Extreme Programming Installed: Ch 4-6

Reference:
Extreme Programming Installed
Ron Jeffries, Ann Anderson, Chet Hendrickson
2001 Addison-Wesley

Chapter 4

Summary:

User stories are used to convey what a system needs to be able to do.  They highlight how the customer wants the system to function.  Ideally, stories are written by the customer.  More stories are required with larger and more complex systems, and if a story gets too big it may be broken down into smaller stories.  If needed, new stories may be added/substituted at the beginning of an iteration.

Discussion:

As an XP veteran, I am all too familiar with user stories.  My experiences had my team (the programmers) coming up with the user stories based on the user's specifications, so I can attest that it is better for the customer to provide the actual stories.  Seeing the many stories associated with a large system can be daunting, but it is a good way to break down a large project.



Chapter 5

Summary:

Acceptence tests are used in conjunction with user stories to define when a story has been suitably completed, or accepted.  These tests define certain criterea that the system must be able to do before any specific story is accepted as complete.  Ideally, these tests should be automated and completed in the same iteration that the story is scheduled for.

Discussion:

The acceptence tests are a great way to gague how far a product is from completion.  Though there are times when it seems like the customer is expecting too much from any given feature, in the end these tests make the whole process run smoother. 



Chapter 6

Summary:

To streamline the development process, it is wise to estimate how difficult any given story is.  Therefore, at the beginning of each iteration, the team estimates the difficulty of the stories in that sprint.  As time progresses, estimations are made more accurate through experience and comparison to previous stories.  However, estimates are unreliable when facing a task that nobody is familiar with. 

Discussion:

 In my XP experience, I often found estimations to be useful.  However, there were occasions where they were quite misleading.  Sometimes people would estimate that difficult tasks would be simple and vice versa.  Extimations are a useful tool, but can't necissarily be relied upon.