It was a two stage-process, first an informal chat with the team lead and a developer. Just to get to know to each other. Then a technical test and, after that, a longer interview to discuss the technical test and some other questions about object oriented programming. The interview is quite challenging as there are lots of theoretical questions, but still worth it. Got an offer but had to decline it because my current company improved it. HR were very welcoming from the very beginning even after I gave an answer on the offer.