I've seen code test in recruitment process for a tiny company. Candidates who had really amazing CVs (multiple projects, leading roles) who were applying for a position of PHP developer when actually sat down in front of a computer with google, text editor and PHP couldn't write the simplest programs. And I'm not talking about reversing binary tree whatever that is or even fizzbuzz. They couldn't reserve a string! Or use any other basic features of PHP language that were all painfully easy to google. One manged to copy paste a solution to a single problem not showing any original thought anywhere. And that was the best candidate. Most of them just crumled and ran away when they saw that they actually are expected to write a bit of code.

If they were hired on the CV alone they would be fired on the first week, possibly first day.