I've seen this question a lot recently, and Scott Bellware asks it again in response to a post by Jimmy Bogard.

"Ok, but why are "contracts" important?  I can write concrete classes that interact with each other just fine without interfaces. And as Roy has already demonstrated, you don't need interfaces for test-focused SoC. To wit, any concrete class's signature is a contract with its user." -- Scott Bellware

First - a small psychology lesson in Cognitive Load theory and Chunking. A human brain can only hold so much information in it's short term memory. The "magic number" of 7 (+/- 2) has often been touted as the average number of concepts that a person can hold in short term memory, and still understand what's going on.

... and we need to recognize this in our code. If a developer who is reading the code has more than 7 (+/- 2) concepts, then that developer is not likely to understand the code they are reading. If you can't understand the code, you can't maintain the code. It's as simple as that. So why are contracts important? An intention-revealing interface, as a contract, can significantly reduce the cognitive load that is required to understand the code in question.

Abstraction and dependency inversion via interfaces help us achieve this understandability by letting a developer's mind chunk a process into what's really important - the "when" and "what" of the process, ignoring the "how". If you eliminated all abstractions and interfaces - even the interfaces that have only one implementation - you are telling a developer that they need to know the details of "how", not just the abstraction of "when" and "what". This puts an additional load on any persons' brain, and can quickly overload the person reading the code.

These theories go so far beyond just code, in software. When was the last time you saw a web site that had more than 8 or 9 buttons in it's navigation/menu, and you thought it was an intuitive and easy to use site? I'd be willing to bet that you thought the site was poorly organized and difficult to navigate. Interaction design is usually the first place that people apply cognitive load and chunking theories. Unfortunately, it's also usually the last. We need to break this cycle of overloading ourselves and our coworkers, and create proper abstractions in our code that fit easily within our own cognitive load, but more importantly in the cognitive load of other developers who have to read/maintain the code.

There's been a lot of recent talk about what is "done" in the Lean / Agile development communities, and the primary focus of these discussions has been focused on individual features or stories and the need to get them completely "done" (dev, test, acceptance test, documentation, delivered to customer) before they can be considered done. I wholeheartedly agree with this philosophy, to the point where I active introduce painful elements of software development to my team members, because the work must be done before we can deliver to the customer.

All that being said - I think we're missing out on some potential benefit by not applying "done" at various and different levels of our software development projects. For example, the concept of "done" can be applied to an iteration. What constitutes an iteration being "done"? It's certainly not just the time-box of 2 weeks, 1 month, or whatever our iteration length is defined as. However, that time box is still important. We don't want arbitrary lengths of iterations.

So how do we know when an iteration is completely "done" versus just being over? My initial thoughts revolve around a pass/fail checklist, similar to the swim lanes (or kanban board, if you want to call it that) that our stories go through. At this point, I would likely include the following:

• Iteration length passed
• All stories in iteration "done"
• Code reviewed (possibly part of story being "done")
• Software is in a stable, working state
• Software acceptance tested by customer (or customer representative / SME)
• Retrospective held

There's probably some additional items to include here - this is just my initial idea list.

Like the user story "done" criteria, an iteration cannot be considered "done" until all of the items in this list have been checked off. We don't give partial credit for a story making it to "in test", when there are 2 more columns to move through - the story is not done until it's completely "done". The same should apply to the iteration.

Why bother making an official "done" list for iterations? For the same simple reason we do this for user stories - transparency and visibility into bottlenecks and problems. It's easy for a team to ignore problems like broken software at the end of an iteration - "oh, it's just XYZ... i'll take care of that tomorrow" - when we don't have the same accountability as we do in our stories. By making the iteration a pass/fail set, we expose those problems for the world to see. This exposure is a great motivational tool - who wants to be caught with an un-"done" iteration because of a "simple" bug?

Do you and your team have an iteration "done" list? Do you even have a user story "done" list? It's all about exposing weakness and waste, then eliminating it and creating the official iteration "done" list is just one more step along the path. Don't stop there. What other processes - higher or lower level - can we standardize and improve?

In addition to our 'Code Review Challenge' that I discussed recently, we have been using another retrospective game - 'Name That Standard'.

The idea is fairly simple. At the beginning of any retrospective, we go around the room and ask each team member to list out a standard that we are using in our project. This can be any standard that anyone feels the team is using or needs to be using, including coding conventions, architectural patterns, business and project management processes, communication means, etc. The intention is similar to the intent of 'The Code Review Challenge' - socialization of the the system. Only in this case, we are applying the term 'the system' at a much higher level - our organizational and project management / implementation system as a whole.

Some thoughts on running 'Name That Standard':

• Require not only naming of the standard, but accurate description of the standard and an example of where it is used. Alternatively, you may want to list a brief description out on a projector or whiteboard and see who can name the standard being described.
  
• Encourage the team to think about the team as a whole, not just their area of responsibility.
  
• Encourage the team to list standards that they don't understand, so that the rest of the team can chime in with assistance and help the team member in question grow
  
• Don't just let people yell out standards. go around the room, one person at a time. we got a little chaotic at first, and it was hard to know who said what.
  
