After your CV is accepted, they give you a bunch of tests (7 tests with 4-6 questions) to solve. The questions are completely unrelated to development, mostly logical and some calculations, analyzing a complicated text (linguistically).
I did not pass, but they sent me a note saying that I did good, they just chose someone who did a little bit better.
All in all, the tests felt like a waste of time (given the amount of time is needed), because they don't really talk to you about your experience or motivation, etc. I understand that competition might be high, though.