1to2: príkaz nenájdený
subunit-1to2: příkaz nenalezen
subunit-1to2: команда не найдена
subunit-1to2: командата не е открита
subunit-1to2: 命令找不到
subunit-1to2: コマンドが見つかりません