A rule I use for testing: If a feature doesn't run correctly the first time it's manually tested, then an automated test should be created which checks if the f

A rule I use for testing: If a feature doesn't run correctly the first time it's manually tested, then an automated test should be created which checks if the feature is working. This rule typically means that tests save time, and that tests are created for the code that's likely to break. I bypass this rule when I think it's obvious I'm going to want automated testing. For example, I needed a customer facing DSL for importing data with a lexer/parser/interpreter; manual testing was bypassed from the start.