AgileAttitudes Article
 
 
 

Vol 02 Issue 04- Like Money in the Bank

  
 
Back to the list of articles Agile Attitudes Volume 2, Issue 04 Feb. 23, 2005 A free bi-weekly email newsletter Brought to you by Agile Rules consulting www.agilerules.com ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Welcome to Agile Attitudes, a newsletter of ideas, insights and technical tips that help people find better ways to develop software. Feel free to share this with anyone - just be sure you send or print the whole thing, including the copyright notice. Directions for managing your subscription are below. O><O><O><O><O><O Watch this space for announcements concerning opportunities to hook up with the growing agile software development community O><O><O><O><O><O Like Money in the Bank by Ron Morsicato If you read the Agile Manifesto, http://www.agilemanifesto.org/, you will note that the founders of the agile movement value “Working software over comprehensive documentation. They mean what they say, and in a big way. In a truly agile environment, you will not find more code-specific documentation than what is needed in the short term, and once it has served its purpose it is discarded. But isn't there a problem here? A large, detailed bank of documentation allows new developers and maintainers down the road to understand how the system works so they can contribute to its development or maintenance. I do not deny that it is important to have this mechanism in place. The point is that a comprehensive set of documentation is a poor way to achieve this result. It needs to be maintained. Worse, it tends to be constricting. Anyone who becomes adept at a game learns how to delay decisions until an optimal moment, that moment when maximum knowledge and understanding are achieved. When you do a detailed design prior to coding, you are ignoring the information that comes from observation of tests, and are forced to make decisions far in time from the technical and business environments within which the software will be operating. And to tell you the truth, my experience as a developer has convinced me that it is never used. You see, no matter how an organization claims to follow a process that keeps documentation current, before you make changes to code, you simply have to examine the code to make sure it's consistent with the documentation. You end up going right to the code! The agile approach is to make it easier to learn how the code works from the code itself. Well-tested code is self-documenting. I can read a subsection in a detailed design document that tells me that such and such a method does this and that. The agile alternative is to observe a test that shows that this existing code behaves correctly. What if I realize that similar functionality is desired elsewhere? An object oriented approach is to refactor by making a method that covers what is common in the two instances of functionality, and derive specific methods from the higher-level one that meets the demands required to implement the specific functionalities. When I do this, I make sure there is now a test for each of the three new methods, and delete the test for the original method from the test suite. I now have the current design documented in an up-to-date fashion. It's nearly painless if I use the Test Driven Development paradigm, where I write the new tests, made sure they fail because the specific functionality I was looking for had not been implemented, and work to make the tests pass by adding functionality to the three methods. What I'm doing is maintaining a test suite that doubles as living documentation of the current state of the system, and I do it by not diverting from my coding practices. It's almost as if up-to- date documentation is a free byproduct of TDD. Take your choice: a shelf of unimplemented design becoming stale like overproduced inventory, or working code like money in the bank. O><O><O><O><O><O More articles on Agile software topics at http://www.agilerules.com Within our company we have a sub-specialty in embedded systems. Our site has articles on embedded XP and we support a discussion list focused on the use of agile methods for building embedded software. The list signup info is at http://www.agilerules.com/mailinglists.phtml O><O><O><O><O><O To help you get started with in-depth research into Agile Attitudes topics, we have added a Library section to our web site at http://www.agilerules.com/library.phtml Order using our links and receive discounts up to 30%! O><O><O><O><O><O If you enjoyed this issue or found it useful, forward it to a friend! Help spread the word about better ways to build software. 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Send feedback to info@agilerules.com To manage your subscription: http://www.agilerules.com/mailman/listinfo/agileattitudes O><O><O><O><O><O Brought to you by Agile Rules consulting 162 Marrett Road, Lexington MA 02421 Copyright (c) 2004, 2005 Agile Rules info@agilerules.com O><O><O><O><O><O Privacy notice: We will not release a subscriber's address to any third party for any reason. This is a strictly opt-in newsletter. No one is ever subscribed without their explicit request. </plaintext> </td id="bodytable_r1_c3_body"> </tr id="bodytable_r1"> </table id="bodytable">