PHP Fatal error: Call to undefined method PHPUnit_Util_Filter::addFileToFilter() in /usr/local/bin/phpunit

I all of a sudden started receiving this error with no clue why. Numerous posts I read told me that I should downgrade from 3.5 to 3.4, which turned out to be a huge P.I.T.A.

The solution, look for the reason on the system. Turns out, my older version was installed in /usr/local/bin/phpunit, w here as the new version was just /usr/bin/phpunit.

Simply delete the old one, and if necessary, symlink the two together.