There is no such thing as bug-free app, and I do not agree for 100% code coverage (rather write test for what's important to you, i.e. prioritise). However, tes

There is no such thing as bug-free app, and I do not agree for 100% code coverage (rather write test for what's important to you, i.e. prioritise). However, tests gives you a higher level of confidence when you perform refactoring. PS. Regression is far worse than momentum against change, when your app is `broken` you can't deliver it.