How to perform tests (PHPUNIT) in Phabricator?

I created a test class in Phabricator and when I ran the following error appeared

  

[Core Exception / PhutilMissingSymbolException] Failed to load   class or interface 'PHPUnit \ Framework \ TestCase': the class or the   interface 'PHPUnit \ Framework \ TestCase' is not defined on the map   from the library to any loaded phutil library.

     

If you are not a developer, this almost always means that a   library is outdated. For example, you may have upgraded    phabricator without updating libphutil , or vice versa. This too   may mean that you need to restart Apache or PHP-FPM.   Make sure all libraries are up to date and all   been restarted.

     

If you are a developer and this symbol has been added or moved   recently it may be necessary to rebuild the map of your   library. You can rebuild the map by running 'arc liberate'.   For more information.

Where can I add PHPUnit to Phabricator dependencies?