I personally recommend taking the actual course, and not just challenging the test. It's well worth it in terms of learning content, but also the exchange of questions and ideas in a group of learners. Also, there's another reason for some to take the course. Now, don't get me wrong on this next point... the testing is actually dead easy... but some people might have more trouble with tests... when you take the course, your instructor wants you to succeed in the testing after they've invested time in instructing you. If you just walk in and challenge the testing, the people delivering the tests don't have the same vested interest in seeing you pass.