Wise Iteration

March 31, 2008

A you move ahead, keep in mind the following:
* Never confuse the map with the journey – The project plan is only an outline (and a guess at that), so you should believe the team’s results and not the plans. Remember, it is the achievement of the objectives that is important, not the production of artifacts or the completion of activities. Be careful not to confuse the ends (objectives) with the means (artifacts and activities).
* Adopt the attitude that continuous planning is a good thing – In every iteration, expect your plans to change (albeit in small ways if your planning is effective). Don’t fall into the trap of thinking that the plan is infallible.
* Mature your process alongside your team – Tune the working practices alongside the plans, adapt your team’s skills as necessary to improve over time.
* Be prepared to cut your losses – Canceling bad projects early is success because you save time, money and resources that can be applied to better opportunities.
* Be honest – Without objectivity and honesty, the project team is set up for failure, even if developing iteratively.Source: “Managing Iterative Software Development Projects”, Kurt Bittner, Ian Spence, Addisson Wesley.

Transitioning from a traditional approach to iterative software development is more a change of mind than a schedule adjustment. So try to be honest… or at least as honest as you can be ;o)

The Three Rules of Test Driven Development

March 6, 2008

Over the years I have come to describe Test Driven Development in terms of three simple rules. They are:
1. You are not allowed to write any production code unless it is to make a failing unit test pass.
2. You are not allowed to write any more of a unit test than is sufficient to fail; and compilation failures are failures.
3. You are not allowed to write any more production code than is sufficient to pass the one failing unit test.You must begin by writing a unit test for the functionality that you intend to write. But by rule 2, you can’t write very much of that unit test. As soon as the unit test code fails to compile, or fails an assertion, you must stop and write production code. But by rule 3 you can only write the production code that makes the test compile or pass, and no more.

If you think about this you will realize that you simply cannot write very much code at all without compiling and executing something. Indeed, this is really the point. In everything we do, whether writing tests, writing production code, or refactoring, we keep the system executing at all times. The time between running tests is on the order of seconds, or minutes. Even 10 minutes is too long.

Robert Martin


Besides these rules and independently of an agile approach, I always like as a developer being able to verify quickly my code, because it makes much more easier to find all the errors I do ;o)

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