Episode 6 of this #RemotePairProgramming series is about Evolutionary Design with Selection Pressure. My coding pairing partner this episode is Julian Ghionoiu
Selection Pressure. What is it?
What is Selection Pressure? First of all let’s give a definition from Biology
Any cause that reduces reproductive success in a portion of a population potentially exerts evolutionary pressure, selective pressure or selection pressure.[1] With sufficient pressure, inherited traits that mitigate its effects — even if they would be deleterious in other circumstances — can become widely spread through a population. It is a quantitative description of the amount of change occurring in processes investigated by evolutionary biology, but the formal concept is often extended to other areas of research.
During this episode we will apply the concept of Selection Pressure from Biology to software development that Julian Ghionoiu came-up with. So check the video to see more!
The third episode of this #RemotePairProgramming series is about Evolutionary Design with Selection Pressure. And, as always, I have coding coding pairing partner, that during this episode is Julian Ghionoiu.
At SoCraTes France I paired with Rémy and Johan to show them how I code using TDD as if you Meant It. We had a few hours to try it, and then Rémy told me he would like me to present this to the Grenoble Software community. So this is how we arranged a remote live coding session on TDD as if you Meant It.
During this session I am using Poker Hands as a problem, and I start with the usual Think-Red-Green-Refactor and Behavior Slicing. Then a lot of refactoring is going on. I invite you to watch the video and come with questions and improvement ideas.
At the end of the remote live coding session we had a remote discussion about what happened. Here is in form of Q&A.
Question: When you want to show the duplication to be sure it is not accidental, you try to duplicate three times the same code. Do we need to do this when we do just copy/paste? It doesn’t really help the tests.
Answer: The fact that you can duplicate the test it shows it is easy enough and we don’t necessarily use the Rule of Three. But there are other cases when it’s more complicated and just duplicating the tests would not show the same. And there is still some duplication that doesn’t prove in the production code. We find that it’s not really the same behavior, and it’s often a surprise. The fact that I can make the duplication the third time is just making the point that we need to remove the duplication. Otherwise I need to search for duplication in another way.
Question: It seems that we create these tests just to follow the Rule of Three, not because we want to.
Answer: I don’t want to create the tests just to follow the constraint of The Rule of Three, I just want to be sure enough that what I am doing is on the good path. I don’t want to rush into refactoring. It is a question of how well you know your domain and how much you trust your instincts. The TDD as if you Meant It comes with the idea you don’t trust your instincts and you need proof.
Question: If you want to create some duplication, we can use parametrized tests.
Answer: Yes, for the tests that are duplicated we can use parametrized tests and compress the code. And probably at the end there will be very little code.
Question: Have you detected different styles of doing TDD
Answer: Yes, but most of the problems I see that people fail to respect the rules and don’t find a way to respect the rules. But of course, there are very different styles. Some go very functional, some like to use more state, I go in very small steps. I like to go in very small steps and focus on triangulation. I like to use it as a machine that is generating duplication in all these tests and then because I have duplication, I extract the methods and the classes. You do need to refactor a lot. And you need very good tools to refactor automatically.
Question: I think this technique is a lot more difficult to use with Legacy Code, is it?
Answer: Yes, it is more difficult. But you don’t need to use it too often with legacy code. I can use it on legacy code, but first of all I surround the code I want to change, put some interfaces around it, and then use the same steps to generate the code to rewrite it with very small steps in a simpler way. There might be situations where I prefer to rewrite some legacy code instead of refactoring. When using TDD as if you Meant It with legacy code you need to take very small steps, and do a lot of refactoring in small steps, understand the flow of dependency injection and understand the patterns. All these I learned by using TDD as if you Meant it a lot. I think it helps you to refactor better. You have this refactoring muscle. With legacy code you have a lot of primitives and so much misplaced code. Here with new code you have the same, and you need to understand how it makes sense to put it together. So I think you can use TDD as if you Meant It especially for the refactoring part.
During this episode from the #RemotePairProgramming series we continue the exercise from previous episode. My coding pairing partner this episode is Michel Daviot.
