"How on earth do you write tests first and then develop?" This was the lecture that first resolved my biggest question (?) about this concept. This is actually the first time I'm leaving a course review after taking many lectures, and I think this is an excellent lecture that covers not just TDD but overall concepts about testing. I always wrote unit tests, integration tests, etc. separately when writing tests. In that process, there were some overlapping parts, and I often wondered if this was really efficient. But I think I just wrote them that way without a clear opinion of my own, simply because that's what people around me did. I really liked how the lecture mentioned and explained these aspects as well. I haven't finished the entire course yet, but I'm very satisfied and enjoying it so far.