Agile Practices and Ajax Toolkits

Dietrich Kappe, Thursday, June 28, 2007 @ 9:32 am

I've been practicing agile development in one form or another through my involvement with open source projects since the early 90's. Of course at the time, we didn't know we were practicing Agile development. We were distributed, we had real jobs, we were pressed for time. Often we compensated by eyeballing requirements, having rapid releases, and evolving the SW over time as new needs and requirements were discovered. Now many of those shortcuts that grew out of necessity are at the core of Agile.

In all that time, I've developed my own philosophy (when you turn 40, your "opinions" turn into a "philosophy") on how Agile development should be done. There are a number of core principles I adhere to:

1. Short iterations. Thirty days is a nice number.
2. Pair programming (not necessarily the one keyboard, one mouse variety). Yes, two developers working on the same tasks do get more done than the same developers working on separate tasks. The practice also really boosts quality and learning.
3. Test Driven Development. If you've ever worked on projects that don't have extensive unit and integration tests, then you've experienced the waves of bugs that appear with every new feature or enhancement. TDD -- rather than after the fact unit test development -- is also the only way to guarantee that the practice doesn't slip during stressful times.
4. Continuous integration. Hourly is good enough. If you've worked on projects without CI, then you've felt the pain of week long "build and deployment" sessions, driven by the poor sods condemned to being the "build masters."
5. Self organizing teams practicing continuous improvement through process reviews.

Everything else is negotiable, as far as I'm concerned. Through #5, each team will find the right agile methods and practices for themselves and the client. No single method (note, "methodology" is the study of methods) is appropriate for all situations and teams. I myself favor Scrum as a wrapper around the development process, as it incorporates #5 as a core principle.

Turning now with these Agile principles to the world of Ajax frameworks, which of them explicitly incorporate unit testing into their development? This is an important consideration, since if a framework doesn't provide unit testing facilities or hooks, you will have to develop and maintain them in step with the framework. As an example, with full unit test coverage (branch and line) in place, you can weather the release of new browser version (think IE7 and Safari for Windows) much more easily. Not only will you know that your sophisticated Ajax interface doesn't work, but you will know exactly why it doesn't work (probably).

So, which frameworks do incorporate unit tests, and how easy do they make it to hook those into your own development machinery?

1. GWT, of course, lets you use JUnit directly.
2. Prototype  and Scriptaculous both use the same unit test harness, which already comes integrated with Rake (Ruby make), but would take a little work to integrate with other build environments.
3. JQuery does have unit tests that can be run with make or ant, but they aren't extensively documented, so extending them to your own development environment will require a bit of work.
4. Of the straight Javascript frameworks, Dojo has the best documented unit testing approach, as well as a build process that can be integrated into your build environment.

(BTW, has anyone else noticed that YUI doesn't have a publicly available SVN?)

The one tricky bit with testing Javascript is that object definition and creation can be pretty complex code itself. Ideally it should be tested as well, though that doesn't always happen in the above frameworks. Whatever framework you choose, make sure that it provides unit testing facilities that your developers can and will use, otherwise your user interface will be the redheaded stepchild of your web 2.0 webapp.

Technorati Tags: ajax, agile development, unit testing, test driven development

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Comments: 1 so far

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1. 

   Hi,

   What about server AJAX framework, have you studied unit testing projects built upon Echo2/Cooee or Thinwire ?

   Regards

   Paul

   Comment by Paul Merlin, Friday, June 29, 2007 @ 3:23 am

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