The hiring process was quite professional, apart from one thing.
Firstly there was an interview with HR and test, which consisted of brain teasers and some combinatoric and statistic questions, but it wasn't as difficult as I thought it would be, no deep stats stuff, many of that problems could be done using logic and some basic math skills, some couldn't though.
After they checked the results, I received a test by email (after I already was at the interview mind it), and was really overwhelmed with it difficulty. The problem was that I applied to junior/internship position, but test I received was full-blown analysis of the dataset to be done, with hypothesis to be checked and you should have created a 10-15 minute speech with presentation to explain your results and decisions. It was really a task for middle/senior analyst, not a junior one, so I explained my lack of skills to do this, and maybe they could give me another task, more suitable for my experience.
Surprisingly, after my message, I was called some days after and invited to second interview with them and lead of the analytics team. There we just talked about the job, stack, responsibilities, and I was in fact told that yes, that task was indeed for senior analyst to handle. I can't understand what they gave it to me for, to see what would I do with that? That was quite strange.
After that meeting, after not hearing from them for a while I reminded about myself by email, and was called shortly to be told that they took another candidate, mainly because there was a lot of work to be done there, but I didn't have experience to handle it immediately. HR was really professional about it all.