This is a lecture that has everything I need! This is a must-see lecture for anyone who wants to introduce practical test code! It doesn't end with mocking to integration testing, but it's so informative, even to static code testing, and it's so great that it doesn't just explain the theory, but shows you how to write code so that you can apply it yourself. Sometimes, after taking the lecture, I only have a vague feeling and can't actually apply it, but this lecture was so useful and good because I could apply it to my project by looking at each sector. I highly recommend it and thank you to the instructor!