Question (Michel): When would you use this remote pairing techniques and pairing (like Strong Style, Farsight Navigator, etc)?
Answer (Adi): When people are very used to their code, but don’t know how to refactor it, it is very useful to use Strong Style, because the Driver would know how to navigate around the code, but won’t know how to refactor or use a specific legacy code technique. The Driver knows the language, the project and so on, but the Navigator knows the techniques.
With new code Strong Style is very useful when you get stuck. And then the driver took control, pushes the rhythm and the steps to have progress.
Question (Michel): Do you explain to the people you use Strong Style?
Answer (Adi): Not really, because just coming up with theoretical concepts up-front feels weird. I just say “let’s pair and try this”. Maybe at the end of the session I might explain.
The other approach is a game called Farsight Navigator, where the Navigator looks far away for the design, and the Driver takes the small decisions. This technique works quite well, but you need to have very good Navigator skills to know where the design is going. So the role of the Navigator is to know which design options are not good and the solution would get stuck.
With Strong Style the Driver doesn’t need to know anything about the code, design, direction, etc.
This is a talk I delivered in Bucharest for the Agile Software Meetup Group. More and more companies want to transition to agile, because the benefits of faster delivery are essential in today’s software market.
Me and Mozaic Works’ approach to transforming an organization to agile has a lot to do with our core beliefs of small steps and fast feedback. For us an agile transformation is a tailored process for each organization, and the context is always essential.
Starting with the WHY is very important. I want to understand the internal values of the company and then decide together with the management, sponsors and the teams why they want to make this transformation. Without having the active involvement in any transformation, the whole process becomes very difficult or even impossible to put in place.
I don’t want to start from “what process to use” (Scrum, Kanban, DSDM, SAfE, etc), but rather discover the process while working with the people from that organization and understanding their needs. Together we create the process by applying things I know work well and by experimenting some things that might or might not work. As with any type of design, I prefer taking decisions as late as possible, because the more I learn the better the decision is.
Don’t commit unless you know why Chris Matts
After in the previous episode I took too bigger steps, during this episode I start all over and take smaller steps. The main differences are:
The third episode of this #RemotePairProgramming series is about Strong Style Pairing. My coding pairing partner this episode is Michel Daviot.
During Episode #002 Llewellyn was the Navigator in a Strong Style Pairing way. This episode I will be doing the same, but with my style. But there is also a challenge, given by my driver: Michel.
I don’t know at all the problem, and I have never heard of it. So I need to be navigating in a Strong Style Pairing without knowing the problem. So my solution is to go in small steps, to minimize the risk.
TDD as if you Meant It: Clean-up before next Triangulation (Episode 13) About This episode is about failure to refactor because of trying to rush to the next step of Triangulation and taking too bigger…
TDD as if you Meant It: Separate Production from Test Code (Episode 12) About When using TDD as if you Meant It we need to have a clear distinction between the test code, and the…
TDD as if you Meant It: Refactor and Clean-Up (Episode 11) About From Wikipedia we learn that Code refactoring is the process of restructuring existing computer code—changing the factoring—without changing its external behavior So clearly not any…
The second episode of this #RemotePairProgramming series is about Strong Style Pairing. My coding pairing partner this episode is Llewellyn Falco.
The Driver is just the typist of the Navigator
Pair-programming is a technique where two programmers stay at the same computer and code together on the same problem. We have two roles: Driver and Navigator.
Driver = the partner who writes the code, and focuses on small details, on short term.
Navigator = the partner who understands what the driver writes and focuses on long term decisions. Typically the navigator’s focus is around the design, architecture concerns, clarity, conceptual cohesion, etc.
During a session of strong style pairing, the Navigator will take all the decisions. The Driver focuses on the small details, just to do what the Navigator has in mind. If something is unclear the two have a dialogue. The same as with traditional style pairing, both roles have the same focus: try to solve the problem as fast as they can with the highest quality possible.
TDD as if you Meant It: Add Missing Tests for untested Branches (Episode 10) About During the first episode of this series I added some initial tests where I didn’t cover all the cases. Now…