-Now that we saw what the main values and practices - -2
-of XP are, I want to go back for a minute - -3
-to discussion of requirements engineering in XP. In XP, user - -4
-requirements are expressed as scenarios or user stories, as we already - -5
-discussed. These are written by customers on cards, and what - -6
-the development team does is to take these cards, take these - -7
-users stories and break them down into implementation tasks. And - -8
-those implementation tasks are then used as a basis for scheduling - -9
-cost estimates. So given these estimates, and based on their priorities, - -10
-the customer will choose the stories that will be included in - -11
-the next release, in the next iteration. And at this point, - -12
-the corresponding cards will be taken by the developers and the, - -13
-the task will be performed, and the relative, and the corresponding - -14
-card will be developed. And just to give an idea of - -15
-the order of magnitude, if you consider a few months project, - -16
-there might be 50 to 100 user stories for a project of - -17
-that duration. So, now let me give you an example of what - -18
-the story card might look like, and I'm going to do it using - -19
-a story card for document downloading and you can really do all of - -20
-this, basically as seeing what the - -21
-scenario is, downloading and printing an article. - -22
-And it describes basically what happens when you do that, what is - -23
-the scenario. First, you select the article that you want from a displayed - -24
-list. You then have to tell the system how you will pay for - -25
-it. This can either be through a subscription, through a company account or - -26
-by credit card, and so on. So what developers do, they take - -27
-this story card, and they break it down in to development tasks. - -28
-So, here I'm showing you some examples of task cards for the - -29
-user story that we just saw. In particular I'm showing three task cards - -30
-and if we look at the third one, there is a name - -31
-for the task, which is implement payment collection. So this is the development - -32
-task that we have the perform and here, there's a description of - -33
-what that developed code should do. And notice that, you know, the task - -34
-card can even be more. explicit than this, more - -35
-specific than this, and talk about actual development tasks. -- cgit 1.4.1