I took W3Schools' online PHP Quiz Test for PHP to check if I still remember the Basics of it. And you know what, I got a Perfect score.. yippee!!! Well, the questions are too basic so if you are a PHP programmer you will surely get a perfect score too. Uhmmm.. this is not a certification test, this is just a short quiz. ^_^
If you want to try, just visit W3Schools' PHP Tutorial.