I found TDD unpractical. Can recall one situation when used TDD. I was writing a printf-like formatter in C++ and prepared a lot of tests cases in advance. That

I found TDD unpractical. Can recall one situation when used TDD. I was writing a printf-like formatter in C++ and prepared a lot of tests cases in advance. That approach worked well at early state of development. however, further development had revealed quirks I hadn't predicted. As a result, the number and complexity of tests got increased. My typical practice is to work out an API, write early scratches of implementation and test only simple cases. Then I can inspect two things: how the API works in real code and what else should be tested. In other words tests help to establish an API, then to stabilize the implementation.