Classes with a lot of lines of code are generally bad. Too many responsibilities, low cohesion, or both. However, sometimes it is not possible to make functions smaller. Reasons could be various. What can be done in this circumstance?

This article describes a TDD (Test Driven Development) approach to implement a Finite State Machine (FSM) using PHP+Laravel. However, such method is general and could be used in the programming language of your choice.

This tutorial describes a TDD approach to refactor code to Strategy pattern. Starting from working code and some test, refactoring steps are applied to obtain cleaner code

This article describes a way of implementing Strategy design pattern using a database-based runtime configuration. The approach allows to dynamically (re)configure class behavior without requiring code-based rearrangements.