By far the best interview I have ever had! They don't care about theoretical stuff, they don't want to you tell them principles or other things. All they are looking for is seeing if they can work with you, have a little knowledge base of TDD to be able to code right there and if they like you. It will be a pairing exercise, to create a little program and along the way they make it harder, to see how you react and how well can you organise your code and improvise along the way. They were super friendly, joking all the time and making me super relaxed, feeling like I'm coding with some friends. And it's not like they're making an effort to do so, because that's how they are in day to day life. And I was asked something that no other company asked me: "Why do you want to come and work here?"