Chapter 8: Design After First Testing


Overview

Unit Test Writer

(Sing to the tune of Paperback Writer by The Beatles)

Don t like UML
Man it s much too hard
Rather scribble some notes on an index card

Hey design is dead
And things couldn t be better
I just got a job
And I m gonna be a unit test writer
Unit test writer
Unit test writerrrrrrrr

Well, requirements
Are a pain in the neck
Good thing that I found this book by Kent Beck
They re the customer s problem
It says so right here
So I don t care too much
Cause I m gonna be a unit test writer
Unit test writer Unit test writerrrrrrrr

Don t do architecture
Haven t got the urge
Rather just write code and let it emerge
At five PM each day
You know I m on my way
Schedule s not our job
Man it s fun to be a unit test writer
Unit test writer Unit test writerrrrrrrr

GROUCHO  

There can be no misunderstanding a specification written in the form of executable code. [1]
”Don Wells

When the acceptance tests are written in high level scripting languages, they are readable by developers and customers alike. [2]
”Robert C. Martin

Human language is not particularly good at capturing the kind of precision necessary for documenting requirements. [3]
”Robert C. Martin

Well, we ve reached the middle of the book. In this chapter we get a bit more serious than usual and look at XP s application of unit testing and its related process, test-first design.

The heart of XP s objection to Big Design Up Front (BDUF) is that it takes longer to maintain a class diagram (and other design documentation) in addition to the code than it does to simply maintain the code, so why maintain the design documentation at all? (Or while we re at it, why spend time up front producing very much design documentation in the first place?)

In this chapter we examine this and other XP attitudes to the process of designing software.

[1] Don Wells, Code the Unit Test First, http://www.extremeprogramming.org/rules/testfirst.html, 2000.

[2] Robert C. Martin posting to the newsgroup comp.software.extreme-programming, subject: Documentation, June 11, 2002.

[3] Ibid.




Extreme Programming Refactored
Extreme Programming Refactored: The Case Against XP
ISBN: 1590590961
EAN: 2147483647
Year: 2003
Pages: 156

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