Lengthy process: I've talked to at least 8 different people. First round with HR, followed by a math test to do at home (pretty easy: they mostly want to see if you can read a table and work with %), second round with the team juniors, third round with the head of the team, fourth round with employees from other departments, last round with an executive. Everything went well, people were not trying to trick me. They answered all the questions I had. Very friendly. One downside however: after all these rounds, they chose another candidate (I guess) without sending me an email or calling me to tell me their choice or to give me a feedback... even though I asked for one.