Tdol has answered your question. But if your place has a few bob you might want to have a look at the "Oxford Placement Test" package.
It has everything you need. From the tests to the answer form, the package also includes an acetate which you apply over the written answers, thus quickening the process of marking. And of course, the diagnostic key, which for you in Europe, is helpful when assessing the learner's level either by the IELTS system, or, for you, the Common European Framework system.
It is most invaluable.