phpunit after upgrade to laravel 5.8 not executing

I've upgraded my application from Laravel 5.7 to 5.8

Before, running $ phpunit on the root level of my projeced executed my tests.

But now, running $ phpunit just returns nothing... I've tried deleting the vendor folder and running composer install and composer update, but nothing changed. I've a phpunit.xml file on my root level where I define the sql table to use in the tests. Running venor/bin/phpunit returns "command not found".

How can I use phpunit?

via Chebli Mohamed