Current, I installed phpunit. i use OS win 10. I think i installed new version from https://phpunit.de/ (current version 5.6, beta 5.7). But when check version with command
You can download as per php version and install it as globally.
wget -O phpunit https://phar.phpunit.de/phpunit-7.phar
chmod +x phpunit
To check version you can use.
./phpunit --version
To set phpUnit as globally you can use.
sudo mv phpunit /usr/local/bin/phpunit
To run and test phpunit you can use.
phpunit
PHPUnit 7.3.1 by Sebastian Bergmann and contributors.