They were coded by Dave, your colleague developer. The classes are full of formatting errors, poor indentation and weird one letter variables. There are so many dependencies you need to scroll down for minutes to escape the bloated constructor. Shacking, you open the unit tests to understand how it should work… but they don’t exist. Horror and misfortune! You could ask Dave to come to your desk, yelling at him that you never saw anywhere such a crappy code, cursing him and his family for generations to come.