I applied online. I received immediately an online test. The process took 3 days because I could't take it that day. A set of questions was about a piece of code (meaning, performance, refactoring). The another set was about a voice mail system, with use cases, actors, variations, exceptions. The overall idea is to know very well the idea of performance and how to implement it in code and have a very good understanding of program design.

The interview was very laid back and the interviewers were super nice. They would ask questions and give you hints to find the answer if needed. The first round was a coding assignment in C++ which was sent to me an hour after I applied for the job. The test was similar to what others have described: telling what a function does, finding bugs, code optimisation, use cases, etc. Then, a phone interview was scheduled for discussing my answers. At the final stage, I had a 3 hours interview in Belfast office. I was asked basic questions about Python, Numpy, Git, Linux, and Machine Learning followed by some behavioural questions. Finally, we had a lunch together. I really enjoyed the friendly manner of the interviewers and the prompt responses after each interview stage (less than a week). I asked for feedback after getting rejected for the position and received some helpful feedback from them.