I write a test for each bug I fix, so it don't show up in production again. And when I do manual testing that get daunting eg. I have to make several steps to r

I write a test for each bug I fix, so it don't show up in production again. And when I do manual testing that get daunting eg. I have to make several steps to reach a state. I also write an automatic test. Or when I'm not sure something will work I make a basic "assert" test or some "defensive programming" that checks if the state is sane during runtime. I don't do unit testing. Most programmers get unit testing wrong, the single reason for unit testing is to get full code coverage. So if you do unit testing you should write tests from day one.