First, an email in which, basically without even saying hi, they ask you immediately about information either already sent in the application, or kind of red flags like whether you would work on holidays. Then a Skill test about lots of topics: maths (derivative, integral, statistics, probability), programming (C++,python,sql,C#,java), mathematical finance, programming assignment in python. I stopped at this stage, since I did not know all the programming languages asked (I don't see the point in asking questions about 5-6 different ones) and the finance questions, which I just never did but would have liked to learn in a job. In general I ahd the impression that, more than the reasoning skills or personal growth, they are interested more in someone already knowing all the things.