And verify it with good tests. It sometimes happens that a certain piece of code is inherently complex, due to a complex underlying algorithm. But often, test c

And verify it with good tests. It sometimes happens that a certain piece of code is inherently complex, due to a complex underlying algorithm. But often, test cases are still easy to define, so it makes sense to heavily make use of them. For example, sorting algorithms may be somewhat complicated in implementation, but it's trivial to come up with some sample before/after lists.