We have no idea! A code refactor will allow you to slowly replace old pieces of code in your system with new ones. But we will deal with that in an upcoming tutorial. On the other hand, the test will fail with an insufficient memory error. We should do the same formatting on the Game.php file also. What would be easier for a customer of a small startup to understand; waiting 3 months with zero progress while R&D does something only they can appreciate or, have a small chunk of time bitten off every sprint to improve the product? I have also gradually shifted a service to work with Mongo instead of Postgres by writing to both DBs during the transition and splitting the logic to accommodate both. Martin Fowler calls it StranglerApplication. The first thing you may try is to run our code for 20,000 game iterations. Possibly on some kind of board? Looking for something to help kick start your next project? But wait! We want to rewrite the purchasing component. The same player wins every time? Understand that refactoring legacy code is different. We will start with the runner. Of course, the industry used the expression for ages, basically for any code that is difficult to change. It’s better to try refactoring legacy rather than rewrite it. Two 55MB files will be generated. The drawback is that you have to maintain two systems while you write the new one and trust me, even though the old system may be in “maintenance mode”, there will be that crucial bug or important client request that will require you to work on it. We will work in PHP, but you are free to choose your favorite one and apply the techniques presented here. One for the number of times we want to run our generator, the other is a destination file. We can see the lines that add the users (9-11), that a roll() method is called and a winner is selected. When working with legacy code, it is almost impossible to understand it and to write code that will surely exercise all the logical paths through the code. Everything you need for your next creative project. For that kind of testing, we would need to understand the code, but we do not yet. The tests are very slow. We extracted the code generation into a method, run it twice, and expected the output to be equal. Every developer has experienced that gut wrenching feeling of having to dig into an old code component to extend it or fix a bug. There is a current location for a player. It has the user history component, profile management component and the purchasing component. Envato Tuts+ tutorials are translated into other languages by our community members—you can be involved too! Here are a few guidelines to help you choose when to refactor and when to do a full rewrite. Which do you think has a greater chance of success with your product/ marketing/ sales team? It explains the problem very clearly, so that the solution becomes obvious. This file is much larger; About 200 lines of code. I gave a presentation about code refactoring or rewrite at the Components Meetup Tel Aviv, watch the session below: There is another way. "Code without tests" on the other hand is very concrete. The greatest benefit of this method is it reduces risk. By definition, legacy code is difficult to understand, especially if we don't even know what it's supposed to do. Behavioral Analysis A technique to get insights from large codebases, using VCS information. We need to find a way to control the seed. If so, you will need to run it through other modules of the bigger application. And don’t forget, once you have implemented that client request into the legacy system, it still needs to be added to the new system. The scope of the golden master is to exercise as much as possible. It describes a series of practicalstrategies that developers can employ to bring their existing softwareapplications under control. The danger in those decisions is somewhat alleviated by microservices and serverless architecture, allowing rewrites of smaller code components, a process that takes less time and affects a smaller part of the product.