I applied through a recruitment agency and the entire process took a bit, but this was due a busy period on my side. There was a test in which there are many probability and statistics questions. Of course I can not say more due to confidentiality agreement. After that there was an interview from junior quants.

Written test first and then if successful oral discussions. There are further rounds if successful. The written test can be taken from pretty much everywhere but I took it from London.