I disagree about coverage. First, I've found tests to be an excellent way to debug, much better than trying to manually get the app into the state I want and t

I disagree about coverage. First, I've found tests to be an excellent way to debug, much better than trying to manually get the app into the state I want and then stepping into the debugger. Second, having a good coverage lets you refactor with a lot more confidence. I often open some file to fix a bug/add a feature and notice some piece of code that is horrible. I can comfortably fix that code too and if the tests pass (including the one that failed before fixing the initial bug/adding the feature) I'm done.