use composer to install phpunit

if you have composer already installed an adde to your project you can simply add phpunit via terminal.

open a terminal and swich to your projectroot wher composer.json is stored:
type:

composer global require "phpunit/phpunit=5.4.*"

sudo ln -s  ~/.composer/vendor/phpunit/phpunit/phpunit   /usr/bin/ 

Composer will add phpunit into your vendor folder