RPM of PHPUnit version 5.3 are available in remi repository for Fedorra ≥ 21 and in remi-test repository for Enterprise Linux (CentOS, RHEL...).
Documentation :
This new major version requires PHP ≥ 5.6.
Installation, Fedora:
dnf --enablerepo=remi install phpunit
Installation, Enterprise Linux:
yum --enablerepo=remi,remi-test,remi-php56 install phpunit
Notice: this tool is an essential component of PHP QA in Fedora.