And how do you know what the code is doing? One of the most effective ways I've found is to look at the tests. If there are none, even better: I can get a reall

And how do you know what the code is doing? One of the most effective ways I've found is to look at the tests. If there are none, even better: I can get a really good feel for how the system operates by writing tests, increasing coverage as I go. Tests aren't an end; they are a means to assuring proper function, but also towards understanding and writing better software (by forcing you to make code testable, which naturally leads to decoupling, etc).