I applied online in September 2017, got an email a month later inviting me to a first round interview and prompting me to undertake a Codility test first (very easy, simple function). The email said the test would not be assessed, just to discuss my thought process during the interview. First round interview was entirely technical, no puzzles or brain teasers or mention of the Codility test. The interviewer introduced themselves and jumped straight into technical questions, with some time to ask them questions at the end. Review OOP and prepare good answers for questions such as "where/how does Google store all its data?" Was called the next day inviting me to an assessment centre.