• Encourage people to ask questions like 'i thought we were using this standard, but i saw someone else doing that standard'
  
• Encourage the standards to become more and more low level and detailed, over time (over multiple iterations)
  
• Encourage the standards to evolve and change for the better, over time (over multiple iterations)

In our implementations of this game, we've managed to get a fairly good list of standards written down and also resolved some questions on what standards we actually are using. For example, we had 3 dynamic mocking frameworks in our code base - Rhino Mocks, Moq, and a home grown one that we lovingly called 'BrandoMocks' (named for our team member, Brandon, who wrote it for fun one night). The end result of that discussion was to throw out Moq and BrandoMocks, adopting Rhino Mocks as our standard for this project.

Having done 'Name That Standard' in two consecutive iteration retrospectives, I think I can say that it has been very successful. The team as a whole is becoming more and more aware of the standards that we are using, and the individual members are beginning to contribute more and more to the standards.

With each passing iteration, and each new technique for creating collective ownership and socializing the system, I see the team coming together and really forming a team vs. a bunch of individual developers working on the same system.

My team tried out 'The Code Review Challenge' in today's retrospective. Overall, I think it went pretty well for the first time that we've tried this. Here's some initial thoughts after our first attempt.

1. Make sure the team knows what's going on before you start. I was not leading the review, and I had to step out right when it started. I believe the team lead explained the idea, but I'm not sure I had fully explained to her. In the end, ensuring that each team member is comfortable with the idea and the process is important.
2. Encourage discussion with the group during the review. Don't force the talk from the reviewer, but ask questions that will help lead them to conclusions and descriptions of what is going on.
3. Don't expect everyone on the team to be able to recognize the same standards, practices, or issues. each team member will have a different understanding of the standards that we are trying to apply, at any given time. encourage learning help others to see what you see.
4. make sure everyone on the team has a chance to review someone else's code. i think we ended up with a good mix of people reviewing and being reviewed, but it wasn't planned, it just kind of happened. next time around, we're going to ensure that it happens by planning ahead based on the work done by the people in the review.

i think there was a lot of benefit in doing the reviews in this manner. we ended up with a lot of good comments, suggested improvements, etc. i'm happy to say that the code review challenge was a success and that we'll continue to do it in future retrospectives and reviews.

A Food Network Challenge

During this season's 'The Next Food Network Star', there was an episode where the contestants had to cook a dish and review it in front of a camera, describing it's visuals and taste. The twist to the challenge was that they were assigned someone else's dish to review, after everyone had already cooked. Once the assignments were made for who was going to describe who's dish, they were not allowed to see the dishes anymore. A given contestant was then put in front of a camera and had their assigned dish uncovered in front of them. From that point, they had 90 seconds to describe the dish that was in front of them - that included figuring out what it was, what it looks like, what it tasted like and what it smelled like. This was a rather tough challenge to watch, and a few of them didn't do so well.

A Code Review Challenge

What if we take the Next Food Network Star's challenge and apply it to code reviews? When we sit down in a code review session, rather than having the person who wrote the code doing the driving and telling us what is going on, have someone who has not seen the code do the driving - read the code, read the unit tests, etc - and describe to us what is going on. 90 seconds wouldn't be nearly enough time, though, so we'd have to change that time limit based on the size and complexity of the functionality being reviewed. Other than that, though, it seems like it would be a great way to test the team's ability to pick up an area of the system that they have not seen before and quickly learn it so that they can work in it.

Standardized Work - Judging Code And Code Reviewer

There are 2 real benefits to the code review challenge, as I see it:

1. Judging how well did the coder apply our coding and development standards
2. Judging how well the reviewer can recognize and describe the standards being applied

We are now building our system from User Stories, with Context / Specification style unit testing. One of the intents of this style of unit testing is to provide an easy-to-read and easy-to-learn set of examples for developers that need to know how to do something or how something works in the system. If the unit tests are properly written and expressive of the code's intent - it should be really easy to see what's going on. If we have good standards in place, a developer should be able to find the code in well organized areas, easily, and know where to look for the various components and parts.

It seems to me that the code review challenge would help to prove a number of these key factors in our projects and our teams:

• Coding and architecture standards
  • How well the standards are known
  • How well the team follows the standards
• Expressive Code
  • How easy is it to read the code
  • How easy is it to understand the code's intent
• Maintainable Code
  • How easily can the code be changed and extended
  • How quickly the team can socialize and collectively own the system

A Challenge In Name, A Learning Experience In Practice

I would avoid applying any sort of point system or other reward / incentive for the code reviews. It seems that this could easily backfire and cause junior team members (in skill or time on the team/project) to feel intimidated or feel that it's an unfair process comparing them to the senior level team members. The intention of the code review challenge is not to cause dismay in any team member, but to create a learning environment by continuously challenging every member of the team. Ultimately, the code review challenge should foster the socialization of the system and lead to a strengthened sense of collective ownership, resulting in a better system.

Nothing New Under The Sun?

With all that being said - I'm doubtful that I'm the first person to ever hold a code review like this. I'd be interested in knowing if there's any standard development practices (Agile or otherwise) that are heading in the same direction. Any advice or opinions of you, the reader, would also be very welcomed.

If you know of a resource that describes the same basic ideas or if you have any input to help me improve the idea, please leave a comment and let me know.