Should you test developers before hiring them?

I have been shifting back and forth on the question if it is a good idea to let developers do some kind of coding test before hiring them. After careful consideration I have come to the following conclusions:

1. Yes! You should test the developers coding skills somehow.
2. The test should be performed in a real environment, using real tools. Not on a whiteboard or by using some online web page.
3. Invite the applicant to take the test at your office. Sit together for a while and help him get started but also give him the chance to sit on his own for a while.
4. The test must be relevant to the kind of job he is applying for.
5. One of the most important aspects is the ability to write extendible and maintainable code. This is very very important.

So here comes the rationale:

1. The number of years of experience stated on a paper DOES NOT SAY ANYTHING when it comes to telling how good a developer is. I have worked with people directly from the University that produce great code that is well tested, easy to understand, easy to maintain and is easy extendible. I have also worked with developers who has more than 15 years "relevant" experience that produce crap. Their code compiles and runs but it is almost impossible for someone else to understand, contains functions that spans over hundereds of lines of code, complete source files that are just duplicated over and over, breaks things you would have never expected on any minor change, and the list goes on. It is a shame these developers sometimes get paid more than twice the amount of the "junior" developer.
2. A whiteboard test is inferior to doing some actual coding. You wan't to evaluate how the applicant uses his tools, his development tools. Whiteboards are good for drawing stuff on, not writing code.
3. You wan't to be sure that the guy who takes the test is the guy you are considering hiring. I read some time a ago that it is actually possible, at least in India, to hire someone to take programming tests for you, they even do phone interviews.
4. I should not need to explain why the test should be relevant. And to be clear, algorithm tests bought from Codility and similar companies are very rarely relevant. When was the last time you had to solve the knapsack problem at work?
5. Code can not just work. A good developer knows that working code is just the first step. Next you need to make it right (i.e. well designed).

Now that you know that the number of years of "relevant" experience written on a paper actually is irrelivant. Stop putting these "requirements" in your job ads as well ;).